Cynic

Is that what he's giving you to take it? Only kidding, i personally wouldn't bother there are plenty out there better than that.Looks like the tank has had a hard life, the seat is well past it too, don't know whats going on at the front but it looks wrong to me, too small somehow. No tail light so rest of the loom is probably in tatters, its on knoblies so worked off road. And the real killer it don't run. Nope move on my friend.

Same as the 125 at 55.95mm and 56.5mm respectively from Yamaha, the pattern boys go up in .25 incriments. Thats with the earlier 1KT engine with iron liners. The later generation motor (although near identical) had the, one nip an its knackerd nikasil coating. The bore is the same the stroke is the same, supposedly the pistons are interchangeable so in theory the deck height and crown are the same. The head IS different as links both cylinders together with cooling and such and i've never had the top off the TDR so i can't say what its like first hand. I can imagine the squish is probably different. There are a couple of proper engine heads on the TDR forum i'll see what gives on there.

Yep same, the barrel in the pics must be a DT one though, the tdr has a different PV and there are no seals in the PV openings, they are o rings in machined groves on the PV is self. This has got me thinking though, what is the difference between a TZR/TDR250 barrel and the 125 version. With the 250 good for 50 hp, surely you would get over 20 with the right pipe and jetting. Got to be worth a look at the ports and wheather they will actually swap. Surely the 250 must have bigger transfers and such to get the extra go, but still at heart a 125 barrel. What do you think?

No its AC, except for the electric start versions, and you don't need to rectify the headlight feed the bulb will be happy with AC or DC, just regulate it.

E-bay is your friend, http://cgi.ebay.com/ebaymotors/78-YAMAHA-DT-125-E-400-175-100-250-XT-VOLTAGE-REGULATOR_W0QQcmdZViewItemQQhashZitem45ef34a35fQQitemZ300365947743QQptZMotorcyclesQ5fPartsQ5fAccessories I know its in the states but it came up in the first search.

Just a headlight? The yellow from the mag is the lighting feed on yours i believe, thing is it doesent work quite that easy. You need to regulate the voltage and that i believe on these is a resistor burried in the loom, a later voltage regulator may be a better option. You really want it switched too. TBH bolting a decent torch on the bars will be as effective. And no i'm not being sarcastic even in good nick these headlights are really dire, an orangy blob 10-15 feet in front of you is about the best you can expect. The light on my mountain bike is as good.

Unregisterd import?? Sounds like a police or customs siezure maybee and they have auctioned off the stock after the prosecution. Probably find he can't sell the frame and the bike has to be 'disposed of'.

Can't really see my ugly mug worth a 6 hour round trip. Its partly from books, personal experience, especially the aircooled (as i've got one) and the dtlc was the weapon of choice when i was 16/17 around 1988ahem. MaD is more up to speed on the liquid cooled stuff but i like to think i can hold my own on the aircooled stuff. Oldgit is another DT nut he's smearing the line buy having the aircooled and the LC although he's 'up in't ills'.

Unfortunate sign to pose in front of

Kind of, the DT name was first used on the DT1 in the States, that was a 250. The DT1-b came to europe in 1969 and the sucess of that led to the whole family of DT's from 50 to 400cc. The AT was the 125 bike that preceeded it and took on the DT (Dirt Trail, i think,) name and the characteristics to complete the family line. The bike that got the DT125 really into the modern mindset was the DT175, which was the CT to begin with and ran alonside the AT. It took on the DT name at the same time and really took off from 77/78 when the engines got CDI and the , at the time, groundbreaking cantilever suspention giving masses of sus travel. I know you want to trace the 125 but the 175 is only different in the fact that the engine is bigger by 50cc. But at the time we were in 250 learner laws and (i may get shot for this ) the 175 was arguably the better/ more advanced bike. When faced with a 125 or a 175 choice its pretty easy to see why the aircooled 125 is a lot rarer, though not notably. The aircooled heyday was quickly destroyed by the competition wiseing up and upgrading their kit to keep up, DT175/125's were practically 2 (sarcasm) for one by 1983/4 when the DT125LC appeared. Essentially a tarted aircooled frame (a lot of the cycleparts will swap directly) but the bodywork and the engine were new. That brought the DT back into the game and around 88 changed again much more completely though, to more or less what you see today with the monocross suspention and front disk. You may or may not know that The DTLC frame with a 175 aircooled motor continued to be produced in Australia and Asia untill recently, around 2007/8 i think. There have been updates since, around 2003 was the last of any consequence i believe when they screwed the nut on the emissions and indirectly made it harder to de-restrict. Something that i think was a backwards step. The ease (compared to others like kawasaki and especially Honda) that the bikes could be made to give far more power than they were legally meant to is the main draw i beleive, especially when the bikes long production and easy spares are taken into account. I'm sure any errors will be pointed out by other shy retiring members, I've had my DT since i was 17, bought in the pub for 25 quid any good to you?

