trouble with the twins

muddy · Post by **muddy** » Thu Dec 10, 2009 5:02 pm

hi gents, thanks for the quick replies.

i managed to get both carbs to suck the same amount of air by doing a proper job synchronising them.

ive had both the carbs apart last night cleaning everything i could see and trying to blow out any passage i could find. i will put them back together now and give it a go.

stay tuned!

muddy · Post by **muddy** » Thu Dec 10, 2009 5:34 pm

oook, we've got a development.

no luck just sticking them back together and whacking them on the car, BUT if i hold my hand partially over one of the carbs, i can get it to rev no probs.

so any ideas? its clear that there is not enough fuel for the air intake, but i wouldve thought 44 jets should be fine, considering theres 2 of them!

Trev · Post by **Trev** » Thu Dec 10, 2009 9:18 pm

Is the engine warmed up? It sounds like you need the choke on when first started.
Just a thought

, Trev

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Scubbs · Post by **Scubbs** » Thu Dec 10, 2009 9:55 pm

Is your fuel pump providing enough fuel to feed the carbs under revs
If its diaphram is damaged and only feeding enough fuel for idle and short bursts then starved till it feeds a bit more fuel.
Maybe replace the diaphram

muddy · Post by **muddy** » Fri Dec 18, 2009 9:53 am

the engine warms up pretty quick (badly needs a radiator flush) and the fuel pump is delivering plenty of fuel.

2 questions - are you meant to move the little link that controls the stroke of the accelerator pump when you run twins? as in the little bean shaped thing with 3 holes in it? the little link is usually in the middle hole.

also, i have been doing all this testing without air cleaners on. a bloke at work mentioned that the extra air velocity from coming in unrestricted may have something to do with it. i thought that if a car ran with the air filter on, it would run with the air filter off. anybody had any experience with this?

thanks

Thommo · Post by **Thommo** » Fri Dec 18, 2009 9:58 am

Gday Muddy
My links are in the middle hole, and
I wouldn't imagine the removal of the air cleaner would alter the tune.
How much air is trying to rush in anyway, its a grey motor!!!
Cheers
Jeff

FB MAD · Post by **FB MAD** » Fri Dec 18, 2009 11:08 am

muddy wrote:oook, we've got a development.

no luck just sticking them back together and whacking them on the car, BUT if i hold my hand partially over one of the carbs, i can get it to rev no probs.

so any ideas? its clear that there is not enough fuel for the air intake, but i wouldve thought 44 jets should be fine, considering theres 2 of them!

By holding your hand over one of the carbs it runs OK............... so is one of the carbs running OK when hand held over it and the other one not run OK when hand is held over it.............. just trying to eliminate a faulty carby if that is the problem.

Also, in theory, the air cleaner will make some difference to the carb tune and performance but, as Thommo said, the part that the air cleaner plays is just a poofteenth amount of difference,so much so, that it is really negligable, unless of course, your air cleaner/s are chok-o-block full of dirt.

The link should be in the middle.From memory, if you put it on the innermost link you get a slightly shorter stroke on the accelerator pump plunger and slighly less fuel on pumping the throttle and vice-versa on the outermost link.I've tried changing these link positions on carbies years ago with little,if any, change in carby performance.

There's gotta be something wrong there,send me your ph number via a PM if you want and I'll talk it through over the phone what you have/haven't done.......... not saying I can help at all but two heads are better than one...even with my rough looking head

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