78 dt175 only idles on choke

[goobsac55]

So I have an interesting development. I Fully believe my bike to be a 78 first letters are 2a7. However the diagram of a 78 I posted earlier does not match what's in my bike however the diagram for a 79 does. So I've gotten a new piolet jet and air screw but for a 78 so that stuff could be wrong plus I believe there's a small o ring that goes on the main jet seat and I don't have that either

[jneiman]

Given a second look at your main jet, I would agree that this is the set up for the 79. In comparing the two carbs, the air screw is the same part number. But, the pilot jet is different - the 79 has a 22.5 jet, while the 78 has a 20. Regarding the washer, I pointed out the wrong part. It really is the rubber o-ring that you need.

[goobsac55]

Yes I can't believe I didn't notice this before but I'm definitely missing that o ring. I'm going to get my parts straight and after a year and a half get this bike going and thank you very much Jneiman

Edited May 8, 2015 by goobsac55

[jneiman]

Let me know how it works out.

[goobsac55]

Not much success I believe I have to get a new air screw still but I think the one in their would work somewhat here's a video

[jneiman]

I have a couple of questions -

- for the air screw, how many turns do you have it out?

- when you cleaned the carb, did you spray into every tiny hole?

- I believe that you took off the oil pump/reservoir. What oil/gas ratio did you use for the fuel in the tank?

[goobsac55]

Turn and a half and I play with it to try and find a happy point. Yes I sprayed into every tiny hole but I can always try again. And I try to run 32:1 nit sure how exact it is however I cut it a bit the other day and it still smokes like that.

[goobsac55]

Here's the actual video sorry

[jneiman]

I have a Couple of 70s 2 strokes - with the oil pump attached. It always smokes like that until it warms up.

[jneiman]

I am now puzzled. Your issue was identical to the Ts90 I was fixing - started easy, but bogged when giving it throttle. My issue was a missing washer under the main jet. Since it starts easy, it shouldn't be the idle screw or the pilot jet.

[SMarquez]

Do you have the carb connected to the airbox? You are starving it for fuel with the airbox disconnected. Jetting is set with the carb connected to the airbox with a filter in place. Also, is the choke moving smoothly up and down? I just helped a guy with a similar problem on a 79 YZ400. His choke plunger was seized in the carb body and wouldn't let the bike rev. Easy start and smooth idle only. Try unscrewing the choke and removing it. It should slide right out.

[goobsac55]

My oil pump isn't attached because I don't have a resivor. But the hole in the carb is plugged. I may try to find a different carb and try that. Also I don't have it connected to the air box but I did and it still ran the same way but I haven't since I put the Oring and new pilot jet so I'll try it I'll also check the choke although my idle isn't very smooth either

[goobsac55]

Little bit of a development! I put the air boot on and a definite difference. The bike will take more throttle now but only if applied very slowly also I put my fingers over the overflow pipe as well as the vent on the top right of the slide tube and this caused my bike to stall. Also I was messing with the cable adjust ment and I'm not sure if this makes sense but I haas it so full throttle wasn't that much throttle.

Here's a new video

http://youtu.be/XjEnZXkdJb4