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Fast idle speed when hot

6267 Views 11 Replies 7 Participants Last post by  terdah2
My idle speed is way to fast when hot and to low with cold engine, when I adjust it down.
What is wrong? It is a single carb. Amal 930 on a -68. Tropy
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Always adjust the tickover on a hot engine, never a cold one, that's what the choke is for.
Always adjust the tickover on a hot engine, never a cold one, that's what the choke is for.
I know what the choke is for, but the rev difference between hot and cold engine is to big. After following the tips on the AMAL home site on tuning the idle I got it better, but it is still a to large difference between hot and cold engine idle.
Just make sure you are not running the ignition a tad too advanced. ( maybe teh advance /retard mechanism is sticking ? ) If not then maybe richen the idle mixture.

As an oddball question? what oil are you using, it ought to be a 20/50 unless you in extreme hot or cold place.

Also check tappet clearances. ( look for too tight).

You are only looking for a small fault.
Just make sure you are not running the ignition a tad too advanced. ( maybe teh advance /retard mechanism is sticking ? ) If not then maybe richen the idle mixture.

As an oddball question? what oil are you using, it ought to be a 20/50 unless you in extreme hot or cold place.

Also check tappet clearances. ( look for too tight).

You are only looking for a small fault.
Thank You Panda! I have set the timing to 11,6 mm B.T.D.C. fully advanced, and the mec. is not sticking. I am using 20w-50 Kendall oil, is that ok? So I think what you say about the idle mixture is right! I think this is to lean.
I am using 20w-50 Kendall oil,
wow, I did not know you could still get Kendall, Anyone know
who bought Kendall out a few years ago? I remember it being
pulled from the shelves here as it was just a rebottled product
when they got bought out and no one wanted Kendall then.

Pookybear
wow, I did not know you could still get Kendall, Anyone know
who bought Kendall out a few years ago? I remember it being
pulled from the shelves here as it was just a rebottled product
when they got bought out and no one wanted Kendall then.

Pookybear
I use the Kendall GT-1 20w-50 c/o ConocoPhillips.

The Harley boys are using this oil a lot, and I think it is the same oil sold as original Harley oil.
check for a leak at the intake (hot)
Yup, that would be my guess. Air leak leans out the mixture and engine RPM goes up.

When the engine is hot and the idle is up, try spraying something benign like WD-40 around the intake connections. If the idle goes down, you found your leak.
regards,
Rob
Instead of WD40, use carb cleaner. Spray it around all intake connections with the engine idling, and if the rpm's change dramatically, you have an air leak. Best on a warm engine.
It is good that you start with factory settings and have set your timing according to teh manual. but remember sometimes a bike likes to be a bit 'different'. Especially now that the carburation and ignition is using a different fuel to the original. With the use of alchohol and lower octane fuel, you may have to use different settings, or even slightly richer jets, and/or run a little retarded.
Instead of WD40, use carb cleaner. Spray it around all intake connections with the engine idling, and if the rpm's change dramatically, you have an air leak. Best on a warm engine.
I always use start gas for this, and no leek! After fine-tuning the carb, I have got the idle down on hot engine, but still a bit to high, but maybee it is as good as I get it?
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