M900 Engine help

[Davy]

I've a broken head stud and have discovered all 8 need replaced so I've bitten the bullet and I've pulled the engine out of the frame taking masses of pics as I go. Now please remember I'm an old brickie. And spanners are new to me.

So far I've got the top dead centre and all the timing marks lined up perfectly, ive marked both belts off the nipples on the heads and engine cases counted the teeth and have transferred these to the new belts which are set aside for now.

I've unbolted the vertical head bolts lifted the head off I've then lifted the cylinder up a tad and have seen the piston is right where I want to be working at the bolts. There's also a very very thin metal gasket there..

Can I rotate the crank to get the piston out of the way? And will I probably have to move the rear piston also and how will I know it's back in the correct position when I'm assembling is it just a matter of lining up the crank mark to the case mark. Can I use the thin gasket again or is this something that needs replaced

Sorry for all the Questions and hopefully you can make sense out of my questions.

[Dukedesmo]

Don't worry about the position of pistons & valves at this point just take the heads & cylinders off, it's easy enough to line everything back up later when reassembling.

I would also want the pistons off the rods and out of the way to work on the studs.

The thin metal gasket under the cylinder is actually a shim to get the cylinder height (squish setting) right and you can reuse it if you don't damage it but they're cheap enough if not, but keep (or accurately measure) the old ones if so as you want the correct thickness.

Depending on the age/mileage it may be wise to look at some level of reconditioning; heads, valves, seats rings etc. and you really should take the opportunity to check everything over whilst apart.

[Dukedesmo]

You'll really want it stripped down to this level;

[Davy]

Thanks dukedesmo. I'll be pulling the Barrels tonight hopefully leaving the pistons in. I'll also have to figure out my pic size they are to big.

[Albie]

Mine needs putting back together Been apart over a year

[Davy]

I should have said the bike has been serviced well and wanted for nothing it's only got 10 k miles on her every nut and bolt came free with no problem.
Want another to assemble Albie.. only kidding I'm actually enjoying doing the work myself with you lads help of course.

[Albie]

Originally Posted by Davy

I should have said the bike has been serviced well and wanted for nothing it's only got 10 k miles on her every nut and bolt came free with no problem.
Want another to assemble Albie.. only kidding I'm actually enjoying doing the work myself with you lads help of course.

I was hoping someone would offer to do mine for me.

[Kato]

It's a really straight forward fairly easy job to do, you did'nt actually need to take the motor out of the bike to do the job, but now that you have it's a good excuse to give it a good clean, and at least it'll save your back doing the job on the bench

[Davy]

Originally Posted by Kato

It's a really straight forward fairly easy job to do, you did'nt actually need to take the motor out of the bike to do the job, but now that you have it's a good excuse to give it a good clean, and at least it'll save your back doing the job on the bench

I'm sort of glad I pulled the motor out now,as you say I can change a few rusted bolts and give it a good deep clean.

[Davy]

So stripped the heads off, the barrels are off and the pistons are in the barrels for less hassell I've been told. I'll hopefully get started on getting the studs out at the weekend.
if yous have any tips or if I'm missing something please let me know.

[Dukedesmo]

Whereabouts has the stud broken? Is there a good piece sticking out of the block to grip onto?

As for shifting them I'll bet they're really tight (strong Loctite and years of corrosion) and would advise lots of heat and 'careful' persuasion, you really don't want to break one down in the engine or strip the threads in the softer aluminium crankcase.

Try to cover the openings into the engine as much as possible, whilst you can (and should) clean it out afterwards, the less debris that goes in there the better.

[Darren69]

Was gonna say they'll probably be swine's to get out. Would something like plusgas also help soften the loctite?

[utopia]

A sharp but not too heavy tap on the end of the studs with a small hammer may help to jar the threads and free any Loctite and/or corrosion.
Its a trick I have often used in the past with great success.
But heat is probably the first requirement to soften Loctite (if there is any).

And I presume you already know that .... black studs are good, silver ones are prone to snapping.
According to legend.

[Davy]

[Davy]