cylinder head overbore

Fidge · Banned Joined: 04 Oct 2014 Karma :

Can anyone on here (or do you know anywhere) that can overbore a cylinder head? It to be done on a lathe so it is even all the way around.

https://i.imgur.com/G87p2MY.jpg

MarJay · But it's British! Joined: 15 Sep 2003 Karma :

You know you have to overbore the barrel as well, right? Also, you want the squish band machining too. I personally wouldn't let anyone other than a respected two stroke engine specialist do work like that, else you'll end up with scrap.
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Fidge · Banned Joined: 04 Oct 2014 Karma :

Yes, I've had the barrel done already.

Pete. · Super Spammer Joined: 22 Aug 2006 Karma :

Post it to me with a diagram and I'll do it. PM for address.
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stevo as b4 · World Chat Champion Joined: 17 Jul 2003 Karma :

Do you want to give more info, why are you wanting the cylinder head combustion chamber diameter opening up? Is it for a big bore kit? And what bike is the head and cylinder from?

Ariel Badger · Super Spammer Joined: 02 Dec 2006 Karma :

Do you not deed the piston as well Pete to get a good squish profile?
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Fidge · Banned Joined: 04 Oct 2014 Karma :

I just got the standard cylinder on my nsr 125 overbored and replated 1.5mm as it was damaged, I thought I should get the head done to make the most of it and so I don't have to worry about having enough clearance between the piston and the top of the head.

- · Super Spammer Joined: 22 Oct 2013 Karma :

Don't forget to machine out the hard gasket too, unless you can find them in overbore sizes.

You don't want 1mm of head gasket interfering with the squish, or possibly top of the piston.

I used to make the hole slightly larger with a grinding bit on a drill.
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Pete. · Super Spammer Joined: 22 Aug 2006 Karma :

You don't have to worry about squish to open it out 0.75mm ffs just follow the profile that's already there.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good Very Happy

Fidge · Banned Joined: 04 Oct 2014 Karma :

okeee, thanks for your help Smile