Rebore

Mechanical issues and How-to articles.

Moderators: DAVID THOMPSON, phlat65

Rebore

Postby Blurredman » Fri Dec 15, 2017 4:57 am

Hi guys,

I'm looking to do some re-bore on some of my cylinders.

I have a 300cc barrel and piston that are very badly worn now. It is a converted 250 barrel with an original size 300 piston being 75.46mm. The barrel is pretty much almost as worn to the extent that a 76mm piston would fit into it. It has almost 0.4mm clearance on one side (0.15 to 0.2mm if i center the piston). I'm going to get it rebored and a 76mm piston installed. With 15 thou clearance I understand. I shouldn't think there would be too much trouble doing this, considering the bore is almost as big as 76 anyway?! Right?

And on the subject I have a spare cylinder and piston which were seized together on a bike I bought that I wish to re-install, and found out the piston diametre is 70.5mm which is 3rd oversize. I can obtain 71mm pistons, and considering the above 300cc conversion I shouldn't have issues with putting a 4th oversize in. At 13 thou clearance.


Thoughts?
1979 Suzuki TS185ER - 9,00 miles - Mud :)
1981 Honda CX500B - 77,000 miles - Long Distance :)
1987 MZ ETZ300 - 29,000 miles - Sun :) - Engine just re-built!
1990 MZ ETZ251 - 40,000 miles - Commute :) - Sleeping for a while! 1/2/18

ftp://blurredmanswebsite.ddns.net/Vehicle_Documents/MZ_Documents/
Blurredman
 
Posts: 322
Joined: Sat Feb 09, 2013 3:59 pm

Return to Mechanic/Tech Talk

Who is online

Users browsing this forum: No registered users and 2 guests

cron