Carb. jetting for LF200 GY-5

RD · 09-02-2006, 10:18 PM

I live and ride at 8500-10000 feet. Anyone know where I can find smaller jets for the LiFan?

RD · 09-10-2006, 06:38 PM

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/...g2_itemId=1805

czowner · 12-11-2006, 03:21 AM

Are thest the fellows?
http://www.racespec.co.uk/rs_shop_fi.../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.

09-02-2006, 10:18 PM	#1
RD Join Date: Sep 2006 Posts: 18	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?
	0

09-10-2006, 06:38 PM	#2
RD Join Date: Sep 2006 Posts: 18	LF200 GY-5 carb jetting for altitude 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.
	0

09-10-2006, 11:04 PM	#3
fashby Join Date: Sep 2006 Location: Orlando Posts: 22	Awesome catalog, Thanks! __________________ Viva GY200 California Emissions Jialing/Chonging - Jesus Rules!
	0

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!
	0

12-11-2006, 03:21 AM	#5
czowner Join Date: Sep 2006 Location: North East England Posts: 313	Idle jets Are thest the fellows? http://www.racespec.co.uk/rs_shop_fi.../dept_416.html Jonathan
	0

12-11-2006, 03:35 AM	#6
czowner Join Date: Sep 2006 Location: North East England Posts: 313	More idle jets. 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
	0

12-31-2006, 03:15 PM	#7
fashby Join Date: Sep 2006 Location: Orlando Posts: 22	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. __________________ Viva GY200 California Emissions Jialing/Chonging - Jesus Rules!
	0