Yamaha YFM100 Champ rear axle
 

Hello from Sweden, I registered here just for a question since these atvs are not very common i Sweden and its hard to find answers.

I have a Yamaha yfm100 Champ 1991 that has a defective rear axle like so many others. I'm trying to find a new or used rear axle complete with swingarm. During my search I have seen some Chinese atv that have a very similar rear axle and swing arm. Has anyone here tried one of these on a Yamaha? Are they similar inside also with drives etc? Have found one at a reasonable price but would like to confirm that it fits.

Is it also correct that this is the same rear axle as on Badger 80 and Raptor 80? Its the one with oil in the diffrential and not grease like the old ones.

Checked some part numbers and looks like the Raptor 80 is the same axle. I found out recently that a Taiwanese or possibly Chinese bike is identical to the Raptor, but can't remember which one. Have a feeling it was Eton. If so, parts won't be available from them as the factory closed in 2013. Someone else bought the Eton name.

Thanks for answer, tried to look for used Eton in Sweden with no luck. It seems like all these Chinese/Taiwanese machines are sold under a lot of different names but with the same parts. Its a bit sad that the Yamahas have this issue with the rear axle, the machines have much more to give.

https://cimg5.ibsrv.net/gimg/atvconn...5baa7ca1e.jpeg
Just bought this scrap Chinese atv! Very interesting to see if it fits but it will take a few weeks before I have time to test

Very few children's Quads have a shaft drive to the rear axle, so you must stand a good chance of it being a Yamaha clone. any idea what make it is?

I have not picked it up yet but i´m pretty sure its called loncin lx110 atv. At least in Sweden/Europe.

Fingers crossed that it works!

When (if) its a clone, is the quality equal to original? Is it made in the exakt same way and material?

I had a Suzuki LT50 clone before and also a PW50 clone and they both felt very solid. Bought original parts that fit with no problem, the only thing that was different was the carburetor as far as I know.

https://cimg6.ibsrv.net/gimg/atvconn...dab304447e.jpg


Have you considered repair, rather than replacement of your rear axle? What is wrong with the shaft?

Here is a Yamaha YFM100T Moto4 Champ that I refurbished years ago. A T-model: 1996

This is a well-made quad, with unusual shaft drive.

When I bought it a few months ago previous owner had taken the rear end off and everything was in pieces with some rust on and parts missing. Would cost more than I think its worth to fix the old one.

The visual fault is the gear on the rear axle. If its even possible to find a original axel it would cost more than I paid for the Yamaha and Chinese together (50+60 $)

Loncin are well known Honda engine cloners, so it is a bit odd if they went for shaft drive, as small Honda Quads are chain drive. Loncin engines are regarded as very good copies of the Honda, so if they have copied the Yam back end, it should be a good one.

Just had a little set back, went out to check the oil level in the chinese rear axle and it was grease on the stick. I can just think of two possible reasons. Either the manufacturer used grease in stead of oil or previous owner "fixed" leaking by draining the oil and fill up with grease. What do you think? The axle is identical to my other champs original axle with a oil drain plug under and a oil level stick on the top plug.

if its made by previous owner, how can i get the grease out to fill with oil again?

How bad is it to drive with grease if it should be oil? It will not drive many miles in a year.

That's great that the parts match up.

If the PO put grease in there cuz the original oil leaked out the seals, that makes sense. That is commonly done
with rototillers. The problem is if the grease is too thick and does not provide adequate lubrication since it does not
circulate well. What I would do is add some oil to the rear end so that it mixes with the grease to form a slurry. You may
want to drain out what you can after a few hours use, then refill with more oil. Do that when it is warm.

Its still on the chinese atv so I dont know if it fits yet. But if it fits then I will do as you say, it feels more correct to use oil even if I have to fill it up sometimes.

It is indeed more correct to use oil. Just use oil that is thick enough not to leak out. If 90W gear oil leaks out, then going
to something thicker is called for. Or change the seals.

Getting grease out is almost impossible without stripping the whole thing. However the problem with grease is it sits where it is put rather than flow into bearings and gears. Topping up with oil will both "melt" the grease and flow into the bearings, etc, to lubricate them.

When you take it apart to put new seals in it you will get it clean with a parts washer. If you are going to go threw all the work of switching it take it to the next level and replace the seals and check bearings

Yesterday I took a little time to start the project. Removed the rear end off the chinese and first thing I noticed was that the drive shaft was different. Thought that this was the end of the project when it turned out to only be one side that was different, so I could use the original shaft. Made a quick try to put it on but its ca one millimeter to small where it connects with the chassie so I will have to use a grinder. A little concerned if there will be a tension on the shaft by some reason. That will proberbly not be detecteble until it breaks?

Now Im waiting for some parts that was broken by PO but there is still good hope that this could work.

Its on! Cant say it was a easy fit but with some blood and sweat it worked. Its to early to say its a succes all the way but this was a big step forward.
https://cimg1.ibsrv.net/gimg/atvconn...c9f8b7e433.jpg

Have to do any mods?

Not really but it was a little bit to tight at the connection to the chassie so I had to use a grinder and I didnt want to grind to much so it was many "on and off" attemps before it was right. Then the holder for the brakewire is to small so I have to think of something to fix it.

After some engine issues i finally got time for a test drive and it was a succes! No strange noices and everything worked very well. So this did work.

Now I have to figure out if it is worth the time and risk to change the grease in the axle for oil or if I take a chanse and leave it as it is. Thinking about what could happen if I add a little oil and just drive, could this be worse than just let it be?

Hi, the one I got was a Loncin lx110 atv or thats what they are named in Europe at least. I have seen many different types and names of these atvs with this rear axle (four bolt) so if its the same in USA its just to search for kids atv shaft drive in the "for sale" sites or facebooks marketplace, that´s how I found them.

If im right the 1988 model have a different type of axle than my 1991. Don´t know what else is different in the connection with the outgoing axle from the gearbox to the shaft but maybe it could work if you find a complete axle with swing arm like I did. I had to use the Yamahas shaft and that is probably not the same on the 1988 model.

Found this on Partzilla for 1988 years model: https://www.partzilla.com/catalog/ya...0u/drive-shaft and there you can see that there is two different types of driveshafts. Number 12 is the one I have.

So a wild guess is that if you find a complete rear axle (four bolt) and swingarm from a chinese atv and have the parts shown in number 12 it could work.

After a quick search in this forum it looks like some of the Yamoto 110 have this shaft drive.

Thanks for the info, I appreciate it!

[QUOTE=sr.ruedas;3405988]https://cimg6.ibsrv.net/gimg/atvconn...dab304447e.jpg


Have you considered repair, rather than replacement of your rear axle? What is wrong with the shaft?

Here is a Yamaha YFM100T Moto4 Champ that I refurbished years ago. A T-model: 1996

This is a well-made quad, with unusual shaft drive.[/QUOTE ]