Needing carburetor and gearing advice Lifan gs200

[anothernewb]

Hi and thanks for having me. I recently bought a 2009 Lifan GS200 sport bike and after a few days riding I have a pretty good idea what it needs to make it run and ride a little better. I have been experiencing what I belive to be lean pop in the upper RPM range at greater than 3/4 throttle. I figure it needs to be up-jetted but for the life of me I can find a definitive answer for what jets it takes. I can tell you it a kan tai carburetor. Through the power of google I can tell you its either a keihen, walbro pz or mikuni... I think. I would really like to know what brand to order jets for since a search for Kan Tai is giving me nothing.

My second concern is I would like to replace the rear 42 tooth, 428 sprocket with a smaller sized socket so I can drop the RPMs down some so I'm not wound clear out doing 65mph down the highway. Any idea what other bikes use the same rear sprocket? Thanks in advanced for any and all help.

[humanbeing]

This brand ? http://searchtmr.com/details?trqi=8bd090948a2c6cc2 They're located in HERE (http://en.wikipedia.org/wiki/Fuding) (that area aka the capital of carburetor ). In most case it's Keihin clone.
Why not measure & match it at jetsrus.com

[anothernewb]

Updating this for the benefit of the next guy trying to figure out what jet and carb this bike uses.

The carburetor is a clone of a kiehin pz30. It uses keihin n424-36 main jets found here: http://jetsrus.com/a_jets_by_carburetor_type/jets_keihin_N424-36_main.html
factory main jet in my bike was a 102. Pilot jet was not marked.

Sprockets are readily available from pmp sprockets in a variety of sizes. Chain pitch is 428

http://pmpsprockets.com/lifan1?b=1
they dont list a 2009 but I called them and they confirmed it is the same as a 2008
Hope this helps someone in the future since I had hell trying to search for it on my own.

[katoranger]

That is great information. I know that others have had difficulty finding jets for the keihin clone carbs. Weld usually recommends a mikuni clone carb swap.

[Weldangrind]

I've found otherwise identical Keihin clones with dissimilar main and slow jets; I've given up on them. I've found Mikunis to be consistent, and you can't argue with the price.

That said, I'm glad that you've found jets to match your carb.

[oviking99]

Weld is right on, with the Mikuni. Here's a link for 34.00, shipped.
http://www.ebay.com/itm/360017096013
In my experience I would also replace the intake manifold, if it is 'rubberized', as they dry out and crack due to the heat dissipation. 10 bucks shipped as well. Make sure it matches yours.
http://www.ebay.com/itm/111160432306?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Lastly, I would check the exhaust to make sure it's tight.

[Weldangrind]

I agree with oviking99 on making sure the exhaust is tight as well. I've encountered a few that were missing the exhaust gasket, which is cheap on eBay. The XR200 size is perfect for Honda clones.

[N3xT s3Qill]

I've got a 2011 lifan sports gs 200cc and it came with 520 sized running gear I swapped the 40t standard rear to a 32t sprocket it sits on 60 mph hour at a nice rev maybe swap those over although taking off needs a bit of oomph to get going I upgraded exhaust and it has k/n filter 115 main jet and runs very well considering I brought it for $700 with 1000 miles on it.

[Weldangrind]

I've got a 2011 lifan sports gs 200cc and it came with 520 sized running gear I swapped the 40t standard rear to a 32t sprocket it sits on 60 mph hour at a nice rev maybe swap those over although taking off needs a bit of oomph to get going I upgraded exhaust and it has k/n filter 115 main jet and runs very well considering I brought it for $700 with 1000 miles on it.

I'm surprised that the engine can pull a 32 rear; what size is the countershaft sprocket? There is some power to be gained by swapping to 428 from the 520.

[N3xT s3Qill]

The front sprocket is a 14t Some guy off another forum I read has a 30t sprocket on his which I thought was real small which is why I stepped it up by 2t sizes quite happy with its performance,still have the 40t as spare and I ain't changing gears every 2 seconds.

[N3xT s3Qill]

My friend works at a dynotune workshop where they work on 500hp plus drag and drift cars I brought some 110 main jets before putting those in we drilled out the 98 standard main jets on my previous bike Kawasaki zzr 250cc which had twin keihin 30mm carbs and it ran absoulutely great on the dynotune and they've got the best wide band air fuel meter money can buy,although it ran slightly richer with the drilled out ones making them around more like a 115 main just thought il state that because I've read people say not to do it because they don't get good spray disperse bla bla bla when drilling main jets which is defintley false and its pretty hard to screw up drilling them too although going up in gradual drill bit sizes helps like a 1mm 1.1 then 1.2 instead of 1mm to 1.2.

[Weldangrind]

I agree. I've drilled out several main jets with no adverse affects. As a bonus, numbered drill bit sets in NA are based on thousandths of an inch, and rarely do they convert to exact MM sizes. IOW, if 112 is too lean and 115 is too fat, you might be able to end up in the middle by drilling.