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Jetting for a modified KZ900Could someone

Posted: Wed Jul 12, 2017 8:21 am
Author: QITMAN
Hi all
Could somebody let me know the jet sizes for my KZ900Ltd please.
Originally the bike I've owned for 23 years had a 4-2 system, it then had a Vance and Hines, then a Harris. I put the original factory jets in the carbs and it ran well.
Two years ago I fitted a 4-4 system and the bike runs ok but seems to strain a bit when opening the throttle (doesn't pull like it did).
Your help would be appreciated
Mike

Re: Jetting for a modified KZ900Could someone

Posted: Wed Jul 12, 2017 8:50 am
Author: zed1015
If it's a pattern 4-4 you will never get it to go like it did with the other pipes.
The pattern 4-4's are nice to look at but are restrictive and strangle the bikes power and top speed by a considerable amount.
I have dealt with quite a few zeds with these exhausts fitted and no amount of jetting, airbox or baffle mods make any significant difference.
The choice is usually either go for the stock looks and potter about or stick a decent 4-1 back on for some proper fun.

Re: Jetting for a modified KZ900Could someone

Posted: Wed Jul 19, 2017 5:23 am
Author: johny brando
zed1015 wrote:If it's a pattern 4-4 you will never get it to go like it did with the other pipes.
The pattern 4-4's are nice to look at but are restrictive and strangle the bikes power and top speed by a considerable amount.
I have dealt with quite a few zeds with these exhausts fitted and no amount of jetting, airbox or baffle mods make any significant difference.
The choice is usually either go for the stock looks and potter about or stick a decent 4-1 back on for some proper fun.


+1 on Robs reply above. Also ....Stick with 26mm carbs if you want more Mid-range or..... stick late model= Z1R / Mk 2 ( better linkage 28mm 's on ) if your chasing more H.P. & top end performance .