Need general information on 69-73 yamaha dt175


City Hunter

Member
Feb 8, 2008
18
0
Hey all. I just picked this beauty of a bike up today. See picture below :) I have no real information on the bike. It was 50 bucks so I figured what the hell, If I toss 50 into fixing small things up and it rides in the woods, then I am doing great. Looks to be a early dt175 The guy I bought it from said it was a dt175 but not sure on the year.

I've never owned a 2 stroke before, always ridden 4's all my life, so this is a bit new. Especially the bike having 2 spark plugs, and all the lights n what not taken off, which I dont really care for, but the headlight would be nice.

I noticed there looked to be a spot for a small battery or something under the seat.

Now I have confirmed I do have spark, and I know fuel is getting to the plugs because they were both wet and fowled, What really blew my mind was I have a ngk bpr8es plug on one side, then some ancient looking autolite that just says 64 resistor which were totally different plugs. The ngk is the same style I run in my large turbo starion engine, then the other seems to be a pretty hot plug.. The guy said his son said it was running in the summer and he just ran it out of gas. I suppose it's possible? It has compression, and kicks over good.

First I need to know what plugs this thing takes, and at what gap?

Second, I seem to be missing a second spark plug wire? Any ideas here? If I am, can I get the setup off any other old yamaha bikes? I didnt see any cut wires , but I havent pulled the tank either.

third Can I just run 2 stroke oil in the oil injection or what? I didnt even know it had injection oil and poured some mixed stuff in the tank. I'll have to dump it out tomorrow.

Anything else I should look out for?

Lastly, do I get the award for ugliest possibly near running bike? :laugh:

I'm heading to the local motorcycle salve yard tomorrow to dig up a seat and some other parts possible. Hopefully I can source a straighter tank and fenders, who knows, maybe even a set of forks. I blew one of the seals out when I strapped it down from the rust on the very top of the fork lol

I'll try and get a vin number tomorrow and some better pictures.
 

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pryor

Member
Oct 21, 2006
171
0
Cool bike, you have a 69-71 ct1 if the tank is correct. Ct1s are one of my favorite bikes, I have a few ct1s and ct2s. the second plug is an extra it only uses one at a time, use a b8es and gap it at .024. If the oil injection is all there and in good shape use injector oil from your bike shop, or you can disconnect the injector and run pre mix at 32-1. If you are going to change forks look for some with aluminum sliders get the tripple clamps and its a bolt on, I have 75 mx 175 forks on mine but the 72 & 73 ct forks are a lot better then the old seel legged ones. Also if yours has a 19" front wheel look for a 21" wheel from a mx. This may be unwanted info I get carried away talking about old yamahas, if you have trouble finding parts let me know I have lots of stuff. :cool:
 

City Hunter

Member
Feb 8, 2008
18
0
actually good stuff. I tore most of the bike down and removed all the electrical minus the wire for the coil the other day. Also wirewheeled the bike and patched a hole in the exhaust and did some painting. It already looks 1000 times ebtter, but unfortunately after draining the milk out of the transmission and then redraining it after putting a new quart in. The bike is passing a ton of transmission oil into the cylinder and out of the exhaust. It will fire up and run so so, but I gotta figure out where the oil is coming from.


I have no diagram of this engine so im not to familiar with what it looks like underneath. I found a thread about someone else talking aboutt his and someone had said it could be the crank seals? Which makes since to me since someone ibviously drove this thing through water or dumped it in water.

I'm hoping there is something I can do without dropping much money into the engine.

Other than that, I cleaned thet ank out, pretty nasty, wirewheeled both fenders down to metal, banged out some dents, and scuffed up the paint ont he tank, and spent a a few hours painting it. I experimented with some metalic silver and a clear yellow, but it turned out like crap, and I thought it looked so good as the metalic silver that I just stripped everything back down, and redoing it in silver with a clear.

I also need to go through the carb. It was pretty gummed nasty. I did a quicky clean just to see if it would start, which it did, but gas is just dripping out fo the overflow so I guess the float isnt working right. Gonna have to go through it a little better next time.


by the way, great information on the forks and wheel.

Any idea if a late model engine say 78 or 79 will bolt into the chassis? I'm 99% sure the engine had a ct1 on it.

