VFR800F 8th Gen Fuel Tank Vacuum Problems

Have any 8th Gen owners had any problems with a vacuum forming in the fuel tank, or have any of you heard of one?

I have 2 friends here in the UK who have both had issues, to the extent that the tank has deformed and the paint has cracked. Both bikes are out of warranty and Honda seem to be avoiding any liability, though one of my friends has had a £200 goodwill gesture paid (replacement tank is over £700).

Honda still have not ascertained the cause but one of my friends is actively investigating why a vacuum should be building up.

There is a Youtube video here showing the tank moving as the vacuum is released - 

Breather hoses are free and ok? 

I believe they've looked at that.

I asking about ;) , if not first must check them , or better disconnect from the bottom of the tank

than must see :

When you apply pressure , max0,2 psi !!! on both petcock under(with open fuel tap) they must free flow

If not , try to set them free

(do not have to add , or may yes : this operations are just for people with a bit of knowledge otherwise workshops are the answer)

Hi Skids.
I've had the high vacuum issue with my tank once, the vacuum was so strong I thought I was going to break my key in trying to open the filler cap.
You will either have a pinched breather hose  (one of the three hoses that ends up at the bottom of your bike) ,OR as I did, a suspected jammed small one way valve thats inside your filler cap. The valve allows for positive pressure to build in your tank but never negative (unless its jammed).
Have a very good look for a pinched tank vent hose, this can easily happen after raising and lowering the tank from the maintenance position. Failing that, remove your filler cap from the tank, there are 5 allen head screws, open your filler cap and you will see only 3 of these screws hold the filler cap in position just remove these 3 the other 2 are dummies. With the filler cap removed undo the centre Phillips head screw to access the one way valve and spring, give the valve and seat a squirt of WD40 then reassemble. While the filler cap is removed have a good look at the vent line for any obstructions, you should also be able to freely blow air through the tank vent hole and feel the air exiting from one of the bottom three hoses under your bike. Its an easy thing to do, I've had no further reoccurrence of the problem since doing this almost 2 years ago.

Cheers.

Grum
 

[image: WP_20160315_004a.jpg]

[image: WP_20160315_005a.jpg]

[image: post-30826-0-59647800-1458042773.jpg]

[image: post-30826-0-02148900-1458042802.jpg]

Thanks for that Grum, I've passed your experience on. :beer:

Breather hoses pinched.  Did it start to happen after the twat nav was installed.  Did on mine, lift the tank and give breathers some more slack.

21 minutes ago, fink

Breather hoses pinched.  Did it start to happen after the twat nav was installed.  Did on mine, lift the tank and give breathers some more slack.

Says he's checked those.

1 hour ago, Skids

Says he's checked those.

When did this start to happen? Was it after the sat nav install? 

Why noy get them to join the forum? 

I've linked to Grum's post so they can find this place. It's up to them if they want to join.

7 hours ago, Skids

I've linked to Grum's post so they can find this place. It's up to them if they want to join.

Hi Skids.

Further to my posting above. This is the method I used to confirm my Breather Hose was not blocked. Simply holding this hose to the breather coupling and blowing I was able to feel air exiting from the other end of the breather hose underneath the bike. Hope this helps.

Cheers

Grum.

[image: P1010205.JPG]

:beer:

Very well timed post ....just had my 16,000 mile service done, went to fill up and when I opened the tank there was a loud sucking noise .... I guess it's back to Fowlers to sort 

11 hours ago, Thumbs

Very well timed post ....just had my 16,000 mile service done, went to fill up and when I opened the tank there was a loud sucking noise .... I guess it's back to Fowlers to sort 

Are you guys getting your tanks blown regularly to help release the built up vacuum pressure?  I believe the owner's manual recommends this service be done at least twice a month in order to ensure proper performance  :tongue:

[image: IMG_2956.thumb.PNG.c43d097ff6375fe1a756fe970e5a6146.PNG]

I got a new tank on mine. My tank got vacuum dents and was totally out of shape because the breather hose was bend. 

The breather hose was bend where it attach to the tank. 

If tank has been rised for service, it is ekstreamly important to check that the breather hose is not bend. It bend very easy.

Well it's sorted after wasting a morning taking it to Fowlers, next time I'm checking the vent line after they have the tank off 

Thanks to Skids for raising the matter and kudos to Grum for solution and how to check the line 

Hi All.

After hearing the bad news that this issue could destroy your tank!!!

