Many of you will have spotted a recent newcomer to VMX in the form of Sammy Lyle and his beautifully crafted Ducati Weslake. Ok some of you maybe thinking what the heck is a Ducati Weslake - well its basically a hybrid built by Sammy based around a Ducati 450S Trail frame and a Weslake speedway engine.
Just as bit of history Weslake have a huge background in speedway with Peter Collins of Belle Vue Aces and England winning the 1976 Speedway World Final on a Weslake bike, and then Bruce Penhall riding a Weslake to many successes in the early 1980s, including two World Individual Speedway Championships. Given the success of the Weslake engine - Harry Weslake was awarded the Segrave Medal in 1976 for his part in developing this amazing engine.
So now to Sammy's creation - best left in his own words.
"The rolling frame was given to me by a mate, it was a 1972 Ducati 450S trail bike. It came to me with no engine, and the shocks and forks were stuffed. But it still had the Borrani mud catcher rims and Ducati hubs, seat base and that beautiful tank. I already had 2 Weslake 500cc 4 valve pushrod speedway engines as I fully intended to build a retro speedway powered scrambler so when my mate gave me the bones of the Duke I couldn't believe my luck.
Then the work started. I lengthened the swing arm 50mm and laid the shocks forward a bit using the original Ducati multi-position mounts on the frame. I then made a a new cradle , including swingarm pivots - the frame is basically all new from the tank down and is coated in HPC exhaust coating (aluma-ceramic) which polishes up same as all the alloy components.
The engine is a 1975 Weslake 500cc 4valve pushrod running 12.5 to 1 compression ratio running on methanol with the original Amal carby. It is fantastically tractable , seemingly unstallable , yet winds out till it sounds absolutely scary. The engine produces around 60bhp and are believed to rev out to 8000rpm. The engine was also modified in the 80's to use a Jawa aluminium conrod , which involved shortening the barrel - not sure what difference that made, but either way there's more power than I will ever use.
The gearbox is a pre-unit Triumph 4 speed that was modified to a 5 speed by the famous Doctor Dave Crone (RIP), a name known well in NZ classic bike road racing circles. Dave also did the machining to adapt the Yamaha XT 250 steering head and forks to the Ducati frame. I made a crossover shaft to bring the gearshift from the right hand side to the left, as whenever I tried to ride right shift bikes (Bultaco or BSA) I kept hitting the brake when wanting to downshift.... I am way too old to learn that new trick!
Starting the Weslake is best done down a big hill. I have some powered rollers that my mates use with their road-race classics , but that only works if everything is bone dry , any moisture and the rollers wont grip the knobbly , I intend to try gluing some grit to the rollers in the future to get grip. When I first came to start the bike, I had a kickstart lever on the Triumph gearbox, but the kickstart ratio is way too high for a high-compression engine like the Weslake , so basically what happened was I pulled the bike back onto compression , got all ready , jumped up in the air , put my full 6ft2' and 95 kg into the kick , and I just stayed up in the air and went nowhere.
The lubrication system on the Weslake is total loss, helps to keep the dust down! Ignition is also total loss points system , after quite a bit of mucking about with radio control batteries I have settled on using one of those wee jump-start packs from Repco, did 3 motos at Argyll no worries.
The guards are UFO Plast retro style with the raised centre strip that matches the stripe on the Ducati tank to perfection. Another mate recontoured and upholstered the seat for me including the heat-sealed pleats. The fat-bars are on risers, and I'm using a Triumph-style twist grip rather than a 1/4 turn mx style one as I want to avoid unintentionally grabbing a handful of 60hp.
I am stoked people like the bike , having been in professional motorsport for over 30 years, I can truly say that there's no longer any ego tripping involved, I made the bike to satisfy only myself really, the fact that others dig it is a bonus , and any car or bike that makes people grin just has got to be a good thing."