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RC51 oil cooler install on 5th gen

41 posts Started 17 Jul 2010 Last recovered post 24 Jul 2020 Wayback Machine snapshot 26 Nov 2020
#1 [unknown member] Thread starter
Got my RC51 cooler in the mail today.  its the same with as the vfr's, but is 5 rows instead of 3.   Also got a 6th gen oil cooler in.     I'll try to do a test for each one but one promises.   Since I dont have an oil cooler gauge all I can go by is the coolant gauge and using a thermal temp gauge.

I do have a GSXR 1000, but I'll use it as a last resort.  It's a lot bigger and I'll have to cut the oil lines.
#2 [unknown member] Thread starter

[image: View Post]rangerscott69, on 17 July 2010 - 12:25 AM, said:

Got my RC51 cooler in the mail today.  its the same with as the vfr's, but is 5 rows instead of 3.   Also got a 6th gen oil cooler in.     I'll try to do a test for each one but one promises.   Since I dont have an oil cooler gauge all I can go by is the coolant gauge and using a thermal temp gauge.

I do have a GSXR 1000, but I'll use it as a last resort.  It's a lot bigger and I'll have to cut the oil lines.

I think 5th gen is 2 row, and 6th gen, a 3 row. -- Veefer800Canuck installed a 2nd gen 3 row on his 5th gen, dunno if he's still running it.
#3 [unknown member] Thread starter

[image: View Post]mello dude, on 17 July 2010 - 12:44 AM, said:

[image: View Post]rangerscott69, on 17 July 2010 - 12:25 AM, said:

Got my RC51 cooler in the mail today.  its the same with as the vfr's, but is 5 rows instead of 3.   Also got a 6th gen oil cooler in.     I'll try to do a test for each one but one promises.   Since I dont have an oil cooler gauge all I can go by is the coolant gauge and using a thermal temp gauge.

I do have a GSXR 1000, but I'll use it as a last resort.  It's a lot bigger and I'll have to cut the oil lines.

I think 5th gen is 2 row, and 6th gen, a 3 row. -- Veefer800Canuck installed a 2nd gen 3 row on his 5th gen, dunno if he's still running it.


Yep, still am, works great!   :laughing6-hehe:
#4 [unknown member] Thread starter
Which RC51 oil cooler you going to use? The '00-'01 SP1 or the '02-'06 SP2?
#5 [unknown member] Thread starter

[image: View Post]RustyA, on 17 July 2010 - 06:16 PM, said:

Which RC51 oil cooler you going to use? The '00-'01 SP1 or the '02-'06 SP2?


The 00-01.   They are silver and only one port is twisted.   The 02-06 are black and both ports are twisted like the 6th gen's.


Here's the three Honda's.   From top to bottom.  5th gen - 6th gen - RC51 ('00-'01)

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5th gen cooler

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6th gen

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RC51

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As you can see. The ports are a tad bigger.

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GSXR 1000

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Edited by rangerscott69, 17 July 2010 - 07:49 PM.
#6 [unknown member] Thread starter

[image: View Post]mello dude, on 17 July 2010 - 12:44 AM, said:

[image: View Post]rangerscott69, on 17 July 2010 - 12:25 AM, said:

Got my RC51 cooler in the mail today.  its the same with as the vfr's, but is 5 rows instead of 3.   Also got a 6th gen oil cooler in.     I'll try to do a test for each one but one promises.   Since I dont have an oil cooler gauge all I can go by is the coolant gauge and using a thermal temp gauge.

I do have a GSXR 1000, but I'll use it as a last resort.  It's a lot bigger and I'll have to cut the oil lines.

I think 5th gen is 2 row, and 6th gen, a 3 row. -- Veefer800Canuck installed a 2nd gen 3 row on his 5th gen, dunno if he's still running it.


I'm gonna stick with my original post.
#7 [unknown member] Thread starter
Got her done.

Loosened the stock cooler and let it hang.

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I was hoping I wouldn't but I had to drain the oil.  I tried using an 8mm wrench, but the bolt started stripping.  Had to get a socket on them.

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Once the oil drains, then you can unbolt the oil lines from the engine.

Left side.

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Right side.

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Luckily the O-rings look brand new.  Not even smashed.

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Might as well wash the lines.  Just tiny spot rust here and there.  Maybe I'll order new ones or have them powder coated.

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Edited by rangerscott69, 18 July 2010 - 11:42 PM.
#8 [unknown member] Thread starter
Time to temporary mount the RC cooler.

