replacing piston

Could anyone give me an outline of how to take a pistonj off of an M1 Cady engine. I got a new piston for it, because the other one was bad. I just can't figure out how to take the crapy one off of the engine.



Re: replacing piston

Hi,Dan! You must have the head off at least to know it's bad,right?Generally you remove the cylinder(just slide it up off the piston)and then remove circlips on each side of the piston,and push out the wrist pin.Some have roller bearings in a retainer so be careful as you remove the wrist pin.When you get that pin out the piston is loose.Ron Brown seems to be the resident Motobecane expert and he may give you some details and tips as my Motobecane manual is at my house and I've never disassembled one.You should really get a shop manual if you're keeping the `ped.Any parts you need for it call 614-299-0550 and ask for Bob Jones.BYE!

Re: replacing piston

i agree with that don guy.

be careful

i lost some pieces and had to buy new rings which were quite pricey

Re: replacing piston

Ron Brown /


Don is giving me too much credit, although I have done a lot of work on my Motobecane model 7's, I have not needed to open up the engine at all.

I did not even recognize this model as a Motobecane!

That said, I checked my manual and it is a little ambiguous on piston removal, it talks about using a piston pin removal tool and heat to re-install it unless it is a later model which is an easy sliding fit. It also mentions that if you heat the piston, you should slide the cylinder over the piston, without rings, to cool it off without causing distortion. The rings may or may not cover the locating pins so watch that.

Obviosly you have to remove the circlips from both sides of the piston pin befor removal and replace them after. Make sure the pin is centered so the clips seat on the groove and do not apply side loads to the piston/rod assembly as you may bend the rod. The piston pin does use a caged roller bearing but no mention is made of the rollers falling out of the cage. Be sure to lube everything with 2 cycle oil during assembly.

Hope this helps.


Re: replacing piston

Hi,Ron! Didn't mean to put you on the spot,but I knew you could handle it.As a side note,I talked to 2 guys in Mansfield that always go to the Mid-Ohio and they said I should definitely not miss it.Must be somethin' to behold! I'll try to get Linda to let me come up for a couple days next year(around July 14th?),but if she thinks I'm buying more `peds she'll probably make it rough on me.I just bought 2 more the other day raising my grand total to 10(wince).See ya!

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