In its day, ten years ago, the Yamaha DT175 was one of the most successful trail bikes on the market. Its single cylinder stroker motor put out enough power to keep the 240lbs in adequate motion, but it was never so vicious or unwieldy as to throw off novices at the first taste of the dirt. The DT125 was a bit too peaky and gutless at the same time, whilst the 250 was a bit too heavy and powerful for those without yonks of experience.
Buying a ten year old mono-shocker was quite an interesting experience. The bike'd been resprayed black, had polished cases and wasn't so dented that I could dismiss the owner's claim to have never ridden off-road. He admitted that the front end was off an earlier model after he'd had a mild prang with a bus. Running a magnet over the petrol tank revealed lots of filler! £250 changed hands, not bad as the engine didn't rattle and there was a new MOT.
The ride home was in the dark. The lights were paltry, just about adequate for warning car drivers they were about to run over me. After ten miles of wrecking my eyesight I was able to test the trail abilities when we ran off the road. On Metz enduro tyres the DT was impressively stable. The only problem was that I hadn't spied the log laying across our path. When the front wheel whacked into the wood we came to a sudden halt. I was sent flying over the bars, which smacked my thighs. After a ten minute cursing fit I was able to walk again. The front wheel was still straight despite the force of the impact.
The engine was a relatively sane unit, able to run between 1000 and 10,000rpm without any glitches, although it'd become more interesting from 6000 revs onwards. The exhaust was patched, rusty but intact, an essential ingredient for long engine life and good carburation. Expansion chambers, and the like, turn the bike's moderate taste for fuel and oil into an addict's desperate need for crack.
After the crash I sped home at all of 10 to 15mph, peering disconsolately over the bars to see where I was going for the next thirty miles. At home I had trouble adapting to the bright lights of the living room, searing brain pains and strange visions for half an hour. There doesn't seem any easy way of upgrading the pathetic electrics (the horn was useless and there weren't any indicators).
The other immediate downer was the front drum brake, which had so little power that I was sure it'd come off a 125 or maybe even a nasty fifty. Every time I tried to use it hard the lever came back to the bars and the retardation faded away to nothing. Coming home in the dark, speeds were so low that the lack of braking wasn't a worry, but rushing the bike through heavy traffic, where it was in its natural habitat, proved as frightening as putting a hand into a crocodile's mouth.
The shoes were down to the rivets. As I didn't know from which bike the wheel came, it was a matter of running around breakers until a used pair were found (for three quid). That made braking tolerable up to 50mph, but it'd still do a disappearing act if used in anger from greater speeds. The rear drum was one of those on-off devices, which helped in the dry but sent the DT into wild slides if touched in the wet.
Engine braking was minimal, but the motor made a nice burble on the overrun with amusing back-fires thrown in to keep the general populace awake. They were less elated by the smokescreen, with oil going through the engine at more than a pint every 100 miles. The tank didn't hold very much, so I had to check it every day. Despite its consumption of oil, the reed valve motor would run along at minimal revs without clogging up the spark plug and starting was a first or second kick affair. Impressive on a motor that had done over 35000 miles even if it had been comprehensively rebuilt 5500 miles before (the bike came with a wedge of supporting bills).
After becoming used to the brakes, I found it a more than adequate town hack. Plenty of speed and enough suspension travel to soak up the bumps. It was also quick turning, just breathing heavily was enough to have it doing a 90 degree turn. Two strokes of this kind of capacity are ideal for town work but come close to being dead meat out of town, where lack of go above 75mph makes them sitting ducks for caged maniacs.
Within about 600 miles, the crankshaft's oil seals were blown, vast amounts of oil being burnt off. As it's only a two-stroke single it wasn't that big a job to do, except that all the engine screws had corroded in solidly, needing the hammer and chisel routine. Some screws snapped off and had to be drilled out, others took out most of their threads on the way out. The steel and alloy had interacted to form an almost solid substance. I only whacked my thumb once!
Once I'd fixed the seals the motor was clean running and quite adequate for pulling wheelies, which got me pulled over. I told the cop I was practising for off-road work and he let me off with a warning. I felt duty bound to head for the nearest council tip, which was surrounded by barbed wire and patrolled by security guards. I found a hole in the wire and amused them no end by avoiding capture for half an hour.
The DT ran over the rough ground in a generally splendid manner. Back wheel slides were fantastic fun and it'd wheelie at just the pull of the bars. The tip was full of tramps, or at least they looked like tramps, who were picking through the mountains of waste. I'd charge at one of these dubious characters, sending him flying, head first into a pile of muck. Hilarious.
A group of weight lifter types with big sticks had congregated around the hole in the wire. I charged them, too, screaming a lungful of abuse. They moved aside, but I hit the wire slightly out of kilter, metal tearing into my jeans, jacket and lid. I got away with some large lacerations in my thighs which needed some stitches. I was impressed by the way the Yam had refused to chuck me off.
Proper off-road work was more difficult, especially if it was wet. My techniques were fairly rudimentary, more experienced trail riders might find the going easier. The back wheel liked to bog down in mud, a vast amount of revving and clutch slip needed until it would free up. I was soon covered in a layer of mud, as was anyone else within a 100 yards. Whilst I could get the front wheel way up in the air, the back wheel would often snag on the obstacle, causing the whole bike to fly backwards and land atop my startled, flattened, screaming form. The easy solution was to ride at 10 rather than 50mph.
Then there was the question of the good old water. Riding across a foot deep stream the motor cut out. I put my foot on what I thought was the stream's bed but turned out to be a deep hole. The bike and I fell into the raging torrent. By the time I'd dragged myself out both DT and I were soaked through. The bike took even longer than myself to dry out!
The same thing happened on really wet days. On damp surfaces the tyres always felt a little unsafe, as if there was insufficient mass to keep the DT on the road, letting it float like a duck instead. But that was the least of my worries. I was more concerned with the way that the vast amount of spray let past by the highly mounted front guard was soaking the engine. By the way, five minutes in the wet or off-road would quickly ruin the appearance of the DT. Replacing the HT lead, coil, cap and spark plug reduced the cutting out to a stutter. After I decided to give up trail riding I fitted a proper mudguard on the lower part of the forks which stopped most of the spray from hitting the motor; end of problem.
The gearchange action was clean, but the clutch, perhaps because of all the abuse it'd taken, started to slip 7500 miles into my ownership. It was another battle with the engine screws to fit some pattern plates. That was 3000 miles ago and now there are some nasty rattles from the barrel, which indicates it's about due for a rebore. Top speed is not much more than 60mph and the smokescreen is back in force.
As for consumables, the tyres lasted 10,000 and 8000 miles, front and back respectively. The chain only did 6000 miles, needing constant care and attention. The sprockets were just as far gone. The brake shoes haven't worn out yet and the brakes need hardly any attention, though they are not much cop. Fuel's around the 60mpg mark when the engine's in good condition and about 45mpg at the moment. All the chassis bearings were replaced just before I bought the bike and an excess of grease is still in evidence (the back end's bearings wear quickly if neglected).
All in all, it's a robust little machine that's ideal for snapping around town. The engine hassles are easy to fix and, well, pretty typical of a stroker of this era. I wouldn't pay silly money for one, but as a bargain basement hack they make the grade.
Tony Klein