Successfully tuning my Lifan LF200GY-5

JimShortz · 05-11-2017, 12:44 AM

I have been doing a lot of lurking on here, but not much posting. Time to fix that by sharing my experience of tuning my four year old Lifan LF200GY-5 X-plore (same engine as the Cross, but different air filter; mine is a nice foam pod within a case as standard). Hopefully my experiences will give some other people a better starting point than I had.

So... what I have done is fitted a nice wide-open slip-on that I picked up cheap secondhand (Leo Vince X3), followed by lots of carburettor (standard PZ30) and intake modding. With that exhaust in place, I did the following:

First I drilled out the standard slow jet (K40A) a little. I found that the drill #78 (0.406mm) slid through the jet, whereas #77 (0.457mm) didn't. I gently hand drilled it out to #77 size. I did this simply on the assumption that the bike would have been shipped lean to meet emission standards, and the plug certainly didn't indicate running rich.

I moved the needle clip down one to increase fuel flow in the throttle range beyond that covered by the slow jet (I tried the bottom clip position too, but this proved to be too much and I went back to second position from the bottom).

I reset the mixture screw from 3.75 turns out (how I found it) to 1.75 turns out. This is where my engine runs fastest (as tested with idle screw at higher revving pace than normal).

With these three changes the bike ran great from idle through to about two thirds throttle, but hesitant/bogging at higher revs still.

Next, to play with the main jet:

Mine was marked as 98, but from measuring with drill bits I had it became clear that it had been drilled out to somewhere between 1.05 and 1.1 - I'm assuming somewhere in the middle then, say 1.08. This was not working well, and I wondered if with the new exhaust it might need a larger jet still. I tried drilling it out to 1.1 - even worse; clearly going the wrong way...

With an ebay jet kit in-hand I next tried a 1.02 - amazing! Sounds and runs superbly. Time to "stick", but of course, who doesn't want to try a little larger... Tried 1.05 - boggy and nasty. Okay, just add more air... replaced standard foam filter with a 44mm neck pod filter.

Aah, no longer boggy, actually runs very well, BUT after a few good long rides out I felt that although now louder it was somehow all airy sound and not as much actual GO, as the 1.02 had been; it somehow lacked throttle response and felt "flabby" instead of "tight" (excuse my adjectives, I am struggling to explain!). I also didn't like the air intake sucking sound, and the thought that it wouldn't be filtering the dust as well as the standard foam filter - not good for engine longevity.

So, out with the 1.05 and this time in with the 1.03 that had just arrived as part of my super cheap (3 dollars?) PZ30 rebuild kit that I had bought from ebay just to have in-hand. Put the standard foam air filter back in (nicely cleaned and re-oiled). Oh baby - that's what I like!

I only made this last change yesterday, but I believe I am "sticking", unless it proves very slightly too rich and I go back to the 1.02. She pulls beautifully right through the rev range with this setup, from what I can tell so far; she sounds "tight" and has a beautiful little burble when the throttle is blipped!

Please feel free to offer advice and share your experiences - share the Chinese tuning love!

Weldangrind · 05-11-2017, 12:53 AM

Hey, Jim; thanks for the write-up. I had similar experiences with my Lifan, except that I switched to a Mikuni. I found it to be very responsive to tuning and new jets are easy to find.

I'd love to see pics of your bike.

JimShortz · 05-11-2017, 01:16 AM

To add a a little more info:

The jets I bought were these

The rebuild kit with the 1.03 jet in was this one

...and a photo of my beautiful Lifun (and it really is fun!) as requested:

ripcuda · 05-11-2017, 12:44 PM

I too went through many rounds of tuning my PZ30 carb on my XT200GY... and also bought a rebuild kit for a few new jets along the way.

I finally dialed in mine with these:

PZ30 carb: #110 main, #40 pilot, 1-2/3 turns out on the mixture screw, Needle clip one below middle.

I'm at 2,000 ft elevation.

Enjoy the ride! Cheers!

JimShortz · 05-11-2017, 05:02 PM

Interesting, ripcuda, that you got yours to run well with a 110, whereas I couldn't get beyond 105, even with a very open exhaust and filter, as well as being 1000' lower than you! I'm guessing that this is the impact of drilling my slow jet out from a 40 to more like a 45. People talk about this having some impact right across the rev range. I'm sure no expert - just trying to figure things out and learn...

