Needle jets fuel level help.

[Yard Dogg]

I am having trouble setting my fuel level in my bank of carbs I just scored recently. I think the PO got some parts screwed up. Whenever I set the fuel level it ether pukes out the back or will not idle. When the fuel level was set too high and it was leaking out the back it idled, when I set it a slight bit lower it will not idle. These are late model carbs with the passage between the main jet en pilot jet. the rubber plugs in the bottom are good. The pilot jets are the right ones with 6 holes, the mains are 115. The po had them tore apart when I got them. These might be from a 1981 cause they had 120 mains for 2 & 3, and 115 for 1 & 4. I put my 115 mains in from my XJ carbs and switched to the needles that were in my XJ. Not right. Looking in the manual, the needles that were in my xj are not what is listed in my manual for the xj. The manual I have for the other years only have the older carbs and have no info for what I really. need. could anyone tell me what needles I need to get this thing running right? Also the proper fuel level measurement will help too. I wish I still had my clymers manual.

[DGXSER]

You have 80 carbs. Only the early 80 carbs were the new style and had the crossover.

The float level would be 23+-.5 mm.

You can get the manuals from Catatonic bugs site. You need the correct needles for the needle jets installed, and for that style carb. I don't have a manual handy, but you can look it up after you download it.

[natemoen]

If your carbs have the passage and the pilot towers are plugged with the plug you need to be using the 137.5 main jets as your starting point.

[bikerphil]

If your carbs have the passage and the pilot towers are plugged with the plug you need to be using the 137.5 main jets as your starting point.

Not true, all XS carbs that use the rubber plug in the pilot tower need the smaller mains (ex. 110-120), the early type carbs (metal screw covering the pilot tower) would use the 137.5 size.

[Yard Dogg]

The carbs are thoroughly cleaned. If I set the floats at 19mm it pukes out the back. If I set them at 21mm, it will not idle. I've tried turning the idle mixture screws out 1 1/2 all the way to 5 turns out. I don't see how the needles could effect fuel mixture at idle. These things are pissing me off. I might just put my old carbs back on until I find what the problem is.

[motoman]

I am having trouble setting my fuel level in my bank of carbs I just scored recently. I think the PO got some parts screwed up. Whenever I set the fuel level it ether pukes out the back or will not idle. When the fuel level was set too high and it was leaking out the back it idled, when I set it a slight bit lower it will not idle. These are late model carbs with the passage between the main jet en pilot jet. the rubber plugs in the bottom are good. The pilot jets are the right ones with 6 holes, the mains are 115. The po had them tore apart when I got them. These might be from a 1981 cause they had 120 mains for 2 & 3, and 115 for 1 & 4. I put my 115 mains in from my XJ carbs and switched to the needles that were in my XJ. Not right. Looking in the manual, the needles that were in my xj are not what is listed in my manual for the xj. The manual I have for the other years only have the older carbs and have no info for what I really. need. could anyone tell me what needles I need to get this thing running right? Also the proper fuel level measurement will help too. I wish I still had my clymers manual.

5GL16 metering rods with 110 mains across for the 80-81 Specials if using the later 80-81 carbs. The 80-81 Standards had the 120centercyl./115outside cyl. thing goin on, but also used different configured metering rods than the Specials of the same years. I assume those carbs have the fiber floats and viton float needles?

[Yard Dogg]

Okay, I solved it. When I first took the carbs apart to check things out, I thought I had 47.5 pilot jets, they were 42.5 jets. The 2 looked like a 7. I replaced them with the 47.5 pilot jets from my XJ carbs and set the floats to 23mm, the bike fired up and ran fine. So now I'm going to home depot to get the things I nee to blck the yics ports to get them synced. After that I need to finish my seat, then I'm tearing up the highway like angry Johnny.

I had a dementia moment for about 4 hours. Thanks for the help.

[natemoen]

Not true, all XS carbs that use the rubber plug in the pilot tower need the smaller mains (ex. 110-120), the early type carbs (metal screw covering the pilot tower) would use the 137.5 size.

That makes no sense in my mind but I shall defer to you experiance.

[bikerphil]

That makes no sense in my mind but I shall defer to you experiance.

The internals seem to differ between the BS34II (early) and BS34-III's (late) somehow.

[natemoen]

Must be, don't know never disected them. Just seems weird.

[DGXSER]

IT always confuses me as well Nate, but I know we had one set on Varnae's 80 in the SWOXS group years ago. He had 120 mains IIRC, with 42.5 pilots, and the plugs. Bike ran, never tuned well, but it ran. Unfortunately, it burnt up before we got the carbs sorted out.

[bikerphil]

I have worked on at least 4 sets of those '80 "bastardized" carbs with the rubber plugs/crossover passage and plastic floats and have never had to use anything larger than a 120 main. There are some super rare early '80 carbs out there with brass floats, I can't say which size mains they would use, I would guess the 110-120.

[Yard Dogg]

Well, I'm pretty sure my bike is running dangerously lean without the correct needles in there. There is a dead spot In the mid range. I'm going bak to my xj carbs until I get the right ones.