750 sf valve guides

Mr Vegetable Trousers

Mr Vegetable Trousers

Junior member
Location
London, UK
Hello
I have two broken valve guides. Both inlet.
Is it possible to just heat the head and drift them out and then drift in new ones?
That’s what I do with my old Triumphs but maybe Laverda’s are more sophisticated??
Gawd knows how it happened.
There’s no damage inside the head that’s consistent with a chunk of valve guide rattling around in there…
IMG_4852.jpeg
 
heat the head to 200C and drift the guides out
clean up the guide bore, heat again and drift in new guides

because Laverda guides are so short you will need to recut the seats once the new guides are installed and honed to size
 
Factory replacement guides came with a few different external dimensions (like pistons). When I swapped to 7mm SFC guides I just bought and fitted what came and they went in no prob. Yep, definitely need to cut seats.

That's a pretty serious breakage there. Wonder there the hell the missing bits went? Were the valve stems loose in the guides? My SF1 guides were still pretty much perfect when they came out at about 160,000km. Never had a prob that none of them had stem seals either (may have helped lubrication).
 
And make sure that a very reputable place does the work. It is important that the interference fit of guide to head is correct and there is no scoring in the alloy before fitting the new guides. If done correctly they will not need much cutting.
 
I have a period 750 race bike. The guides are cut where they would protrude into the inlet. No doubt improves flow.
You might consider that as a cheap alternative.
Paul
 
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