PLEASE HELP!! My '82 175 tri moto

[Cnelson]

My 1982 Tri moto 175 will not run correctly. The oil inject has been removedand i have no clue where all the remaining lines connect to. The one on the reed housing I know goes to the fuel pump but don't know about the one on the motor under the carb. Also, there are two "nipples" on either side of the carb that go down into the bowl (these have nothing hooked to them), and the float over flow hose drains fuel like crazy. And lastly, should there be an o-ring on the mixture screw? The thing will fire up and run but has absolutely no power under a load then will stall and not start with out a shot of carb clean. What is up with this thing? I've been mixing the gas roughly 35:1, just need a little help here, i down loaded a manual for it but has very little help in it. I have only been on this thing a couple times where it has ran decent and its a blast (does wheelies like crazy and super fast) but I am to the point where I am thinking of selling. Thanks in advance

[DohcBikes]

there are two "nipples" on either side of the carb that go down into the bowl, and the float over flow hose drains fuel like crazy. And lastly, should there be an o-ring on the mixture screw? I am to the point where I am thinking of selling.

I'm not a Yamaha trike expert by any means, but I'm willing to bet the "nipples" are bowl vents to provide atmospheric pressure.
If the bowl is overflowing, either the float needle is stuck, there's debris in the carb, or the float is set too high.
Yes, if the Yamaha's mixture screw is a fuel mix screw it needs an o_ring, not sure about yamaha air mix screws.
Don't sell it unless you need the $$!.... just keep at it, it will be worth it!!

[Cnelson]

Thanks for the reply. I'm gonna give it another go tomorrow. I don't wanna give up the wheelie machine but its really getting to be a pain. And naturally there's no diagrams or much for decent manuals online for Yamaha.

[DohcBikes]

This site may have one. Click on service manual. Also check the home page where it says Yamaha wiring diagrams.

[Highhorse78]

Theres a lot of speculation and half truths floating around about hose routing on these things. Heres how its supposed to be... Tube on float bowl has hose that connects to one nipple of black plastic cover on clutch cover. The other nipple has a hose that gets routed up into the backbone of the frame. Doesn't matter which is which. All it is is a catch for overflowing fuel. The two black ports on either side of the carb have lines that also run up into the backbone. The other port on the throat of the carb is the oil injection port. Block that off with a rubber cap. The crankcase breather port on the case halves has a line that runs up into the backbone. The two ports on the clutch cover are oil injection ports. Block those off with rubber caps. And lastly is the port on the intake boot. Either delete your fuel pump and block it off or connect to the middle port on pump. That sould be it and get you a lot closer to running better. Start there and report back, hope that helps.

[DohcBikes]

Oh good there's a Yamaha guy in here now thanks highhorse

[Cnelson]

Thanks for the help I'll give that a try. I also discovered that the crank case was full of gas so I drain that and added new 10/40. Got it to run for a few minutes then back to no start and when it did start just idles high with no power. The mix screw is missing that o ring so I'm ordering that and I actually borrowed the float and needle seat assembly from a carb off of a dt175 so that may be the wrong stuff. But I'll start with the hose routing. Thanks again.

[DohcBikes]

Get the correct needle and seat in there.

[just ben]

It's been nearly 20 years since I had one of these but I think there was a rubber cap on the nipple on the intake and the vacuum line for the fuel pump was on the cylinder. If either one of those is left uncapped or connected to the fuel pump you will have a big air leak and that is probably why its revving high.

[Cnelson]

Thanks for the help guys, I'll work on it this week and give some feed back. I suppose the most obvious question though is just how much will that missing o ring on the mixture screw affect how it runs. We had this thing running great for a short while then when it gets good and warm it stalls and will only idle and rev up a bit but has no power under a load.

[Cnelson]

Also, does anyone know what is a good price to pay for a running Honda 250x (four stroke). ? I can pick it up for $150