Piston question

Either get the current guides sleeved or bore enough out so the thin wall of guide that's left collapses enough so it does not damage the head bore as it's pulled out.

I have some standard sized OEM pistons, rings and wristpins from a MK3 hi rider The bike appears to have gone a fairly short distance before gearbox trouble sidelined it , until now.
The top ring has 4 thou ring to land clearance, the others show 2.5.

I'm using the engine for a 920 build, won't be using these pistons and rings.

Glen

920 eh?

Yes, but a girlie 920, stock cam , carbs maybe 9.5 to one Cr.

Glen

Well, as I recall you’re quite happy with your stock motor, sounds like your 920 will be basically the same spec... but with 90cc more... which is most likely to be felt exactly where you want it most. Can’t really fault your logic.

I agree with KOMMANDO get the guides relined , causes minimal disturbance to the head, it's not the top of the line performance route but for JOE average to putter around the country side it works fine.
When I started working we used to machine piston grooves all of the time, holdens, falcons , Hillman hunters, Vauxhall vivas they all got a second life, but parts were expensive so it was a cost saving measure, I would be very doubtful if the inserts are readily available any more they were getting hard to find 20 years ago.
To me the price of a piston kit vrs ring set is a bit of a no brainer some suppliers want stupid money for rings
Vauxhall vivas were machined with a hammer and chisel, all the british motors had good potential only to have cost cutting drag them back ,minis were the only thing they mass produced well