200s timing chain / piston codes

[PAPA250r]

been working on an 84 honda 200s

2 part question. is there an easy way to install the upper timing gear and chain ? I had a lot of trouble with it coming off the bottom gear and I could not get it back on the bottom gear with out taking the head back off . are there any tricks to making this easyer ??

question 2 -

I have a piston for the 200s marked ''4156p2 xa 0.50mm '' can anyone help me ID the bore and comression on this piston ?

thanks !

[TheRealFatShady]

I am not sure on the timing chain, but there may be a tensioner screw on the engine somewhere. I need to do a top end job on the same engine this week so I'm curious as to what the experienced guys have to say.

[Vealmonkey]

Well, the .50mm would be a piston .50mm bigger than the stock bore. As far as compression, I can't help you there. A clue would be how high the piston dome is above the cylinder top when the piston is at top dead center and how deep the grooves for the vavles appear. If the piston sticks way above the top of the cylinder, then I would say a higher compression piston low or flat to the top of the cylinder, than I would expect a pretty much stock piston. I'm sorry I can't be more technical. And most times, a higher compression piston can be a pain in the butt. Most people are better off sticking with stock type pistons.
And as for the timing chain, almost forgot, I use a long piece of wire or coat hanger and keep the timing chain hanging off the frame or the handlebar. It won't work for everyone, but it helps me.

[PAPA250r]

thanks for the tips. i did use some string but it was a real pain in the but to keep the chain on the lower gear while trying to time it .

after the fact i realised that if i pull the flywheel and take off the stator housing would make the job nice and easy..lol