Engine won't hold idle

[volks28]

Just finished replacing intake o-rings (between head and carb) as well as exhaust O gastkets (between engine and pipe).

Now the bike starts, but won't idle after it warmed up :evil: Checked the plugs, they are dry black after a very short run :?

1) I have removed the throttle cable to get the carbs out. Does the throttle cable need to maintain a small opening (tension) for idle??

2) Since there was an intake leak before (dry o-rings), would I need to reajust the carb idle? I'm thinking it was running fine before because it was taking it's air at idle mainly from the intake leak :?:

3) I put a small gas tank (snowblower style) instead of newly painted gas tank). I blocked the vaccuum tube at the carb - is this alright for troubleshooting?

4) Any clues on my idle /stall problem?


PS bike is an 83 GS 850
Thanks!

 

[earlfor]

Re: Engine won't hold idle

If you have a stock vacuum operated petcock and the vacuum tube is not connected, the diaphram will not open the fuel passageway.

Since there previously was an intake leak/leaks and the bike apparently did idle, I would guess that your carbs were set too rich and that was compensated for with the leaks resulting in more or less normal operation.
A vacuum carb synch is the first thing I would do. I suspect that will solve the problem.

the throttle cable should be almost tight with throttle in the off position. slight bitsy bit of slack, but there should be some free play. Use the idle adjustment screw for setting idle speed. That will not work consistantly though unless the carbs are in synch.

Earl

Just finished replacing intake o-rings (between head and carb) as well as exhaust O gastkets (between engine and pipe).

Now the bike starts, but won't idle after it warmed up :evil: Checked the plugs, they are dry black after a very short run :?

1) I have removed the throttle cable to get the carbs out. Does the throttle cable need to maintain a small opening (tension) for idle??

2) Since there was an intake leak before (dry o-rings), would I need to reajust the carb idle? I'm thinking it was running fine before because it was taking it's air at idle mainly from the intake leak :?:

3) I put a small gas tank (snowblower style) instead of newly painted gas tank). I blocked the vaccuum tube at the carb - is this alright for troubleshooting?

4) Any clues on my idle /stall problem?


PS bike is an 83 GS 850
Thanks!

 

[volks28]

Re: Engine won't hold idle

So now my engine is running *pig* rich and there is so much gas it won't hold idle?

Is there a possibility that I didn't hook up the exhaust pipes right, causing an exh. leak? Would I notice/hear it?

 

[earlfor]

Re: Engine won't hold idle

You did say the plugs are "dry black after a short run". What can I say? if the plugs are black, I guess the answer is yes. Your idle circuit is "pig rich".

When combustion reaches the exhaust, the engine is though with it. It would have no effect on carb settings for idle.

Earl

So now my engine is running *pig* rich and there is so much gas it won't hold idle?

Is there a possibility that I didn't hook up the exhaust pipes right, causing an exh. leak? Would I notice/hear it?

 

[Anonymous]

From your text, I'm wondering if you've readjusted your idle yet.

Do not, under any circumstances, try to maintain an idle by making the throttle cable taut. Make sure there's some slack with the bars at lock, left & right.

If the idle adjustment screw doesn't get the job done (unlikely), there's a problem with the engine that needs correcting.

 

[volks28]

whoops, thats what I did to temporarily fix it, before getting it to a shop for a sync. What harm can it do, just curious.

From your text, I'm wondering if you've readjusted your idle yet.

Do not, under any circumstances, try to maintain an idle by making the throttle cable taut. Make sure there's some slack with the bars at lock, left & right.

If the idle adjustment screw doesn't get the job done (unlikely), there's a problem with the engine that needs correcting.