The DT was never meant for these shores. It was developed in the early sixties in an American desert by a genuine desert racer, financed by men in ties from Yamaha. An undeniably successful bid to cash in on the Great Outdoors rush that was mushrooming in the States. Its chassis design was finalised on a series of whoop-d-whoops. Anyone who’s ever tried to speed over a series of of thirty foot high mounds will be aware of the retribution incurred when your nuts are kissing the tank and you're nose diving sideways towards the middle of the third hump...
Apparently, Yamaha never quite got the chassis design right, but back in the seventies they were the only Jap manufacturer who were producing a trail iron that, with a few sensible modifications, could actually work off road without the rider being abruptly savaged by some dirt induced trauma.
Britain is littered with Americanisms, envy has taken over from disdain. I find myself the owner of a little bike that was, and is, the very epitome of soul searching America, which is despite the fact that I have neither time nor envy for most things Yankee (starting with white wall tyres down to JR romping on top of Joan Collins).
I bought mine new, just after they finished making them in ’83. It was looking lost and collecting dust, discounted to a mere £584 probably one of the last ones sold in Britain. The first prototype 250 dates back to 1959, so the basic two stroke single engine had a pedigree of 24 years. Despite reports in Motorcycle Sport on the superiority of XL185 and that the DT175 wouldn’t go beyond 10000 miles without a rebore, they forgot to mention that it’s much easier to rebore the DT than resleeve the camshaft in an XL alloy head, sort out the camchain and all the oil leaks (I’d done 25000 miles on the similar engined RS250 for my sins).
The fact is, I’ve done 19000 miles on the DT. I ran it in carefully and it shows little sign of giving up yet. My model, the MX, has 17hp, monoshock, CDI, six gears and chain tensioner. The motor is so full of torque that you can lift the front wheel in third gear without really trying. In fact, it’s geared for off road use and benefits from going up two teeth on the gearbox sprocket (to 17 teeth), giving much less busy cruising on the road.
Running it from Cambs to the New Forest, it would hold over 70mph, amazing my friends on their superbikes. It is essentially a solo machine but that didn’t stop me loading it up with panniers, sleeping gear, rucksack on the rack, and guitar strapped to the front forks, with my wife sitting on the back mudguard (I kid you not). On the way back we raced an Astra. The result of such highway madness was that the gearbox sprocket was left with just four teeth!
If the DT is a fast little bike, it has hopeless drum brakes. The front fades faster than a self induced hard-on and the back doesn’t work at all in heavy rain or duck ponds. With the correct exhaust, and a motor in good condition, it will do 8Smph - even with raised gearing it'll run to the redline in top gear. It will accelerate as rapidly as something like an SR500 up to 60mph, but the handling is something else again.
At first, fuel consumption was 65mpg. Oil usage was, er, interesting and nowadays it would be worth keeping the oil in the petrol tank and fitting a sidecar full of petrol honestly, consumption is terrible in later life, mostly due to non-standard exhaust and sloppy piston fit in the bore - performance suffers very little though.
The DT was bought for use solely on the dirt, but due to cash shortages has done everything else. Cycle part maintenance is an on-going thing on a dirt bike. The bars were bent like a hairpin once after failing to negotiate a council gravel heap (this one wasn’t even in the middle of the road, mind you neither was I). Parts have been bashed straight, welded - only a cast footrest bracket proved a real problem, but this was eventually bodged in true Heath Robinson fashion using a bit of a ship! The tank dents are now hidden by a cover and the indicators have been thrown away, despite well designed rubber mounts.
Rubber covers prevent water from entering anywhere something all bikes need, even the kickstart is sleeved (and has never seized up). The mudguards are scarred and discoloured but I haven’t managed to break them yet. The spoke wheels haven’t collapsed yet and still have their original bearings, but the front spokes have to be tightened regularly - a can of WD40 is needed to free the rusted threads.
Tyre wear is reasonable, probably because knobblies have a lot more rubber than others, and, anyway, come free from the MOT reject heap outside the local Grab-The-HP-And-Run-While-The-Going’s-Good motorcycle shop. The swinging arm bearings went at 16000 miles. Their replacement revealed that the whole monoshock set-up was about to fall apart. Fibre bushes, steel axle and inner bushes were replaced after much work with enlarged EN16 steel spindle and phosphor bushes - I even added a grease nipple.
A base gasket blew at around the same time, but was simple to replace. A chronic problem is condensation in the gearbox, turning hypoid into thick white (no I won’t say it) sludge, which pumped itself all over the engine one hot day at 75mph on the motorway after the breather had fallen off. This was probably due to the vibration, which also took out things like seat bolts, exhaust brackets and the ribbed chrome guard over the headlight - which is illegal but standard and saved the headlamp a few times. Vibration takes the form of a buzz (not the illegal sort) felt harshly through the bars flat out on a long run and through the footrests in town.
Don’t know about ignition timing but the DT has always had an annoying stutter at around four grand - which has become worse with age - but you just power through it most of the time. There is no power band as such, the engine has enough guts to pull, two-up, in top a from 20mph or to get out of most muddy fields in third. This was spoiled when I fitted a Gianelli pipe at 17000, which produced more power at the expense of a hole at five or six grand. The pipe is about to rust through soon, so the engine will get a rebore at the same time - which it surely deserves. The total cost of doing a decent rebuild comes out at around £340, which includes a new crank and rechromed original exhaust. Expensive but I think the bike is worth it.
The gearbox has a brilliant action, but the clutch drags when warm and sticks like a dead cat to a radiator when cold. I hope when rebuilt the engine will last to around 45000 miles before a new barrel, head and gearbox internals will be needed.
Some bikes you buy, ride, love, live with and hate then sell, but for the life of me, I’ve done the DT up twice immaculately in anticipation of finding someone to give me loadsa money, but I just could not sell it. I reserve such affection for only two other bikes - a CB450 in heavily modified frame and cycle parts that is nearing completion and a Harley!
The bike is great fun to ride. It has many subtle design points - like the chain tensioner that cuts adjustment out for months, monoshock that soaks up huge pot- holes, fork gaiters that’ve left the bike on the original seals and eccentric snail type rear wheel adjusters. It still starts second or third kick and the only maintenance, apart from changing the gearbox oil, is the chain and spark plug (although coking up is minimal).
If you want a spare bike for going wherever you want and one that will hold its value (DTs are overpriced in MCN and local papers - anything older than ’82 should be less than £250), it is one of the best two strokes ever made, worlds apart from the scrapheap bound plastic 125 trail bikes...
Michael Fairbairn