Decided to have a very close look at this problem and think I have discovered why this is happening, and, as reported, this is a SERIOUS situation the vacuum created can be so strong it can seriously DAMAGE your tank!!!!

It seems there are a few people that have had this happen after any servicing has been done around the airbox (air filter replacement etc.) requiring the tank to be extended in maintenance position. 

When the tank is placed in the Maintenance position the small breather hose is pulled up by a few inches through a whole lot of clutter. The problem is, when the tank is lowered back to normal position the hose doesn't naturally go back from where it came and bunches up and gets crushed and kinked against all the other clutter so close to the breather inlet to the tank. See attached photos.

The solution is to simply pull at the small to large hose coupling area to take up the slack while lowering the tank. (see photos).

You should always be able to blow air from either end and feel air being expelled at the opposite end (fuel cap open of course).

Hope this helps.

Cheers.

Grum.

Post Edit - Some clarification here, there is a difference in being able to Blow air through the breather hose (positive pressure) than able to Suck air through it (negative pressure). A kinked partially blocked hose will allow blowing air to flow, However suction could further help to collapse the hose causing a complete blockage.

[image: P1010005.JPG]

[image: P1010007.JPG]

[image: P1010013.JPG]

[image: P1010015.JPG]

Great job Grum - big thanks!

Sent from my SCH-I545 using Tapatalk

Thanks again Grum ....

This should be the first 8th gen sticky

Good write up there Grum.   

  Should also maybe include the signs that it occurring. ie Difficulty in trying to open the fuel cap followed by a hissing sound as the pressure is released, as well as the aforementioned tank deformation in some cases.

Just some pictures what vacuum can do to your tank. 

Pictures show the marks on the breather hose where it was bend.

And the dent and deform tank.

The dealer replaced my tank under warranty.

Your tank will for sure deform and get dents before first fillup if vacuum hose is bend, the fuel pump will do the job.

As Grum already tells, first thing to check after service is the vacuum hose, it's very important.

[image: 20171007_203644.jpg]

[image: 20170505_200328.jpg]

Hey All, Thanks for the heads up and follow up info!  Quick question (sorry if it's been answered already, I didn't see/remember it) - at what point (how much fuel used) will the tank start visibly deforming?  I like topping off as often as possible - I think the most I've used before refueling is about a little more than half tank (fuel gauge reads under half full)...  

24 minutes ago, Samuelx

Hey All, Thanks for the heads up and follow up info!  Quick question (sorry if it's been answered already, I didn't see/remember it) - at what point (how much fuel used) will the tank start visibly deforming?  I like topping off as often as possible - I think the most I've used before refueling is about a little more than half tank (fuel gauge reads under half full)...  

Don't know. I did not notice when i happend. But the dents will come on each lower side of the tank and will be identical. You can see it on my picture just above the black plastic. 

Also the black plastic attached to the tank will fit very bad if the tank has vacuum damage. It will fit even worse when the tank is under vacuum.

Thx jangermann!

Btw, can someone give a thumbs up to Grum for me?  My computer doesn't show any blue heart icons for his posts...  >:|

I get a little bit of suction noise when opening my petrol filler cap, but not so much that I've ever struggled to open it. How much is normal; a little or none?

NZCam, 9 October 2017 at 7:56 AM

I get a little bit of suction noise when opening my petrol filler cap, but not so much that I've ever struggled to open it. How much is normal; a little or none?

Hi Cam.

There is a small one way valve in the fuel cap that is lightly spring loaded. It should keep the tank in positive pressure but when venting is needed a small amount of suction is going to be required to overcome the small spring tension on the valve. Pretty sure that's how it works!

Cheers.

Post Edit - Close inspection of the fuel cap shows independent Pressure and Vacuum relief vents. The Vacuum has the valve, yet the two vents end up at the same point being the breather hose! So you could end up with slight tank vacuum because of the valve, but next to no positive pressure.

Shouldn’t have any suction noise at all.

11 hours ago, fink

Shouldn’t have any suction noise at all.

Agreed.  I've never had any suction noises on mine and I'd be worried if I had.  I know the 2 chaps Skids mentioned in this post and neither are getting much joy from Honda and at over £700 for a new tank I wouldn't want to fork out for a new one :(

2 hours ago, StubyDoo

Agreed.  I've never had any suction noises on mine and I'd be worried if I had.  I know the 2 chaps Skids mentioned in this post and neither are getting much joy from Honda and at over £700 for a new tank I wouldn't want to fork out for a new one :(

Agreed.   However my origin question was never answered in fact a Whole host of questions left unanswered .

