CorradosandYahas

Well the way I see it you are going to have to get familiar with your carburetor eventually so why not just give it a good cleaning. If you suspect its not getting fuel at kick over with the throttle closed its going to be an issue in the pilot jet. But if you have tried starting it in all different throttle positions even WOT I would suspect that the carburetor isnt getting fuel at all. Remember you have three different "jets" on these mikuni carbs. Pilot jet controls fuel at closed throttle to 1/8th open. Then the Needle valve Tapers the fuel from the main jet until 3/4 throttle. And from there to WOT is all main jet. So if its not even farting at any of these throttle positions I would bet your problem lies elsewhere. If it is a fueling issue Check and make sure that your float is adjusted correctly and that the valve underneath the float isnt stuck closed. Have you tried giving it a little ether to confirm its fuel? If it still doesnt kick over with ether check your ignition timing.

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As unsafe as it sounds a coworker of mine started his in neutral then propped the rear wheel up by leaning the bike over on the kick stand. With the wheel in the air he gave it a little throttle and popped it down into first gear and rev'ed it up with the rear wheel still in the air. As he did this he walked the clutch handle back and forth until the clutch came back. If either of these methods work, Id say drive around the block a few times to get the old dirty oil even dirtier. Then change it out for fresh oil.

Usually the hardest part is getting the clutch side case cover off. I just did the clutch on my dt175 last week and I had to loosen a few of the phillips head bolts with a chisel and hammer because they were so badly stripped. Once you remove the cover the clutch is right there. Sachas advice is good though. Get a clymer manual. If you have any mechanical inclination a clutch should be a walk in the park.

Well i have no idea if the 78 is a hot performer compared to other bikes, I just know its a ton faster than the 75. And I'll post the VIN this weekend. After tearing down snow cat suspension and doing head gaskets on Mercedes 460 series all day I dont really feel like wrenching on bikes when I get home so that stuff usually doesnt get touched during the week. What is the name of the color that your bike is painted Airhead? I really am in love with your moto.

AJ i would probably kiss you right now if there wasnt this damn ocean between us. The yard I went to has at least a dozen of the MX style stator plates/ magnetos, but not a single DT set up. I could see that the retaining screws were in the same places but the holes on the mx models are slotted I assume this is for advancing or retarding timing? Can I use the timing instructions for the MX to time the DT if I have all the appropiate parts from the MX?

Im gettting my list of thing to do this weekend together. And I have seen alot of you guys talk about de-resticting these two strokes. I have a 75 and a 78 both dt175's what should I look for as far as restricions go?

Yeah the mag side crank seal on the 1975 is toast, and the 1978 has a leaking kick crank seal. They both idle great and the 78 is a quick little bike.

Give grim a call if you want a faster response

Whats the make and model of the carb? A buddy of mine had his float valve stick open on his drz400 and it filled the crankcase with fuel. Im not sure if this was the product of a clogged relief or if there was no relief like you suspect with yours.

I always wore a helmet on the dirt roads of montana where there were no other vehicles on the road. Now that I have a bike in the city and no helmet it terrifies me, i perceive every car as a threat. I have never taken a fall on a motorcycle that warranted a helmet, but still know it could happen in an instant. I have however cracked two helmets clean in half skiing and walked away with nothing more than a minor concussion and a prescription for oversized ibuprofen. The reasons to wear a helmet greatly outweigh the reasons not to wear one.

I lost spark on my DT over the weekend when I got to looking into it I saw that one of the wires going from the stator coil on the left side of the points had been rubbing on the magneto. I tried to gently push it out of harms way and the wire and insulation fell apart. It goes from that coil straight to the condenser. Can I simply pull a little more wire off the coil re-insulate it with heat shrink and re-solder it to the condenser?

We have two really good yards here. The one i have been to is called bills boneyard, the other is larger and more organized but I havent been yet, and its called grim motorcycle salvage. Another avenue worth pursuing is getting a quote on having it rebuilt by an alternator/generator shop.

