I just fixed up a 125 four stroke. The first few days when I would test drive it short distances it seemed like something was slipping. It would jump off the line, then flatten out very quickly, when the revs got to a certain point in each gear.
I thought maybe that's just the way they were geared. Took her for a long ride in the forest yesterday and parked it. I tried taking it for a spin about five hours later and something very strange happened.
The clutch was slipping to the point that you could put it in gear, let out the clutch, and the atv would just sit there rocking forward slightly, even when gassed.
When I took the clutch out, you could almost turn the basket/plates by hand under full spring pressure! The friction plates had plenty of 'tread' left and seemed in good shape. The drive plates were moderately glazed so I removed the glazing. I happened to have a set of higher-tension springs that fit, so I tossed those in also.
When reassembled the problem had not improved. For some reason the clutch is failing to lock up when engaged. Because of the wet clutch I used 10w 40 motorcycle grade oil. Should I have maybe used something a little less slick? Regular 10w 40?
This is confusing.
I am going to order a new set of friction plates, but in the meantime I'm thinking about trying to de-glaze thecurrent friction plates (seems strange, right? but who knows)

Any other ideas?

 

You said you let on the clutch? Is this model an manual clutch model? If so what year? Im not familar with an manual clutch 125 Honda atv!

 

It's actually a motorcycle. it's a 04 xr125. The drive/friction plate tech ought to be the same though.

 

I would stay with the motorcycle oil for sure....What does the friction disc look like? Is cable and lever in good shape? have good freeplay in cable?Does basket have alot of grooves in it were the plates and disc slide in and out? just afew question to get some overall ideal condition of bike.

 

Just replace the friction plates and check that the steel plates aren't warped from over heating.Friction plates can mic out good and even if you sand over the glaze if they're oil saturated over a period of years nothing will help,they'll still slip even with heavier springs. Ran in to that a lot over the years in dirt and street bikes.Best plates are Barnett or Ebc heavy duty.

 

The drive plates appear to be in fine shape, and de-glazed well. I ordered new friction plates, I suppose I will just leave her disassemble and throw the new ones in when they get here- and hope that solves it. Looking at the current friction plates they are pretty worn, and I have no idea how long this bike sat before I got my paws on it.
Thanks, all

 

New friction plates should give it new life and solve your problem.

 

I agree, sounds like the friction plates are bad regardless of how they look. You actually want to run the motorcycle spec oil, it doesn't have the friction modifiers car oils have that cause a wet clutch to slip. An alternative are the diesel motor oils as well. Let us know how it runs with the new plates!

 

I'll let you know how it goes.
Thanks, guys