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The mount on the cooler is more offset than the stock one.   It'll be a little closer to the right rad.

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Here's the fun tedious fun part.   Bending the lines to fit.  You'll be pulling them out and putting back multiple times.  The right one I used a rubber mallet.  I placed the right oil line on the ground with the cooler mount upward.  I smacked it down with the mallet.  No science there.  

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The left side you have to twist the oil cooler  line where it bolts to the cooler.  I used a pair of pliers and my manly strength.  Of course a vise would have made it easier.

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Once they're lined up as good as possible, get the engine side ready.

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The middle o-ring is what I used.  I also used one smaller one to fit inside that one.  Double the sealing.  LOL

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Bolt the oil cooler lines on first, then bolt the cooler to it's brackets second, and last bolt the engine side of the oil lines.

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The right side does have a slight problem.  Since the line is lowered from the oil rad being taller.

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The left side has no problem with hitting anything.

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Edited by rangerscott69, 19 July 2010 - 10:24 PM.
#10 [unknown member] Thread starter
Is a bigger oil cooler always better?   I've read that there is an ideal oil temperature, and lower than that is not ideal.  Certainly thicker oil and less flow would come to mind.

Anyone got any better knowledge on the science of oil coolers?
#11 [unknown member] Thread starter

[image: View Post]kaldek, on 04 July 2011 - 06:49 AM, said:

Is a bigger oil cooler always better?   I've read that there is an ideal oil temperature, and lower than that is not ideal.  Certainly thicker oil and less flow would come to mind.

Anyone got any better knowledge on the science of oil coolers?


Good question.

I also wonder how the oil pressure is effected by having an oil cooler with larger diameter piping.


Anyone do a mod like this on a 4th gen?
#12 [unknown member] Thread starter

[image: View Post]rangerscott69, on 18 July 2010 - 11:59 PM, said:

The right side does have a slight problem.  Since the line is lowered from the oil rad being taller.

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You have a CA-spec bike?  IINM, the interference is being caused by the California-only charcoal canister, with the obvious solution being... :biggrin:

Ciao,
#13 [unknown member] Thread starter

[image: View Post]kaldek, on 04 July 2011 - 06:49 AM, said:

Is a bigger oil cooler always better?   I've read that there is an ideal oil temperature, and lower than that is not ideal.  Certainly thicker oil and less flow would come to mind.

Anyone got any better knowledge on the science of oil coolers?

I thought that the ideal oil temp was in the 185 to 215 degree F range and that if you are lower than that you could be asking for flow and lubrication issues. Dunno if I would go to a 5 row cooler on viffers unless I had an oil temp gauge at the oil filter inlet - thats where it runs the oil to the bearings. I would want to keep an eye on things.
#14 [unknown member] Thread starter
Well ya'll are not fun.   :goofy:
#15 [unknown member] Thread starter

[image: View Post]rangerscott69, on 05 July 2011 - 11:02 PM, said:

Well ya'll are not fun.   :goofy:

Sry - didnt mean to be the turd in the punch bowl, just throwing out some stuff to think about.
#16 [unknown member] Thread starter
It's all good.   It's 100F here regular here during the summer and stop and go traffic doesn't help.    During the winter I just watch my temp gauge and just block off until the temp holds as high as possible.
#17 [unknown member] Thread starter
Sorry to bring up a pretty old thread, but what was the verdict with this MOD? I know it bugs the crap out of me when I see my 5th gen start going up past 215*F
#18 [unknown member] Thread starter

[image: View Post]PishvaianRider, on 01 May 2012 - 11:43 AM, said:

Sorry to bring up a pretty old thread, but what was the verdict with this MOD? I know it bugs the crap out of me when I see my 5th gen start going up past 215*F

Since the 6th gen uses a 3 row cooler, it probly wouldnt hurt to a least bump up to at least a 3 row on a 5th gen. Also I hear that the 6th gen radiators are larger than the 5th.
#19 [unknown member] Thread starter

[image: View Post]mello dude, on 01 May 2012 - 11:55 AM, said:

[image: View Post]PishvaianRider, on 01 May 2012 - 11:43 AM, said:

Sorry to bring up a pretty old thread, but what was the verdict with this MOD? I know it bugs the crap out of me when I see my 5th gen start going up past 215*F

Since the 6th gen uses a 3 row cooler, it probly wouldnt hurt to a least bump up to at least a 3 row on a 5th gen. Also I hear that the 6th gen radiators are larger than the 5th.

I was actually considering doing the RC51 oil cooler depending on his report of how it worked, the mounting setup just looks so much simpler than trying to fit the 6th generation
#20 [unknown member] Thread starter
I bought the RC51 cooler last year after running in consecutive 117 deg days.  That coupled with the fan running the wrong way, effectively blocking one radiator made the engine & me very uncomfortable. I changed to the VTR fan immediately but not the cooler.  I bought another set of oil lines & will but both on when the temps get really hot on my summer rides.

That way I can change from one to the other when I change the oil & not have to worry about the engine running too cool or too hot.
#21 [unknown member] Thread starter
Sounds like a lot of work to switch between the two depending on the time of the year, let us know how the RC51 oil cooler does on the bike!
#22 [unknown member] Thread starter
I put a 3 row cooler on my 5th gen probably 12 years ago and it's been great ever since. Not as large as an RC 51 unit, but if you are in the desert and it 100 degrees, I could see it being handy for sure.

Riding in near freezing temps, not so much.

When I have ridden in cold temps, my bike goes up to 83'C, the thermostat cracks open, then drops to 79'C, then slowly back up to 83 again.

You can watch the thermostat cycle over and over again. No idea what the oil temp is though, I haven't got a gauge.
#23 [unknown member] Thread starter
http://www.thurn-mot...tor-rc46-1.html
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I might try this from thurn before I do the swap to see if I get a change.

Mello Dude said above that he thought that ideal oil temps are between 185 and 215, but that sounds like the radiator fluid temp that the bike reads out on the display? I'm not saying that he is wrong, I just don't know. Anybody else have any imput?
#24 Veefer800Canuck
slowbird

I also wonder how the oil pressure is effected by having an oil cooler with larger diameter piping.

Nothing really. Once the line is full of oil the first time, your pressure will not change. The slightest increase in flow will occur, due to less frictional losses from the fluid moving through a larger diameter line, but we're talking slight fractions of one PSI, not at all worth fussing over.

So if you have 1/2" cooler lines instead of 3/8", you really will not notice anything negative at all.

#25 Ranger77

Still all is well. No leaks either.

#26 Auspanglish
Veefer800Canuck

I put a 3 row cooler on my 5th gen probably 12 years ago and it's been great ever since. Not as large as an RC 51 unit, but if you are in the desert and it 100 degrees, I could see it being handy for sure.

Riding in near freezing temps, not so much.

When I have ridden in cold temps, my bike goes up to 83'C, the thermostat cracks open, then drops to 79'C, then slowly back up to 83 again.

You can watch the thermostat cycle over and over again. No idea what the oil temp is though, I haven't got a gauge.

I reckon that's where engine temp or coolant temp should be... right where the thermostat is constantly working... that way you are making the most of such a system... if the bike's always so hot that the thermostat never comes into action except when warming up the engine on start up, it sounds less ideal...

Of course the 6th gen requires certain conditions for VTEc to kick in... 64ºC "engine temp" being one of them... in cooler climates or in winter this may become a problem...

#27 tinkerinWstuff

I did the RC51 oil cooler on mine and am quite pleased. It doesn't do anything for stop and go in town traffic, but once you get moving in clean air, temps drop much faster. Fantastic mod for the price and simplicity.

I have to tear my front end down this winter for some other projects and will probably build a different bracket to move the cooler back to center.

#28 Mogman

Hi guys- I'm doing this mod right now. Did you cut the extra brackets off of the RC51 cooler, or just leave them alone? Also, do you think it would be better to shift the new cooler so it is centrally located with an offset bracket? Thanks,

#29 Mohawk

I've been thinking about this & as the RC51 rads are hard to come by in the UK. Another option would be a second 5th gen rad (which are cheap) welded to the existing one or 2 x 5th gen rads made up to replace the existing one which could be resold.

The process is simple, take one rad & cut off the oil pipe mounts, then take the 2nd rad & cut/grind off the frame mounting tab on the top. Drill an 8mm hole in the top at each end inline with where it will align with the holes in the bottom of the first rad & then rim weld them together. Job done, a 4 row cooler.

I'd be inclined to replace the pipe mounts with oil cooler hose mounts & have a set made up to replace the oil cooler pipes which are known to corrode & leak on the 5th & 6th gen if not looked after ! This will be my first project next winter :wink:

#30 vfrcapn
Mohawk

I've been thinking about this & as the RC51 rads are hard to come by in the UK. Another option would be a second 5th gen rad (which are cheap) welded to the existing one or 2 x 5th gen rads made up to replace the existing one which could be resold.

