Rough Idle

BIGKEVIN wrote:

...noticed that the idle screw was not touching the lever on the carb at all. The bike would idle good and then shoot up to about 2500 - 3000 rpm. I could get it to idle back down to 1000 rpm by adjusting the air screws on the side of the carbs. Anyone have any ideas ?

idle screw was not touching --- perhaps due to incorrect bench sync.

Sticking advancer could cause inconsistent idle.

could get it to idle back down to 1000 rpm by adjusting the air screws --- likely just getting the pilot circuit fuel mixture so far out of adjustment as to drag down the rpm.

Good Fortune!

I am new to carbs. How do you do a bench sync ? Can you go into detail on it ?

BIGKEVIN wrote:

I am new to carbs. How do you do a bench sync ? Can you go into detail on it ?

Would refer to FSM regarding bench sync equalization of carb throttle slide height adjustment on manual slide carbs. Is also applicable to Mikuni 29mm smoothbores. (See link in OMR's earlier post).

With carbs on the work bench, while setting the slides to equal height positions at closed throttle, the idle thumb screw should be positioned with sufficient threads remaining available to allow further lowering of the slides during the later carb vacuum sync on running engine.
Necessary because often the later carb vacuum sync on running engine will require that the throttle slides be lowered further than their on-the-bench settings.

Good Fortune!

Well I think I really messed up my carbs this time. I took them apart to clean them and when I put them back on the bike and started it, there was guel running our of the # 1 carb. I took the carbs apart thinking the float my be the problem and when I took the bowl off, the main jet fell out also. I tried to put the jet back in but it will not screw in. I guess when I put the main jet back in, either I tightened it up to much or did not get it over the needle. Can this be fixed, or am I looking at getting some new carbs ?

BIGKEVIN wrote:

Well I think I really messed up my carbs this time. I took them apart to clean them and when I put them back on the bike and started it, there was guel running our of the # 1 carb. I took the carbs apart thinking the float my be the problem and when I took the bowl off, the main jet fell out also. I tried to put the jet back in but it will not screw in. I guess when I put the main jet back in, either I tightened it up to much or did not get it over the needle. Can this be fixed, or am I looking at getting some new carbs ?

If dealing with Mikuni 29mm smoothbores, information in the following link may be applicable:

Click here > www.wgcarbs.com/index.php?option=com_con...view&id=30&Itemid=42

Pics of carbs available?

Good Fortune!

BIGKEVIN wrote:

Well I think I really messed up my carbs this time. I took them apart to clean them and when I put them back on the bike and started it, there was guel running our of the # 1 carb. I took the carbs apart thinking the float my be the problem and when I took the bowl off, the main jet fell out also. I tried to put the jet back in but it will not screw in. I guess when I put the main jet back in, either I tightened it up to much or did not get it over the needle. Can this be fixed, or am I looking at getting some new carbs ?

if there 29's you need a new jet block now.
there are people out there who repair them.
google search " jet block repair "
it's $49 per block to have them fixed.
that's cheaper then and faster then trying to find one.
a member here hooked me up with one so you might want to post a new topic asking someone to sell/trade you for one.

edit:
patton beat me to it. he's just too damn fast

kawsakiman wrote:

...he's just too damn fast