SF2 tappet adjusters

martymoose

martymoose

Hero member
Location
Sydney, Australia
Many years ago when my SF2 was my daily transport, I got hold of a set of adjusters with a ball end, so the foot sat flush. Don?t think they where genuine Lav, something aftermarket. Anybody use this sort of adjuster?  Brand name? 

Thanks
Marty
 
Marty, I've used Rotax tappet adjusters in several motors with excellent results. I buy them from the importer, Floods. They're in Lilydale (outer Melbourne) but I'm sure you could phone them or buy online. You do need to shorten them a tad and possibly grind a little off the tip of the valve and maybe a tad from the underside of the rocker arms. It sounds complicated but if the head is apart it's nothing And I can VERY HIGHLY recommend the mod. No more ugly pitted tappet adjusters and valve heads.

Beware of imitations - not just any old 'elephant's foot' tappet will work.
 
Met Gary and Trevor (? don't quote me - could be other brothers!!) at the place in Lilydale. Their wives all work there too i think - family business of old. Yes, Burt was synonymous with Bultaco - shop in Box Hill. The new biz is huge on light aircraft, hence the Rotax motors, which are the bees knees for ultralights or whatever.
 
I had this on my 73 trident, the valve stems were eaten with the originals, changed as a guarantee by the mechanic
 
sfc28 said:
I had this on my 73 trident, the valve stems were eaten with the originals, changed as a guarantee by the mechanic
Click to expand...

Can't imagine the Trident used M7 threads in their tappet adjusters, so could have been a more complicated affair - but sounds like it was well worth it - as it is with SFs
 
Piranha Brother 2 said:
Can't imagine the Trident used M7 threads in their tappet adjusters, so could have been a more complicated affair - but sounds like it was well worth it - as it is with SFs
Click to expand...
Plenty of other vehicles used that type of adjuster, Rotax didn't invent it. The clever mechanic would have found some imperial ones that fit. Tridents problem was also that the valve lifters didn't operate ideally through an arc of movement, but pulled the valve as they opened it, according to Britbike boffins at the time. Piet has come across this type of mod that has busted up, and I have seen Ducatis with broken ones, so make sure you buy the real deal.
 
Marty,
I'm sure I have the part number somewhere, I put new ones in the racebike and the sfc, but I can find every other receipt but not that one.  I just rang the rotax aircraft mob and told them what I wanted, M7 thread etc.  I don't think there are many different types.  Aircraft engines change s-l-o-w-l-y.  Didn't seem like an issue IIRC, just call them.
 
I found one of the screws of the trident, it is not metric, very English, 7.73mm .... In any case this bike was a real shit, engine exploded 23000km
 

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martymoose said:
This from our spare parts supremo Brett
Nuevo genuino Rotax / Aprilia v?lvula de ajuste Tornillo ap0240205
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, and one hopes Brett also knows of a low cost supplier.
adjusting_screw_240-205.JPG

I thought Rotax UK was just a tad high?  (dunno)  no?
Ya gotta luv ya Lav  8)
 
P & M recommended mushroom headed tappets over elephants foot type on both my T160 and Hurricane: far easier to measure the clearance correctly too.
 
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