1981 Yamaha YT125 Trimoto - Need Help!

[L-Train]

Hey guys,

I'm new to the forum and just an average mechanic, so please forgive me if some of the questions I ask are stupid. I'm not new to discussion forums, so I want to make sure everyone knows I've searched through several threads already and already gotten some answers to my questions.

I've got an 81 Yamaha Trimoto YT125. Typically I only ride it in the winter. I use it to pull my kids around the neighborhood on a sled. It runs relatively well, but it does needs some tweaks. So if any of you guys can help me out, I would really appreciate it!

1) There is oil in the exhaust and it blows a lot of white smoke. It's very sluggish in 1-3 gears. In fourth and fifth it runs a little smoother. Any ideas here?

2) The headlight and taillight don't work. Both bulbs are good though. What's the first step I should take to test the electrical system?

3) Do you recommend bypassing the fuel oil injection system and just mixing it manually? If so, what's the recommended ratio? I don't have the manual.

I think that's it for now. Thanks in advance for all your help!

Eric

[Vealmonkey]

With the oil in the exhaust, I mean it's a 2 stroke so I would be worried if there was no oil in the exhaust pipe. As far as the lights, you need one of those 12v test lights that look like a pointed screwdriver with a lightbulb in the handle. Hook the alligator clip end to a good ground on the bike. While the trike is running, stick the test light where the bulb should go and see if the light lights up. If it does, then you have power to the light socket, but you probably have a bad ground. You may need to clean up the inside of the socket where the side of the bulb touches the inside of the socket so it gets good contact. If there is a ground wire, make sure the ground wire is connected and make sure where the ground wire is connected to isn't all rusty so there is good contact between the wire and the ground. Also make sure all your wires are connected. You should be able to do the same with the rear tail light bulb. As for the proper mix ratio, I don't have my owners manual here at the house buy you should follow the mix ration recommended by the manufacturer of the pre mix oil, some manufacturers recommend different ratios for their products.

[L-Train]

Here's one more question I forgot to ask:

How can you tell if the engine oil is low? I found the engine oil cap, but there is no dipstick. Should the oil be up to the top?

Thanks in advance!

[Derek]

Here's one more question I forgot to ask:

How can you tell if the engine oil is low? I found the engine oil cap, but there is no dipstick. Should the oil be up to the top?

Thanks in advance!

im not shure about this model but there should be a circle shaped view near the oil cap on the engine case. The oil should be half way up the view. If you did fill it to the top thats most likely why its sluggish.

[Dirtcrasher]

If there is no visible window, then there should be a screw with a copper washer about halfway up the clutch case that you pull out and oil should dribble out. It's best to get help here, or find the manual for the correct amount and type of oil, drain it and refill.

Yamaha makes a great oil injection. Has worked for years and years and they set it up rich to cover there but. To eliminate it reduces that as being a potential problem. But, you have to drain the fuel in the carb, drain every drop of gas in the tank and block off the hoses after you drain the oil tank too. Then just mix up 5 gallons of some good stuff. I'd fill the carb and drain the fuel bowl one more time (should have a screw by the side of the lower part of the bowl).