Join Date: Aug 2010
Location: Ontario, Canada
Rep Power: 1
I'm a little concerned about the buying price on this bike. It is in the range that suggest that something is wrong. Lot's of sellers will simply say that the carbs need cleaning when there is something more serious wrong.
Key things to watch out for include dropped valves, worn cam lobes, blown rear air shocks and petcock problems.
Before spending much time on the carbs I would do a compression test and a real good inspection of the valve train. I would first do a compression test. Depending on the mileage, they might be below spec, but as long as they are all fairly close to each other, say withing 10% then your ok.
Pull the valve covers and check everything out. Check for anything unusual then check the clearances. The 500's drop valves because of under-engineered valve springs. When fresh, the springs do their jobs, but when fatiqued they begin to float at high RPM and eventually piston/valve collision occurs. This is a very frequent failure on the 500. Since springs are no longer available, the best wisdom is to keep the revs way below the 11,500 redline. Many suggest keeping the revs below 9k.
When he cleans the carbs, DO NOT separate the carb bodies from the plenum plate!! These carbs are a nightmare to get back together and you can do everything that you need to do without taking them off the plenum. Every VF veteran will make that recommendation!
Keep in mind that the screws on the float bowls are not Phillips, they are JAS and strip fairly easy if you use a Phillips. The dot on the screw head is how JAS screws are marked.
The throttle cables are a real bitch to get back on. Be sure to study them closely when you take them off. Having a friend with a 10mm wrench turning the
Carb synch's are a bitch on these as well, mostly because the adjuster screws are very awkward to get to. Be sure to "bench synch" them before putting them back on the bike. To do this, simply adjust using the three tiny holes as reference points relative to the butterfly valves, using #1 carb as reference. This will get you close enough for test runs and rides.
Use good old dino oil (non-synthetic) on these old bikes. It is somewhat common for people to develop leaks on these older bikes when using synthetic.
Off the top of my head, that's some of the key stuff. I highly recommend that your friend introduce himself in the 1st generation section of VFR World and start a project thread with pics. We all love that? Then when questions come up everyone is ready to go.