Yamaha TW 433

[yooper360]

Hi all,

Just picked up this 1974 Yamaha TW 433 yesterday. I'm excited to work on it as I have never done bogie wheel suspension. Been watching some youtube videos which have been helpful. The neat thing about this sled is that it has a hydraulic drive. It has a torque converter driven by a belt from the crankshaft. It's got Hi - Lo - and Neutral, although I am not entirely sure how to use it... yet. One piston has a hole in it, so that will have to be replaced for sure. It has good spark, although I couldn't get the good cylinder to pop with some premix down the plug hole. I am thinking the ignition is out of time.

My goal is to get it usable. I want to pull some logs out of the woods with my dad at the farm and pack down trails through the woods. Not looking to make it a speed machine either. I have a 1980 Trailfire that will be my main trail sled, and I want this to be my backup in case it dies on the trail so I can tow it home.

With that in mind, I am not looking to do a total restoration. The sled has 714 original miles on it and I picked it up for $175. Anyone know if it was a good deal? The outside is not pristine but the engine bay is clean. Everything is there, nothing is missing that I have found so far.







I've done Keihin Carbs, but only on motorcycles and not these kind. Any tips on things I should replace off the bat to make it reliable enough for my purposes? Should I reseal the engine? Is it worth replacing all bogies or just as required? Also, if my pictures uploaded correctly, how does the track look? Thanks for taking the time to read, I am looking forward to learning all I can about this thing and enjoying it!

Dave

[SS440-80]

Congrats for getting a cool sled
The TW is a really rare sled, or the the drive is rare... The rest of the sled is the same as SW440.

The engine are like all japanese motors reliable, but the Kehin membrane carb is not.
Here's a link that can get you some help to understand the carb. http://www.vintagesnow.com/Carburetors_ ... Manual.pdf

The track looks just fine from what I can see.
You don't have to change any boggie wheels unless they are without rubber. Just change the bearings on the wheels.


If you need parts and have trouble finding it for the TW-model, you can go in to Partzilla and find your sled and the part you need. When you click on the part number, you will get a cross reference on witch Yamaha models that use the same part.
https://www.partzilla.com/catalog/yamaha/snowmobile

You said that you was planing on pulling out logs from the woods. That will for sure make you a pro on knowing howe to handle a sled. If you make one little misstake, you will get stuck. To little throttle or to much throttle, or either in the wrong moment... you will get stuck But it's good lessons.
The old Yamahas was good sleds, but allergic to snow. (I love them)

Let us see pics of the progress fixing the sled, lots of pics.

[yooper360]

Thanks for the info, much appreciated! That makes me feel better about my buy that I won't have to replace everything suspension related. That carb is unlike anything I have ever seen or worked on before, but I am always looking for something new to learn. I believe the fuel lines running from the tank to the carb are rusted out so I will have to replace those. First thing is to find a manual on eBay though so I have a better idea of what I am looking at. I will be sure to post plenty of pics!

[SS440-80]

Here you can find some cool ads for Yamaha models. http://www.vintagesnowmobiles.50megs.co ... AMAHA.html You have to scroll down much to get to the ads and info.
There are some more models with hydraulic drive. EW643, TL433 and PR440. I don't know if the converter parts fits between the models.

And here you have a service manual that shows the hydraulic converter and how to work with it. http://www.vintagesnow.com/Yamaha_files ... 33F_SM.pdf

This service manual is for the SW440 1973, and it pretty much shows your sled (not the drive) with many details. Even the carburator is the same as yours, so it can help you a lot to solve the Kehin problems. http://www.vintagesnow.com/Yamaha_files ... 33B_SM.pdf


Other sevice manuals for old Yamahas (and other brands) you find here http://www.vintagesnow.com/index.html

[yooper360]

Thanks! That helps a ton. I figured there had to be a free downloadable manual out there. It will probably be a bit before I can really tare into it due to money constraints this month (heck, why else do I mess with old stuff besides the fact that they are cool) but I will be sure to post updates.