thanks Adrian...looking through Ringoism,s post page one..about turning down IB guides to match the AVL barrels, with an alloy coller march 2018...My tappet guide snapped at the narrowed pushrod holder due to some mechanic putting it on a dyno when new. didn't notice til years later. replaced it with a new avl tappet guide. now that the cases are apart...I have a pair of IB tappet guides and tappets
but have no experience as a machinist. I live in a retirement community, and they have a metal shop with a lathe . And I was wondering how to attach the alloy coller.
wont be able to do this til fall. as all the locals here are snowbirds and have gone back to Canada or where ever. shops closed til October.
found a little bit of hard metal shavings on splitting the cases this week... so I have plenty of work to do this winter.
So is this something a newbie can learn easily..or best left to a master machinist?
Since October ('19???) was in view:
You don't need the alloy collar, I installed mine without any. Just turn down the OD of the IB guide to the same as that of the AVL guide, BUT do NOT machine the OD all the way to the original flange, cut it laterally only as far as it needs to go so as to produce the same installed height as the original. The difference in original IB guide OD and newly cut AVL diameter naturally creates a "step" that is enough "bottom" the guide firmly when pressed into the case. Not sure I have a photo of this... if I find one will post it. Honestly if the guide was installed a millimeter higher or lower in the case it probably would make no difference whatsoever. I don't see anything critical about this, there's a fair amount of leeway. I think it's the AVL intake guide that's actually a lot shorter than it needs to be - meaning a lot of space between the bottom of it and the tappet foot / cam lobe. I wondered sometimes if this was part of the problem with the feet snapping off - just too much tappet stem too far away from any kind of support.
Anyway, you don't need to be a master machinist, but the press-fit should be right, meaning you should be able to hold a half a thousandth tolerance, anyway. In my case I was working on a really crappy, oversized lathe and the press-fit ended up a bit light... so used loctite sleeve retainer and also drilled/tapped horizontally into the timing-case casting to add a couple bolts to lock the guides in place... just extra insurance.
Maybe I've been in India too long - but the bike seems to be running just great.
No bike model would have survived in India for seventy-odd years if it were not at least minimally tolerant of hack-jobs...
-Eric