1985 VF500 F Problem

So I got a 1985 Honda Interceptor VF500F last week and it had some starting problems. At first we thought it was the battery, but it seems to be soemthing else. Basically, I can start it from a cold start, but from a hot start it has alot of trouble starting, usually not even starting. It will try and try and try but just not quite turn over from a hot start. The battery will seem to die then I will wait 15-20 minutes and try it again when it has cooled down and it will start right up most of the time. It is really wierd and I have no clue but its annoying on my new bike. Spark plugs? Fuel Pump? Any clues? Im lost.....

Thanks

 

start with the obvious, the bike is warm, could be the starter if its turning slow, a starter can pull all the power away from other things, like your ignition, so you get weak to no spark.

if its turning over but not firing try pulling a plug and checking the spark,
you could also be over-fueling, causing the bike to have too much fuel,

on these old ones toe cutter or crustyrider are the better ones to ask

 

This is going to sound silly, My 84 has the same problem when hot, at first I though it was flooding from being to rich, but one day out of frustration I cracked the choke to full and it went from trying to start, to running, I have still not worked out the problem so if anyone has some ideas I am all ears. But at least when it stalls in traffic I can now restart it when it is hot.

I was starting to think it might be fuel pump related with not enough in the float bowls, but that does not explain letting it sit for 15 to 20 and fire straight up or that it pulls all the way through to red line no problem???

p.s. after reading some other threads I am starting to lean towards a vacume leak, I know this bike is really susceptable to vacume leak as I had to replace what looked like a perfect vacume hose to the fuel cutoff valve just to get it to run at all when hot.

 

I actually have tried throwing the choke open and it does not really seem to do anything for me. Last night it stalled out and I had to sit on the side of the road for 10 minutes until I got it to start again. Honestly, my #1 guess right now is Spark Plugs, im sure they have never been changed... Its just wierd to me that EVERYTHING works awesome except for the starting, it runs like a dream once I get it on, haha. We start cheap then move on up, hopefully its spark plugs!! let me know if you figure it out on your bike daydreamer

 

Many 500's have this problem. There was a TSB that described an adjustment to the idle screw setting that was supposed to help with hot-start issues (you lean it out). Mine has this trouble sometimes too but I haven't made the change yet so I don't know if helps or not.

 

TOECUTTER and some others told me it could be fuel pump, so to bypass the fuel pump and go with a gravity feed straight from tank to carbs. im going to try that. Whats TSB JamieD?

 

TSB - Technical Service Bulletin

I highly doubt it's the fuel pump. That would cause the engine to stop work while you are riding, not on startup. As mentioned, this is really common and due to a rich mixture - the TSB has you lean out the pilot screws.

 

Ok, Im actually going to start with just a fuel pump bypass, takes 10 minutes, then try the idle if that doesnt work then spark plugs. One of those three should help it out. Where is the idle screw? I do not have a manual yet

 

Boy, I've got to tell you..... I really don't think any of those things are going to make a difference. Neither plugs, fuel pump, nor the idle speed have any effect on hot starting of your bike.

There is one pilot screw per carb. In the factory condition they are behind aluminum plugs, but most often those plugs have already been removed. You'll want to get a manual to help you out.


Here are links to the TSB for this problem:

Page 1
Page 2
Page 3

 

Jamie, I guess it makes sense, Im just not as confident in my ability to work on bikes to do this, but I got buddies who can help i guess. Where can I get the kit? Also, were you going to install this on your bike soon?

 

Based on the TSB and what other things I've read, the key part is the leaning out of the pilot screws. Once I get my 500 out of winter storage (yes, I know it's July!) I will be making the adjustment and see what happens. I don't think that kit is available anymore anyway.