Ariel Red Hunter · 05-11-2017, 07:39 PM

Quote:

Originally Posted by JimShortz

Interesting, ripcuda, that you got yours to run well with a 110, whereas I couldn't get beyond 105, even with a very open exhaust and filter, as well as being 1000' lower than you! I'm guessing that this is the impact of drilling my slow jet out from a 40 to more like a 45. People talk about this having some impact right across the rev range. I'm sure no expert - just trying to figure things out and learn...

Yes, the pilot jet affects fuel mixture right on up the range to wide open. When you get to 1/4 throttle, the needle starts adding fuel to what the pilot jet is already delivering. At 3/4 throttle, the needle has done all it can, and from here on up, it's 100% main and pilot jet. The needle controls fuel flow through the main jet from 1/4 throttle to 3/4 throttle...ARH

JimShortz · 05-11-2017, 08:25 PM

Thank you ARH, that's much appreciated - and makes it all add-up. :-)

If anyone is interested in what you need to drill out the pilot jet (since getting other pilot jets for this carb seems impossible), I did it with:

These drill bits

held in this pin vice

The drill bits are so miniscule that the pin vice is essential. I have done a few now with no problems - just turn the drill bit a tiny amount and pull back gently; rinse and repeat. It's soon done, even with minimal force.

Also, if you bought one of the cheap rebuild kits that I linked to above you already have a spare pilot jet in-hand, should things go awry.

humanbeing · 05-12-2017, 12:29 AM

Quote:

Originally Posted by JimShortz

...If anyone is interested in what you need to drill out the pilot jet (since getting other pilot jets for this carb seems impossible...

At least 2 type of PZ30... Bad guy (example: Sheng wey - Taiwan brand) = Hen's tooth Good guy: 100% Keihin compatible http://www.jetsrus.com/a_jets_by_car..._selection.htm had sample pic ...
===
Basically if can't find from https://shop35091180.taobao.com/ (Located in a place known as Capital of carburetor ) = NO affordable non-genuine parts in whole planet...

JimShortz · 05-12-2017, 01:17 AM

Quote:

Originally Posted by humanbeing

Sheng wey - Taiwan brand) = Hen's tooth Good guy: 100% Keihin compatible

Aah, good information, thank you. I guess I dropped lucky - mine is Sheng Way.

05-11-2017, 12:53 AM	#2
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Hey, Jim; thanks for the write-up. I had similar experiences with my Lifan, except that I switched to a Mikuni. I found it to be very responsive to tuning and new jets are easy to find. I'd love to see pics of your bike. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

05-11-2017, 01:16 AM	#3
JimShortz Join Date: Apr 2017 Posts: 7	To add a a little more info: The jets I bought were these The rebuild kit with the 1.03 jet in was this one ...and a photo of my beautiful Lifun (and it really is fun!) as requested: Last edited by JimShortz; 05-11-2017 at 04:59 PM.
	3

05-11-2017, 05:02 PM	#5
JimShortz Join Date: Apr 2017 Posts: 7	Interesting, ripcuda, that you got yours to run well with a 110, whereas I couldn't get beyond 105, even with a very open exhaust and filter, as well as being 1000' lower than you! I'm guessing that this is the impact of drilling my slow jet out from a 40 to more like a 45. People talk about this having some impact right across the rev range. I'm sure no expert - just trying to figure things out and learn... Last edited by JimShortz; 05-12-2017 at 01:30 AM.
	0