 Did this start to happen after the sat nav was installed & who was last to lift the tank?

If it was a member of staff at the dealer then I would have said the dealer would have been responsible for the replacement.   How long was it like this before the owners noticed there was something wrong?   As the owners are happy to let someone else ask the questions rather than participate themselves???????????????

  I noticed on my first fill up  and looked into and resolved problem myself after the third ( initially I thought it was unusually hot weather) no tank deformation with mine.

I'm not sure the gentlemen in question are aware of this site but I have pointed them to this thread as did Skids.  I know one of the chaps did fit a sat nav and I did ask him if he lifted the tank to which he replied no, he only took the black trim off.  He knows the original owner and both are adamant the tank hadn't been lifted by themselves.

I changed my air filter a couple of weeks back and the breather hose is well stuck and became detached from the tank.  I had to pull it up to reattach it as there is no slack on it so I'm grateful for this thread as I could have easily caused the same issues and I'll be uber careful in the future!

If the indentation was caused by a vacuum then save the £700 because it's pretty easy to get those dents blown out and the tank refinished 

2 hours ago, Thumbs

If the indentation was caused by a vacuum then save the £700 because it's pretty easy to get those dents blown out and the tank refinished 

I was wondering if that was possible.  Is it just a case of sealing it and pumping air in?

Honda included a notice about this issue in my quick shifter kit I sourced from Japan.

[image: kzG4Opa.png]

[image: ezdpm09.png]

[image: 0ruBkdu.png]

[image: GTD2qGg.png]

Finally... Thanks Skids. I'm already a member but couldn't recall my site name so I've been trolling along trying combinations of emails, passwords, eventually just gave up and started afresh...

Mine is one of the "Collapsing Tank" VFR 800F's. It's been a long saga but I have temporarily  cured it in a way by removing the carbon Canister system and simply running a vent to atmosphere.

It's also, somehow, made it much better on fuel. It's just done circa 260 miles before the fuel light came on, I don't hang about on my journeys, but keeping it below Vtec has just given me that figure. That's a journey to and from work (Hayling Island to the Science Museum in London) back to work a 2nd day and approx half way back again. Can't knock that because I usually cruise at just about fast enough to collect speeding tickets. So it's about 7 miles of twisties off an Island, about 50 miles of very smooth dual carraigeway mostly national limit, and about another 12 of London Traffic filtering to Exhibition Road more or less.

So: I bought the bike as a two year old, just had it's 8,000 service and found that as I was commuting and doing circa 150 miles a day, the suction on the tank was steadily getting worse. It has reached the stage where the tank is now creased and damaged, it's been to a Honda Dealer who thought they had found the problem but they didn't. They thought they found a kink in the breather pipe that runs to the carbon canister, but it continued to build vacuum when commuting. The previous owner told me he'd never noticed a problem so it's a bit of a mystery.

I and a friend lifted the tank whilst it was "holding vacuum" at both ends at the same time and the tank started to expand again as air started to get in, yes it does have a Tomtom but I routed the cables along the cable clip route and never lifted the tank. I re-routed the breather pipe and put a piece of plastic inside it to stop it collapsing but it still carried on shrinking...

I have tried all the usual issues, I can easily "blow" into the tank, when the cap is in place, it's only when the carbon system is connected, it seems, that I have the problem. So for now it's running a proper bodgy tank vent until I get time to strip it down. Which will be pretty soon, it's just clicked oveer 16,000 miles so the tank has to come off anyway to do a valve check. I think the Video that Skids loaded was of mine with the tank popping back out. That was after a 75 mile run. Yes it has Satnag installed, but it did this before I got around to fitting that.

I've had all kinds of theories, over filling the tank (the handbook, which I read for once, says never to fill over the plate in the tank. I tend to do this occasionally though, it's not the easiest tell tale to spot) the valve that releases the contents of the carbon canister sticking open, the little spring loaded valve in the cap, I've tried most all of them. The separate vent works though. I plugged the carbon connection with an M6 bolt, as you do... Whist I was sorting the vent, there was a noise like a very quiet escape of intestinal gasses every so often until I plugged the connection, so there's a lot for me to look at.

