virginiatrials

Just aquired a fairly nice 1975/76 350 sherpa t (159)that has been sitting for at least 10 years. Tonight I disassembled the stock bing carb and it is worn out. The VM28 Mikuni is cheap and is an excellent replacement from what information I have been able to find. Hard to go wrong with a mikuni. Like to know if anyone has the jetting specs for the VM28 for my bike and any other pros and cons concerning this swap. Thanks in advance,cheers,Jim

The Bultacos,TY Yamahas, and Montesa are the most common.Genuine Yamaha Majestys are rare but clones are fairly common.Later Honda's seem to dominate the upper Vintage classes. SWM's are around and competitive ,but not common. Cheers, Jim

The greatest weight savings I found other than the silencer was the aluminum swingarm(about 1.4 lbs lighter than the chromemoly steel unit and much more rigid). I replaced the heavy steel spacers between the wheelbearings with titanium tube saving almost a pound(titanium tubing is available from McMaster-Carr). I was tempted to have titanium axles made, which would have saved a pound or two, but could'nt justify the cost. I also made a aluminum replacement for the steel airfilter housing. Removal of the rear frame loop for the newer style fender saved a litttle. Lastly,since the kickstand mount was broken off the Aluminum swingarm when I found it, I opted to run the bike without the kickstand,saving another pound or so. Cheers,Jim

Thanks all, Tried to upload more than one picture but could.nt for some reason. Johnny, the axle worked fine ,just needed to be shortened a bit. I will be moving to vintage B this year, thanks for your help.See you at the Candytown event. Jim

I thought you SWM enthusiasts might enjoy a picture of my SWM project .The bike is a 1980 Tl 320 that was originally sold in England, imported to Califoria in the late 80's and found last year in a salvage yard in Montana. I have tried to replicate Bernie Schriebers last Factory TL320 before he started riding the Jumbo. My project incorporates all of the mods from the french Burgat article on this forum and everything I could see from the photos in Bernies' book "Observed trials". My only real change from the original factory bikes is a modified Pro Circuit Racing silencer that weighs about a fourth of what the original did. That and other weight reduction mods bring the weight down to about 190lbs. I also moved the footpegs back and down which made a world of difference in handling.The original rear frame loop has been modified and the rear fender changed to the later type configuration. Lots of other mods have really transformed the bike to a great twinshock competition machine. Many thanks to Martin, JohnnyB,Tony 283, pedronicsman and many others who have offered parts,help and advice. Cheers, Jim

Hello Martin, Neat find. The chrome head pipe looks like a TL320 item. It would look great on my Schrieber 320 works replica which is nearly complete. As always, I am interested in buying works parts if you will part with it. Also, is the interior of the mid box on the modified pipe/silencer stock or modified? Does it have the perforated tube inside or has it been gutted and made into a sort of expansion chamber?,Cheers, Jim

Thanks, I found Comeca. They are in Canada and have the kickstart hub and various other Rotax/Can am parts. thanks ,Jim

Anyone know a source for rotax kick start hubs(not the lever, the piece that clamps on the shaft)? Mine snapped the other day and I have not had much luck finding a replacement. Is Comeca still in business, they were offering them a few months back, but I can't seem to find them on the web now. Help! Thanks ,Jim

The core/perforated tube is intact, but no remains of packing were found. What did SWM originally use for packing that would disintigrate entirely? Seems strange that some of the original packing would not be found. Maybe the factory simply accidentally left the packing out of this particular midbox. Thanks, Jim

As many have suggested, I opened up my exhaust mid box and found plenty of residue which I removed, What I did'nt find was any sign of packing. Is this correct? Should'nt the box have fiberglass packing? The box showed no sign of having been cut open before. Any suggestions? Thanks and happy new year,Jim

Pedronicman,Thanks for the reply. Your setup is exactly what I had in mind with the exception of replacing the midbox with a custom made aluminum through core type silencer with the same internal diameter. The original midbox seems to be nothing more than a heavy, through core type. I removed the airbox lid(as shown on Burgats' bike in the article)last season and it seemed to improve breathing substantially but, I think I will also inlarge the filter surface area as you have. Again,thanks for the help. Cheers, Jim

Has anyone tried removing the perforated tube inside the midbox to make it more like an expansion chamber? With the perforated tube in place it seems that the midbox is really just a muffler. A straight section of pipe would have virtually the same effect performance wise it would seem ,although the exhaust note would be a bit louder(but the bike 2.4lbs.lighter). I am considering combining a gutted midbox and a MX type rear silencer or custom aluminum replica SWM rear box to improve power( and save about 5lbs). I am familiar with making changes to the exhaust systems on piston port engines , but less informed on rotory valve engines, so I am not really sure if this would be a waste of time and effort, or a worthwhile modification. Anyone tried this sort of combination(or any other exhaust mods on the 320)?Any insights /ideas are appreciated. Thanks , Merry Christmas all, Jim

Martin, Thanks for posting the pic of Bernies bike. Good to know these bikes have survived. I guess the bikes simply run well enough on points that the factory saw no need to change. Jim

Hello Martin, I was afraid of that. Did any of the works bikes have a motoplat or other CDI to your knowledge? Speaking of works bikes,does anyone know the whereabouts of a genuine one,especially Burgat's or Schieber's? Jim B.

Will the CDI from the CanAm motocross bikes fit the TL 320(might have to modify the flywheel somehow to make it work on a trials bike)? Seems like I remember almost all MX bikes had CDI by 1980, something from the 1975-77 CanAms should fit ,anyone checked this out? Did the SWM factory TL320's have CDI(I bet they did)? Jim B.