Shaun
 
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fatboy570

~SPONSOR~
Feb 19, 2000
94
0
I was going to tell you to try to find pryor. He has a lot of older stuff and is good to work with, but it looks like he already found you. You might be able to find a carb from Vintage Iron if you need a new one. If you remove the oil pump, you will want to make a block off plate and gasket to cover the hole. I have done this on other oil injected engines with no problems. By the way, pryor, I converted my 73 MX 250 over for flat track and need a few parts. Shifter, brake pedal, and foot pegs if youve got them
 

pryor

Member
Oct 21, 2006
171
0
City hunter it could be a crank seal on the right side, your yamaha dealer can still get them for you, buy a puller for the fly wheel while your there it costs around 12 bucks and you will need it to change the left crank seal. A 78 motor wont bolt in but could be made to fit, but you could just get a newer bike and save a lot of work. The ct1-2 motor can be made to run good. My 69 ct1 has a at2 mx close ratio gear box, CDI IGN. from a 74 mx 175, highly modified ct2 cyl, reed block , boyseen reeds and spacer from a 74 mx 175, the piston is from a 76 yz 175 the head is a webco I found at a swapmeet for 10 bucks, the pipe I like the best is a torque industries, another swapmeet find. This bike is the fastest 175 I have ever ridden and shocks everyone that rides it. There was no good reason to build this bike its impractical, burns up clutches and handles bad. Along with the forks and wheel use a fork brace you will need to go with a high mount fender but the brace helps a lot with those skinny forks, if you cant find one let me know.
 

City Hunter

Member
Feb 8, 2008
18
0
Hopefully it is the seal. Our tuesday night car meet is coming up, so I figure we have a tear down project to play with. I'll snap some more of the bikes current progress tonight if I get a chance.
 

zoommx

~SPONSOR~
Apr 23, 2001
282
0
pryor said:
the head is a webco I found at a swapmeet for 10 bucks, the pipe I like the best is a torque industries, another swapmeet find.

Why couldn't I find a deal like that for one of my bikes!!!! :cool:
 

pryor

Member
Oct 21, 2006
171
0
zoommx, I think the trick to finding good deals on parts for vintage bikes is to have interest in mediocre bikes with high production numbers. Parts for my old yamahas are easy, my sachs and CZ are a lot harder to get deals on, probably close to impossible on a 68 bultaco pursang :cool:
 

CT-Jimbo

Member
Apr 28, 2008
4
0
I also just picked up a CT1 175. A '73 and am looking for a wiring diagram for it. Good sources would be appreciated. I also have a '74 DT1 175 bored 1mm. It was the only piston the local dealer had so we went all the way. No lights, but a strong runner. Would like to run headlights on both bikes. Wiring diagrams or sources needed.
Thanks for any help.
CT-Jimbo :bang:
 

robertof

Member
Jun 29, 2008
3
0
73 yamaha CT1 wiring diagram

CT-Jimbo said:
I also just picked up a CT1 175. A '73 and am looking for a wiring diagram for it. Good sources would be appreciated. I also have a '74 DT1 175 bored 1mm. It was the only piston the local dealer had so we went all the way. No lights, but a strong runner. Would like to run headlights on both bikes. Wiring diagrams or sources needed.
Thanks for any help.
CT-Jimbo :bang:
When I restored my 73 yamaha I made my own diagram to the wire color detail ,I would be willing to share it with anybody if I can get a contact source .
 

ross t

Member
Jul 2, 2008
5
0
i have a bunch of dt 250 stuff most in very good conditon if either of ya are interested. i bought a very mint (restored 72 dt 250) and got all the left overs from two other bikes that were picked from to do the final from.
 

Knight08

Member
Jul 29, 2008
1
0
Awesome bikes you guys have! I just picked up what I believe to be a 1977 Yamaha DT 175 enduro. It is GREEN, and it seems impossible to find parts for. Does anyone know where to cross reference my frame #no. 2A6-002335 ? I need to make sure it is a DT because it doesnt say anywhere. It is an enduro, It is 175 cc, and the tag says 1977.
Thanks in advance!
 

dirt bike dave

Sponsoring Member
May 3, 2000
5,349
3
Knight08 said:
Awesome bikes you guys have! I just picked up what I believe to be a 1977 Yamaha DT 175 enduro. It is GREEN, and it seems impossible to find parts for. Does anyone know where to cross reference my frame #no. 2A6-002335 ? I need to make sure it is a DT because it doesnt say anywhere. It is an enduro, It is 175 cc, and the tag says 1977.
Thanks in advance!

Is it a single shock or twin shock?

When you say enduro, do you mean street legal (like a DT) or an off road enduro bike (like an IT)?

Does it have oil injection?

According to this site http://www.merrittmotorcyclesalvage.com/yamahamodelcodes.htm the 2A6 is a 1978 DT125. Not uncommon for a '78 model to have a manufacture date in 1977.

The '78 DT125 was available in a bright green. Here is a link to a bunch of high res pics of many years of DT125s. It looks like the '77 may also have been available in green. http://images.google.com/imgres?img...t125+yamaha&start=18&gbv=2&ndsp=18&hl=en&sa=N
 

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