reboring technical advice please

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llewdaert
Cucciolo - the Lil Pup
Posts: 16
Joined: Mon Nov 01, 2010 8:02 pm

reboring technical advice please

Post by llewdaert » Mon Oct 03, 2011 1:32 pm

hello I have a problem with the re-boring of my 860 GTS;

the machinist has used a torque plate process, and is unsure if he has got it right. Apparently the cylinder is clamped into the borer and tensioned to mimic in service condition.

In this shop the cylinder was clamped to a purpose modified flywheel and done as they do harleys and other similar applications.
The boring and honing was done and the bore measured up correct in the jig under tension.

The jig was released-the cylinder was then remeasured and is significantly distorted in the untensioned state. The machinist is a friend and very experienced and is having anxiety

So has he done it wrong?

Advice would be appreciated-Thanks

wdietz186
888
Posts: 656
Joined: Sun Sep 10, 2006 4:40 pm

Post by wdietz186 » Mon Oct 03, 2011 7:25 pm

I suspect they only clamped the cyl. casting and not the sleeve. The fit of the sleeve in the barrel isn't the tightest or most accurate so something must have moved when things were cinched down. If they did clamp the sleeve it is also possible the base of the cylinder barrel wasn't true to the top surface of the sleeve and when torqued it pulled it sideways.

llewdaert
Cucciolo - the Lil Pup
Posts: 16
Joined: Mon Nov 01, 2010 8:02 pm

I will investigate

Post by llewdaert » Tue Oct 04, 2011 11:19 pm

I figure the best action is to bolt the barrel up to the crankcase and remeasure. I will need to make up a ring to act in place of the head and see what happens

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