140cc on 138cc ??

[Divy]

i was just wondering if a lifan 140cc bore an piston would bolt straight on a 138cc oilcooled lifan??

if it can is there gonna be any decent gains??

 

[Bones]

not worth it mate, the difference between a 2cc displacment will not be noticable at any stage unless your 138 is actually a older 127cc in which case the gain will be slightly noticable.

with regards to fitting, provided your replacing the cylinder / barrel and piston etc... make sure your piston pin is the right size, and if your stud pattern is the same you shouldnt have a problem.

my advise, dont do it, not worth the cash, better spent on a hc piston / IRK / cam etc etc...

Cheers, Tony.

 

[cass38a]

Will it bolt up to a 125cc start in any gear Lifan?

 

[Divy]

how would i know if it an older 127cc?? i got the bike not long ago an the bore has 138cc printed on it

 

[Franky]

Its 127cc......

 

[Divy]

how can you tell??

 

[IAMPETEY]

how would i know if it an older 127cc?? i got the bike not long ago an the bore has 138cc printed on it

any bike older then 4 months roughly have that 127cc problem

 

[Divy]

well i have a 140cc lifan bore an piston 54mm what size will the 127cc piston be???
cause i think ill pull the head off an see for my self if its the smaller 127cc an if it is ill bolt the 140cc on
so would that be worth doing??? will i have to do anything to the carby ie rejet

 

[Mack]

I doubt any of the 138's are even close to 138. The only way they can be even close, is if they are bored to 56mm which is the absolute max for a standard cylinder. This will still only make a 136. The factory certainly won't bore that big, they were nervous about going to 55mm for the 140cc. So the only way is if some other Chinese bodge bored the 54mm bore 138's to 56mm. I've never seen one and only ever heard one claim by roost that he had one once.

Now, even if you did have a true 138, it would still be worth getting the new 140 because of its stroke. Big bottom end, big torque big difference in the engines. I believe this motor will make all others obsolete, a bit like the 110's are now.

Back to the question, no you can't use the 140 piston in a 138. The piston pin is 15mm.

 

[Divy]

hmmm so the 140cc barrel an piston wont bolt straight in??
so what do i need to do to do it??

 

[Mack]

Your options for the 138 are bore to 55 or 55.5 or 56mm with the standard cylinder. And find a 14mm pin piston

 

[Dreamah]

I was thinking Adventually of getting a 140cc Kit for My motovert, would it be worth Even doin, or Should i Maybe do the cams or Something...?

Heres some Jailing Parts, notice the head kits, the Black one i think is their 140cc - which is what I would go for, or Maybe just go the race cams they have... Meh i duno

 

[Divy]

the piston pin is that the gudgen pin that holds the piston to the crank shaft??
if so the 140cc piston i have the pin in it is 14mm wide so it will bolt on??
an is the 54mm piston a true 140cc???
sorry for all the questions

 

[Mack]

Ah well, yes that piston will fit. Sounds like it is the same as the one you've already got in your engine. The new 140 pistons are 55mm with 15mm pins. The barrel is also cast iron and longer. Did you buy a alloy barrel and piston off ebay? If so, you just bought what ya already got.

 

[Divy]

i got it from dhz ebay can you jump on a have a look to see if its the same as what i have please the bore that i got looks different

it says its 55mm but maybe i measured it wrong