The process is simple, take one rad & cut off the oil pipe mounts, then take the 2nd rad & cut/grind off the frame mounting tab on the top. Drill an 8mm hole in the top at each end inline with where it will align with the holes in the bottom of the first rad & then rim weld them together. Job done, a 4 row cooler.

I'd be inclined to replace the pipe mounts with oil cooler hose mounts & have a set made up to replace the oil cooler pipes which are known to corrode & leak on the 5th & 6th gen if not looked after ! This will be my first project next winter :wink:

Dusty thread but did you ever get in to this?

Ranger, how is your install going a few years later?

RC rads are cheap, looking at doing this.

#31 Mohawk

Did the lines part, see here;- http://www.vfrdiscussion.com/forum/index.php/topic/80631-replace-your-oil-cooler-lines-diy/

I may look at the stacked cooler depending on how the temps work with my new tuning setup, I'm expecting 120+hp.

The current 112hp was fine last year with the electric water pump & lower temp fan switch keeping everything at a perfect temperature, even when carving through some hot gorges in Spain last year in 30+C temps.

That said, I've already replaced the long rubber hoses on the right side above rad & the cross tube between rads with custom alloy pipes, which definitely reduced the temps a bit.

More when I have news.

#32 JZH

I like your elegant drill and tap solution for the coolers. Do you have any pictures of the engine block fittings before you fitted the new hoses?

Ciao,

#33 Mhammer

Hi guys, I'm considering this on by 2001 vfr because I was reading that it is good bang for my buck.

One question: do I need the rc51 oil lines with the cooler? The cooler itself is $35ish. With lines it looks double.

Sent from my SM-G903W using Tapatalk

#34 Stray

Out of interest, does anyone know which way round the oil flows on a VFR 800? 
 

Does it flow into the right side of the cooler (throttle side), or into the left (clutch side)? 
 

Also, does anyone know how much air gets trapped in the cooler? I’ve been reading about air hampering a cooler’s effectiveness if the fittings are at the bottom. Fittings on the top help fight this but pain in the arse to drain oil for a service. 
 

Got a 5 row RC51 cooler on my 5th gen and it works fine. Was wondering if part of it was full of air. Made a different mounting bracket to centralise it in the frame. 
 

Just curious on the above, really.

Stray

#35 Grum
1 hour ago, Stray

Out of interest, does anyone know which way round the oil flows on a VFR 800? 
 

Does it flow into the right side of the cooler (throttle side), or into the left (clutch side)? 
 

Into R/H side. Out of L/H side.

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#36 Stray

Thank you Grum - that’s brilliant! 
 

Same as coolant flow: right to left. 

#37 Terry
Stray, 7/11/2020 at 1:07 PM

Out of interest, does anyone know which way round the oil flows on a VFR 800? 
 

Stray

With a K&N oil filter fitted, the answer occasionally is from the inside to the outside....

#38 Grum
48 minutes ago, Terry

With a K&N oil filter fitted, the answer occasionally is from the inside to the outside....

Love it Terry very funny, but oh so true!

Cheers to you.  :beer:

#39 Ranger77

Glad to see people are liking the rc51 oil cooler swap.

So many years have passed and with the double o-ring setup, shes never leaked.

I've been off the forum for some years now.  Ive been so busy that riding got left behind.

Ive now got two 5th gens.  LoL. Such a good deal I'd be crazy to not have gotten it.

#40 Stray
Ranger77, 7/14/2020 at 10:02 PM

Glad to see people are liking the rc51 oil cooler swap.

So many years have passed and with the double o-ring setup, shes never leaked.

I've been off the forum for some years now.  Ive been so busy that riding got left behind.

Ive now got two 5th gens.  LoL. Such a good deal I'd be crazy to not have gotten it.

Ranger, were you the first to do the swap? Awesome mod! 

#41 Ranger77
Stray, 7/18/2020 at 4:57 PM

Ranger, were you the first to do the swap? Awesome mod! 

I guess.  With the 6th gen cooler only being 1 row more and having to bend both lines I just ebay shopped amd found the rc51 cooler.   

Helps in the Texas heat and I just use velcro with cardboard to block it off during the winter.

End of thread · 41 posts recovered Wayback Machine snapshot 26 Nov 2020