Ok, working on a 76' GT500. The engine has been rebuilt from the crank up, with bored out cylinders and oversize suzuki pistons. Running stock full exhaust but no baffles in the mufflers, and pod filters on the carbs.
Having a problem with the carbs. It runs but not the best. After taking the carbs apart i found that the needle jet threads were stipped out of the carb body on one of the carbs. I am looking at some new mikuni VM series round slide carbs to replace the bad one. If i am correct this bike came with a VM32? Also i know it needs rejetted with the bigger pistons, pod filters, and straight through exhaust. It has stock 97.5 main jets and 30 needle jets. What should i go up? I size on both?
BTW, this bike was a barn find with less than 9k miles.
You can't know where your going until you know where you've been.
I'd strongly recommend putting the baffles back in. All that happens with them out is that it makes more noise but no more power and it makes a mess of the carburation.
What series are the needle jets? They should say something like 159 P-4. What do yours say and what needles are currently fitted?
Dont have the baffles. They were missing. Anyone make replacements? I havent even looked at the needles. I will today and ill post up what they are.
As far as the carb, on the link there is all the carbs im looking at. Are any of them the same as the stock since im only looking to replace the one carb that is messed up and not both.
AFAIK, baffles are still available from Suzuki. Try your local Suzuki dealer or ebay.
For the carbs, if all that's required is a new needle jet, I was suggesting that we discover what that one is and see if a replacement is available from SUDCO. That's why I asked what needle jet was fitted. I don't have a GT500 and I have no idea what series of jet it is. I'd guess a #159 but it's better to get the right one.
tz375 wrote:AFAIK, baffles are still available from Suzuki. Try your local Suzuki dealer or ebay.
For the carbs, if all that's required is a new needle jet, I was suggesting that we discover what that one is and see if a replacement is available from SUDCO. That's why I asked what needle jet was fitted. I don't have a GT500 and I have no idea what series of jet it is. I'd guess a #159 but it's better to get the right one.
Actually the carb body threads are stripped out where it screws up into the body. So when the jet is screwed up into it, it just falls right back out. I thought you were talking about the slide needle when you asked about that in your last post. Sorry. I dont know of any way to repair the threads in the carb body is why i was asking about a new carb.
Ill check with Suzuki about the baffles. Thanks
You can't know where your going until you know where you've been.
without baffle, you must put main jet 100 or 102.5 and if you have about same gasoline as in France, 32.5 and 100 with all origine and 32.5 and 105 without baffle.
dinogt wrote:without baffle, you must put main jet 100 or 102.5 and if you have about same gasoline as in France, 32.5 and 100 with all origine and 32.5 and 105 without baffle.
Thanks for the info. I still need to figure out what to do about a carb though. Anybody on what the stock carb was or if any of the ones in the link are the correct one?
You can't know where your going until you know where you've been.
That doesn't sound right. When you try to screw the main jet in place, it is going into a brass piece hanging down slightly into the float bowl from above. Yes? If not, please post a picture of the jet and where it goes in.
That brass bit is the needle jet and it comes out of the top of the carb.
Oh my. Those are a bit crusty. The main jet goes into the center of the carb body, where you see that brass thing. That is the needle jet that the main jet screws into. It should easily tap out upwards from the body for cleaning, but I suspect that one may be a little more difficult to break loose. It needs to be removed for cleaning.
The top hole ringed in your picture is where the pilot jet goes in and is a much smaller hole. Looks like you could be right about needing a new carb. there's a few pairs on ebay at wildly differing prices.
tz375 wrote:Oh my. Those are a bit crusty. The main jet goes into the center of the carb body, where you see that brass thing. That is the needle jet that the main jet screws into. It should easily tap out upwards from the body for cleaning, but I suspect that one may be a little more difficult to break loose. It needs to be removed for cleaning.
The top hole ringed in your picture is where the pilot jet goes in and is a much smaller hole. Looks like you could be right about needing a new carb. there's a few pairs on ebay at wildly differing prices.
Yeah, the spot where the pilot jet goes into has no threads left in the body. For the price of a new one (around $100) if one of these will work, i might as well just go new instead of unknown codition used.
The one im looking at is the VM32 part number 42-6010. Would that be the same as the other one since im just looking to replace the bad carb? I already know that the jetting will need changed if i get one of these...
You can't know where your going until you know where you've been.
I don't see why not, but I'm guessing that all the jets and needles will need to be swapped out. That takes us back to your original question and that was how should it be jetted. With pods I would expect one size up on the mains and maybe one up on the slow jets. Start with a #35 slow jet as Dino suggested.
For some reason I have been thinking you were talking the main jet falling out, but it's the pilot jet you're talking about.
If you are 100% sure that carb is stripped - and the threads are usually a long way up inside - would you be better going up a size to 34mm. But I guess you just want to buy one. I am not familiar enough with the 500 carbs to say if that's a possibility, but I'd be tempted top replace them as a pair.
Anyone fitted 34mm carbs on a basically stock 500 wish to chime in?
