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carb rejetting

Posted: Sat May 03, 2008 12:04 pm
Author: kwaka
I want to attempt rejetting my carbs on the Z1B ( If needed ) but not sure how to determine what jet size is required. The engine has 70mm carbs, 4 into 4 exhaust with no baffles ( not popular with the neighbours ) :cheek . I'm not sure whether the cams are stock or not. I'ne done all the timing, mixtures and synchronising but it still sputers and i'm worried about running too lean. Is it just a matter of trying larger or smaller jets and see how it runs or is there a more sophisticated diagnostis method for checking?
Cheers

Posted: Sat May 03, 2008 1:40 pm
Author: Pasc
Get it on the dyno to find out how its fueling throughout the range.
70mm carbs ? You sure ?

Posted: Sat May 03, 2008 4:54 pm
Author: sweptail
70mm? They will take some jetting. Tc

Posted: Sat May 03, 2008 7:22 pm
Author: CRISPY
Could have problems with small children being sucked in if you dont run air filters :lol: :lol:

Posted: Sat May 03, 2008 8:37 pm
Author: Pigford
Air filters... :?: ..... Gonna need a large roll of chicken wire for them :!: :shock:

Posted: Sat May 03, 2008 10:27 pm
Author: Geoff Meager
KIN ELL...is there enough room under the tank :?: :?: :?: ..... :shock:

Posted: Sun May 04, 2008 4:25 am
Author: kwaka
Quickest way to get a response is post a ridiculous blunder :oops: That was meant to be 70mm pistons ie the 900 has been bored to 1000 cc. Everything else is accurate i think. So any suggestions on how to rejet myself? i dont have access to a dyno either.

Posted: Sun May 04, 2008 8:23 am
Author: FER
Try 125 main jets and move the circlip on needle down toward pointy end one groove . If really worried about running lean go up one size on pilot jet and adjust air screws to suit .





fer

Posted: Sun May 04, 2008 8:24 am
Author: Pigford
Sorry for that Kwaka, but you asked for it :wink:

Std or K&N air filters :?:

If std, the jetting shouldn't be far out on jets, maybe up a size or two :|

K&N type, then = 10 - 15% on std (120 - 125 :?: )

But as you say, aim a bit rich to start, then its a bit of playing around :??

Posted: Sun May 04, 2008 12:56 pm
Author: kwaka
Thanks for that, it will give me something to start with, I guess i can keep an eye on exhaust residue and plug colour.