140 with 125 head ???

[Sly93]

And there is two different gaskets ones got the oval shape hole and the other one has the circular hole so witch gasket do i use ?
Cheers, Kurt

 

[my67xr]

sorry,
yeah i meant the rubber seals that sit inside the cutouts in the gaskets
oval one for the oval hole

 

[Sly93]

Success i got it running purchased a brand new head didnt wanna muck around with a second hand one it runs now and idles but at high revs and the idle wont screw out any more and it is also blowing a hole lot of smoke then adjusted the air ratio but still heaps of smoke checked the bore and there was a slight score on it but i didnt bother with it the rings on the piston where a bit loose but it didnt seem that bad so maybe im thinking it might have been bad ? And will need a new piston and rings ?
Any suggestions .
This is it with the new head .

 

[DustyFork]

Success i got it running purchased a brand new head didnt wanna muck around with a second hand one it runs now and idles but at high revs and the idle wont screw out any more and it is also blowing a hole lot of smoke then adjusted the air ratio but still heaps of smoke checked the bore and there was a slight score on it but i didnt bother with it the rings on the piston where a bit loose but it didnt seem that bad so maybe im thinking it might have been bad ? And will need a new piston and rings ?
Any suggestions .
This is it with the new head .
View attachment 9989

Sounds like your old head may of had a bent valve, but you did the right thing by buying a new head than mucking around reseating new valves. Carefully take your rings off ya piston ans insert them one at a time in the bore. Then use ya piston and put the rings down a little so it squares the ring up in the bore. Measure the gap in the ring with some fealer gauges. Also inspect the rings make sure there round and not warn in sections. Check ya piston for scores, if you have some. Don't worry if there not deal you can still use it with new rings(it's only a china bike). Also check ya slide in ya carny that it is bottoming out. Take off ya air filter and lock in side the venture while twisting the throttle make sure it seats all the way to the bottom when your off the throttle and it's not sticking. Adjust throttle cable

 

[Sly93]

Hey dustyfork thanks for your suggestion . I will check that tomorrow but i think i might just throw a new set of rings and maybe a piston to save the mucking around but the bore is what im worried about because that has a pretty bad score/gauge so im thinking it might maybe it might need a hoen ? And or new bore ? And the slide was getting stuck at first but its free now and seems ok but i will check the clearance between the slide and carby tomorrow .
Cheers, Kurt

 

[zwebx]

it it a brand new head?
Sick of mechanice just looking at rings and guessing.. A real mechanic measures the piston to ring clearance and ring gaps Aswell as feeling for bumps and visually inspecting.. Also feeling for a blunt edge on the top side (if theres a little blunt side the gasses will go around the ring and not on top of it ergo why you loose power and heat the piston heaps and also burn oil when its on the lower part of the stroke.

Dont rule out the head valve stem seal leaking its a possibility too
if its under power (eg under load instead of engine braking) then i would replace the rings and maybe hone out the bore (or go bigbore)

 

[Sly93]

Yea new head well i just wanna fix it cheap but if i can hone it cheap i will or if i can get a new bore cheap enough i will rather then go big bore. So with what i said its doing what wiuld you do ?
Cheers, Kurt

 

[zwebx]

Yea new head well i just wanna fix it cheap but if i can hone it cheap i will or if i can get a new bore cheap enough i will rather then go big bore. So with what i said its doing what wiuld you do ?
Cheers, Kurt

If its only a small score, get it honed or buy one and diy
If its a large one then get a new cylinder on ebay or from a shop Pretty sure Atomic motorsports has one

 

[Sly93]

Alright will do thanks mate if i pull it down tomorrow i will try and take a photo of the score and show you . I was thinking of the diy hone but it will nearly cost me the same to buy a new bore but i would say i would use the hone more then once so hard decision lol but i should work it out lol.
Thanks mate .

 

[Rizzo97]

If you are getting a single blue spark each time you kick it over than the coil is f'd get a new one orone u have n another bike, or test your other bike that runs and you should see tp the difrence between the sparks. Mine wouldn't run with the single blue spark, it did a few times but it didn't run right. Proper spark should be multiple (like a lot) or golden sparks. That's what my plug dose now and my lifan 125 runs great again

 

[my67xr]

Rizzo, you are wrong with what you said above.
A good spark is Blue, and bad spark is yellow, not the other way around.
Motorbike's running CDI's put out a multiple spark, but you won't be able to see them unless you blow compressed air over it as it fires.

If you have a 2x terminal Ignition Coil and fit the wires the wrong way around, a coil that used to put out a blue spark can then put out a yellow spark.
It takes about 40% more energy to fire an ignition coil with the wires the wrong way around (wrong polarity)