Bought a sports exhaust but have no power help

Alright lads bought a sports exhaust for me gy6 chinky clone the other day but I've got no power. I upjeted from a 110 to a 115 and I'm running on stock air filter. Any ideas why I've go no power? It's sounds great but rides crap. Also the Exhaust is completely sealed and its all brand new including gaskets& a Brand new cylinder head. (Snapped me old exhaust stud and had to replace as I couldn't get the snapped stud out)

 

assuming your chink is 4 stroke,your broken exhaust stud came off your head..2 stroke exhausts go on the cylinders...first check your cam is Lined up at top dead centre.there are 3 holes on the cam.the large one goes straight forward and the 2 small ones should be level with the cylinder at top dead centre.there are marks on the flywheel to tell you or you can feel it by putting a thin screw driver or stiff wire down the plug hole and move the fly wheel till it feels at the top.then if its out your see it..it can still start with it out by a tooth but will run like shit.if that's fine,check your valves are gapped correctly..put the standard jet back in and try it...if it don't run after that...refit the standard pipe.youve changed 3 things...head,pipe,jet.gotta do it one step at a time..cam check first.dont want valves bending banging on the piston...may have already..worse case scenario.jet to get the carburation back to a known point then pipe to see if it ain't suffocating the engine.good luck.

 

Cheers mate checked my timing like 3-4 times. Put the stick exhaust back on and jetted back down to 110 as it was originally. Still not as good as it was but better. Will double check the valves again. I think I done them to 0.05 is that right? Also would it take a while for the new head to brake in so to speak

 

could have a slight leak on the valve side.if you've got a compression tester that will tell you.not sure what the gap is meant to be but a bit of slack ain't gonna do as much harm to the running as a tight setting.if their a bit tight they wont seat proper on the seat and the compression suffers a bit.sounds like you could do with a compression test if the standard pipe and jet have been replaced.I'm assuming youve got no oil leaking out of the gaskets at the head and the cam chain is adjusted properly.may need a re jet in this particular instance but cant say for sure till youve ruled out the compression side first.

 

Haven't got a compression tester mate. Will have another look at the valves, got no oil leaks. It's a 4 stroke aswell

 

wouldn't be surprised that youve got a leaky valve.chinky quality control ain't up to much to take as gospel.i fitted a cheap pipe to my chink and it ran fine with out giving any signs it needed re-jetting..
I'm thinking your heads the problem..if your cam timing is ok and the jet/pipe is standard,the only thing left to check is the head really..theres two different heads available for gy6 qma/b heads.64? and 69mm valve.but 69mm needs a rocker arm and carrier rig change to get them to run anywhere decent.chances are its a valve...have a look at the carb manifold for air leaks too...mine ran better with a bit of sealer and a file round to bring every thing in line.quality control has a lot to be desired on chink bikes...like jigsaw puzzle...all the bits are there but you have to finish it off...

 

Will have a good look at the valves and the carb manifold as soon as I get the chance mate and let you know if I can see anything out of the ordinary. The head was exhactky the same as the old 1 as I checked it all before I put the new 1 on. Thanks jim I will keep you posted bud

 

no probs.thinking earlier...have a shoofty at the auto choke too...dodgy wiring on them chinks too...basically your gonna have to check EVERY THING you touched moved or breathed on ...I couldn't even mention some things on mine within ear shot without it throwing its dummy out.

 

Thanks mate I will go over it with a fine comb, the auto choke is brand new tho cos it's had a new carb about 4 weeks ago! Cost me a bloody fortune but it'll all be worth it once she runs right

 

gotta be the head then.can never take anything for granted on these things..what bike is it?.

 

It's a lexmoto zoom 2. The engine is a gy6 clone 125cc Mate

 

Got a photo of the exhaust you bought?

 

thats the 1 mate straight thru pipe

 

m
looks like the same as I've got on my chink..same place as mine too.made my chink 50 sound like a much bigger bike....

 

Yeah sounds amazing mate lol

 

upjet required

 

Steve I upjetted from 110-115 and it was even worse. Found out why I had no power jim. Done the valves again today and it wasn't them. Stripped the carb and the diaphram was like saggy and didn't fit the top on the groove in the carb properly. It sort of like stretched. Good job I had a couple of spares in the shed. Seems to have a lot more power now and actually some pull haha. Gonna put the new exhaust back on when I get time and cross me fingers that its ok

 

well done mate...chinese quality control hey...dont ya just love the way it tests everyone.glad that probs sorted..cant take anything for granted as "fit for purposes" on a chink".I'm off to work now...see ya later in the evening...can stop tinkering and ride it for a while...byeeee..

 

Yes jim it's great when you solve a problem init mate. Thanks for the help bud. Speak soon

 

no probs.its taught me a thing or two too..old dog has learnt a new trick.honestly would not of thought it was carb...new jobby too...can stop thinking about it now...owning a chink is a pain in the brain...enjoy..... TILL NEXT TIME...