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can i re-sleeve a 250 cylinder toa 350??

Posted: Wed Oct 26, 2011 9:03 pm
by Clark
Hello, this is my first post on this site and very sorry if the topic has been covered.... i looked and did not see any threads similar.

I have a couple complete 250cc motors but i am wanting to restore a 350 scrambler. I have the wide case bottom end and the head for the 350. Can i purchase a 350 sleeve and piston and have that put into the 250 cylinder? Was there any difference between the cylinders other than bore?

Would the 250 cylinder and stock piston work with a 350 head? (checking options)

Thanks in advance, i just got three old Ducati's with allot of parts. I am finishing another bike first and am collecting info and parts as the 350 scrambler is on the bench next. :P

Posted: Thu Oct 27, 2011 4:40 am
by Jon Pegler
The 350 cylinder barrel was deeper with 9 fins as opposed to the 8 fins on the 250.
The 450 had 10 fins.
There are slight differences between wide and narrowcase 350 cylinders although they are interchangable.
You may need to fit a compression plate under the cylinder to get the required compression ratio as well as avoiding the piston touching the head.

Jon

Posted: Thu Oct 27, 2011 9:07 pm
by Clark
Thank you Jon, most valuable information. I think i will just seek a 350 cylinder and do it proper.

Enjoy, :-D

Posted: Fri Nov 04, 2011 5:10 pm
by chimera
You'll also need a longer bevel tower shaft and the taller base flange that the tower shaft tube slips into. The tower shaft tubes are the same. As you've already observed, the 350 bore is slightly larger (250=74mm, 350=76mm). Buona avventura!

Posted: Sat Nov 05, 2011 2:01 am
by Eldert
the 350 headbolts are longer to so you need them also

Eldert

Posted: Sun Nov 06, 2011 2:13 pm
by Clark
thanks for the head bolt info. If anyone reads this and has a 350 cylinder that they want to sell let me know, i'm interested.

Posted: Tue Nov 29, 2011 5:10 pm
by Clark
i found me a cylinder... all is good!

Posted: Tue Nov 29, 2011 5:18 pm
by Clark
i found me a cylinder... all is good!