XS650 need help

 

Hi all,

I have a 1980 XS 650 sidecar rig in need of some diagnostic expertise.
Cutting to the case.....it runs at idle, but will not rev beyond idle.  It
just falls flat on its face.  Burbles, pops, spits.  The problem started
about 5 miles after filling the tank. Cleared up briefly, than reverted back
to the not running above idle.  I drained the tank and put in fresh gas.  I
pulled the carbs X2 and cleaned them to no avail.  I replaced the CDI unit
suspecting there was a problem with the ignition not advancing. I have had a
CDI unit puke before causing intermittent problems. .  I can pull either
plug wire and the revs drop, from idle, the same amount.  What ever the
problem is, it effects both cylinders equally.  I see a strong spark at the
plug at idle, and it weakens as I attempt to rev the engine.  I have cleaned
the plugs and tried a fresh battery.  Actually, I run it off a car battery
in the sidecar trunk. Coil, perhaps?  Also, I do not think there is a
problem with the tank petcock.  I tried running the bike with the petcock
set in the prime position.  Any help much appreciated.  I cannot afford to
take it to a shop, but I really would like to get the beast running again.
FYI,  here is a link to pictures of the rig.
http://webpages.charter.net/clickfam/pictures.htm

Thanks,

Ron
www.mondo-ron.com

 

Ron scribbled;

 



did you take a close look at those cv carb rubber boots?
tiny cracks and leaks will do exactly that.
also, there are excellent google and yahoo 650 owners clubs
with much more help than here.

 



Yea, there were a bunch of cracks in the boots.  When I pulled the carbs the
first time, I swapped them out with a pair that were in better condition,
but it did not help the not running above idle thing.  Before the
aforementioned problem started, the bike did backfire when I rolled the
throttle off indicating there was a bit of an air leak.

Thanks,

Ron
www.mondo-ron.com

 



rebuild kits are available and i would replace everything
possible. i once tried to cheap my way out of a rebuild and
it was worth the $50 i would have saved.
backfiring could be carbs or electrical. make the carbs
perfect and eliminate that.
let us know, always up for learning.