When I took it to the Honda Dealer for them to have a look.... Well they sent it back with the tank top hat washers upside down and when I spotted that they had also put copper ease all over the studs. The tank was wobbling all over the place, I think they literally didn't have a clue but told me they had found a kinked hose. It isn't nice dipping into a corner gripping the tank with your knees and having it feel like it's coming off.... This was Crescent Honda in Southampton. Not impressed... The tank is permanently creased, but I've managed to "inflate it" back to roughly the right shape. But it needs a new one now. There are creases on the sides and under where the Airbox area is shaped to clear the plastic box, it's actually bad enough that paint is coming off the tank now.

fink, 9 October 2017 at 11:14 AM

Shouldn’t have any suction noise at all.

Hi Fink.

Wonder if NZCam is experiencing a positive pressure, vapours expelling from the tank when cap is opened. I get this often, just back from a ride today, bike in the sunshine, opened the filler cap and had positive whoosh of vapours from the tank, it's relatively slight though. Info - No Carbon Canister on the Australian version.

Think we might hear of many a sad story of tank deformation due to a pinched breather hose after the first tank raising. The problem is the first 12inches of small hose from the tank.  BE AWARE!

Cheers.

Grum.

3 hours ago, Sparticus

Whist I was sorting the vent, there was a noise like a very quiet escape of intestinal gasses every so often until I plugged the connection, so there's a lot for me to look at.

Hi Sparticus.

It sounds like you have diagnosed a faulty Carbon Cannister. Got the same gastric bubbling sound the other day whist I had my breather tube disconnected investigating this issue. Suspect it was the tank venting and the valve in the fuel cap bobbing.

Real shame about the quality of workmanship you received at the Honda dealership - Bloody disgraceful. Don't know wether you could claim warranty on your tank caused by faulty Carbon Canister, I'd sure be pushing for it. Good Luck.

Cheers.

4 hours ago, Grum

The problem is the first 12inches...

That what Mrs Skids always says.

Usually every 3rd Friday. :goofy:

There's one thing that's missing. If you shake a petrol can full of petrol for a while if it's plastic, it would tend to expand somewhat. Tin ones do as well if left in the sun.
By definition. If the "Breather" is kinked stopping the air getting in, wouldn't it also stop the fuel vapour expanding in the tank from venting? Wouldn't the the tank have had pressure popping the cap off on a hot day, after having the heat of the day, and possibly the Sun play on the tank all day?
Well mine still had suction.

1 hour ago, Skids

That what Mrs Skids always says.

Usually every 3rd Friday. :goofy:

:beer:

6 hours ago, Grum

Hi Sparticus.

It sounds like you have diagnosed a faulty Carbon Cannister. Got the same gastric bubbling sound the other day whist I had my breather tube disconnected investigating this issue. Suspect it was the tank venting and the valve in the fuel cap bobbing.

Real shame about the quality of workmanship you received at the Honda dealership - Bloody disgraceful. Don't know wether you could claim warranty on your tank caused by faulty Carbon Canister, I'd sure be pushing for it. Good Luck.

[image: WP_20171003_18_50_19_Rich.jpg]

Cheers. I think the noise was coming from the Carbon connection. The tank "vent" I put in is simply a plastic piece of hose from my Vacuum gauges, I cut the hose from the canister so it was open to atmosphere, pretty sure that this is where the noise was coming from. I could be wrong, my daughter picked up the noise before I did, having 60 year old ears means I don't always hear stuff as well. But once she pointed it out, it was plain as day. Oh. And I'm still missing the Linked Brakes my Vtec has.

[image: WP_20171003_18_50_01_Pro.jpg]

Hi all ! I've been lurking here for a while but this post prompted me to join.

Just to add to the Discussion. My bike is just reaching 10k so it hasn't had its 10k service yet. I use it every day to commute. .My problem only started about 3 weeks ago. I went to fill it up and I thought the Fuel Cap Lock was "Jammed with Gunk "or something. I managed to get it open after a struggle and lots of Pushing Down.

When I got home, I opened it and it worked fine. So I put some Silicone down the lock. Checked the key, and tested it again. Everything fine.

I run the Bike from Full to Virtually Empty...Next Refueling, I have the same Problem...And Again.

After reading this Post, I dismantled the Fuel cap Valve and lubed it. I blew down the vent tube and it doesn't seem to be blocked....Right now the bike is Empty and I just went out and tested it. It

opened fine with that "Gasping" sound but it has always had that Sound.

Thanks for the great Info lads.

Did I just read that right? The Aussie version doesn't have the carbon canister system?

16 minutes ago, Sparticus

Did I just read that right? The Aussie version doesn't have the carbon canister system?

That's correct, no Carbon Canister. The breather goes directly from the tank via the small and large hose to the underneath of the bike, the forward hose of the three.

