So, with the help of TwoMany and RG I was able to fix my clutch issue, a 3mm valve shim on the push rod and new clutch discs resulted in a very functional clutch. However, this allowed me to finally get a little bit of riding in. This revealed a new problem, as it runs for a bit the idle begins to move from 1.5 all the way to 2-2.5k. This doesnt worry me too much, however after about 5 minutes of use it begins to incur a stumble, or pop at around 3-3.3k rpms as I throttle up. I've also noticed that at this point each cylinder (it happens intermittently to each) will produce a very dark smoke for a few seconds. Once this begins happening it becomes a challenge to ride because the throttle seems to miss in this rpm and the bike will die shortly afterwards, it is then very difficult to kick over and start again once it does. This is a freshly rebuilt motor, it only has 17 miles on it because of the various issues. Bored out to 680, new gaskets, valves lapped, fresh plugs, uni pods, and ya-mama exhaust. My carbs are set as such. 1 up on main, stock pilot, second second to highest (to raise) needle setting, and about 3/4 (+/- 1/8 turn on either side to match at idle)
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Gets Worse as it runs.
- Thread starter T3chnic4l
- Start date
At 1500 RPM, your idle is set too high. The spec is 1200 hot. At 1500, you're starting into the advance. As the timing advances, the motor will speed up, which will advance the timing more, etc. It's sort of a self-feeding problem. Your idle will slowly work it's way up like you're seeing without you even touching the throttle.
I'm not understanding your needle setting explanation. Explain it properly and maybe I will. Mikuni needle positions or clip slots are counted from the top down like so .....
You also haven't said what carb set you're running. If your needle is set richer, like in the #4 slot, that may be too rich for a later carb set but it would be stock for an early one.
I'm not understanding your needle setting explanation. Explain it properly and maybe I will. Mikuni needle positions or clip slots are counted from the top down like so .....
You also haven't said what carb set you're running. If your needle is set richer, like in the #4 slot, that may be too rich for a later carb set but it would be stock for an early one.
Sparky
XS650 Addict
possible vacuum leak? they can cause a high idle.
Short duration dark smoke?
Could be a momentary rich/flood condition, or a momentary loss of ignition allowing fuel load-up...
Could be a momentary rich/flood condition, or a momentary loss of ignition allowing fuel load-up...
Do we have to pull teeth here? Correct for what year? Yeah we could go look through your posts and probably figure it out but....
Lots of guys add a short description of their bike to their siggy, it often saves a lot of time and increases the likelihood of accurate help.
Have you used an overhaul kit? Did you compare all the brass included to be SURE it is right for your year of carbs? Hint a lot of kits have the wrong brass.
Lots of guys add a short description of their bike to their siggy, it often saves a lot of time and increases the likelihood of accurate help.
Have you used an overhaul kit? Did you compare all the brass included to be SURE it is right for your year of carbs? Hint a lot of kits have the wrong brass.
Gary, I apologize I thought I had made that clear. They are BS38's, that came with the XS650B in 1975. I rebuilt them but not with a kit, I had hear kits had wrong components so I purchased new gaskets individually, and purchased a wide variety of each jet (pilot and main). Everything that I replaced matched the original components.
Also I have read the carb guide, and re-read it several times to attempt to ascertain the source of my problems, while reading the guide has been helpful and gotten me to this point, often times experience with tweaking carbs yields greater knowledge, hence my post.
Also I have read the carb guide, and re-read it several times to attempt to ascertain the source of my problems, while reading the guide has been helpful and gotten me to this point, often times experience with tweaking carbs yields greater knowledge, hence my post.