05-11-2017, 12:44 AM	#1
JimShortz Join Date: Apr 2017 Posts: 7	Tuning my Lifan LF200GY-5 with PZ30 carb I have been doing a lot of lurking on here, but not much posting. Time to fix that by sharing my experience of tuning my four year old Lifan LF200GY-5 X-plore (same engine as the Cross, but different air filter; mine is a nice foam pod within a case as standard). Hopefully my experiences will give some other people a better starting point than I had. So... what I have done is fitted a nice wide-open slip-on that I picked up cheap secondhand (Leo Vince X3), followed by lots of carburettor (standard PZ30) and intake modding. With that exhaust in place, I did the following: First I drilled out the standard slow jet (K40A) a little. I found that the drill #78 (0.406mm) slid through the jet, whereas #77 (0.457mm) didn't. I gently hand drilled it out to #77 size. I did this simply on the assumption that the bike would have been shipped lean to meet emission standards, and the plug certainly didn't indicate running rich. I moved the needle clip down one to increase fuel flow in the throttle range beyond that covered by the slow jet (I tried the bottom clip position too, but this proved to be too much and I went back to second position from the bottom). I reset the mixture screw from 3.75 turns out (how I found it) to 1.75 turns out. This is where my engine runs fastest (as tested with idle screw at higher revving pace than normal). With these three changes the bike ran great from idle through to about two thirds throttle, but hesitant/bogging at higher revs still. Next, to play with the main jet: Mine was marked as 98, but from measuring with drill bits I had it became clear that it had been drilled out to somewhere between 1.05 and 1.1 - I'm assuming somewhere in the middle then, say 1.08. This was not working well, and I wondered if with the new exhaust it might need a larger jet still. I tried drilling it out to 1.1 - even worse; clearly going the wrong way... With an ebay jet kit in-hand I next tried a 1.02 - amazing! Sounds and runs superbly. Time to "stick", but of course, who doesn't want to try a little larger... Tried 1.05 - boggy and nasty. Okay, just add more air... replaced standard foam filter with a 44mm neck pod filter. Aah, no longer boggy, actually runs very well, BUT after a few good long rides out I felt that although now louder it was somehow all airy sound and not as much actual GO, as the 1.02 had been; it somehow lacked throttle response and felt "flabby" instead of "tight" (excuse my adjectives, I am struggling to explain!). I also didn't like the air intake sucking sound, and the thought that it wouldn't be filtering the dust as well as the standard foam filter - not good for engine longevity. So, out with the 1.05 and this time in with the 1.03 that had just arrived as part of my super cheap (3 dollars?) PZ30 rebuild kit that I had bought from ebay just to have in-hand. Put the standard foam air filter back in (nicely cleaned and re-oiled). Oh baby - that's what I like! I only made this last change yesterday, but I believe I am "sticking", unless it proves very slightly too rich and I go back to the 1.02. She pulls beautifully right through the rev range with this setup, from what I can tell so far; she sounds "tight" and has a beautiful little burble when the throttle is blipped! Please feel free to offer advice and share your experiences - share the Chinese tuning love! Last edited by JimShortz; 05-14-2017 at 07:01 AM.
	3

05-11-2017, 12:44 PM	#4
ripcuda Join Date: Mar 2015 Location: Spokane, WA Posts: 253	I too went through many rounds of tuning my PZ30 carb on my XT200GY... and also bought a rebuild kit for a few new jets along the way. I finally dialed in mine with these: PZ30 carb: #110 main, #40 pilot, 1-2/3 turns out on the mixture screw, Needle clip one below middle. I'm at 2,000 ft elevation. Enjoy the ride! Cheers! __________________ '20 TaoTao Hellcat 125 "grommet" '04 Yamaha TTR-125LE '00 Yamaha TTR-90 '07 Kinroad XT200GY Runmaster (sold) '07 KMD GY6 150cc ATV (sold) '07 Kangchao 250cc ATV Monster (sold) Baja Moto DB-30 "Doodlebugs"(x3) (sold) '06 Hi-Bird 200 parts bike (sold)
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05-11-2017, 08:25 PM	#7
JimShortz Join Date: Apr 2017 Posts: 7	Thank you ARH, that's much appreciated - and makes it all add-up. :-) If anyone is interested in what you need to drill out the pilot jet (since getting other pilot jets for this carb seems impossible), I did it with: These drill bits held in this pin vice The drill bits are so miniscule that the pin vice is essential. I have done a few now with no problems - just turn the drill bit a tiny amount and pull back gently; rinse and repeat. It's soon done, even with minimal force. Also, if you bought one of the cheap rebuild kits that I linked to above you already have a spare pilot jet in-hand, should things go awry. __________________ If you have to grind your welds to make them look good, you are a grinder, not a welder... I'm a grinder!
	0