View Full Version : Carb. jetting for LF200 GY-5
I live and ride at 8500-10000 feet. Anyone know where I can find smaller jets for the LiFan?
OK: I found what I was looking for...carb main jets.
For my altitude (9000 ft.) and the nominal air temperature we typically ride in, I've ordered some smaller main jets for my daughter's bike. The stock jet in my LF200 GY-5 was a 98. I'll calculate that I'll need either an 88 or 92. Ordered both and a couple more sizes from ww.sudco.com (minimum order is 4 jets).
The carb main jet is from a Keihin Carb. Use 99101-393-xxx for Honda VB, VD and VE series carbs: 6mm round head diameter and 8mm overall length.
Good luck and hope this helps.
PS I also dropped (leaned) my needle one notch. I'm assuming that helps although I did not notice any part throttle (< WOT) problems. I thought I would also order a smaller pilot jet but could not find the type of jet. Since I've not had part throttle issues, I'll probably jet focus on the main jet for now.
fashby
09-10-2006, 11:04 PM
Awesome catalog, Thanks!
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/main.php?g2_itemId=1805
czowner
12-11-2006, 03:21 AM
Are thest the fellows?
http://www.racespec.co.uk/rs_shop_final/en-gb/dept_416.html
Jonathan
czowner
12-11-2006, 03:35 AM
Forgot to mention, I once drilled a Jikov (CZ) idle jet with a .5mm drill, alternative idle jets are non existant for road going Jawa/CZs they all have a 45 be it a 125 or 350.
Jonathan
fashby
12-31-2006, 03:15 PM
No this is not the one. Mine has the thread at the very tip of the jet. I raised the needle one notch and it runs good now.
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