popping from carbs on fresh rebuild

[kzcafe]

This is my second xs650 build however this time I went a little crazier. I installed a PM generator, pamco ignition (always), split the cases and changed out fifth gear, new piston and cylinders, and (this is the part that worries me) installed xs performance cam (new cam chain and guides of course). I've also taken the liberty of installing new Carb from 650 central, pre-jetted for my setup. It's kick only because its cooler right? (not went it won't start). So I went to start it the other day and it spends more time kicking back, backing, or popping out Tue Carb then actually trying to run. Both valves are closed at TDC on their respective cylinders. I'm familiar with the Pamco ignition having set it up before. I trust the Carbs are not the problem. Oh its an 81' xs650. I originally set the valve lash to factory setting but then later opened them up to try and get the valves to open later and close sooner. My brain is a bit fried thinking up all the possible problems so I'm hoping calmer heads on here prevail. Sorry for type-os using cell phone.

 

[5twins]

Kick back and popping the carbs out usually indicates the timing is off. That could be because you don't have the Pamco dialed in exactly yet but there's also that aftermarket cam to consider. Many times, they need to be dialed in. You should at least check it. It may be OK but you won't know unless you check.

 

[kzcafe]

This forum is as great a tool as any I own. Did a little research on here and I realized I was making a rooky mistake. The performance cam I purchased had no dowel/key for the mechanical advance plate nor did the old cam because I have an 81'. So I neglected to install one, I found a perfect size dowel trimmed to fit and installed. Engine fires right up, HOWEVER now I have a run away engine, as soon as I start it, it SCREAMS. I have new advance springs installed and even put paper behind the weights to keep it from advancing, still runs away. Played with the idle mixer screw, and even the timing on the electronic ignition, still screams. Any thoughts?

 

[kzcafe]

Ok runaway engine problem solved. Throttle too tight, however I'm not completely familiar with the aftermarket split throttle cable. And it just needs another 1/4 in. Of slack that I can't seem to find, by that I mean I think I have everything adjusted all the way out and I still need just a smidge more. pics to come.

 

[kzcafe]

where to make room?

 

[5twins]

It appears you have two adjusters up at the twist grip, one on the cable and one in the housing. I would remove the one in the housing or at least the lock nut on it. Maybe just removing the lock nut will give you that little bit extra slack you need. Other things to check would be if the cable ends are properly and fully seated in the slides and in the junction block inside the 2-1 splitter. I think that extra adjuster up at the twist grip is your problem, though.

 

[kzcafe]

I ended up doing pretty much just that. More or less removed the adjusted nut at the throttle drilled a bit deeper, shaved, and left out lock nut. Also you are right about room down at the Carb found some extra room at the adjuster nuts directly on top of the Carbs. Thanks for the reply, much appreciated.