Xs400 auto advance

[yamaridersd]

my 77 xs400 is having some idle issues!! I cleaned and rebuilt the carbs. Got new points, condenser, coils, plug wires and plugs. Did a static time and synced the carbs. Everything was running perfect until a couple weeks ago!! I was out on a ride and the ide started staying high!! I figured it was running lean and was a little worried the stick carbs were failing so I got brand new carbs and the problem was still there!! I’ve heard the 650 guys talking the auto advance springs being the culprit!! I can’t seem to find ones for the 400!!!! Does anyone know if the springs for the 650 would work on the 400?? Or know where I might be able to find some??
Any Indy would be great!!

 

[NewHavenMike]

Examine the advancer first and get it lubricated. If the weights move freely, then its probably related to your throttle cable and not timing. Maybe the carb boots are loose or have a leak.

 

[yamaridersd]

Thanks!! I will check that out!!

 

[yamaridersd]

Thanks!! I will check that out!!

Thanks!! I will check that out!!

Thanks!! I will check that out!!

new (lubed!!) throttle cable, intake manifolds, (S.W.R. Flat slide carbs) and gaskets! No leaks or sticking there!!! Auto advance is moving freely!! Still have the same problem!!??? Checked the timing (Statically) still right on!! Getting a bit frustrated!! Any other ideas???!!!???

 

[BBS360]

Do you have access to a timing light? It'll allow you to verify the advance through the full RPM range.

 

[NewHavenMike]

Your timing could still be advanced too much when its running.

Also, i find it easier to adjust the carbs when the throttle cable is disconnected. That way, i know there is no influence from the cable in any way. Just have to keep you hand ready for the kill switch.. i do this when i set idle as well as carb syncing.

 

[yamaridersd]

Perfect! Thanks!! Got a timing light! Left side was advanced a little! Runs like a dream now!!!! I’m loving these new carbs!!!!!