Remove cylinder head 2 chinese motorbike GY 125

Part 2, removing the cylinder head from a chinese 156FMI 4 stroke single cylinder motorbike engine.

Category:

Autos & Vehicles

Tags:

• Bike

[Mantas402]

and should both valves be tightened same tight?

[spidiq8]

@Mantas402 Not entirely sure what you mean here, if you mean the clearance, usually the inlet and exhaust are slighty different gaps, if you mean the adjusting screw and locknut assembly they're nipped up to be sure they're tight enough to not come loose, if you can clarify what you're asking i'll try to help better.

[Mantas402]

hi so this engine doesnt have a chain in it which is opening the valves right? sorry for my english it sucks :)

[spidiq8]

@Mantas402 No, you're likely thinking of an overhead cam design where the camshaft are chain driven by a chain running from the crankshaft up through the casings to the camshaft or shafts at the top, on an overhead valve (OHV) engine the cam is in the bottom of the engine and usually driven by a meshed gear system from the crank, this moves pushrods up and down to operate the valvetrain in the head.

I recommend you check out howstuffworks(dot)com and look for 4 stroke engines.

[blayinlines]

i have a question if u take the head of do u have to replace the head gasket if its fine?

[spidiq8]

never try to re-use a head gasket on a high comp engine or water cooled BTW, if you do try, any signs of blowing, replace immediately

[thestar111]

Great Work :)

[wackedoutdude]

A friend had one of these engines in a gy200 dirt bike every one thrashed the hell out of it and it just would'nt die there better than people think these chinese engines.

[Chrisnewland84]

Great videos, Very well explained and helpful! I have a yamaha 125cc that needs the head gasket changing and this will really help me do the job myself.

[spidiq8]

Yes you do.

The reason being that the head is torqued to a specific tension and this compresses the gasket during this process rendering it unuseable once the head is removed.

However it is possible that re-using one on a low compression engine, you just might get away with it, frankly for the cost I just wouldn't bother.

I do have a GY head gasket I can sell, brand new unused for when I did a second head off check but sold the bike before this, let me know if you're interested.