Popping Carbs and Dies on throttle input

Mine are on the side, but carbs are all a little different. You could try those. They regulate the mixture. Your manual should tell you what the starting point is.

For mine you turn them all the way in until the seat, then back them out one and a half turns. Then fine tune from there. Not sure what yours would be.

So, I adjusted the pilot screws, started them at factory setting and hooked back up the airbox, I had read that it could be causing part of the problem, during all of this testing I've had the airbox unhooked for ease of removal of the carbs. I'm getting closer, it idles now, it bogs a bit until higher rpm's and then it operates fine, I'm gonna add another half turn on the pilot screws and see if I can get the low rpm bogging to go away. Oh, what are those two vaccume ports on the carb for, the ones by the inlet into the engine, both of mine are uncapped. Should I cap those? They seem like they would be letting in a whole bunch of unmetered air. One place I read said they should be connected together. any info on what they were originally hooked to and what I should hook them to now would be helpful.

John Jones

Pictures of the carbs would help. There should be a couple vent tubes facing upward; they should have tubing running from each of them to the open air. You may also have a tube facing up for a vacuum operated petcock, that should have tubing running from it to you vacuum port on your petcock, or if the petcock was replaced with a non-vacuum type that tube should be capped. There should also be 4 tubes sticking downward out of your carb holders. They are for synching the carbs and should be capped. Different carb sets have somewhat different configurations, so pictures of the carbs and the tubes you need info on would be helpful so each tube can be positively identified. Ed

My carb holders have vent tubes that are supposed to be connected with a "balance tube". Mine were capped when I bought the bike. I just used some fuel line to connect them.

I have to get ahold of my brother, my cam is busted at the moment. I will get pictures posted ASAP. I do have a port coming out of my petcock, is that for vacuum? Then that's where those two ports have to be hooked to then, because there is no other vacumme ports anywhere. The carb holders have nothing on them. What does the vacuum port on the petcock do? I also have two separate outlets on the petcock, one of them is capped though. Should both of those be combined to one and sent to the fuel inlet on the carbs? Well, I guess I need to make a trip to the parts store to get some vacuum lines and T's and fuel line and T's. Geeze, I hate people who hack stuff up just to do it.


So the latest news with the bike is that it's running. Not too well yet though. It's still sluggish on throttle input, though not as bad as it was. The problem I'm having now is that it only runs for maybe 5 minutes before it just shuts off and wont restart. Almost like there isn't enough fuel getting to the carbs to deal with the bike running. The a little while later, it fires right back up again no problem. Though when I start it up the RPM's go insanely high, like 5k RPM. That can't be good on a cold start. It stays there for a minute or two and then works it's way down. But shortly after that, it shuts off and wont restart. It's getting better little by little. Does the vacuum on the petcock allow it to flow more fuel or something?

John Jones

I think I'm out of my depth here as your carbs are a world different than mine.

When you post pics of the carbs post a pic of the petcock too. Ed

ok, I finally got it running right.....mostly.....I switched the petcock over to reserve, even though there was pleanty of gas in it, and I bridged the two vacuume ports together on the carbs, and things seem to be working just fine for the most part. There is still a little bit of hesitation right off throttle, but I think I can tune that out with some adjustments. I will still post pics as soon as I can of both the carbs and the crazy dual outlet vacuume operated petcock that the vaccume port doens't seem to do anything.

John Jones