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Twin su too rich
Posted: Mon Aug 21, 2017 8:50 pm
by 46entry
My 1500 HL has twin su's with locked mixture adjustment, running too rich, any ideas ?
Re: Twin su too rich
Posted: Tue Aug 22, 2017 7:49 am
by GTS290N
Hi Barry,
Welcome to the forum.
May I suggest you post this in the 'main' forum? You'll get a lot more views and a quicker response.
Yes..
Posted: Tue Aug 22, 2017 9:54 am
by sprint95m
GTS290N wrote: ↑Tue Aug 22, 2017 7:49 am
Hi Barry,
Welcome to the forum.
May I suggest you post this in the 'main' forum? You'll get a lot more views and a quicker response.
Good point Bill,
I have relocated this thread.
Ian.
Re: Twin su too rich
Posted: Tue Aug 22, 2017 10:23 am
by cleverusername
46entry wrote: ↑Mon Aug 21, 2017 8:50 pm
My 1500 HL has twin su's with locked mixture adjustment, running too rich, any ideas ?
The obvious answer is the needle/jet are worn and need replacing.
Re: Twin su too rich
Posted: Tue Aug 22, 2017 11:05 am
by markas
46entry wrote: ↑Mon Aug 21, 2017 8:50 pm
My 1500 HL has twin su's with locked mixture adjustment, running too rich, any ideas ?
SNAP! My 1500 went for her MOT yesterday. The tester had to fight with the carbs and make several adjustments to get emissions readings close enough to the 'approved' figures to pass her. Good job that apparently there's a 4% tolerance
Now need to get the carbs set up properly again
No major problems in any other areas though, just 3 straightforward advisories.
Re: Twin su too rich
Posted: Tue Aug 22, 2017 12:21 pm
by Richard the old one
In your post you state your car has locked mixture adjustment. I have not seen the plastic locking arrangement but I believe that it is just a matter of breaking the plastic off to get at the standard adjusting nut. All my later cars which would have been built with the locked mixture adjustment had been converted back by the time they came into my ownership. I am surprise there are any still around with the plastic locking arrangements still fitted. Once you have removed the plastic it is just a matter of screwing the nuts up slightly to weaken the mixture. I believe the problem now is the younger mechanics do not know how to adjust SU carbs. It is easier to get at the nuts and to see what you are doing if you take the air filter box off.
Re: Twin su too rich
Posted: Tue Aug 22, 2017 12:36 pm
by 46entry
Many tks for that, I was contemplating doing that but thought I would check first - flew through Northern Ireland MOT (1st mot for 7 years as she was mot exempt in Southern Ireland where I found her) even though I know she was running rich, tester must have been a dolly fan in an earlier life !