original cylinder head By mpdunhill73 (Read 1,307 times)

[mpdunhill73]

can I continue to use my original 125cc cylinder head with a 150cc cylinder barrel and piston?

[imnts2]

Probably. It might even be better. Should add just a little to the compression pressures.
cheers

lefty2

[mpdunhill73]

Thanks for your reply lefty.
I've still got the head to an old 180cc kit I had but I really wanted to keep the original head of the 125 with the 150 kit as I think the 180 head maybe just too much for the 150cc

[Deleted]

yup that stock 125cc head will work just fine with a 150cc cylinder kit. and like lefty said adds a little compression pressure.

[mpdunhill73]

thanks scooterelements, it's always good to have another response on board

[Deleted]

Jan 23, 2012 12:36:05 GMT -6 mpdunhill73 said:

thanks scooterelements, it's always good to have another response on board

No problem thats why i am hear to help others out with questions when i can. about a year ago i actually left my stock 125cc valve head and upgraded to a 58.5mm cylinder kit and it worked great!

[mpdunhill73]

i went for the 150cc set up cos i didn't want to machine the crankcase halves and also don't want that much power i just needed a little more for headwinds and hill climbs

[Deleted]

Jan 23, 2012 13:11:48 GMT -6 mpdunhill73 said:

i went for the 150cc set up cos i didn't want to machine the crankcase halves and also don't want that much power i just needed a little more for headwinds and hill climbs

I understand that. When i first bought my 2004 scooter it was actually 125cc and not the 150cc like the paperwork said and of course it sucked on climbing hills and in Puerto Rico There is nothing but hills and mountains. so i upgraded and that helped alot. Remember tho on a 125cc scooter you can go up to 58.5mm without boring the crankcase! Let us know the improvements you have on your new setup

[mpdunhill73]

i will post back once the scoot is back up and running after the new piston goes in and ive ran it for a good few miles
thanks for all your responses

happy scooting

[sprocket]

Be certain to hone the cylinder walls...

[mpdunhill73]

well here's a thing right?
The camshaft is completely different to any previous gy6 i've worked on!
It seems to be integrated into the rocker assembly. there are two bolts on the camshaft sprocket that are holding it onto the bearing assembly, i assume that i would have to remove those in order to release the cam chain so that i can pull the cylinder head off any further. i need to get my hands on a 7mm spanner to do this though as my range starts at an 8mm set upwards

[sprocket]

If it a GY6 you should still have a cam chain tensioner... simply unbolt or release that to loosen the cam chain...

[mpdunhill73]

Absolutely distraught!!
I got the new 150cc cylinder base and piston which stated that it was for engine models beginning with 152QMI only to find that the engine studs don't correspond with the new parts even though my engine is a 152QMI version

Does anybody know where I can get the correct 150cc cylinder base for my engine? I'm in the UK if I can get postage here

Note: Hey sprocket, I managed to get the chain off, I just wasn't pulling hard enough to release it as well as turning the engine while doing it :/

[sprocket]

What sized wheels are on the scooter? If they are 16" then it could be a type B engine. The cylinder studs are spaced further apart

[imnts2]

Good point sprocket.