Vintage Thing No. 15 - Armstrong MT500

This ex-Army Armstrong MT500 belongs to my mate Pete Low and is an excellent example of a “back to basics” motorcycle. These bikes have established something of a cult following. They were never available in the shops but were the British Army's despatch bike of choice for many years. As they've been sold off as military surplus, a number of people have realised what great bikes they are.


“I bought mine in late '05,” says Pete, “partly with the idea of doing MCC trials on it. I liked the ruggedness, no chrome or shiny paint etc. but discovered the less desirable points that most MT500 owners will not admit to.

“It was difficult to start from cold, and had a tendency to cut out at low revs, especially, it seems, at traffic lights. Both these problems are increased by the awkwardly placed left hand kickstart, but can be improved upon by junking the standard Mk2 Amal concentric carb and fitting either a 32mm Mikuni or 34 mm Dellorto. This also helps a bit, but not much with the poor fuel consumption. I was lucky to get more than 45mpg ! This thirst also makes the 13 litre fuel tank a pain as well, offering little over 100 miles range. Also the MT500 has a pretty poor 6" drum front brake.

“So after enjoying a few months evaluation, I fitted the Mikuni carb and the front wheel and disc brake from an MT350 Harley Davidson, which is the successor to the Armstrong and shares 80% of parts. This mod also requires the nearside fork slider from the MT350. The result is a very effective brake. I increased the range by fitting an aftermarket Acerbis tank. First I used an 18 litre one for a Yam. XT500, but then got a 22 litre tank for a Honda XL 500. Both fit the MT500 well with few complications.

“As I was still planning a go at MCC trials, I didn't fancy getting stuck halfway up a muddy track with a stalled engine and only the horrid lefthand kicker. So I got hold of a Rotax engine with electric start, which from its grey paint was probably from a CCM. I expected it to be a 600cc, but it turned out to be 640cc and capable of maybe 55bhp, compared with the MT500's 32bhp ! However as it had the 670 "scrambles cam" it turned out to have loads of lowdown torque rather than bags of power at alarming revs.


“Modified in this way, the Armstrong turned out to be a really good bike, immensely satisfying to ride, as something I'd created, and one of the best bikes I've owned. I still wanted to have a go at MCC trials and got an entry in the "O" class, suitable for beginners or those running delicate antique machinery. I had a streaming cold, hadn't got anything like the optimum tyres allowed by the regs, but still decided to have a go at the 2007 Exeter Trial in very early January.

“I got a bit disheartened during the night, but carried on, footing out of anything that wasn't tarmac and was astounded to get a finishers certificate at the end, despite having missed out some sections all together. As several kind friends in the MCC pointed out, I wasn't fit, didn't have proper tyres and they reckoned an MT500 was an awkward great brute of a bike to begin on.

“So it may not have worked out well as a trials bike, but in September 2007 it proved to be a great Grand Tourer, possibly even with Round the World capability! It was enormous fun on a 3 week, 4,000 mile trip around France, the Pyrenees and the Alps. Luggage went in two Andystrapz soft panniers - 40 litres each and a good fit in the tubular steel army pannier racks - a tank bag and a pair of gas mask bags at tank pannier bags. The bike never missed a beat (well, apart from a broken throttle cable) and with a Scottoiler fitted the chain would only take one notch of adjustment when I got home.

“The 640cc engine was remarkably economical at touring speeds, easily capable of 60 mpg - thats what I call an improvement! Despite being no lightweight it took me over some great long distance, high altitude trails and I reckon that apart from pillion capacity, there's nothing a BMW 1200GS can do, on that kind of trip, that my "ratty old army bike" can't do just as well.

“But, I still fancied a proper go at the MCC trials. So in late '07 I got another MT500. They weigh 161kg. as standard, so off came the luggage racks and a lot of other unnecessary bits of metal saving at least 25kg and further weight savings are planned such as lightweight indicators, LED tail light and an Acerbis headlight.

“But still the nightmare of being stalled without an electric starter looms. Yes the starter motor is extra weight and so is the bigger battery, but I could leave the kickstart lever off! Well I've now got another electric start Rotax engine 560cc from an Aprillia Freewind.

“Fitting the electric start engine to the MT 500 frame requires cutting a bit off the frame's front (oil bearing) downtube but, having done it before, the hacking bits off doesn't scare me and a friend will TIG weld it all to ensure oil tightness.

“Early in '08 another MT500 came my way! As I had rendered 2 MT500s completely non standard, and as this one showed distinct traces of sand coloured paint, I've decided to restore it to standard army spec. in desert trim. I am on the track of its full service record, so it should be possible to tell if it served in the 1st Gulf War, or was just painted in readiness but sat in a warehouse. Its not that I think the 1st Gulf War, or the present one, are anything to celebrate. But these bikes were ridden by our forces, in unmodified state, and such things should not be forgotten.

“So I have become a bit of an MT500 specialist/nut/addict. But they are such brilliant bikes, built to such a high spec. The front wheel has 4 ball races and the rear wheel has 6! This compares to 2 bearings per wheel on most bikes. Swing arm has needle roller bearings and a grease nipple. The Rotax engines are reckoned to be unburstable and the frame and cycle parts are similarly rugged in construction. As I've said they have their faults, but all of them can be easily sorted and as many others have found, can be extensively modified.

“The MT350 Harley Davidson came about when Armstrong sold the design to them. Main differences are disc brakes and an electric start engine. So it is easy to slot a bigger electric start engine into the 350's frame. 350's date from the 90s and are younger bikes and fetch higher prices, sometimes up to £1,500, though non runners can be had at surplus auctions for as little as £400!

“Armstrong MT500 were built by CCM in the early 80's, and sold off by the MOD around '96, and command lower prices. A sound one with all its pannier frames etc. shouldn't cost more than £800. Be aware that many have had years of abuse, either as "just a winter hack" with minimum care or maintenance while others have descended (shudder) to the depth of being a "field bike", something thrashed around a mud patch by kids with zero mechanical understanding. If offered one of these, walk away, unless you can get it for less than £200.

“There is an excellent internet forum for MT500s & MT350s with space also for the Can-am Bombardier army bike which preceded them. The "MT Riders Club" began in April '07 as a "virtual motorcycle club" but has become a real motorcycle club. There have been green lane events, there is a national meet in July and we have 300 members from Inverness to Penzance, as well as the U.S., Holland, Germany and even Jordan. Every day there are posts on technical questions and answers, and also spares wanted and for sale.”

Thanks Pete for your glimpse into the secret world of the Armstrong MT500. I remember the "spray it matt black" survival bike craze of the last century - the Armstrong green army is a much more practical movement IMHO and just as matt. they are far too good to be used as mere field bikes. I find myself quite tempted by one but then that's nothing new when it comes to Vintage Things - I always want to take them home with me. I'll try and resist temptation and save up for a stainless zorst for my BMW.

Having seen and heard Pete's MT500 - the first one in his growing collection - I can tell you that his is very well sorted and very well thought out. I look forward to seeing his second and third Armstrongs!

Variations on a theme by a motorcycle composer.

To see more pictures of Pete's bike – in some very exotic locations on last year's Tour de Col – follow this link.