Engine Starts rough but as it warms up it smoothes out

[gorrbert]

1983 GS1100GL

I had my Engine rebuilt. New oversized pistons, rings...
When the bike starts, it misses and backfiers. When the choke is no longer needed, and the bike warms up it sounds great. It's steady and reacts to the throttle instantly, and then goes right back to idle when the throttle is closed. The bike seems to have all the power it should have. I am running with gas that has been stabilized. I've only put about 5 miles on it since it was rebuilt. Because it runs fine when it's wamed up, I feel like I should ride it and see what happens.

Any help is most usefull. Thanks ahead of time, Gord.

[chef1366]

Break in the build and then worry about jetting. Give it at least 500 miles.

[Nessism]

Sounds like the carbs are a little gummed up from sitting. I'd go ahead and ride it for a while to put some miles on the engine. Of course this assumes the carbs are appropriately jetted, or the bike is stock.

Have fun.

[rudy]

When is the last time the valve shims were checked? Carbs synced?

My 1000 runs a little rough at startup when it's below freezing. I have to keep the rpm's low by fiddling with the choke because cold oil creates too much pressure for the pressure gauge and will peg it and wreck it. I'm sure it would run just fine if I let it wind itself out right away.

[gorrbert]

Valve Shims

The valve shims were updated when my engine was rebuilt and my carbs were cleand and jetted last year. I road the bike today and it flies. I'm not real worried about my engine that much. Should I be? Gord.

[chef1366]

The valve shims were updated when my engine was rebuilt and my carbs were cleand and jetted last year. I road the bike today and it flies. I'm not real worried about my engine that much. Should I be? Gord.

You were worried enough to post in the tech section.