Thumper Club Forum

Technical => Bike Problems/Questions => Topic started by: andy230 on April 24, 2008, 04:05:55 PM

Title: booooo!!
Post by: andy230 on April 24, 2008, 04:05:55 PM
Just checking on a (final) dry build last night.  (Thanks for the shims rog, they're just lovely)

The collets contact the valve stem seal at full lift...  Why oh why oh why is it never f'kin easy?!!

www.team-thumper.blogspot.com

a
Title: Re: booooo!!
Post by: Steve H on April 24, 2008, 08:45:31 PM
I had to buy different guides which sat lower and held the seal lower (XL500), but presumably the cam has run in this head before, and so should have lower guides if required. Did it have seals fitted when you stripped it ?
Title: Re: booooo!!
Post by: Steve Lake on April 25, 2008, 05:39:10 AM
oh bugger....how much needs to be removed to give clearance?....should be able to remove a little of the guide top without creating other problems
Title: Re: booooo!!
Post by: andy230 on April 25, 2008, 08:26:59 AM
But presumably the cam has run in this head before, and so should have lower guides if required. Did it have seals fitted when you stripped it ?


Yes and yes

The cam has run with these guides in this head.  The guides are already shortened.  But I replaced the top retainers and collets (with the springs).  And I am pretty sure it had seals.  Hopefully will have some on my doormat from Fowlers this evening.

oh bugger....how much needs to be removed to give clearance?....should be able to remove a little of the guide top without creating other problems

1.5 to 2 mm??  Quite a lot!  Not sure how to go about removing material from the guides in situ.  (and quickly!)

Lets see how the genuine seals fit... 

Will report back soon!

a
Title: Re: booooo!!
Post by: guest146 on April 25, 2008, 11:51:00 AM
Andy are they cast (would shatter) or bronze or something that would stand a little pressure.
Would they push through the distance you need or do that have stops at the base.
It would be possible to grind a drill bit almost flat and turn it in a brace and remove as much as you like but if its cast it could crack.

Ken