You can also consider putting an inner rotor kit on the motor, which helps performance by lightening the flywheel, which makes the motor rev a HELL of a lot quicker than standard, and can be found pretty cheap on ebay. HOWEVER, IRK's are not the easiest thing for a beginner to ride, need plenty of clutch and revs to keep the thing on song, so it depends on your skill level, but if your chasing performance, then one would assume you can ride a little bit... some dont like the inner rotor kits, but i like em. mind you, been riding for 25+ years, so bit of experience under the belt...
i run a lifan 140 oil cooled on my custom mini... just over 10hp at the rear wheel. Doesnt sound like much, but it's a savage little motor in a bike weighing less than 60kg... power to weight is good....
Basically the motor mods list looks like this:
IRK ( inner rotor kit)
33mm header pipe with big bore carbon muffler
7mm lift cam (coincidentally, i bought the springs, but didnt need to install them. have sufficient valve/piston clearance)
28mm OKO Flatslide carby (dont recommend the 28mm for beginner riders or beginner tuners... try a 24 or 26mm OKO or mikuni)
Now this is important... if you change the carby, you will need to tune the jetting.. a lot of kids go chasing extra power, buy the gear, bolt it on, and the bike runs like a dog, and they go blaming the ebay seller or store they bought the stuff from, saying their bike used to work, now after putting their items on, it doesnt..
The IRK is pretty easy, but you'll need a flywheel puller to get the stator off..
the pipe will be a straight up bolt on part, but will effect jetting.
The Carby will definately effect jetting. when you buy one, try and request a #95 main jet from the seller, and use that as a starting point. for some reason, china carbies seem to come with #125+ main jets, way too big...
anyway, here's the links... go nuts..
IRK:
INNER ROTOR KIT FLYWHEEL CDI CRF50 XR50 XR CRF 50 LIFAN - eBay, Other Accessories, Motorcycle Parts, Accessories, Cars, Bikes, Boats. (end time 24-Jul-09 22:55:00 AEST)
I got one of them from these guys. got here in under a week, works great. same quality as the ones you get here in AU, just cheaper...
however if you wanna support local businesses...
IRK:
INNER ROTOR KIT FREE OIL SLING 140cc 125cc CRF 50 - eBay, Other Cars, Bikes, Boats, Cars, Bikes, Boats. (end time 03-Aug-09 10:44:28 AEST)
EXHAUST:
BIG BORE ALLOY PERFORMANCE EXHAUST 125CC 140CC CRF50 - eBay Other Makes, Bike Parts, Motorcycle Parts, Accessories, Cars, Bikes, Boats. (end time 28-Jul-09 13:51:49 AEST)
Carby: (OKO Flatslide - more expensive, slightly tricky to jet, but easier to work on and tune than a mikuni, better performance when jetted right)
NEW OKO 26mm FLATSLIDE RACE CARBY KIT 140CC 150CC 160CC - eBay Other Makes, Bike Parts, Motorcycle Parts, Accessories, Cars, Bikes, Boats. (end time 26-Jul-09 15:39:47 AEST)
Carby: (Mikuni Roundslide - cheaper, easier to jet, harder to tune in bike, reasonable performance)
NEW MIKUNI 26mm RACING CARBURETOR KIT 140CC 125CC LIFAN - eBay Other Makes, Bike Parts, Motorcycle Parts, Accessories, Cars, Bikes, Boats. (end time 26-Jul-09 15:36:59 AEST)
Cam:
NEW GPX 7MM RACE CAM, DUCAR LIFAN THUMPSTAR DHZ PITPRO - eBay Other Makes, Bike Parts, Motorcycle Parts, Accessories, Cars, Bikes, Boats. (end time 24-Jul-09 11:43:39 AEST)
good luck with the auctions, but i dont recommend installing the cam yourself if you dont have a lot of spanner experience... only gotta get the timing wrong, and you're looking at a new head/piston etc...
All the above mods should see you get around 9-10 hp, with a redline at about 9500RPM... pretty similar to what mine runs with the same mods... and it's very quick for a baby motor...
Go nuts!
