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jetting question

Posted: Tue Sep 15, 2009 8:54 pm
by brido
Hi all I have just bought a full tyga system for my nc30 and what I was wanting to know if someone could tell me is, do I need to rejet the bike after the system is fitted? Just to add that this is for road riding and not racing.
cheers ....

Re: jetting question

Posted: Tue Sep 15, 2009 9:03 pm
by viper_biker
Simple answer - Yes. Get it set-up correctly so you are burning the fuel efficiently.

Re: jetting question

Posted: Tue Sep 15, 2009 9:04 pm
by alexwitham
I went from a totally standard bike to a Tyga system + airbox and found 125's main's all round worked well. But keep and eye on 'stock dyno results' to see graphs on how well she's fueling on those sizes. You may want to try slightly leaner sizes if your using the standard box + filter.

http://www.400greybike.info/newforum/vi ... 24&t=11503" onclick="window.open(this.href);return false;

Re: jetting question

Posted: Tue Sep 15, 2009 9:18 pm
by brido
Thanks lads but what would happen if I didn't get it rejetted and running standard jets?

Re: jetting question

Posted: Tue Sep 15, 2009 9:29 pm
by viper_biker
Worst case scenario, you will starve the bike of fuel, it will run very lean and over time you can overheat the bike and kill the motor.I'd start with 102f/122r as a base setting, 2.5 turns out on the A/F screw and a 0.5mm shim under the needles. Once you have the carbs off, you might as well give them a good clean and balance too.

Re: jetting question

Posted: Tue Sep 15, 2009 9:36 pm
by brido
viper biker can you define kill the motor??

Re: jetting question

Posted: Tue Sep 15, 2009 9:39 pm
by viper_biker
'Kill the motor' - Dead, Kapoot, cease to exist, not longer running etc etc :up:

Re: jetting question

Posted: Tue Sep 15, 2009 9:46 pm
by CMSMJ1
you can run lean and the bike will run very hot in the cylinders..leading to piston issues, valve issues and in the end a very dead motor.

you need to budget for at least 1 dyno run if you are willing to splash 500 quid on a system.

Kill the motor is just that - kill it dead.

also - viper meant 120F and 122R jetting - get some jets in at a couple of quid and sort it out...simple to do and you need to do it :ugeek:

Re: jetting question

Posted: Tue Sep 15, 2009 10:03 pm
by brido
Thats what I thought you meant but just wanted to make sure. Thanks for the help fellas..

Re: jetting question

Posted: Wed Sep 16, 2009 2:52 am
by J.B.
If you have the time and somewhere to run the bike at Wide Open Throttle in high gear (not on a public road please) you can do the jetting yourself. I'm sure it's been posted before but here's a link to the excellent CV carb tuning procedure on the Factory Pro website:

http://www.factorypro.com/tech/carbtun.html" onclick="window.open(this.href);return false;

If you plan on keeping the stock airbox & filter you will probably just be going up 1 or 2 sizes in the main jets and possibly shimming the needles. Keihin main jets are easily available and Rick Oliver sells .5 mm and 1 mm shims. When you remove the carbs to re-jet it's a good opportunity to check the valve clearances too if you haven't already done so.