I don’t intend this to be a blow-by-blow account of
rebuilding an SL350 motor. An engine rebuild is an
engine rebuild, and the SL isn’t even a common
model, anyway. This will be more a description of the
journey itself, along with a few noted points of inter-
est, er, pointed out. So, in 1972, while Triumph own-
ers were still trying to squeeze a bent feeler gauge,
a 7/16” spanner, a pair of pliers to hold the square
end of the adjuster and three hands, all into the small
space under the rocker cap, Honda owners revelled
in the luxury of eccentric rocker shafts. Just adjust the
valve clearance with a screwdriver in the slotted end
of the shaft and it’s pretty much set for life.
Whoever last worked on the bike made sure the little slotted screws holding the cam
sprocket on were never going to come loose – by chiselling over the ends. Getting them
out again was, er, challenging.
Right enough, something had got trapped between the cam lobe and the floor of the
cambox, and clearance here is minimal as the floor acts as an oil bath to lube the lobes
by splash. In fact, the piece which had been broken out was still sitting on the top of the
cylinder head (you can see it just below the hole). Funnily enough, a spare secondhand
SL350 cambox appeared on eBay that same week not ten miles from where I live for
£15. But it was a bit too clean to go on this motor – and 15 quid is still 15 quid out of the
budget. Besides, repairing things is much more fun, and my mate Billy has some really
strong glue in stock...
I’m not usually this precise, but then I usually work on beat-up old Brits. So, seeing as how
it would be a kind gesture to mate all the rockers back up with the same cam faces they
were running on, a bunch of freezer bags made for simple and effective identification.This is an unauthorised hole. Unauthorised holes in motorcycle cases are not generally
A Good Thing. As it happened, I’d already realised something was awry earlier on; I’d
removed the cam cover to pour a little clean oil over the cam before kicking the bike over,
only to see it pour straight out again and run down the left hand cylinder head. So lifting
the cam out only revealed what I’d already suspected.Sometimes you have to admit defeat. I’ve puzzled and pondered over why anybody would
cover all the mating surfaces of a cylinder head with random chisel marks and gouges,
but, in the end, I just gave up trying to figure it out.http://www.100-biker.co.uk | issue 250 | 100% Biker | 97