Guess mines an Aussie version then now. :cheerleader:

Why not just replace the small and very thin vacuum hose with a armed fuel hose that do not bend that easy?

I'm gonna do that. It will just be a matter of time before you forget to check the hose after a dealer service.

I'd suggest the dealer should be checking it if I'm honest.

17 hours ago, Grum

Hi Sparticus.

It sounds like you have diagnosed a faulty Carbon Cannister. Got the same gastric bubbling sound the other day whist I had my breather tube disconnected investigating this issue. Suspect it was the tank venting and the valve in the fuel cap bobbing.

Real shame about the quality of workmanship you received at the Honda dealership - Bloody disgraceful. Don't know wether you could claim warranty on your tank caused by faulty Carbon Canister, I'd sure be pushing for it. Good Luck.

Cheers.

Only usa bikes have the carbon cannister.

Hi All.

Some more general info regards the Filler Cap.

I was unaware that the two vents in the cap are independent! The left one provides Pressure Relief while the Right provides Vacuum Relief (via the slightly spring loaded valve). Yet both of these vents end up at the same point being the breather hose! ------ WHY? Stuffed if I know. :blush:

The bottom line from this is, provided your breather isn't blocked you should only ever have very slight vacuum (due to valve spring tension) and virtually no positive pressure.

( Ignoring all the Evap Canister plumbing stuff, its not on the Aussie version. )

Cheers.

Grum.

[image: P1010028.JPG]

9 hours ago, fink

Only usa bikes have the carbon cannister.

Nope. UK VFR 800F's have them to meet the "Euro 4" emissions standards.

5 hours ago, Sparticus

Nope. UK VFR 800F's have them to meet the "Euro 4" emissions standards.

Gonna post a pic as mine doesn’t appear to have one.  

Here it is. Well hidden though.

I'll quote from another forum how it works, as far as I can tell if it's a "Euro 4" spec it has this as a finished product...

"The EVAP canister has 4 opening in it. One is connected to the breather from the tank where the fuel vapour enters the canister. Another is the purge line where the vapour is drawn, via a solenoid valve, into the throttle bodies. The third is a fuel drain line, presumably in case the canister becomes saturated with vapour, which is open to air via a short hose. The last is the air intake where fresh air is drawn in as the vapour is sucked out. I've attached the diagram from the service manual. It looks to me like there would have to be 2 blockages for the canister to allow a vacuum in the tank: the fuel drain and the fresh air intake". Or the valve stuck with two blockages.

[image: VFR800F-evap-1.jpg]

Not on mine...

[image: EVAP.jpg]

Might be because the requirement came out in 2016, so 2015 bikes most likely needed it to be installed to allow them to be sold in 2016/17. The VFR 1200 hasn't got Euro 4 for some reason, and cannot be bought new anymore.

I'm not certain of this, but a 2014 version might well not have it installed?

Where did you get the fender extender from?

2 hours ago, fatshoutybloke

Not on mine...

[image: EVAP.jpg]

,

My 2014  doesn’t have it either.  Fische only shows it on 2017 models

5 hours ago, Sparticus

Here it is. Well hidden though.

I'll quote from another forum how it works, as far as I can tell if it's a "Euro 4" spec it has this as a finished product...

"The EVAP canister has 4 opening in it. One is connected to the breather from the tank where the fuel vapour enters the canister. Another is the purge line where the vapour is drawn, via a solenoid valve, into the throttle bodies. The third is a fuel drain line, presumably in case the canister becomes saturated with vapour, which is open to air via a short hose. The last is the air intake where fresh air is drawn in as the vapour is sucked out. I've attached the diagram from the service manual. It looks to me like there would have to be 2 blockages for the canister to allow a vacuum in the tank: the fuel drain and the fresh air intake". Or the valve stuck with two blockages.

[image: VFR800F-evap-1.jpg]

Basically it’s the evap system that the Californians have insisted on for more than 2 decades. ?. My bike doesn’t have it.

Evap. canister was just for Cali and swiss till 2017

Now all they get it  with new euro4 models 

I THINK 2014-2015 VFR800's are all 50 state models now - no difference between CA and the rest of the US?

13 hours ago, Sparticus

Here it is. Well hidden though.

I'll quote from another forum how it works, as far as I can tell if it's a "Euro 4" spec it has this as a finished product...

