163 FML cylinder head
 

Anyone know where I could purchase a new
or used (no cracks!) Lifan 163 FML head? Looking
to do a full port job, and still want to keep my
low mile stocker as a backup.

You can buy a whole engine for under $400 last I checked.

I don't think you will find a seperate head though. Just cause of the small useful life of a china bike.

Many thanks for the reply. What sort of "high wear parts"
should I expect from the 200? I'm also running a custom
stepped header (1" to 1.250" to 1.50" collector) and
noticed your jetting. I appreciate
the openness to share performance insites. Was wanting to
flow around 80-85 percent exhaust to intake ratio, and feel there is
a lot of potential in the little engine. Thanks again for the reply.
By the way, what combinations of piston and connecting rod options
are available for it? Flycutting, decking the piston, re-ground cam, etc. isn't a problem.

Everything on these bikes like to go pretty fast, but I have heard of more electrical problems than any other thing. Mainly the battery and charging systems.

As far as performance there is not much you can do. I guess high modification isn't a problem, but I don't know if the little motor could take it. Custom from a machine shop is going to be your best bet.

You could mabye find a piston, cam, or rods at a dealer ship, but they usualy don't do "parts in a bin" any more so you'd have to know a motor thats simmilar.

You might want to post in the wanted section and also give Bruce a call at EJcycles. 330-274-0098 He may have one.

Allen

Many thanks for the replies. Glad I found the forum,
it's proved to be very informative. Might do some
research into Honda engines to find a close match
to piston diameter, stroke, rod length, cam timing, etc. Good forum
ya'll have. Clean and lots of info.

For the honda look at the xl185 and the atc engines. Also the crf230 I think. One of them might be close.

Allen

New Cylinder Heads
 

This may be what you're after. Says from a GY6, but being sold as a "150".

http://www.chineseatvpart.com/cylind...50cc-atv/p221/

Any Honda CG head will probably do as well.

Re: New Cylinder Heads
 

I think that one's overhead cam. I think he's looking for a pushrod head.

This is what an OHC should look like:

http://i21.ebayimg.com/03/i/001/24/1c/fe28_1.JPG

Thanks for clarifying. My suggestions would be OHC and probably not work.

Need to look at the GY2 type engines. Again Bruce may have one from a damaged engine etc.

Allen

Mine's definately the OHC. Wish there was enough meat in there
to press in a cast iron cylinder wall. If I come up with anything, I'll
post up. Many thanks for the replies. Again, you folks have a very
good forum. Glad I found you folks.

If you need any help with the cam, and can take a few measurements, let me know, I'm in the custom cam business.
I likely don't have any good profiles for your application, but I can probably point you in the right direction

What are your re-grind parameters as far as
tightening up the lobe center, lift change in
thousandth's and duration gain? I'm Sure there are no
cam cores for this thing! I'm guessing duration is around
210-220 . Emailed the company with the cylinder head
(150 and suposedly 200 sport bike) and have yet
to hear back.

Good call on the duration numbers.
It sounds like you know cams.
My guess would have been exactly the same.
As far as lobe center, I would leave it.
If you're after a lift/duration increase, you're going to eat up all the spare lobe you have doing that. I don't know what you want to do, but I think a D around 235-245 at .050" might be a good start. Lift on those cams is probably somewhere in the .200"-.240" range.
Depending on base circle diameter, I like to stay in and around +.035"-.040" in lobe lift, and and +20-30 in duration at .050". That usually keeps the geometry OK, and has little effect on rocker ratio. Those lobes will likely also have a real steep ramp on one side. Try to stay with a profile similar in appearance. It will help performance, but also reduce base circle reduction.

This picture is a head for a GY-6 150cc Scooter engine. The engine sits almost Horizontal, and yes it is an OHC engine. The camshaft for the GY-6 engine sits in the head with a carrier over the top of it. This engine is used in almost all 150cc CVT atvs too.

Oops, a GY-6 scooter??

That's weird. Well scratch that one! :oops:

Bruce is back.

Allen

Re: 163 FML cylinder head
 

I have a complete new untouched 163fml head I'd sell. It was a very tough item to acquire. I took the head to George Shear of Total Concept Racing Engines to evaluate. George has 49 National Championships with his engines in the last 27 years and while he is not completely familiar with the Lifan based engines this was his evaluation.

If you slotted he bolts on the intake to line up better with the head you could "lightly" remove enough material to port match the head to the intake.

You could polish the intake runner. But if you try a full port job and grind on the runner walls you will most certainly bust through. The intake walls are paper thin and probably 2mm or less thickness.

He thought he could get a little better performance out of it but without modifications to the rotating assembly it would not be enough to make it worthwhile.

My plan was to go ahead and polish the intake and slot the intake... but I've got so many projects right now with these bikes I havent had the time. I'd probably sell it if someone wanted it.... if not I'll eventually get around to working on it.

Seems like by raising the valve guide up to
the roof and doing a good bowl clean up, the head would
flow much better. Did a few little 110 Lifan heads, and they
are deplorable in there. No wonder they make 8 horspower!
Working on getting my 200 Lifan powered bobber street legal
right now. Gonna do the cylinder head work after I deal
with Florida DMV on a scratch build. Oughta post a few pics, I reckon...