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View Full Version : rattley sound 6k rpm?!?!


chimp007_uk
02-08-09, 02:55 PM
Afternoon...

I set all the fuelling up on the carbs last week and balanced them. Now at about 6,000rpm it has a pinking/rattley sound. I've retarding the ignition and its still there.

If i back of the throttle it stops. It doesn't do it under heavy load at any other point acros the RPM, just top RPM...

Any suggestions?

Cheers

Chris
chimp007_uk
02-08-09, 03:58 PM
Any ideas?
saloon3
02-08-09, 06:26 PM
it is running way weak at the top end , you need bigger main jets and lift the needles to bottom notch ...
chimp007_uk
02-08-09, 07:12 PM
I had the wide band llambda on it last week and it was only running 13.8 top end, which isn't ideal but far from lean. Going to try drilling the jets out to 185 when i get a chance but don't have access to the llambda anymore :(
chimp007_uk
02-08-09, 09:52 PM
Changed the plugs from NJK-R to Bosch ones, still the same and it doesn't idle as well... Will put the NJK's back tomorrow evening.

Any other ideas?
philip
03-08-09, 01:23 AM
wtf! get those bosch plugs out straight away.

get decent leads and some bcr8es ngk plugs or i think bcrp7es plugs.and get it too a rolling road. you cant set your car up on a drive way. need to be under load
saloon3
03-08-09, 03:08 PM
dont drill the jets just buy the correct ones
chimp007_uk
03-08-09, 09:55 PM
wtf! get those bosch plugs out straight away.

get decent leads and some bcr8es ngk plugs or i think bcrp7es plugs.and get it too a rolling road. you cant set your car up on a drive way. need to be under load

I didn't set the car up on the "drive way"... I set it up on the road under load. I had an innovate wideband llambda that I borrowed off another member.
chimp007_uk
03-08-09, 09:57 PM
dont drill the jets just buy the correct ones

I'm running Yamaha R1 bike carbs, no such thing as off the shelf jets for running on a car conversion. Currently running 180 jets.


I think it's a plug gay issue and i'm getting detonation at high rpm.

Going to re-gap the njk plugs i have and see if that's any better.

Didn't get a chance to play tonight, spent all evening trying to fix the door locks on my mk4 golf :(
saloon3
04-08-09, 12:58 PM
you can buy mikuni jets any size

http://www.allensperformance.co.uk/mikjets.html

i use these guys all the time.