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Quandary
Posted: Sat Jun 27, 2009 3:52 pm
by dapper
Had a seize after downpipe came adrift and tried to wet 'n dry but loads of piston slap, so needs a rebore and oversize piston. Got the new OS piston and stripped engine out and top end down. The kit is a 185cc Dave Betts (RIP) tuned SR type kit and he put a boost port in the cylinder with a window to match in the piston. Now this is all on a standard crank which has no big end shims. When I first built the kit with the piston that came with it I followed Sticky's and many on here and put shims in at the small end. When I now compare the gap in the two pistons, I won't be able to get any shims in with the standard small end bearing in the new piston as the gap is smaller.
What do I do? And who can I send it to to get it rebored and the window put in the piston to match in the south east? Desperately want to be back on the road soon.
Re: Quandary
Posted: Sat Jun 27, 2009 5:00 pm
by bristolmod
I think some pistons are made to eliminate the need for shims at the small end due to the "gap" underneath the piston being smaller. If I remember rightly you have an SX crank in that engine which should require small end shims. If the piston won't take shims at the small end then its OK to leave them out.
I use "Piston Broke" in Easton, Bristol. Steve, the owner and one man band is very good and will do mail order on rebores etc. I'm sure he could do the boost port as well with no probs.
His number is 0117 9412300
Beware- he is an old Rocker from the 1960's and takes great pleasure it taking the wotsit out of scooterists. He can talk for England as well! Nice bloke and knowledgable as well
Chris
Re: Quandary
Posted: Sat Jun 27, 2009 6:22 pm
by shocky
out of interest what does he charge for a rebore as my local dealer cant be trusted to change a plug or pump a tyre up properly , and most local enginnering firms wont deal direct with the public and as im often in briz or corsham it wouldnt be to far out of my way
Re: Quandary
Posted: Sat Jun 27, 2009 7:24 pm
by bristolmod
I think its probably around £20 + VAT for a rebore or thereabouts.
He'll do it whle you wait if its not too busy.
Top bloke- never had any problems with his work.
Chris
Re: Quandary
Posted: Sat Jun 27, 2009 7:44 pm
by shocky
id ot be in a rush so will bare him in mind