Yamaha DT2 Build - Smoke if you got 'em...

Sonreir

Oregon
Grabbed this bad boy for $350 over the weekend. Missing just about everything (including paperwork) and someone tried to convert it to MX at some point. The engine sputtered on starter fluid, so hopefully everything is OK in that department.

Plans are to bring it back to a streetable state, so I'm on the lookout for a tank and seat. The left engine case is also missing, so I'll have to track down one of those. 12V DC conversion is in its future.

I can't wait to start throwing cash at this money pit. :p
 

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Sonreir

Oregon
I'm going to try the Vermont trick and see how it goes. If that doesn't pan out, I have a friend who's specially registered with the state and can get me a title for anything.
 

whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
I'm in too.

Would like to have something like this to fool with.
 

Pete12

Member
I've got a bunch of DT stuff at home, mainly later models, but I'll have a look when I get back in a couple of weeks.
 

Sonreir

Oregon
I took things apart a little bit last night.

Tank is definitely plastic and looks to never have been used. There's still a little yellow overspray on the inside, which I assume the gasoline would have made short work of.

Wheels are almost definitely not stock. I don't think this bike would have come with shouldered aluminum? There are also there weird bolts poking out at regular intervals. Purpose?

Finally, I didn't realize that the DTs had a compression release? Unless this is something else.
 

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Those bolts are clamps (rim locks) to keep the tire from slipping on the rim. They have to be loosened before you can remove the tire.
 

teazer

Active Member
DTT BOTM WINNER
Rims are DID and look the same as were used on road racers and motocross bikes. That suggests that the rims or wheels may have come from a MX version of that bike or something similar. Also possible that a PO re-spoked the wheels with rims from a different bike. What diameter are they? The front sticker appears to say 1.60 - .... I can't read the diameter. The front hub looks like a DT style rather than MX250 style. Rear could be either, so probably re-spoked.

They are like the rims fitted to a TD3 which had a 1.60 -18 but the spoke angle would be wildly different on that bike. We picked up a NOS 1.60 -18 at a swap meet a few years ago and it ended up on the front of a CB160 road racer. They are generally slightly lighter than the H section flanged (Akront style) rims we all used to love.

Turnturtle is correct. That's a rim lock to prevent the tire moving on the rim when it runs with low air pressure for more grip.

BTW, what ignition is hiding under the end cover? Has it been fitted with an internal rotor Hitachi CDI or just a weight loss external rotor street design?
 

Sonreir

Oregon
Looks like the ignition is probably stock? I need to dig in further.

The ignition coil is one of those small orange ones you see on scooters and the like.
 

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Hey Matt,
The decompressor aka "deke" looks to be aftermarket - maybe a Yamaha accessory. The DT's came with the head already tapped (and with an aluminum "plug" in it) for either a second spark plug or a deke. A deke really helps slow down a two stroke - especially when those skinny ass old drum brakes get wet LOL. Had one on my 250 dirt tracker and used it instead of the brake most of the time.
Unless you're trying to do a "Pebble Beach" resto, I'd keep the tank you have - probably period-correct. Match it with a Preston Petty enduro headlight / number plate and some Petty fenders (they're making them again if you can't find NOS ones) and you'll look like an enduro guy from 1975.
The rims are a nice upgrade - the DT's still had steel rims as far as I remember (but I HATE rim locks LOL).
Had a couple of DT2's of similar vintage, got rid of them and am low key looking for a CT1 or CT2 (the 175cc enduro), as I found the 250 a bit big for me (I'm slow, old and not very tall LOL#2).
Get rid of the rear shocks - they look way too long to me - put on an old school Circle Industries fork brace and you'll be good to go.
Will be watching this build.
Pat
 

teazer

Active Member
DTT BOTM WINNER
Good news about the ignition as long as the PO left the lighting coil/s inside. And if not, it should be easy to find a similar unit that will do the job.
 

Sonreir

Oregon
pacomotorstuff said:
Hey Matt,
The decompressor aka "deke" looks to be aftermarket - maybe a Yamaha accessory. The DT's came with the head already tapped (and with an aluminum "plug" in it) for either a second spark plug or a deke. A deke really helps slow down a two stroke - especially when those skinny ass old drum brakes get wet LOL. Had one on my 250 dirt tracker and used it instead of the brake most of the time.
Unless you're trying to do a "Pebble Beach" resto, I'd keep the tank you have - probably period-correct. Match it with a Preston Petty enduro headlight / number plate and some Petty fenders (they're making them again if you can't find NOS ones) and you'll look like an enduro guy from 1975.
The rims are a nice upgrade - the DT's still had steel rims as far as I remember (but I HATE rim locks LOL).
Had a couple of DT2's of similar vintage, got rid of them and am low key looking for a CT1 or CT2 (the 175cc enduro), as I found the 250 a bit big for me (I'm slow, old and not very tall LOL#2).
Get rid of the rear shocks - they look way too long to me - put on an old school Circle Industries fork brace and you'll be good to go.
Will be watching this build.
Pat
Thanks, Pat!

I now have a Petty rear fender and three number plates on the way.
 

Rider52

Member
"I now have a Petty rear fender and three number plates on the way."

Perfect! I was hoping you would keep the tank and add Petty fenders. This is going to be a fun bike!
 

bracketmaker

New Member
I own a dt250 DT2. do yourself a favor and throw out the rim lock. I used tiny square cut from a tin can and plumbers epoxy. makes for a smooth ride over 50 instead of an angular momentum tsunami. when you have this part in your hand you will see what I'm talking about. I run a 17t JT front sprocket. put shinko 244's. they definitly don't help on grooved highways or bridges.

tortured myself with the 6 to 12 conversion. did not unground the stator. I floated ground. yes it worked full wave. at idle it was 8v with the stock headlight. you need to run an LED headlight if you want to run batteryless.

if your carb is jetted like mine it comes with a 60 pilot. pollution was not a thing, today it pisses people off. 35 will still run like stink.

cool project, kept mine stock except for lane splitter bars because I live in NYC. mine does not have a decompression valve. vermont went fine with mine.
 

irk miller

You've been mostly-dead all day.
DTT BOTM WINNER
Takes a lot of weights, but you can balance a rim with rim locks. On bikes I run on the street, but do real single track, I run them. If you’re dropping air pressure for off-road, they’re important. That said, if you’re running mostly street and nothing more than fire roads off-road, then get rid of them. It won’t hurt to keep that hole open, but I put a strip of duct tape, folded sticky side in, over the spokes.


Sent from my iPhone using DO THE TON
 

bracketmaker

New Member
irk miller said:
Takes a lot of weights, but you can balance a rim with rim locks. On bikes I run on the street, but do real single track, I run them. If you’re dropping air pressure for off-road, they’re important. That said, if you’re running mostly street and nothing more than fire roads off-road, then get rid of them. It won’t hurt to keep that hole open, but I put a strip of duct tape, folded sticky side in, over the spokes.


Sent from my iPhone using DO THE TON
its easy to do a good repair, go with the physics. EK=1/2m x v squared. you always want to loose weight and this crap is heavy. instead of adding lots of dead weight to compensate put the thing into the round file, do a quality repair of the rim and never look back. the 250 is rated at 20 hp so its not much of a stump puller. some contact cement a piece of leather over the hole, but I'm a jb weld and tin snips kind of guy.
 

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