VF500F carb/overheat question

Our vf500 is running way too hot and I'm having problems figuring out what it is, to make it worse this is our first v4 so I have no clue if every component on the bike is factory especially the mufflers because I've yet to see another '85 interceptor identical to ours. the bike sat for who knows how long and didn't run when I got it but that was due to bad gas/varnish in fuel system but it's up and running now except i can't ride it more than 5 miles before I have to turn around and head home because the temp gauge keeps climbing. It's boiled over once already so the bike is parked till I can figure out what's up.
So far radiator has been flushed.
Cooling fan works.
Thermostat tested good.
All air was bled/burped out of cooling system.
No leak down test on cooling system but I don't think it's a leaky head gasket because I'm not seeing any air bubbles or foam in radiator when it's running.
Don't have tools needed to test rad cap but a new one has already been ordered anyhow.
Water pump looks to be in excellent shape as in no sludge, no scuff marks in housing, no up or down play on the vanes shaft.
Set lash on all the valves.
However when setting my valve lash I checked the spark plugs and all 4 looked way too lean. All boots are in great shape and all clamps are tight. Maybe this is due to the fact that I didn't soak the carbs as thoroughly as I thought and could use another cleaning but at the same token I'm not convinced the bike has factory mufflers and I'm thinking maybe just maybe these are hi-perf exhaust mufflers that may require the carbs to be rejetted to work. While cleaning the carbs all had the correct jets that it would've came with from the factory so if the mufflers are hi-flow aftermarket pieces then they might be the cause of my bike running lean causing it to run hot because the carbs still have stock jets. I need some input really bad on this one before serious damage occurs due to overheating.

 

What year is the bike? Different years require different heat ranges of plugs.

ANy pics of the bike and these mufflers?

 

I have a busy evening planned so I don't have time at the moment to be specific so I'll try to post a pic and more info tomorrow but it's an '85. I do appreciate you responding.

 

Please let us know what you find to be the cause and how you rectified it. You have been very thorough with all your checks so far, so I am curious what you find. Mine is running a little hot too and I am having a rough go figuring out why.

 

Right now the plan is to have all the carbs ultra sound cleaned to try to make sure all crud is out of them. I've seen worse but in our case our 500 had sat just long enough for the gas to go bad and the gas in the carbs turning into varnish just enough to freeze the slides. That's all been taken care of but all it takes is 1 tiny piece of crud in the wrong place to screw up the metering of fuel. It wouldn't be so bad if pulling the carbs on this bike wasn't such a pain in the ........

 

We bought it about a month and a half ago at an auction and it wasn't running. From the looks of the fuel it hadn't run in at least a year because it had a full tank of gas that was starting to varnish which is why it wouldn't start for us. It took me a good 2 weeks to soak and clean all the carbs. This is our first V4 so I have no clue how well it's supposed to run so basically yes, it has been overheating since we first started it but I can say it does quick work of our '71 CB350 twin.

I'm really in no mood to pull the carbs off again unless I have to so what I did in a last ditch effort before pulling them off and having them ultra sound cleaned was put a bunch of Sea Foam carb cleaner in the tank, rode it around a bit to make sure it had made it to the carbs and then let it set overnight. Since then we've been taking short blasts with it allowing the Sea Foam to do what ever it can and each time taking the bike for a bit longer ride than before and so far the temp gauge hasn't made it past the 1/3 mark which from everything I've read so far, that's where it's supposed to be. So far so good but before all of you run to your local auto parts store and nab a can of Sea Foam for your bike, keep in mind that I also left the lower half of the faring off. The main reason I haven't found another vf500 identical to ours is because I believe ours has an aftermarket fairing kit giving it a "full fairing" look and I intentionally left that bottom half off because I thought it might be inhibiting air flow around the engine. Besides I haven't ridden it far or long enough to confirm I've made a positive difference but she does seem to be running in a much normal heat range than before. I've got the rest of the week off so therefore I won't have any excuses for not posting a pic of it so you can see what I mean so I promise I'll have a pic tomorrow.

 

Good update. Keep us posted.

 

You have the right idea but this is a pic of it at the auction. I pretty much have stopped looking at the exhaust as a culprit because it it was an aftermarket exhaust like say a Kirker or Vance and Hines, it would most likely say so somewhere and in my case it's not

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As it stands now the bike is running cooler but I think that has more to do with removing the lower half of the fairing than anything else. It runs like crud at the moment but that's mainly because it still has a tank of gas thats got an overdose of Sea Foam still in it. I feel the bike is still running on the warm side but I'm still in the process of begging and pleading with my nephew who's a Honda mechanic to spend the weekend here and properly tune the carbs.

 

Well you would think that being my nephew is the chief mechanic and oversees the whole shop where he works that I, the coolest Uncle in the whole wide world would have all the tech resources I would ever need not to mention parts availability. NOPE. He lives a good 4 hour drive away, works 6 days a week and is near impossible to get in touch with unless I call him up at work and even then it's hard for him to find the time to do a parts # search for me. I cruised with him a few weeks ago during Hot Rod magazines Power Tour in my brother's small block chevy powered '66 Corvair and I bugged the daylights out of him to bring his kids and spend the weekend here. He promises he will but it'll have to wait till after the 4th of July. Bummer.

 

I had ordered #95 jets to replace the #90's that were in it and while I was waiting for them to arrive I went ahead and shimmed the needle/metering rod to see what kind of response the motor would give and it was a positive response however I kept fowling my #2 plug. i got the new jets in today and removed the floats to make sure the needle and seat on all were clear and noticed the float on the #2 carb wasn't setting right. It turns out I forgotten to tighten the seat when I initially cleaned the carbs and it had gradually worked itself loose so even though the float was closed, fuel was still coming in around the threads of the seat thus flooding that cyl. I took care of that and installed the #95 jets and the results are that my VF500 runs like a completely different animal than ever before. it idles smooth, very snappy throttle response and last but not least the temp gauge never made it past the first 1/3 mark except in stop and go traffic but it would cool right back down once the bike was moving again. For those of you monitoring this thread, keep in mind that if you decide to put richer jets in your VF500, make sure you know what you have first because the 85 VF500 used different jets than 84 and 86 models. Mine came with #90 jets on all 4 carbs while the 84 and 86 models used a different size jets on the front 2 cyls compared to the back cyls ...... at least that's what my factory manual says. To seal the deal and make sure we have this overheating issue taken care of, we're leaving the aftermarket fairing off and have ordered a factory "chin" or lower fairing which I feel will help direct more air to the engine thus helping it stay within proper operating temps.

 

Good deal! Glad this gremlin has moved on.

 

Good to see you got it running good, thanks for the good info, and to change the subject I used to have a 65 Corvair with a 327 in the back, I'd like to see pictures of your brothers car.