Cylinder Head

[Dave.B]

Is there anywhere on the internet to show of how to take these off and what ill be faced with. eg bits falling out or what. i dont have a clue when it comes to the inner magic of motors and i want to find out just not get stuck not riding for a few days cause of my curiousity. Plus i gotta remove a snaped bolt so id rather have the space to work with. thank you heaps

 

[pitmaster]

youl have to take off the cam chain, cam sprocket, than youll need new head gasket and when you put the cam chain etc back on youll have to make sure you have the timing correct etc,

do you really need to take it off??? cause if like you say you have now idea about engines, doing this could just be bad!

what broke??

find a screwed engine and pull that apart first if you wanna learn!

 

[daniel40]

i pulled my top end down on my mxb, if you can avoid doing it i would its pretty hard there is a link that has step by step instructions on how to do it ill try find it.

 

[jamie__1221]

this is a good help
4th link down engine tear down
Technical --Dano's Bike Shop-- 50cc MotoX, Fifty, Fiddy, Minibike Information Source

 

[daniel40]

the one jaimie posted that the one i was talking about lol

 

[Dave.B]

u could just mark your timing right? what broke is one of the bolts that holds the carby manafold down... i dont an old engine laying around hey, kinda sucks but if i learn it all by myself i guess its kind of an achievement, ill do my research before i jump into it, just gotta learn somewhere i guess. would be good to be able to have input into some of the questions on this website instead of lurking 24/7 like i have been trying to absorb as much as i can. I got all the externals down to pat, wiring, brakes bla bla bla just wanting to broading that. thanks everyone for your help.

 

[Cactus Jack]

That's the right attitude mate - I taught myself at 13 on XR75's that I was racing at the time and it has paid off bigtime for me over the years . After a while you develop to see all engines in the same way ..... I went on to modify all types of car and bike engines including transmissions , differentials and chassis ....... and can do any engine without a manual .

So never be afraid to open your eyes up and have a go ........ How do you learn to be competent and skillful at ANYTHING ???? By actually doing it and keeping at it until you reach the level of expertise where you end up getting bored and sick of it ........ LOL ......

Small 4 stroke engines especially are so simple that you'll be able to do them with your eyes shut after a while . I can't understand why people think they're hard to set up ........ you simply torque the head down in stages in a cross hatch pattern , play "match the dots" with the flywheel and cam sprocket , check valve clearances and that's it .......

The best advice I can give you is to thoroughly scrub your engine spotlessly clean of any dirt , grit , grease or oil BEFORE you go pulling it apart ....... degrease it and use detergent and then work on it in a clean dust free area using clean tools ..... dirty reassembly will cause more grief than you can imagine ..........

Don't be afraid to have a go ....... do it all methodically and organised and you'll be right ........

 

[Cactus Jack]

Plus i gotta remove a snaped bolt so id rather have the space to work with. thank you heaps

Incidentally ....... to fix this problem you don't need to remove the head ..... just take the engine right out of the bike so it's easy to get at the snapped bolt . Even a bike shop would leave the head on to do the job ......... just make sure you plug the inlet port tightly with something to avoid letting damaging particles get into the cylinder ...........

 

[Dave.B]

yeh i know to get it off just to leave it on but like i said i want to know whats going on inside. thanks heaps everyone been lots of help. cheers

 

[THUMPY125]

just go buy a scre extrator set, drill the hole then screw it the screw extractor and unscrew the bolt, replace the bolt and its better than new

 

[Dave.B]

what if by a chance my thread inside is farked?

 

[Cactus Jack]

what if by a chance my thread inside is farked?

If it was ..... the the bolt wouldn't be stuck OR have snapped off ..... it'd be easy to turn ........ I talked about methods of removing studs and bolts in another thread ..... I'm a fitter/machinist/ tool maker and welder .... I've done hundreds of repair jobs on engines and fabrications ........ if there is bolt sticking out .... you can also give it a few raps on the end with a hammer to loosen the thread as you try to undo it ........ spray it with WD-40 first and allow it to get in so that the thread will let go of the bolt .... otherwise the thread can strip ........

As I said before ...... you must have used too long a screw which bottomed out and you've kept on tightening it and snapped it off otherwise the thread would be loose - either that or you've cross threaded it in which case the thread will be stuffed anyway .......... LOL ........

The use of bolts to hold the intake manifold on is actually an extremely bodgy idea ........ studs , nuts and spring washers are the proper fasteners to use ...... that way the studs can bottom out and the nuts will turn without jamming or pulling the threads ....... screwing bolts in and out eventually wears the alloy thread ........ that's why it's important to lubricate intake manifold bolt threads before you go screwing them back into an alloy head ..........
If your thread has had it ..... you can drill and re tap to the next size up .... then drill the manifold hole to clear the larger bolt ....... you have to do it to fit a heli coil anyway if you strip the threads .......