Lifan 125 rebuild project

[Dr.UnkyTux]

Hi all wanting some help with a rebuild, my cousin recently gave me an atomik( I think) with a lifan 125. We managed to get it running pretty nicely but it would not take second gear.

In short i have comeplety torn down motor but found no visible damage to any dogs or gears in the crank case or gear set I did however notice the star selector was was extremly flat where second gear slotted in and the roller was not rotating properly. This is only my guess as the bike skipped to third no probs which i think rules out the gear selector\linkage being bent as I also cant see any damage to it .

My second question is WTF is the go with a 138cc head\bore that makes no sense, as its is not even close to the 127cc i worked out with bore x stroke.

This build is to be done on a budget, so far i have aquired new forks, new front brakes, full gasket set, and cylinder

I have cleanned all my parts ready for a bottom end reassebly as sson as new gaskets arrive, happy to post some more pics of the reaseembly, amyone got any warning or advice for me that would be sweet.

The Frame

Bottom End, crank case etc all nice and clean ready for rebuild

Gear shaft one

Drum selctor I believe second is the notch in top right correct me if i am wrong here

Gear shaft two


As yoiu can proboalby tell or not from the photos all is in pretty good nick in terms of dogs and gears just theat selecotor star that look wrong, note i have already hit it with the dremel to dish it out some more.
Cheers

 

[rotn50]

the 2nd last pic shows the drum selector, the forks(selectors)look good were they sit on the gears but is there any wear on the other side of the forks that we cant see.

 

[rotn50]

2nd gear is the notch on the top right mate, can you send a pic of the drum selector from the other side and a pic of the gear selector that pushes and pulls the gear on the drum, and welcome to miniriders mate

 

[Dr.UnkyTux]

I will grab a shot of the drum selector in more detail in a sec and cheers bud. I did notice some wear on the other side of the forks and also on the inner part as well

 

[Dr.UnkyTux]

Okay Some shots of the gear selector, I think I am seeing what your are talkin bout rotn50 with otherside, there is visble wear about 1mm into fork and the small square notch at the base of the fork. It appears there is also visible wear on the on the gear side wear the fork pushes and pulls on the gear arm.
So is the drum selector shot or the the entire gearbox gone. Cheers In advance for the help.

Drum Selector






And the gear arm





Not sure if u can see it that well in the pics or not, I dont have the greatest camera. Cheers

 

[rotn50]

That is your gear selecting problem right there 100% mate, we see this at work quite a bit in lifan 140s and 150s mainly and 1 or 2 125cc. the engine seems as if there is a smashed gear inside but in actual fact the gears have slightly meshed but not enough to stop them jumping the teeth. we just did a lifan 140 the other day was grinding in 2nd gear and was not engaging the gear fully at all, we think there may be a tolerance prob with the shimming of the gears or the drum selector has some sort of imperfection in the casting, the 140 reacted well to having another drum selector installed and we have not seen it back, considering we installed the engine and that happened after 2 hours total use on the new engine.

 

[rotn50]

let me know if you cant get one and i will see if i can get a decent undamaged 2nd hand one from work for ya,if we have any.

 

[Dr.UnkyTux]

That would be sweet bud, cant seem to find any that are readily availbe just flipping through fleabay anyway cheers for your help mate.

 

[Dr.UnkyTux]

hmm just found one ebay, $75 for gear selcetor, 15 for gaskets and 20 for a new cyclinder, i Think i am better off buying a new motor for $275 and keeping this lot for spares.

 

[rotn50]

hmm just found one ebay, $75 for gear selcetor, 15 for gaskets and 20 for a new cyclinder, i Think i am better off buying a new motor for $275 and keeping this lot for spares.

Sounds like a wise decision mate, most would percivere but honestly if the tolerance is out in the box somewhere then you may have the same prob, and may be putting wasted money into it also being 2nd hand you dont know its history. i know what i would do if i had the coin.

 

[rotn50]

Hey to the gutless grub that left me negative rep for trying to help someone out atleast put a reason and your name, not 1 other person has helped out with advice on the thread except me and thats how ya get treated, im nearly over it, were is the advice you have if mine is so wrong, dont need neg rep for just helping out.

 

[FDChappy]

Well you know what they say "No good deed goes unpunished". So it looks like you done good!:crucified: