gsxr 400 gk76a issues

ripzay · Nitrous Nuisance Joined: 01 Dec 2008 Karma :

ok.. problem is...

between 0 and 4000 rpm the bike runs on 3 cylinders (or sounds/feels like it is at least)

between 4000 and 10000 rpm the bike runs on 4 cyl and is fine and has full power.

over 10000 rpm it drops back to 3cyl and behaves like it does under 4000 rpm..

i have replaced spark plugs, HT leads, and checked the wiring to the coils.

any ideas ?

reg/rec on its way out ? coils fscked ?
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Current: 2005 KTM SuperDuke 990
Previous: 1996 Suzuki Bandit 600
Previous: 1994 Suzuki GSX-R 400

drew70 · Trackday Trickster Joined: 28 Jun 2008 Karma :

Probably knackered carb seals causing one cyl to over fuel, but carry out a compression test just to rule out mechanical problems.
There is lots of 76a info on 400 greybike, Hope that helps.
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Wafer_Thin_Ham · Super Spammer Joined: 18 Nov 2005 Karma :

Have you checked the actual coils themselves?

That sounds most likely to me.
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ripzay · Nitrous Nuisance Joined: 01 Dec 2008 Karma :

Hi all, quick update..

it was / is the coils.

i've borrowed some coils and leads off an RF900 that belongs to a friend and the bike runs sweeter than it has ever run before.

now i just need to buy some of my own, hehe
____________________
Current: 2005 KTM SuperDuke 990
Previous: 1996 Suzuki Bandit 600
Previous: 1994 Suzuki GSX-R 400