SlowMaintenance
'76 XS650 Chopper
Hey everyone, so my brother just moved home from Philadelphia and with him he brought the 1980 XS chopper he purchased from a guy out in Ohio. It wouldn't start when we got it back so I figured we'd clean out the carbs and see what the problem was.
I've done plenty of work on my bike but when it came to carb choice I went with a brand new single VM36 so I wasn't very familiar with what to expect from stock carbs, seeing as I sold mine without even opening them up. Here's what I found when we opened his.
Closer shot of that red liquid
And a glamour shot of the bike itself
So obviously something is wrong. The tank isn't red koted, and the red coating was only in ONE of the two carbs so I don't believe it came from the tank. A friend of mine suggested it could be silicone used to seal the carb, and the torn gasket we found on that carb would support that theory. Curious to know your thoughts as well.
Needless to say, we spent a good deal of time spraying carb cleaner throughout the various areas including the main, pilot and air jets checking visually to confirm the passageways were not clogged and all appeared to be in good standing. When we were finished cleaning there was not one spec of red left in that carb.
Before closing them back up though, I thought I'd confirm that the float levels were set correctly. Seeing two different floats in the carbs was a big concern as I've never seen them mixmatched like that. There's some confusion as to whether this bike was a 79 or an 80 but this seems more like a PO replacing one with the incorrect float set. Either way, brass floats should sit at 27mm and plastic floats at 22mm. This is assuming these are BS34 carbs which they appear to be.
In checking the levels the brass float carb was set correctly at 27mm. Perfect. Checking the plastic float carb found something unusual though. The float was set at 24mm, but it was bottomed out on the carb body. This is to say that the height of the actual float was such that it could not be adjusted any lower than 24mm. This makes me think that the PO installed plastic floats in a carb that wasn't meant to have that style. Can anyone confirm if that conclusion makes sense?
I set both floats to 27mm for the time being, as lowering the plastic float height was not possible and I opted for consistency between the two settings. We put the carbs back on the bike and fired her up. Got her running but signs are pointing to a lean condition with a wandering idle. Did some tweaking to the throttle cable slack and also to the idle screw but I couldn't get rid of two things...the wandering idle and a very slow throttle response.
I didn't take the tops of the carbs off so I'm thinking there may be more issues that lie underneath those covers, also the torn gaskets on these carbs will need to be replaced so maybe there is an air leak from there if that's possible.
Big thank you to Griz and 5twins as your carb guide helped me to get this far along, now I'm just throwing this post up here so anyone with some additional insight can chime in if I'm missing something.
Tonight I'm heading back over there to check his cam chain tension, valve lash and timing. The bike has the stock TCI charging system and I believe a points ignition. I'll confirm tonight when I pull the covers. We also need to reweld the frame downpost which the previous owner was riding with ONLY A TACK WELD. Ugh
I've done plenty of work on my bike but when it came to carb choice I went with a brand new single VM36 so I wasn't very familiar with what to expect from stock carbs, seeing as I sold mine without even opening them up. Here's what I found when we opened his.
Closer shot of that red liquid
And a glamour shot of the bike itself
So obviously something is wrong. The tank isn't red koted, and the red coating was only in ONE of the two carbs so I don't believe it came from the tank. A friend of mine suggested it could be silicone used to seal the carb, and the torn gasket we found on that carb would support that theory. Curious to know your thoughts as well.
Needless to say, we spent a good deal of time spraying carb cleaner throughout the various areas including the main, pilot and air jets checking visually to confirm the passageways were not clogged and all appeared to be in good standing. When we were finished cleaning there was not one spec of red left in that carb.
Before closing them back up though, I thought I'd confirm that the float levels were set correctly. Seeing two different floats in the carbs was a big concern as I've never seen them mixmatched like that. There's some confusion as to whether this bike was a 79 or an 80 but this seems more like a PO replacing one with the incorrect float set. Either way, brass floats should sit at 27mm and plastic floats at 22mm. This is assuming these are BS34 carbs which they appear to be.
In checking the levels the brass float carb was set correctly at 27mm. Perfect. Checking the plastic float carb found something unusual though. The float was set at 24mm, but it was bottomed out on the carb body. This is to say that the height of the actual float was such that it could not be adjusted any lower than 24mm. This makes me think that the PO installed plastic floats in a carb that wasn't meant to have that style. Can anyone confirm if that conclusion makes sense?
I set both floats to 27mm for the time being, as lowering the plastic float height was not possible and I opted for consistency between the two settings. We put the carbs back on the bike and fired her up. Got her running but signs are pointing to a lean condition with a wandering idle. Did some tweaking to the throttle cable slack and also to the idle screw but I couldn't get rid of two things...the wandering idle and a very slow throttle response.
I didn't take the tops of the carbs off so I'm thinking there may be more issues that lie underneath those covers, also the torn gaskets on these carbs will need to be replaced so maybe there is an air leak from there if that's possible.
Big thank you to Griz and 5twins as your carb guide helped me to get this far along, now I'm just throwing this post up here so anyone with some additional insight can chime in if I'm missing something.
Tonight I'm heading back over there to check his cam chain tension, valve lash and timing. The bike has the stock TCI charging system and I believe a points ignition. I'll confirm tonight when I pull the covers. We also need to reweld the frame downpost which the previous owner was riding with ONLY A TACK WELD. Ugh