Yeah i may have to pull one off a bike in the yard. I looked through the crates and crates of magneto/stator parts. And did not see any coils like the one from the drawing. Ill be back there this weekend, and ill try to find a crate of armature parts.

Copy. Ill try to get some pics up later tonight. It has full lights and gauges. Where is the VIN located? I fear it has probably been painted over by the PO.

The MX will wheelie if you shift fast into second as well. Ill Have to start looking deeper into the DT, As always thanks for the advice guys.

So I have been driving my 75 dt175 for the last week or so and thought that it was great. The power band is very smooth but it is all in all a very slow bike. Today the magneto shit the bed so I decided to focus on the 78 dt175mx for a day. Got it up and running and holy hell. That thing runs like a raped date. You hit that power band and it puts you back in the seat a good bit. Should there be this big a difference between the two bikes? Or do i have some power loss issues in the DT?

Yeah we think we are clever here in Salt lake city, Utah.

Yeah i try to avoid spending to much time in Idaho (to many mormons ), But next time Im headed to Montana Ill let you know. With any luck I'll have both these bikes in the truck.

Made some progress today. Got a nice seat, ign switch, and clutch for the MX. Got it all installed now i just need a wheel and tire. Ill try to post some pics this week.

Yeah 410 euro is nuts. I would be willing to bet anything this yard has one or three dozen of these. It was insane, More yamaha parts than than you could possibly imagine. And I walked away with a seat, tachometer cable, ign switch w/key, sprocket cover, and clutch for $105 USD. I went first thing this morning before your reply. So i wasn't able to look today for ya, but if the yard is open I'm going back tomorrow for a wheel. Do you have parts number by chance? Is the number clearly marked on the armature somewhere? Alot of the parts from the bikes are pulled and stored on shelves in sheds. So I would need some way of identifying it from the rest. Hitachi is a start, but he doesnt label any of the parts as they come off the bikes they are just stored with like parts from the same manufacturer. Its hard to tell from the drawing but this is essentially just the generator coil correct?

I'm going to a motorcycle boneyard tomorrow if you can post an exploded parts diagram with what you are after highlighted I can see if i can find one. Edit: is it on here somewhere? http://www.cmsnl.com/yamaha-cs5-1972_model8398/armature_1738115510/

Yeah SkiDoo is still making sleds. Yamaha actually makes one of the best four stroke sleds though with there fx nytro. And all getting the deposit back at the end of a rental means is that you didn't ride it near hard enough. And Sacha I'm glad to see a fellow mountain wester(and skier) on here. Thanks for the warm invite. -Dave.

Arrrghhh so much peer pressure. Alright you talked me into it. I actually found a local motorcycle "boneyard" that specializes in 70's and 80's japanes motorcycles. Gonna check it out on friday. Definitely going to use your MX as inspiration Airhead, that is a great looking old yamaha. I do have a few questions. What is a good premix ratio? Both autolubes are capped until i can check the integrity of the pumps. The book calls for 15:1 for the non autolube dt125. I'm running a 20:1 right now. Is that to rich or lean a mixture for the 175? What things commonly go bad or need to be re-spec'ed on these 175's i.e. breaker point gap, ign timing, base gaskets? I think I'm honestly just astounded that with a cumulative twenty years of sitting un-ran they both started up with minimal restoring. It seems to good to be true. Thanks for the input and encouragement -Dave

Hey you guuuuyyyyyssss. I'm new to the Yaha's and motorcycles in general. Just picked up a 1975 DT175 and 1978 DT175MX for a case of beer. Both were parts bikes but between the two I got the 1975 driving pretty well. And I didnt have to pay anything for either bike so its all just for fun. I work as a vehicle maintenance technician for Alta ski resort so I'm familiar with two strokes they just usually have tracks not tires. Can't wait to get to know you guys and girls(unless this is like the VW forums). -Dave