piston and rings required

[chris wastell]

Can anyone please help with a +80 piston and rings please? I’ve just had a small end go which has resulted in catastrophe on my ’38 flying sqirrel
Fingers crossed and thanks in anticipation.
Chris Wastell

[Roger Moss]

Hi Chris
I assume you have a 600 long stroke engine with a nominal bore of 73.02mm / 2.875″
+ 0.080 would give 2.955″
I am told that “Bantam John”

Bantam John alias John Phelan
01246 290 021
has
Scott ex wks piston blanks
M/c with rings and pins £150 / pair
Many other pistons
Scott headlamps, wiring looms etc

I am not sure about the £150 bit and understand that he has blanks that need machining up, but insists on getting these done himself.
I believe Ken Lack has had pistons from him
Give Ken a ring on 0114 281 1250 and see what he says
Otherwise
I could fit Silk pistons
The minimum bore would be 2.976″
The pistons must be ground to the correct taper for an iron barrel so can be taken down a bit but 2.976 is the minimum or the ring grooves become too shallow.
I have never heard of +80 pistons, but perhaps they exist.
You say you had little end problems.
I presume this could mean that you have deep scoures down the bore.
In this case, it is perfectly feasible to fill the groove with braze and reskim out and hone without going to so large an oversize.
I have run with such an arrangement for years in the past.
I hope this is of help
Kind Regards
Roger Moss

[chris wastell]

Thanks for that info, Roger. I thought, myself that +80 seemed large but I have them here as large (literally)as life. The engine was alledgedly rebuilt by Silk when they were still on the go and then not fitted into a machine until I did so a year or so ago. I shall have to think hard about remedies. Naively I had held a small hope of a s/h piston to finish the summer with!

thanks,
Chris

[Shaun Matthews]

Chris

My pistons are up around this size (+.088″) – same problem – totally buggered barrell .

Tim Sharp machined me some custom pistons and rings and rebored the barrell for less than 200 quid. – Nice job, bike goes like stink and holds together well.

However he does work at his own speed so you will need to work on him if you want the bike on the road this summer.

Tel # in Yowl / on the website under suppliers

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