There is a detent but its just to control the actual movement of the selector drum. If its jumping out under acceleration then its the torque forcing the gear out of position and that can only happen if the dogs are worn. Sorry i can't give you a better answer , if there is anything that may help blackhat will know...

I'll have a look and see what there is.

That piston is for a TDR250, and the barrel specs for the 125 and the tdr250 seem to tally, my TDR motor is Prefixed 1KT. BUT and its a biggy. The 250's PV is TOTALLY different to the one in the pictures, its a lot thinner and is more of a blade, its also made from several parts instead of one piece and it is chamferd both sides presumably to give piston clearance. Dont forget the 1KT TDR has iron liners not the nikasil and goes up a couple more sizes. Maybe its a TDR/TZR250 barrel with the 125 valve?

The thing to remember with 2 strokes, the oil light isn't what it is on cars. Its telling you that the oil tank for the 2stroke oil is running low. The light comes on when in neutral as a test. Keep an eye on the level manually to be sure it works if you have just got the bike, or top it up once a week when you give the bike a once over. 2 strokes ALWAYS smoke from cold, when the motor is shut down and cools a little oil will stay in the cases with a didy bit of water (condensation). When you start the bike up all this heats up and mixes back in with the fuel mix, (which is already rich from the choke) and messes it all up this generates smoke untill it burns off. Once the engine is hot and you have run through the revs it should clean up. Running gently without wide throttle openings helps reduce it but you will never stop it. Its normal.

Sorry to be negative here, but you want to increace the gearing on your motor in 4th gear by a factor of 2, most would sruggle to pull a quarter of that.

Before or after the 175?

Can't say i have, can't see the point, torque converters are heavy and suck up gobs of power just to work. Alright on something like my Rangie, at nearly 5litres the engine can happily deal with the losses. Cant see a bike engine dealing with it. The drive on the karts is centrifugal as i understand, friction pads thrown out by the rotation transmit drive. Lot different to a torque converter.

Classic signs of a dished disc, the disc should be absolutely flat. If not the caliper has to squeeze it flat before it can actually get on with stopping the bike. It will also cause the pads to drag.

Dont get carried away with the headlight OG, check it first. A lot of bikes dip up and down, not down/left. The headlight my suzuki did up and down and that was a Frenchie, the TDR also dips up/down with no bias.

Found one uuuup north, black all original jap import 9kmiles on a E plate. VERY happy bunny, trapped in the garage till the gritters go home due to the bare ally the japs have.

Hi all, having a few troubles tracking down a good replacement headlight for my DT, the old one has corroded and the lampholders have been brought back from the dead one too many times. I couldn't give a monkeys for originality either. So long as it fits and its 6v. Trouble is the replacements on evil bay dont have a sidelight, small issue i know but still important. Or is it? Do we have to have one on a bike of this age (1981). Also i need the lamp holders too, not always supplied, after reading the small print on a few of the 'bargains', mutter, e-bay, mutter, mutter. Anybody shed some light on it (couldn't resist). Or reccomendations of places to contact.

Voltage regulators are on Ebay for around 20 notes. Look, http://cgi.ebay.co.uk/Yamaha-DT100-DT125-DT175-DT250-Voltage-Regulator-QR498_W0QQitemZ310177918810QQcmdZViewItemQQptZUK_Motorcycle_Parts?hash=item48380b6f5a You need to find out for certain which year. There is a critical difference between the ignition systems between 78 and 81. The cdi units on the earlier bikes use 2 coils on the stator and a 7 wire cdi the later bikes use 1 coil and have 6. Its a red one thats deleted. It isn't a problem so long as the stator and the cdi match, you can add the extra wire in there if you need it. As far as looms go, this any good to you..... http://cgi.ebay.co.uk/YAMAHA-DT125-DT175-4J3-WIRING-LOOM-HARNESS-1980-1-QH019_W0QQitemZ310198712539QQcmdZViewItemQQptZUK_Motorcycle_Parts?hash=item483948b8db

HOW MUCH Thats an awful lot of money for an overlander. Gas just what could you do with that as a trip buget? Bearing in mind that apart from 30-40mph that bike has no advantage i can see over yours and several disadvantages. Aside from looking like a tarted up TDM. Price of Tenere? It was around 5 grand when i had a look. That would leave around 8 grand to GO SOMEWHERE on it. I'm willing to bet that is aimed at 40 somethings who DREAM of the Long way round, but the most taxing thing they will deal with is traffic on the A4 into the city. As for it being dearer than a Bavarian, thats stupid. How are you going to take sales from the apparent masters of the type. Mind you there are an awful lot of em with aloy wheels, sticky tyres and lower suspention .

No problem happy to help.