"The EVAP canister has 4 opening in it. One is connected to the breather from the tank where the fuel vapour enters the canister. Another is the purge line where the vapour is drawn, via a solenoid valve, into the throttle bodies. The third is a fuel drain line, presumably in case the canister becomes saturated with vapour, which is open to air via a short hose. The last is the air intake where fresh air is drawn in as the vapour is sucked out. I've attached the diagram from the service manual. It looks to me like there would have to be 2 blockages for the canister to allow a vacuum in the tank: the fuel drain and the fresh air intake". Or the valve stuck with two blockages.

[image: VFR800F-evap-1.jpg]

Hi Sparticus.

Sorry but don't understand your reasoning for Two blockages. Surely tank Vacuum venting is via the fresh air inlet hose through the canister to the tank breather line. So if you are confident of no pinched or blocked hoses, then you should be suspicious of a faulty canister. Would imagine you should be able to blow air through the ait inlet hose of the canister and with your fuel cap open feel the air exiting right at the fuel cap coupling. 

Cheers.

I am suspicious of a faulty canister. It's just getting the time to pull it apart and have a look that I need. And as the bike is running fine with it effectively bypassed, the urgency has moved on somewhat.

And I may have found another tank, so I need to be sure it's "fixed" before I go that route. I think I'll be looking to remove the thing completely, bit more weight gone?

can you bypass this canister system all together without a check engine light?

Yup. Just remove all the gubbins. 

Yup. Just separate the pipe where it goes into the bottom of the tank, plug the pipe that leads to the canister and run a separate breather pipe from the bottom of the tank to somewhere under the bike. That's all that I have done, and if anything the bike runs better now. 

Sparticus Here it is. Well hidden though.
 
I'll quote from another forum how it works, as far as I can tell if it's a "Euro 4" spec it has this as a finished product...
 

"The EVAP canister has 4 opening in it. One is connected to the breather from the tank where the fuel vapour enters the canister. Another is the purge line where the vapour is drawn, via a solenoid valve, into the throttle bodies. The third is a fuel drain line, presumably in case the canister becomes saturated with vapour, which is open to air via a short hose. The last is the air intake where fresh air is drawn in as the vapour is sucked out. I've attached the diagram from the service manual. It looks to me like there would have to be 2 blockages for the canister to allow a vacuum in the tank: the fuel drain and the fresh air intake". Or the valve stuck with two blockages.
[image: VFR800F-evap-1.thumb.jpg.e2070b57ab5e685460e182e47110a320.jpg]

19 hours ago, 4corsa

So I have a 2014 US version with the 3 grouped hoses out the bottom of the bike, so I assume I have the carbon canister. After noticing some increased suction recently, I lifted the tank and confirmed no kinked hoses. But when blowing through a spare hose connected to the hole under the back of the gas cap (both with tank up and down) it was pretty difficult to move any air through it. I noticed there is a splice connection point on the small vent hose about 10 inches down from where it connects to the bottom of the tank, which is accessible with the tank down. I disconnected it and could blow air through the cap vent hole much easier. This confirmed I had no hose kink or blockage under the tank, and any blockage was occuring below that point or due to the canister itself.
I decided to just leave it disconnected at the splice point and go for a ride. I rode 90 miles, with a fair amount of redline runs[image: emoji4.png] and no problems or fault lights. When I stopped to fill the tank, there was just a tiny "chuff" sound when I opened the filler cap, hardly any suction.
I confess to not fully understand how the 4 hose canister system works, but would anyone happen to know if there is any reason why effectively disconnecting the one vent hose as I did, and leaving the other 3 connected would be problematic?

Sent from my SCH-I545 using Tapatalk
 

Hi 4corsa.

All variants of the 8 gen will have the 3 hoses at the bottom of the bike so that doesn't mean you have the carbon canister (mine being the Australian version has no canister but has the 3 hoses). The hoses are in order so from the front the first is the Tank Breather(or if you have the Canister - the Canister Breather) followed by the Coolant Overflow followed by the Fuel Filler Overflow.

If you have the canister it's located down near the oil filter behind the lower Radiator(see attached diagram). The splice you are talking about I think you are referring to the coupling joining the small hose from the bottom of the tank to the larger breather hose.

Sounds like you have diagnosed some form of blockage within the Carbon Canister. Having the breather hose disconnected from the canister shouldn't cause any issue at all, the only other restriction could be caused by the common issue of lowering the tank from the maintenance position squashing the small breather hose - as per the discussions in this thread.

Cheers.

