ChinaRiders Forums - View Single Post - Carb. jetting for LF200 GY-5

fashby · 12-09-2006, 01:30 AM

I removed the baffle from my muffler and installed a performance air filter on my GY200 which created a need for more fuel to the engine.

My first try was raise the needle valve 2 notches on my 30mm Keihin carb and adjust the fuel/air valve on the front. This greatly improved performance, but it seemed to be too rich on the low end and too lean at wot. I read that this is not the best way to approach the problem because it doesn't provide the best fuel mixing at low RPM's. It is just a quick way to increase the fuel mixture.

I recently replaced the stock 98 main jet with a 99101-393-105 and put the needle valve back to the stock middle position. Now the bike has better top end, but it seems to be too lean on the low end. I would like to replace the slow jet with a larger size, but I can't find anything that looks like it on the Keihin or any other web site so my only option will be raise the needle back up one notch.

Does anyone know where I can get a bigger slow jet for this carb? The stock is a size 40. Here is a picture. The slow jet is on the right and has a thread at the tip:

http://www.chinariders.net/gallery2/...g2_itemId=1805

12-09-2006, 01:30 AM	#4
fashby Join Date: Sep 2006 Location: Orlando Posts: 22	Carb Jetting GY200 I removed the baffle from my muffler and installed a performance air filter on my GY200 which created a need for more fuel to the engine. My first try was raise the needle valve 2 notches on my 30mm Keihin carb and adjust the fuel/air valve on the front. This greatly improved performance, but it seemed to be too rich on the low end and too lean at wot. I read that this is not the best way to approach the problem because it doesn't provide the best fuel mixing at low RPM's. It is just a quick way to increase the fuel mixture. I recently replaced the stock 98 main jet with a 99101-393-105 and put the needle valve back to the stock middle position. Now the bike has better top end, but it seems to be too lean on the low end. I would like to replace the slow jet with a larger size, but I can't find anything that looks like it on the Keihin or any other web site so my only option will be raise the needle back up one notch. Does anyone know where I can get a bigger slow jet for this carb? The stock is a size 40. Here is a picture. The slow jet is on the right and has a thread at the tip: http://www.chinariders.net/gallery2/...g2_itemId=1805 __________________ Viva GY200 California Emissions Jialing/Chonging - Jesus Rules!
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