Lifan monkeybike copy tuning

[Fiddy@norway]

alright so I got myself a 50cc Lifan monkeybike clone, I know this is a cheap POS but it's plated and streetlegal here in norway, and the thing is epic to ride, so I wanna pimp it out some.

1: anyone know a decent set of shocks to run on these? the stock are worthless as they are all spring and no dampening, I don't need world-class suspension, just some basic one will be an upgrade from the stock pogos, I'm thinking of getting a set that's 320\330mm instead of the 280mm stock.

2: I've been running some cheap 10w40 mineral oil on it, is this OK for road use? (constant high RPM) or should I swap to a semi\ full synth?

3: what's a good sized exhaust for a bike of this cc? I will be adding a 72cc bigbore kit with a BVH + carb and want a decent exhaust, I already got this "performance" exhaust on it, but it's loud and the headers have a bigger ID than the headers on my XR650!!

4:would a high-volume oilpump be necessary with a big-bore for road use?

 

[The_GDFP]

alright so I got myself a 50cc Lifan monkeybike clone, I know this is a cheap POS but it's plated and streetlegal here in norway, and the thing is epic to ride, so I wanna pimp it out some.

Congrats on the new ride. Nothing wrong with a clone, especially with what Euro prices on restored Honda's have risen to.

1: anyone know a decent set of shocks to run on these? the stock are worthless as they are all spring and no dampening, I don't need world-class suspension, just some basic one will be an upgrade from the stock pogos, I'm thinking of getting a set that's 320\330mm instead of the 280mm stock.

TB/Takegawa/Kitaco all have decent shocks, for the money.


2: I've been running some cheap 10w40 mineral oil on it, is this OK for road use? (constant high RPM) or should I swap to a semi\ full synth?

I'd switch to a mineral oil designed for cycles rather than auto's. Honda GN4, Bel-Ray, Maxima, etc

3: what's a good sized exhaust for a bike of this cc? I will be adding a 72cc bigbore kit with a BVH + carb and want a decent exhaust, I already got this "performance" exhaust on it, but it's loud and the headers have a bigger ID than the headers on my XR650!!

I'm guessing the "big bore" needs to be marked "49cc" and you're talking about a 23/20-valve e22 head? There are bigger versions, fwiw. 85cc bolt-on stays ahead of traffic nicely If not, an alloy jug TB 88 or 95cc kit is an option. Similar cost, better cooling, more bigger many cc's.
Stock Head, 88cc Bore Kit - 88-09 Models
Full package with head and carb:
Race Head, 88cc Bore & 20mm Carb Kit - All Models
Mix & match always welcomed.

Z50 Exhaust Supertrap (72-99)
Tune-able noise level, moderate tubing size, nice fit & finish.

4:would a high-volume oil pump be necessary with a big-bore for road use?

Shhhh, but your cheap Chinese bike came with a high-volume oil pump
Maybe look in to a better cam chain, though.

 

[Fiddy@norway]

alright, just wanted to make this post to thank terry, finally got around to installing the 88cc racehead kit on my lifan 50, installation went problem free, only thing was my original cam cover didn't fit the racehead, had to break the tabs inside it so it wouldn't hit the cam.

bike started right up and WOW, what a difference, pulls pretty smooth from the bottom and revs to the moon compared to stock, I have some issues with jetting, but I'll sort it out once I get my slow speed jet kit (found one dirt cheap on fleabay).

I'll probably end up ordering the stroker crank in the future, how big of an issue is piston\head clearance with the stroker crank?

 

[The_GDFP]

Glad to hear the install went well!
The stroker crank is a no worries swap. The rod is shorter, so piston height is the same as stock and there's no clearance issue. The stroker will still rev out nicely, but you get an extra-big serving of low and mid rev torque, so a tooth or two can be added up front.

Thanks again!

Terry

 

[Fiddy@norway]

I'm vent from a 13 front sprocket to a 17 and it still revs out with ease, don't wanna mess with the rear sprocket since police has been known to check the gearing on 50cc's here in norway (all streetlegal 50cc have the stock gearing stamped on a plate mounted to the frame).

are the crank bearings on these engines a drop in or press fit in the cases?

 

[The_GDFP]

Yikes. I'd leave it alone, then. I had some 19t fronts made, but a 108 will have trouble pulling it, any way, I think. Bearings are pressed on the crank and slip-fit to the cases. New crank comes with bearings installed. Decent ones, even. You probably have the taller primary gears, but if not, a switch from 50 to 70 type will add 10%.

 

[sean01]

alright, just wanted to make this post to thank terry, finally got around to installing the 88cc racehead kit on my lifan 50, installation went problem free, only thing was my original cam cover didn't fit the racehead, had to break the tabs inside it so it wouldn't hit the cam.

bike started right up and WOW, what a difference, pulls pretty smooth from the bottom and revs to the moon compared to stock, I have some issues with jetting, but I'll sort it out once I get my slow speed jet kit (found one dirt cheap on fleabay).

I'll probably end up ordering the stroker crank in the future, how big of an issue is piston\head clearance with the stroker crank?

id be a bit worried about running it like that.. get the correct cam cover or you will wear out the cam chain as the cam will try and walk out of the head, not the mention the stress it will have on the rocker gear