WHO IS JON SLENZAK?
When it comes to working on Can-ams there is no better person than qualified suspension technician Jon Slenzak. An American who now resides in the UK, Jon is well known in the suspension world. On completing my bike, Jon told me his story:
“I started within Can-am at the beginning in 1973 and lasted three seasons to 1976. I worked for Malones in New York, who was the distributor of Can-ams on the East Coast of the States. I later transferred direct to Can-am to lead the building of their race bikes. My main role was to build the race bikes for Buck Murphy, Tim Harte and Mike Runyard, the main American enduro riders at the time. They never seemed to stay healthy, so it was an up and down time.
“I had the displeasure of driving the Can-am race truck. Damn, that was a bus to drive, weighing well over its safe load, it had a full machine shop in the back. You simply couldn't stop it. I drove all over the US in that thing. Although the bikes were built in Quebec, our main test facility was in Talladega, so we were always back and forth. I later moved to Europe in the Eighties to set up a company specialising in race suspension for road racing. I got involved again with Can-am via WP Suspension used on the monoshock bikes.”
Although in his Seventies, Jon still works every day from his home workshop rebuilding suspension for bikes and cars. In addition he works on complete rebuilds of bikes with his workshop full of Montesas, Suzukis, AJS, Husqvarnas and obviously a few Can-ams when I visited.
The bike is based around the 1987 Can-am
ASE frame and body components, with direct link suspension and an earlier Eighties drum-braked Marzocchi front end. By using Rotax's 350 Jumbo trials motor in an enduro rolling chassis, CCM came up with the really modern concept nearly 30 years before the current trend of European bikes featuring the same set-up – think KTM Freeride and Sherco Long Ride as a couple of examples.
The bike arrived in a condition typical of a 30-yearold dirt bike – unloved, covered in spray paint and with all its plastics missing, which is never promising. However a good clean-up revealed a much nicer prospect and showed the bike was actually in good condition. More importantly the bike had a clean frame, devoid of rust, showing little wear and was straight, all of which are indications of not too hard a life. Best of all, the header pipe was dent free and the airbox was complete, which was unusual as these two items rarely arrive in good condition or complete given their actual location on the bike. As we were in the middle of another Covid lockdown I decided to tear the bike down and rebuild it.
As far as I was concerned the good news carried on through the strip-down of the bike; its initial looks belied the actual condition and the further I went into the strip-down the more it appeared to be correct, complete and unworn. The usual items like handlebars, cables and levers had suffered but they are easily replaceable; original-looking, rather than original, was going to be acceptable on this bike. For the same reason the missing plastics weren't going to be a problem either. The go-to place for cables, in the UK at least, is Venhill, with the company providing not only new cables but Magura levers and one of its own proprietary throttles, all of which are off-theshelf things. A quick call to Renthal had one of its Classic bend enduro 'bars heading my way and this rounded off the controls set-up.
A quick look inside the motor showed it had a new piston so this boded well for the rest of it. To be on the safe side, and it being the same Rotax unit as used in the SWM Jumbo trials bikes, I packed it up and sent it down to Martin Matthews at MOTOSWM for a look over. Although the piston was new, Martin thought it best to swap out all the bearings and seals to give it a
complete refresh. At the same time he installed one of his electronic ignitions, thus doing away with the hassle of points ignition. This should allow for easier starting and greater reliability of spark.
When built this particular bike would have worn plastics from a variety of places such as Acerbis items with proprietary Armstrong side panels. Luckily DC Plastics in the US make reproduction side panels to fit the bike and which MOTOSWM was able to source for me as part of its usual shipment from the US. I swapped the other plastics for UFO vintage units from MD Racing Products as I felt the vintage range better suited the bike and provided an improved enduro rear fender with tail-light. I did revert back to Acerbis for the headlights, using its classic Elba enduro headlight.
The only original part missing from the bike was the side stand. Luckily, I knew exactly who to ask. Jason Adams of 219MX in Canada is a good friend and regularly travels over to the UK simply to attend the Telford show. Jason's day job is a supplier of Can-am parts, both second-hand and NOS. A quick message saw a stand arriving in 48 hours, not a bad delivery giving the pandemic and nearly 3500 miles of shipping.
When a bike is in good basic condition, rebuilds happen quite quickly and straightforwardly with only the issues arising from 30 years of standing in a barn… the bike that is, not me. Anyone talking about frame finishing these days mostly means powder coating and so it is with this bike. As the main point of the build was to create a usable enduro bike which looked nice too, I didn't go overboard on the polishing side with the alloy components. Instead I cleaned and polished them by hand but not to a mirror finish by any means.
Once the bike was in one bit it was time to start it up. Always a nervous time as one can assume things are okay but… Initial starting and running of the bike showed the original Amal carburettor was not a strong performer, making the bike very difficult to get started with almost no idle adjustment. SWM Jumbos run a Dell'orto carburettor so it made sense to try a new one of the same type. The difference was remarkable, second kick and with plenty of adjustment for idle. Once the bike was running to my satisfaction I modified a few bits such as the airbox. The original box contains a foam air filter stretched over a steel cage but I wanted to make use of the UNI composite filter as used on the later model Canams. These are much better, being more modern. A modification for me personally was a lever-operated decompressor, as a combination of high-compression trials motor and arthritic knees meant I had trouble giving it a good kick to start.
Once the bike was working I checked over the wheels. With drum brakes at either end the best way forward is to have the shoes relined, which Saftek did with its eco-friendly green lining, which is waterproof too. Michelin enduro medium tyres by Endurotyres sorted the wheels and new Talon sprockets on the engine and rear hub rounded out the basic rebuild. To finish the exhaust system I gave it a light rub with sandpaper and a rattle-can of heat dispersant paint brought it up to spec. I ditched the original end can, favouring a new FMF universal two-stroke silencer, as the stock inlet diameter matched the header pipe, allowing for a simple slip-on fitting.
All good so far, unfortunately, the bike came with the traditional CCM suspension set-up – an impossibly high seat with an odd bike geometry – which makes me wonder how much growth the designers expected the human race to achieve in a couple of years. Luckily, I had the correct contact to solve the problem, step in Jon Slenzak. The bike makes use of a 4:1 suspension ratio – one unit of shock movement equals four units of rear wheel travel, giving Jon a head start in making the bike more usable for a 5ft 9in rider. Changing the geometry slightly, dropping the rear shock by 25mm and the front forks by 50mm, the end result was a seat height dropping from 1000mm to a friendlier 800mm.
Hopefully with the pandemic in decline and the dirt bike season once again kicking off, we will be back on the Vinduro scene.