Rode Hard & Hung Up Wet: My 1986 VF500F

Was just closing the shop up for the night, decide hey what the heck, let me grab the key for the Interceptor, it lit right up with the choke, running on three cylinders now?! So today it's just the LF dead, who knows about tomorrow...if I still cared I really wouldn't know whether to crap or go blind.

 

wow... that kind of stuff drives me crazy... did you check that bowl drain screw to see if it's getting fuel? Maybe coil? Maybe cdi box buggin out? maybe pulse generator?... I guess you already know USED cdi boxes and coils are pretty easy to find but you have to get lucky to find cheap good ones.... and it could get pretty expensive just going by trial and error...

 

Jrod I have all new float valves in it, and the floats have been set with the gauge. Fuel in every bowl. I suppose if I get back into it I'll pull it all the way down to the valvetrain and go from there.

 

A small update, as the two front cylinders are "dead", today I did a compression test. 125psi on all cylinders except the left rear which is only coming up to 72psi. Any input would be appreciated.

 

that's a quick one year reprieve, did you try swapping coils? since one coil does the front and the other the back, that could be it... it could be worth a shot just putting in a new(er) top coil in to see if that works. Good luck man.

 

Jrod that is a good idea! I will try that and let you know. Thanks so much.

 

Jrod I swapped the coils over and still have the same problem, front two cylinders are dead.

 

I believe you can switch the CDI boxes around and see if that helps. I believe that one of the boxes might power the tach, which would not work if you switched them , but if the lf cyl. is running and another one goes out you know it is the CDI unit.

 

Rollin'

Okay, finally an update on some progress! Pulled the carbs AGAIN, cleaned the slow jets on the front bank, and pilots too. To fully confirm I am a hack when it comes to carburetors, I guess the last time I had them off for "cleaning" (round 14 or so), I failed to tighten both jets in the RF carb, so that was not helping!
Of course the brand new battery is toast, no amount of pampering, auto trickle, etc. did any good. Had to jump it off a tractor in back of the shop, but it did fire right up on three. I monitored the still dead LF cylinder with an IR thermometer while noting small fluctuations in RPM. The fluctuations were in sync to variances of temperature readings...Hmmmm. Anyway after a few minutes it started to fire, and I was then able to set the idle to specs with a half turn of the knob.

It sat there and ran beautifully for a half hour or so, and showed excellent throttle response as well. So I shut it down to put some StarTron in the tank and called it a night.

So let me take a whack or two at the dead horse: the fuel around here is absolute garbage!!!!

I will pick up ANOTHER new battery (#3 and still hasn't been on the road), which I am reluctant to do because it will likely be roached by warm weather. Thanks for help everyone.

 

Way to stay the coarse, some things just need to be worked through. it's a motorcycle, whats ya going to do

 

Man I know, 31 freaking years I have had this motorcycle, can't give up now! I hope I can ride this year, it has been too long...

 

I'm going to need some fork seals for this piece, and I think I will put chain & sprockets, plus the tires have cracking on the sidewalls.

 

I have installed a new battery, replaced an instrument cluster bulb, and changed the oil. Also had to clean the turn signal switch. I plan to go check out the local motorcycle shop and get a price on tires and chain and sprockets. And I am putting insurance, tags, and stickers on any day now. I also need a new set of feeler gauges, so I can check the valves, I swear I cannot remember when they were last adjusted, so better check.

 

Hey Surf,

I don't know if you mentioned how many miles are on it but super tight valves could be causing issues for you, i.e. low compression. These valves get tighter (not looser) with normal use. Make sure you tighten down the adjusting nuts very well after you get done. I always go with not-so-snug .006 feeler on mine. Those adjuster nuts though easily get loose and will ruin your engine if the cotters/valve locks get knocked out. Good luck man.

 

Thanks Jrod, I am just under 35K miles. I did not know about the valves tightening up like that, I appreciate that info. In my OP I may have mentioned dropping a valve at 138mph, so I am afraid I am somewhat familiar with the pitfalls of abuse and neglect. Thanks again chief .

 

Right now I am seeing a fair bit of slop in the rear wheel bearings (original). So I suppose there's another task I will need to take care of. Abuse and neglect *sigh*...

 

I was doing about 90 when my valve dropped... so I know, I know.

Anyway, we all know this stuff gets super frustrating but have you tried switching out the voltage regulator? Those don't last forever and can cause all sorts of weird problems. I've run the cheapy chinese ones off of ebay (less than 20 bucks) and haven't had any problems since the original went out. Just a thought but I know it gets expensive and infuriating replacing parts that don't solve the problem.

wait...138? you sure that wasn't 113.8 or even 103.8? Was that going down a super steep grade with a 100 mph tail wind or something?

Good luck man.

 

Yep, 138 on the speedo, flat ground a long straight stretch, trying for 140 but she had enough. It was in February, 10 degrees Fahrenheit, the cold air really gave a noticeable boost, enough to almost throttle roll a wheelie in 2nd.

 

Jrod I think I am ok on the electrical aspects, aside from a couple of manky switches. One thing that I have been through a couple times is a battery fault. When that happens the ignition system does go haywire! I have had that happen while riding, power loss and misfires. YMMV

 

I am proceeding with this project, I have on the way tires & stems, rear wheel bearings, fork seals & dust seals, slave cylinder rebuild kit, drive chain, air filter, and fuel tank coating. So I have to get those items taken care of, and will also be adjusting the valve clearances while I have the tank off. And I will look at the spark plugs while I have them out. Also I need to refinish the wheels when I remove the old Dunlops. Putting insurance on it tomorrow.