Author Topic: Big bore XBR???  (Read 1474 times)

SteveC#222

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Re: Big bore XBR???
« Reply #15 on: October 23, 2009, 10:56:29 AM »
Might be worth sending GC a brief write up for the newsletter if you have time. I'm sure a lot of other members would appreciate knowing how to do the convertion.
Growing old is inevitable, growing up is optional!

blew

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Re: Big bore XBR???
« Reply #16 on: October 23, 2009, 04:53:30 PM »
Once I've sorted everything -slipping clutch etc.-I will make a report.

guest564

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Re: Big bore XBR???
« Reply #17 on: October 26, 2009, 02:19:29 PM »
I was actually a bit surprised how simple it was to change the barrel and piston.The piston is 100mm,and the small end 24mm.The barrel fitted straight on and everything bolted back easily.The ring end gap was 13thou,and the piston was a close fit.The old piston had one seized ring,and the other had a gap of 35thou,and the piston felt rather loose.That explains why it used a pint of oil every 100 miles!!

What year was your engine? I have done two 1985/86 motors and I had to open up the crankcase mouths on both of them.

blew

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Re: Big bore XBR???
« Reply #18 on: October 27, 2009, 08:09:23 AM »
My bike was registered in 88-E reg.I presume the later ones must be different??When I lifted the barrel,it left the base gasket intact in place.I put another XL base gasket on top of it,as per GB FAQ site,to lower the c.r. slightly.Both gaskets were identical.This is the only XBR I'm familiar with,so I can't comment on earlier ones.The barrel and piston were bog standard XL600 items.  Have you had clutch problems??

guest7

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Re: Big bore XBR???
« Reply #19 on: October 27, 2009, 06:47:32 PM »
Having dragged a heavy sidecar around for years on an XBR without problems I can't imagine what would cause the clutch to fail... tough as old boots.

GC

blew

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Re: Big bore XBR???
« Reply #20 on: October 27, 2009, 07:20:25 PM »
I presume that the plates or the springs,or both,are tired.Some years ago,Rod Gibson wrote an article about putting a 650 lump in his XBR.He used the clutch and alternator from his 500.He also had clutch slip,so he replaced the springs and plates with 650 ones.Maybe the 650  springs are stronger??