I go buggy'ing around the other day (okay, it's not a VFR, either...it's a minibuggy with a '98 VFR800 engine), everything's fine. I park in the driveway. While there, I relocate my lights from the front end to a light bar, and try hooking fan's ground back up to the temp switch in the cooling line like it's suppose to.

Fire her up, everything is gravy...until it warms up. Then sputtering and backfiring, RPM drop, and dies. Since then the thing will start up and run beautifully cold, but once it's warm nothing.

I have so far:

Moved the fan ground back to the frame.
Moved the ground for the lights back to it's original location.
Checked codes (no codes).
Tried disconnecting the block temp sensor (harder to start, no other effect).
Inspected other grounds, all good and ohm out.
Checked vacuum...it bounces over the 20lb mark at idle.
All four cylinders are firing until it's warm.
I've inspected the wiring harness for general damage and can't find anything amiss.

Then the problem started I thought I was fuel starving...fuel pressure was at a nice 36~40psi all the way up until it died, on both sides of the filter. I cleaned the tank out and changed my filters...and even changed the oil since I was down there. This problem persists with the gas cap off.

Any help at all with this issue would be tremendously appreciated. If someone can tell me what's up I'll buy them beer. I've posted this problem on reddit, vfrworld, and vfrdiscussion and have not been able to sort it out...if there are any other resources I can try to hit I would appreciate the leads.

 

on facebook are some groups for the VFR 800,try to join there maybe someone can help you.. here is the link of all the groups
https://www.facebook.com/search/grou...85731146577746

 

Just guessing here......
If it has a manual chocke, try using some when its warm, if it clears up the carburation then you might have a fuel problem. If injected, then its related to the choke problem but electronic in nature, a sensor gone bad or something like that.

 

Its getting fuel so.... I would suspect maybe tight valves that don't full close when warmed up. I had a Morris Minor that would die when warmed up due to tight valves. It ran 100% and then died like the key was turned off.

 

Alright I never came back and updated this...I ended up pulling the wiring harness off and completely unwrapping/trimming it. It was FULL of water. After getting the harness trimmed down, greased up where needed, and re-wrapped the thing ran better than it ever had.