Author Topic: Running rich  (Read 802 times)

Offline martyn1061

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Running rich
« on: December 15, 2021, 10:42:47 AM »
Hi
Just overhauled carbs, started up and motorcycle running very rich. Any ideas how to adjust mixture strength.
Thanks

Offline taysidedragon

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Re: Running rich
« Reply #1 on: December 15, 2021, 11:03:56 AM »
Check float levels, make sure choke is fully off when lever moved (it may need adjusting) and set airscrews about 1 and a half to 2 turns out from fully in.
Gareth

1977 CB400F
1965 T100SS

Offline martyn1061

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Re: Running rich
« Reply #2 on: December 15, 2021, 11:13:34 AM »
Hi Gareth
Thanks for that, i have done that, I have even adjusted the air screws out 2.5 turns to weaken it further but still running rich.
Unless I re-strip the carbs and recheck float heights.
Martyn

Offline McCabe-Thiele (Ted)

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Re: Running rich
« Reply #3 on: December 15, 2021, 11:46:19 AM »
I'm a novice here - my first question is are the compressions good - does it fire up from cold easily? Do you have standard a air filter arrangement. If the answer is yes to all I would re-check float levels & needle positions - are the carb floats, needles original or good quality replacements?
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Offline Dave

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Re: Running rich
« Reply #4 on: December 15, 2021, 02:46:35 PM »
If running a standard carb setup, check under the seat. Is the air intake blocked / restricted?

Dave

Offline martyn1061

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Re: Running rich
« Reply #5 on: December 15, 2021, 03:26:11 PM »
I'm running single filters, compression good, all new jets etc. I have removed the carbs again now so i will re check float levels.

Offline Bryanj

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Re: Running rich
« Reply #6 on: December 15, 2021, 03:53:21 PM »
Put the original jets back in, aftermarket are notoriously innacurate

Offline K2-K6

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Re: Running rich
« Reply #7 on: December 15, 2021, 03:54:10 PM »
Presumably a 400 four ?

You'll probably need to tell us what jets are in there to get more considered view and input.

Individual filters can be difficult (but not impossible) to get a consistent setup, but with some baseline settings that look odd to the std factory baseline.

Offline martyn1061

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Re: Running rich
« Reply #8 on: December 15, 2021, 04:50:18 PM »
Hi
As i have got the carbs back out i will put the original jets back in and recheck float heights

 

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