[image: Canister.JPG]

Grum  
Hi 4corsa.
All variants of the 8 gen will have the 3 hoses at the bottom of the bike so that doesn't mean you have the carbon canister (mine being the Australian version has no canister but has the 3 hoses). The hoses are in order so from the front the first is the Tank Breather(or if you have the Canister - the Canister Breather) followed by the Coolant Overflow followed by the Fuel Filler Overflow.
If you have the canister it's located down near the oil filter behind the lower Radiator(see attached diagram). The splice you are talking about I think you are referring to the coupling joining the small hose from the bottom of the tank to the larger breather hose.
Sounds like you have diagnosed some form of blockage within the Carbon Canister. Having the breather hose disconnected from the canister shouldn't cause any issue at all, the only other restriction could be caused by the common issue of lowering the tank from the maintenance position squashing the small breather hose - as per the discussions in this thread.
Hopefully the "chuff" sound you heard when you filled up was pressure escaping and not a vacuum! 
Cheers.
 
[image: Canister.JPG.d0799d2780474ef6591ad6e32d6ffab2.JPG]

8 hours ago, 4corsa

Thank you Grum for the clarification, and helpful diagram.
On my bike, the small breather hose from the bottom of the tank comes down the left side of the bike, and splices to another same size small hose which heads down to the canister. I'll take a photo and post tomorrow.
So my only concern in disconnecting this line is if it has any affect on the other lines to the canister - such as changing any positive or negative pressure that may be required.


Sent from my SCH-I545 using Tapatalk
 

Hi 4corsa.

Need to clarify myself here regards the "chuff" sound you heard when opening the filler tank. A small amount of vacuum is required to overcome small spring tension on the tiny valve in the fuel cap. So it could be either very slight vacuum or positive pressure.

Have you downloaded the 8gen Service Manual ?

Having the hose disconnected as you've done shouldn't effect the ops of anything (apart from the fact that's it's illegal to mess with this stuff!!), you've pretty well confirmed that by the good test run you did.

The canister simply stores fuel vapour when the bike is stopped. When you start your bike the ECM will energise the Purge Valve (possibly for only a short burst) allowing the vapours to be sucked into the intake to be burnt.

Grum Hi 4corsa.
Need to clarify myself here regards the "chuff" sound you heard when opening the filler tank. A small amount of vacuum is required to overcome small spring tension on the tiny valve in the fuel cap. So it could be either very slight vacuum or positive pressure.
Have you downloaded the 8gen Service Manual ?
Having the hose disconnected as you've done shouldn't effect the ops of anything (apart from the fact that's it's illegal to mess with this stuff!!), you've pretty well confirmed that by the good test run you did.
The canister simply stores fuel vapour when the bike is stopped. When you start your bike the ECM will energise the Purge Valve (possibly for only a short burst) allowing the vapours to be sucked into the intake to be burnt.
 

14 minutes ago, 4corsa

Thanks again Grum.
Always wondered how they work - not a bad idea as long as they don't get clogged...
I have not yet downloaded the service manual - is there a free download somewhere? Otherwise I'll order a hardcopy, just saw one for $38.


Sent from my SCH-I545 using Tapatalk
 

Sure,  you can Download the Sevice Manual here. Just go to the HOME page, scroll down to the lower right section and you'll see the manual downloads.

Cheers.

to confirm (if it wasn't clear already): 2014 models have the evap canister. pulled that leach off my baby just this afternoon-- as well as a bolt that the previous owner had used to block off the SAS -___-

AFAIK all you need to do to delete the canister is to block off the hose that goes to the throttle bodies (i did that at the solenoid connection) and reroute the long line from the tank down into the slot with the other drain hoses. i took the tank line right off the evap canister and looped it through the holder for the (now removed) canister drain line and back to the slot for the other two drain hoses on the bottom of the bike. did that since i wanted to be as non-destructive as possible with this--i'mma take it out for a long spin tomorrow and if i get any problems from this configuration i'll be sure to tell you all about it...

50 minutes ago, TheLoneReader

to confirm (if it wasn't clear already): 2014 models have the evap canister. pulled that leach off my baby just this afternoon-- as well as a bolt that the previous owner had used to block off the SAS -___-

AFAIK all you need to do to delete the canister is to block off the hose that goes to the throttle bodies (i did that at the solenoid connection) and reroute the long line from the tank down into the slot with the other drain hoses. i took the tank line right off the evap canister and looped it through the holder for the (now removed) canister drain line and back to the slot for the other two drain hoses on the bottom of the bike. did that since i wanted to be as non-destructive as possible with this--i'mma take it out for a long spin tomorrow and if i get any problems from this configuration i'll be sure to tell you all about it...

