Need 5Th Gen Thermostat Replacement Diy

Curious if there is a thread on this with pictures?  Could not seem to find one.

The main challenge is removing the throttle body and re-installing the airbox, there are some good threads on doing that which should help. Once you get the TB out of your way it's just a matter of getting the hard old hoses off. Might be good to have new ones ready in case you decide to cut them off.

Should be real close to this one!

BR

http://www.vfrdiscussion.com/forum/index.php/topic/37-thermostat-vtec-replacement/

Hi,new owner here so forgive my lack of knowledge,I may ask some silly questions too,LOL

My issue is on the other side of the temperature issue,the easier side to fix I suppose, does anyone know where I can find the air temp sensor?

I am getting a - - - - reading so I assume its the sensor that's gone or maybe has become disconnected, thanks

I also removed the snorkel from the air box but don't know where this 'flapper' is that its suggested to remove also,must order a replacement air filter as the one that's in her has seen better days.

I suppose the aftermarket air filter will be ok,or is it worth getting a K&N?

Thanks

The air temp sensor is in the right side inner side cowling. There are two snorkels. The flapper is in the one on the left. If it is still there and working I would keep it.  I think the K&N will save you money in the long run.

Looks like I am going to have to replace the stat on my 5th gen,the bike is running at around 76 degrees celcius after a few miles and maintaining that temp,heats up a bit to over 80 say in traffic,it will reach 104 if stationary for a while and the fan kicks in.
I did a test on her today,side fairings off,
bike on sidestand,started and kept check on temp and radiators. ambient temp about 12 degrees today.
radiators, particularly the right one began getting hot gradually from say 50 degrees on,the top pipe on the right rad in particular, and the front of both rads began getting warm,bike took a long time to reach 78 degrees probably 25 - 30 mins,
from what I have read rads shouldn't get warm till engine temp reaches around 78,so I'm thinking the stat is stuck partially open.
Though a dealer has told me that the stat is designed to let a small amount of hot coolant through as the bike warms, and this is the reason the top pipe and rads are getting hot as the bike warms.
I still think I'm right that the stat is stuck open,a local mechanic and a Honda technician I spoke to by telephone agree with me.
I was just about to change the coolant and began reading about how to check the thermostat on another vfr forum(ssshh) maybe I am reading too much!! I was reading on there about types of coolant etc and came across a post from a guy who described how to do the test I done today,up till that I thought running at 76 degrees after a few miles meant the stat was good,you live and learn as they say.
 
Does anyone know if the stat from a Honda civic from the early 80's will fit the VFR 800 Fi ? I used one before on my ST1100, thanks          

Cracked,

I'm not following your post. If the 'stat were stuck open, coolant would be circulating all the time, regardless of temperature. In moderate ambient surroundings the engine would run cold (because it is being cooled by, well, coolant), not -- as I think you are suggesting --  hot. I went through this once, and it was very obvious.

I dunno, the conditions you desribe sound normal to me. My 5th gen runs 170-ish  (F, so 80 or less Celsius) while in motion on a lukewarm day, and can definitely heat up enough to trigger the fan while I wait at a stop light. Veefers run hot and like it hot.

Did I miss your point?

Aram

I had a coolant leak. It took some time to collect the stamina to investigate:-) Put pressure on the coolant system with a big syringe trough the coolant reservoir hose, and found 2 of the hoses around the thermostat to be leaking. Tightened the clamps on these hoses and everywhere else I could find. The system is all right now. But...

I also found 2 of the hoses to be ready for replacement. The 2 hoses are on order now. Since it is such a tedious job I have ordered a thermostat and an O-ring as well. Just preventive:-)

Hope not to have to go there again soon!!

You'll need a pair of small hands to mount the air filter box, just sayin':-)

VFRcracked > I think your thermostat is performing just as it is supposed to.

Thanks everyone,

After some further investigataion I think my stat is fine,I have been told that the right rad will begin getting warm first( from say 60 degrees) as there is a coolant bypass designed into the thermostat housing,only when the stat opens fully will the coolant begin circulating through the entire system,

so I breathed a sigh of relief when I copped on that all was ok.

The internet is fantastic for info but sometimes it can send you on a wild goose chase,especially if you're an amateur mechanic like me. I didn't get this mis-information on VFRD by the way.

If I was to replace it I would get the OEM stat,as you say SPUD why risk it, the early 90's Honda civic stat would work(or so I have read) but has to be modified a bit, if the stat was easy got at I would take a chance on it with the non oem.

Just going to change the coolant now and fit a new air temp sensor, then go and enjoy the bike,

What a fantastic bike it is,had a spin on a friends cbr 600 yesterday,nice bike but in my opinion the VFR is twice the bike,glad I bought one.

Im not following your trouble shooting, on what rad warms up quickest or not.


Start your bike from a cold start ride off, if not at full operating temp within two miles(170 degrees), thermo isnt working right, if your on the interstate in cool weather at speed and the bike drops below 150 degrees, thermo isnt working right.

Thats how you can tell if have a thermo issue, which in most cases of failure, they are stuck open, or in some cases half stuck open so you have both overheating, and underheating. I dont know what transilation 150 degree is, but that number is a low extreme, you should really never seen that low, 160 dgrees, is really the lowest worst case. I have seen 158 degrees as an extreme low, in sub 30 degree weather at high speed. But if falling down to around 150 dgrees stuff like vtec will stop working.

Thanks Spud, Yeah I am now convinced my stat is fine, went to see a friends vfr 800 fi this evening just to a comparison,and my bike is 100% fine thanks God,

wasn't looking forward to that piece of work.

If I were to check and adjust the valves would I have to remove the throttle bodies etc then? just think that when valve check/adjust is due next year at 32,000 miles it might be a good time to fire in a new stat, seeing as the bike will be torn down anyway, preventitive maintainance?

No need to remove the throttle bodies for a valve check.

[image: IM000700_zps87989970.jpg]

Thanks, so I just have to remove the tank and the airbox then? is that correct?

No need to remove the throttle bodies for a valve check.

[image: IM000700_zps87989970.jpg]

Thanks for this pic, vfrcapn. I have always removed the airbox when I check my valves, and have been wondering if it was really necessary. It looked like access might be marginal with the airbox in place. You answered my question. (And a good answer it is! Airbox removal/installation is a PITA).

Aram

Ughh -- I cringe at the thought of having to get under the T-bodies and the airbox to do the thermostat.  Been riding here in the NE some this winter, and my bike does not come up to temp easily, and runs at 135-155 degrees on the HW so I think it is stuck open.

My understanding is that at lower than optimal running temps, the engine does not burn off the moisture vapor from combustion, hence the poor MPG i am getting (160mi/tank)  and the kind of cloudy film on the oil fill plug.   Correct with these?

You can just use a thin coating of engine oil or WD40 to help slip the boots back on.

How did you get on RedRum? what parts did you need apart from the new stat?

How did you get on RedRum? what parts did you need apart from the new stat?

I just finished this job myself.  I went in there to fix the two leaky hoses to the wax thingy.  On advice from this forum I replaced all the hoses in the v, the thermostat and the o ring on the housing.  Quite fiddly but it's all back together and runs great.  Dont forget to lube the starter valve linkages with a shot of WD-40, found this out after the fact.