piston woe`s

[Tosh]

tried 3 different piston`s 200cc goetze,mahle,and asso,and all 2 ring and have had the same problem`s
the pin that stops the ring from turning keeps coming out,sick of keep cleaning the bore and rebuilding
anybody got any idea`s .
Ta Paul

[Adam_Winstone]

Sounds like you have another issue at play that is causing peg failure, rather than peg failure causing your issues.

Peg failure can be caused by your exhaust being too wide and the rings catching in the port, which puts loading on the pegs when the rings take the strain. Rotational loading can also be caused by crank to bore misalignment or other factors. Are ring ends being exposed in ports?

Typically, I'd expect rings to break before pegs come out so it might suggest that your exhaust is not too wide, however, ring wear to the exhaust port would support the theory.

What is the kit, has it been 'worked on', how wide is the exhaust port?

Adam

[Tosh]

Thanks adam for the reply
I took some photo`s but can`t seem to sort it for the web page,but ive measured the exhaust port its 44mm wide and 23mm depth I run with 110mm yam rod,2.5mm packer

[Lambretta Sash]

Wide ports can cause trouble but more so the shape of port where radiussed at top edge.
If there's bore to crank misalignment there will be blueing on small end eye or big end plus it would get through alot of drive side bearings

[Muppet]

your not putting the pistons in upsides down r ya ? thatll snap rings

[Adam_Winstone]

44mm is the standard SIL 200 IV width so you really shouldn't be suffering because of that aspect, not unless the port is horribly square. I'd look for other causes.

Of you Indian piston choices, have either been the standard 3 ring item with chrome top ring, perhaps just running the top 2? If so, these are normally bullet proof, which again would get me looking for another cause.

Adam