Armstrong CMT 350


So here we have the very rare Armstrong CMT 350 one of only 25 ever produced , using the Rotax engine as fitted to the SWM TL350 Jumbo.


Production started in August 1984 and stopped 11 months later in September 1985. Despite its revised frame and rear shocks many felt it wasn’t as good as the Hiro engine bikes. This is understandable for those of you who know what the SWM Jumbo was like, quite a handful at times and not to everyone’s taste. The early bikes or pre production bikes had SWM silencers fitted.


Although this isn't my bike , its one exciting project ...............


As you can see the top left bike has a complete SWM exhaust system. The bike above which John Lampkin is riding has a totaly different front pipe and again had the SWM Silencers. The other two pictures show the final production models

For more information on the Armstrong trials bikes , spare parts and  expert advice click the link below

The first few pictures  show how the bike developed and how it should look?

Below is the project bike , all complete but in a sorry state at the moment, that said nothing a bit of TLC wont sort out !

As you can see the exhaust is complete and Armstrong even added there version of the clutch lightening arm !

For the eagle eyed , you just can't beat a spanner for a rear brake arm.........

Here we have the project as you can see its in a pile of bits alot of original and some new parts already ,  first job is to do list of parts i will need to bring this bike back to its former glory. Then alot of time cleaning, repairing and painting.

The owner has already done all the engine work , stripped down checked and bearings replaced, all I have to do is the cosmetics and final adjustments. The frame is in good shape just one exhaust lug to fabricate and weld on for the middle box , swing arm needs a stand bracket and chain tensioner bracket (both missing?)

Here we have the engine in a sorry state the crank cases are in very good condition already changed by the owner because the front sprocket chain protector lugs had smashed off , can be a common thing with the rotax engines.


Two things different to the SWM engine , exhaust front pipe mountings are studs in the barrel and the head looks machined for the frame down tube ?

Head now finished with heat resistant satin black paint then some time spent on the fins to finish it off, still got the barrel and crank cases to do.


Flywheel and clutch cases both stripped,cleaned, etched and then high build primer to help remove minor marks once flatted .


Finished off with a satin black , once fitted with new allen bolts should look mint


Engine now looks like it should pleased with how its turned out given its starting condition.

Exhaust bracket weld ground off and new bracket made and welded to frame, used a thicker metal to give it more support. Front pipe in a state but managed to make it look 100% better before i paint it, very bespoke exhaust this must be the 3rd or 4th different front pipe designe i have seen

A quick look at both 350 motors SWM and the Armstrong


A picture for reference Can-Am  350 trial  as you all know same bike different badge

Taking shape , frame painted and engine sat back in.


Barrel and head tight fit to frame, SWM Jumbo finished off better to be fair and no need to machine the head on SWM


Exhaust now painted and fitted to bike along with bash plate, bash plate cleaned and polished quite well to say whats is condition was like

With work and one thing and another not worked on this bike for best part of  6 months, thought it was time to do at bit more !


The tank I have been putting off  not because its hard to repair , its just messy ,dirty and takes time to get right . The bike never had a tank when the owner bought it , so its not just a simple patch up job as you see in the pictures I have to make it fit the frame  and clear the exhaust front pipe and middle silencer, making it look nice and painting is the easy bit. Fibre glass is easy to use , easy to re fabricate things  and strong when done . Whilst the tank looks like the later CMT320  it has different shock mounting positions

The swing arm on the  left is a special one , its about one inch shorter than the other one , it also has a smaller brace to allow the wheel to fit


We think it was a prototype or may be a works swing arm , anyway it now has a stand bracket made and welded on , just waiting for a new stand to be made 


Below you can see years of the chain rubbing on the swing arm the top is the worse obviously  never had a chain tube on for some time.


The rear brake mount  welds are poor , an easy fix bit of welding and grinding required.


Once done it will have a top chain tube  in future !

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