Hi Ian

I’m about to send off my cylinder to get it bored out to fit the 90mm piston I got from you. I note that by boring to 90mm this will remove the spigot at the base of the cylinder which locates into the crankcases. Does this present any problems with cylinder orientation later, or will the cylinder base studs suffice to correctly locate the bore?
How critical is this, and am I paranoid?


Cheers
Pete

email (option): petercomley@web.de

Hi Peter...The barrel will locate OK on the barrel studs, over which it should be a fairly snug fit. You will also need to remachine (or file by hand) a tapered 'lead' to help the rings to enter the bottom of the bore when fitting.
I usually file the lead by hand. Mine is to this spec. and has now covered quite a high mileage...So far none of the big motors have been troublesome....Ian

email (option): ian@wright52.plus.com

I've just rebored my barrel to 82.5mm and found that the easiest way of insertion of the piston is with the aid of a jubilee clip to act as a ring compressor. Just ensure that the rebore is at least 1.5 thou under size and this 1.5 thou is honed to get the require surface finish.

email (option): 79aust@sky.com

Hi Ian
Thanks!

Cheers
Pete

email (option): petercomley@web.de