You could simply just pull the electrical connector off the Purge Valve and not have to worry about blocking off hoses, also the ECM has no fault status for the Purge Valve - just a thought.

TheLoneReader to confirm (if it wasn't clear already): 2014 models have the evap canister. pulled that leach off my baby just this afternoon-- as well as a bolt that the previous owner had used to block off the SAS -___-
 
AFAIK all you need to do to delete the canister is to block off the hose that goes to the throttle bodies (i did that at the solenoid connection) and reroute the long line from the tank down into the slot with the other drain hoses. i took the tank line right off the evap canister and looped it through the holder for the (now removed) canister drain line and back to the slot for the other two drain hoses on the bottom of the bike. did that since i wanted to be as non-destructive as possible with this--i'mma take it out for a long spin tomorrow and if i get any problems from this configuration i'll be sure to tell you all about it...

46 minutes ago, 4corsa

That's great to hear TheLoneReader.
What would you guesstimate the weight is of everything you removed?

Sent from my SCH-I545 using Tapatalk
 

Easy answer to that one = Stuff all, seriously though, it's probably not too much more weight than an oil filter at a guess! OK maybe an oil filter full of oil then :wacko: .

Not as heavy as you'd think. Maybe 2 pounds, definitely less than 3. I did it mainly because it was annoying me and because now I can actually change my damn oil filter

Grum  
Easy answer to that one = Stuff all, seriously though, it's probably not too much more weight than an oil filter at a guess! OK maybe an oil filter full of oil then wacko.gif .

TheLoneReader Not as heavy as you'd think. Maybe 2 pounds, definitely less than 3. I did it mainly because it was annoying me and because now I can actually change my damn oil filter

Had my bike out in the hot sun the other day (32-35 degC), and it started leaking petrol. The tank was about 20-25% full (so lots of air volume), and the bike was in full direct sunlight at about 11:30am, and had been since sun-up at 6am (southern hemisphere high summer). Thinking that it was a pressure-related issue with fuel leaking out the overflow pipe, I opened the petrol cap, and got a huge swoosh of positive pressure. The engine had been off since the evening before, so no residual running heat.

Anyone got any ideas about the cause (other than hot sun, of course). I would have thought the bike could handle hotter conditions without problems. Kinked breather pipe maybe? The leak stopped as soon as I moved the bike into the shade, and had released the pressure from the tank via the filler-cap.

Sounds like your breather pipe is either blocked or kinked

Even if the breather was blocked a 1/4 full tank should NOT leak fuel as its below the level of the breather. Taht then begs the question of where was it leaking fuel from ? If the breather is blocked which is the normal escape route, then ut had to be coming from somewhere else, like the Fi lines, tank pump seal or worse from a tank seam !  I'd check the source of the leak IIWY.

17 hours ago, NZCam

Had my bike out in the hot sun the other day (32-35 degC), and it started leaking petrol. The tank was about 20-25% full (so lots of air volume), and the bike was in full direct sunlight at about 11:30am, and had been since sun-up at 6am (southern hemisphere high summer). Thinking that it was a pressure-related issue with fuel leaking out the overflow pipe, I opened the petrol cap, and got a huge swoosh of positive pressure. The engine had been off since the evening before, so no residual running heat.

Anyone got any ideas about the cause (other than hot sun, of course). I would have thought the bike could handle hotter conditions without problems. Kinked breather pipe maybe? The leak stopped as soon as I moved the bike into the shade, and had released the pressure from the tank via the filler-cap.

Hi Cam.

Agree with Mohawk here, not possible for a 25% full tank to exit fuel from the breather hose. Both tank Vaccum and Pressure are relieved through the Breather hose. Has your bike been recently serviced requiring work around the air box? If so it is vital that when the tank is lowered the breather slack is pulled through so it's not pinched. A pinched breather is going to allow high pressures when sun soaking and nasty vacuum whilst riding possibly in cooler conditions.

The lower three drain hoses are in an order of Breather front hose, Coolant Overflow middle hose and Fuel Filling Overflow the rear hose. Never heard of raw fuel exiting the Breather hose and I generally fill the bike to the max.

Perhaps you've had a major service done with a coolant replaced and a new air filter. So maybe it was some excess coolant overflow you saw and they have pinched your breather causing your pressure situation - Just a thought.

Cheers.

Grum.

Removed the EVAP on my 2017, weight 600 gr(1,3 pounds). No more tank vacuum problems.