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Main air jet

PostPosted: Wed Jul 23, 2008 10:01 am
by Trunks
Hey I just got a Factory Pro jet kit and advancer for my 2000 ZX9r and I'm in the process of fiiting them both. All is good except the jet kit requires me to drill out the main air jet and I'm not sure where it is :? As i dont want to screw this up can anyone tell me where this main air jet is or explain it in a way that I can work it out myself? I'm pretty sure its in the bellmouth on the filter side of the carb and is linked to the main jet but some more info is required before I go drilling willy nilly :twisted:

Re: Main air jet

PostPosted: Wed Jul 23, 2008 2:29 pm
by mike-s
The thing they wanted me to drill out was on the carb slide, its the small hole on the slide just next to the main jet needle.

Re: Main air jet

PostPosted: Wed Jul 23, 2008 9:53 pm
by IsleofNinja
Check this out all ....

http://members.aol.com/roundr1/CVK40.html


well worth a read....

Mike - The hole you drilled in the slide affects the rate at which the slide rises ie enlarges the orifice that actuates the diaphram ..

Hope it helps.. 8)

Re: Main air jet

PostPosted: Thu Jul 24, 2008 11:29 am
by mike-s
Yup i knew that, but i was just pointing out where he needed to drill. :)

Re: Main air jet

PostPosted: Thu Jul 24, 2008 1:05 pm
by Trunks
Thanks I think I know where it is but still have some doubts. I dont think I need to drill the slide cause its a CV type carb which is different to slide carbs. I think suzukis us a different type of carb to the zx9's.

Re: Main air jet

PostPosted: Thu Jul 24, 2008 8:50 pm
by IsleofNinja
Trunks wrote:Thanks I think I know where it is but still have some doubts. I dont think I need to drill the slide cause its a CV type carb which is different to slide carbs. I think suzukis us a different type of carb to the zx9's.


GSF1200's , GSX1100's and many others use the CV's also . Normally really lean on the jetting compared to Kwaka's though stock with a piss poor excuse for an air intake!!

Did you check the link? I think you'll find your answer there. - prob a good idea to save to favourites..

Yeah Mike didn't think you were a dummy but as stated different carbs/kits require different mods... Stuff it up and she'll run like a pig , flat spots ,surge etc...

80/90's carbed bikes can be pretty bloody temperamental if you don't get it right as you probably know.
NOI 8)

Re: Main air jet

PostPosted: Thu Jul 24, 2008 10:14 pm
by mike-s
For what it's worth the instruction sheet that came with my kit seemed pretty generic, with any specific info for my kit (including approximate dyno charts with the various stages and appropriate mods installed) on a seperate peice of paper.

Those links about how to tune your bike are an absolute life saver though.
Yeah Mike didn't think you were a dummy but as stated different carbs/kits require different mods... Stuff it up and she'll run like a pig , flat spots ,surge etc...

80/90's carbed bikes can be pretty bloody temperamental if you don't get it right as you probably know.
NOI 8)
Yet another spot "measure twice, cut once" is very applicable. And yeah, the gpx was a pig with a stage two and wouldnt go above 8.5k full stop, drop to a stage one (which was reasonable as i had the required mods to use it) and it would cough and fart but not stop revving. Then stock jets in, voila, it worked.

Re: Main air jet

PostPosted: Fri Jul 25, 2008 9:52 am
by Trunks
Yep ur right :oops: , the kits are designed for each application and some need the slides drilled some the air jets and some are just needle and jet changes, I have contacted a local bloke who does racebike tuning and has a dyno with a good rep so I think I'm just going to get him to do it as much as I like doing this kinda thing myself for what hes gona charge me I'm gona get a much better improvement and I now thats its right ;)

Re: Main air jet

PostPosted: Fri Jul 25, 2008 11:21 pm
by IsleofNinja
Trunks wrote:Yep ur right :oops: , the kits are designed for each application and some need the slides drilled some the air jets and some are just needle and jet changes, I have contacted a local bloke who does racebike tuning and has a dyno with a good rep so I think I'm just going to get him to do it as much as I like doing this kinda thing myself for what hes gona charge me I'm gona get a much better improvement and I now thats its right ;)


Good stuff - If he's a decent bloke he'll set it up and do a carb balance for you --- Many people under estimate the power gains in this alone particularly off idle through mid range (where a 9 loves to be when on song!)

I do the carbed bikes about every 20,000km or so. 1 or 2 In/hg out per pot can seriously hurt the power delivery.
8)