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MG MGB Technical - K&N filters fitting info

Hi Guys, I have fitted the K&N filter kit, the two filters with the metal plate with MG on it, but when I started up the engine is was racing like I had my foot on the gas, I guess this is because there is air going almost straight into the carbs rather than being funneled with the old style filter holders. Am I correct in thinking I'll have to retune the carbs, is this easy?

Cheers Jack.
Jack New Forest

Something is wrong here. You should be able ro remove the air filters and it shouldnt make much difference to idle speed, You also should not have created a leak downstream of the butterflies as you were not working there. so I would suggest you check to see if you have snagged the throttle cable , make sure the damper pistons are falling back onto the bridge with a nice click and you have not some pushed one of the butterfly actuating forks out of position. Another possible is a problem with the choke cable bringing the carbs onto the fast idle cam.
Stan Best

Thanks Stan all good stuff there, I'll do some investigation first thing in the morning, I think I may have pulled the choke or throttle cable that might be the problem, I did not touch anything else.

Thanks for the info Stan.
Jack New Forest

I agree with Stan, the fitting of the K&N plate will make no difference at all to the idle speed. It seems certain that you have upset either the choke or accelerator linkages or perhaps one of them is fouling the assembly and not being allowed to return properly. Have a look, I'm sure you will find it.
Iain MacKintosh

Actually just because you were not working there it doesnt mean you arent getting unofficial air in after the butterflies. the carb fixings are a poor design with all the bolts in one line. So putting some force on the inlet could have broken the seal if they were a bit loose.
Stan Best

Thanks Iain and Stan, found the problem, you were right, The choke linkage was fouled up, just pushed it up and down a bit and it freed itself, sound fine now.

cheers Jack.
Jack New Forest

This thread was discussed between 22/03/2012 and 24/03/2012

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