"Topp Racing" Cranks
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wack 63
- registered user
- Posts: 1254
- Joined: Fri Nov 27, 2009 9:33 pm
- Main scooter: '71 GP TS1
- Location: Lincs
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I could be wrong but the piston looks like a genuine Honda MTX 200 as it has the cut outs for the special Honda circlip tails.As for the crank I agree that the MEC ones are the best for the money,I have a drawer full of AF and Mazzuchelli ones either twisted too much to true up or busted big end bearings.When I check a crank I have two dials one on each end and aim for 0.002 to 0.003mm run out ,max is 0.005mm.
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shamrockexpress
- registered user
- Posts: 330
- Joined: Mon Sep 28, 2009 12:44 am
- Contact:
Took the MEC crank to a crank builder today and he said the reason it has twisted so bad is to do with the web area being so thin due to the thickness of the conrod!!!!A thick strong conrod is a good thing for strength but this is at the expense of thinner webs having less area to grip the pin hence its easier twisted!!!!so i,m gettin it trued up and tig welded.
Thanx wack for info on the piston this was the consequence of the crank damage I reckon the crank was never 100% as the drive seal had went with this motor before so the piston seizure was probably down to an air leak. Although the rings are done, piston to bore clearence is 0.003 so i,m hoping to give it a light emery sanding of the high spots and it can be a reserve kit for now.
Its a long shot but does anyone have 1.2mm x 66.8 rings???
Thanx wack for info on the piston this was the consequence of the crank damage I reckon the crank was never 100% as the drive seal had went with this motor before so the piston seizure was probably down to an air leak. Although the rings are done, piston to bore clearence is 0.003 so i,m hoping to give it a light emery sanding of the high spots and it can be a reserve kit for now.
Its a long shot but does anyone have 1.2mm x 66.8 rings???