1984 VF500F interceptor dying issue

New here. Just picked up a VF500F.

What it does:
Start it up, ride around for about 5-10 minutes, and it starts to misfire on one cylinder. Shortly thereafter if you try to keep going / push it then it will stall out. I have to wait about 1-5 minutes, then it will restart and run fine again for another 5-10 minutes. The duration appears to be dependent on RPM. At about 4000rpm in sixth, I was going a little over 10 minutes between the misfiring. I did take it on the freeway and opened up the throttle, when it started misfiring it was smoking out of the left tail pipe.


It looked to me like the carbs were rebuild, based on the traces of RTV around the bowl seals. Which means to me that the carbs will need to be rebuild again without use of RTV. I also suspect that anybody that would use RTV near gasoline might not know to keep all the pieces separate and numbered to each carb, which I experienced on my 700 Sabre (another V4).

I have a few questions on the carbs used here, specifically how to tell which jets go on the vertical carbs and which jets go on the horizontal carbs. I usually get parts for my Sabre from the V4market, but they don't have the carb kit listed for the 500 Interceptor. Does anybody know if the kit for the 500 is the same as any of the other V4 carb kits (Magna, Sabre, etc)? Or is there another source for the carb rebuild kit?

I will need to rebuild the master cylinder, replace the brake pads, all of which the V4 market has.

I would like to change the drive/driven sprocket out for something geared more for freeway use though. ~8k RPM at 70mph seemss a little overkill to me. Are there any options?

 

I would look at the carbs 1st. RTV on the float bowl seals would lead one to believe that there are probably pieces of RTV inside the bowls and maybe causing some clogging.

'84 Jets: Front carbs (2&4) 105 mains, 38 pilot. Rear carbs (1&3) 105 mains, 38 pilot.

Misfiring could possibly be a bad pulse generator or a bad igniter box.

Check the sprockets for factory gearing, should be 15/43. My '85 @ 70 mph was turning 7K.

 

the first check I'd do would be a spare spark plug and a ride. Once it dies pull each plug wire, slap the spare plug on that wire and check to see if it has spark. Sounds like a coil breaking down to me. I've had several 2 strokes do the exact same thing and it was the coil every time.

Once the coil gets hot the internal resistance changes and they drop out.

 

Thanks for the info.

I didn't realize the carbs were all jetted the same. The front two looked more vertically oriented.

 

I made a rare mistake LOL! The rear carbs on the '84 take 102 mains, not 105s as I stated. For clarity....

Fronts: 105 mains, 38 pilots
Rears: 102 mains, 38 pilots.