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piston pin removal and cylinder studs

Posted: Wed Aug 28, 2019 3:28 pm
by philcarmell
Got the motor stripped and ready to remove piston from rod and pull cylinder studs. Any advice before I hurt something?

Re: piston pin removal and cylinder studs

Posted: Wed Aug 28, 2019 3:48 pm
by BrianZ
Carefully remove the circlips using needle nose pliers or a pick. If you are not splitting the cases, stuff the crankcase opening with rags so the circlips don't fall in. Gently tap out the pin without putting any side pressure on the rod. Heat the piston slightly if the pin is stubborn.

Not sure why you want to remove the studs? I usually lock two nuts on the end of the stud and turn them out. If they require any undue force, heat the cases with a propane torch. Reinstall with blue thread locker.

Brian

Re: piston pin removal and cylinder studs

Posted: Wed Aug 28, 2019 4:40 pm
by Bullfrog
. . . and mark the studs if you remove them, they have a "top" and a "bottom" end.
Ed

Re: piston pin removal and cylinder studs

Posted: Wed Aug 28, 2019 4:45 pm
by viclioce
I put rubber fuel lines over the cylinder studs for protection. I agree with stuffing the cases so clips don’t fall in, and I ONLY use needle nose so I can hang on to the clips!

Wrap a soft cloth around the piston to prevent damage to the piston.

I use a wooden dowel slightly smaller in diameter than the wrist pin, to push out the wrist pin. Use a light duty hammer on the dowel if needed. Don’t swing like an ape. Tap with finesse! You don’t want to loosen your crank bearings! :ugeek: Victor

Re: piston pin removal and cylinder studs

Posted: Fri Aug 30, 2019 8:19 am
by Dale
Make or purchase a piston pin extractor tool. The only way to go.

Re: piston pin removal and cylinder studs

Posted: Sat Aug 31, 2019 4:23 am
by viclioce
Dale, I’ve never seen one of those! Do you have any pics? :ugeek: Victor

Re: piston pin removal and cylinder studs

Posted: Sat Aug 31, 2019 4:02 pm
by taber hodaka
Mine is home made and it works well. Motion pro makes one, if you go to ebay and type in "motorcycle piston removal tool", it lists 66 of them that's what they look like. There are other models like what Dale is referring I would guess. ------------- Clarence

Re: piston pin removal and cylinder studs

Posted: Sun Sep 01, 2019 6:37 am
by Bullfrog
Build your own piston pin extractor with:
1. Approx. 2" long piece of white plastic plumbing pipe with ID large enough for piston pin to go inside
2. Long screw or bolt (approx. 4"+) which is small enough to fit through the piston pin.
3. A large flat washer or two (fender washers) - plus other washers as needed.

tightening nut on the screw/bolt will "pull" the piston pin sideways out of the piston and into the plastic pipe. Easy-peazy - and no hammering/pushing side-loads on the rod.

Ed

Re: piston pin removal and cylinder studs

Posted: Sun Sep 01, 2019 7:11 am
by taber hodaka
the bolt I use is has the allan head. ------------------Clarence

Re: piston pin removal and cylinder studs

Posted: Sun Sep 01, 2019 9:09 am
by Bullfrog
Allen head bolt sounds good. Head of bolt against one end of the piston pin. Allen wrench keeps bolt from turning as nut on the other end "draws" the bolt head and pin toward the plastic pipe. Nifty.

Ed