how much more can you bore out the 140cc!!

[dhz138]

hey all

i got a 138cc oil cooled N1234 DHZ pitbike... its allrite, 30mm carb n all goes pretty good. besides the forks were **** and pissed out out straight away, got them replaced for an IRK..

a while ago when i bought a container of pocket bikes n ****.. which was a big waste of cash since all thoes laws come in..

the company in china i got the pocket bikes from also sells a heap of pitbike parts n such, and i plan on getting a whole heap of parts...

140cc bore - 55mm x 59mm
HP CDI
HP ignition coil
IRK
lightened oil sling
37T rear sprocket
CNC 1/4 turn throttle setup -
oil cooler (GREEN) - side cylinder cover - (RED)
hydraulic clutch setup

and they sell a shitload more.. CNC sprockets and everything

i was wondering would a 140cc big bore fit straight onto my 138 ? because the 140cc has a stroke of 59mm which is 3.5mm bigger then the 138cc..

Does the 140cc have a bigger crank ?

How much can you bore out the 140cc bores ?

i want to bore out the 140cc head as much as i can, and find a road bike piston that will fit, because my mate did this and it raised the compression of his pitbike a shitload

 

[Le|Garage]

Hey there, the big bore for the 138cc won't work on the 138cc..because the cylinder is about 10mm longer (which will cause timing and compression issues) and the piston is 15mm pin and not 14mm like your 138cc..even if you did get it to work, the 140cc kit is only 55.5mm piston, and will only bring your 138cc engine to about 134cc anyway..the only way you can get 140cc out of your 138..is to buy a 57mm big bore kit. OR!! bore and stroke..

 

[Mack]

He means fit the entire 140 engine to his currently 138 bike I think.

Yes you can do it. And without case boring you can bore a Lifan to 57mm. This leaves you with .75mm skirt thickness and is about as thin as you would want to go.

With case boring you can very safely go 59mm and more riskily 60+.