154 FMI Slipping out of gear
 

Just got this last fall. Have been out on it a dozen times, actually my son. I have a 166 FMM.

Today it starting slipping into neutral. Seems to do it when not under load, when I let off on the gas for a second. Seemed to happen more as the engine warms up, maybe or it could be my imagination.

I am running fully synthetic Shell Rotella T6. I have been running this since the start of the year and have been out 2 previous times without any slippage.

If you pull in the clutch and tap it back into gear it goes again... sometimes for only a few hundred feet though :-(

I verified the chain tension, clutch cable.

Any ideas?

Thanks,
Ross

Remove the clutch cover and check the shift drum index plate screw. It's probably loose.

Thanks, I will do some googling and hoping find some reference instructions or videos.

I removed, what I think is, the clutch cover and took the attached pictures. The screw was not lose, but the piece with the bolt through it had some play left to right and also in and out.

The two close up pictures show the extreme of the play on either side, only 2-3mm total I think. In and out play was about the same, likely less I think.

http://i.imgur.com/veZTpOp.jpg?1
http://i.imgur.com/VeFzBKO.jpg?1
http://i.imgur.com/2KtwOto.jpg?1

I also changed the oil from Shell Rotella T6 to plain Shell Rotella T.

Took the bike for a ride and it still was happening. If it is the oil, I don't know if it would be immediate with a change.

What bike is it mounted in ?

It is a Gio/Apollo

https://www.gvabrands.com/gio/dirt-bikes/gio-gx125-17

It's a zongshen engine if it's a Gio ,usually they are very good .I have a good one here on the shelf ,I will look and see if I have any parts engines like that as well .

To me it sounds like it's in the gear box.... poor harding on the gears & the dogs
have started to lose there edges...
while you have the power on the force holds them in mesh... once you
throttle off and unload them they jump out...
or the selector is not indexing correctly...



..

My current thought is that there is too much play in the end of the clutch rod... if that is the correct name. From what I have read there should only be about 1/2 turn of free play in there and I think there is definitely way more than that. I was definitely about to wiggle it in and out yesterday. I speculated above 1-3 mm. It is sloppy.

I watched many video's, but this video around the 5 minute mark shows a similar if not identical engine. He does not mention backing off the screw the half turn, but many others did.
https://www.youtube.com/watch?v=dpy5Us6wG70

When I get home I will try it and report back.

That did not help, at all.

One other symptom, which may or may not be relevant, or maybe not even a symptom.

If the clutch adjuster is bottomed out, the cable is as slack as possible, the clutch does not grab and as soon as you put it into gear the bike takes off. If I extend the adjuster to be about 1/2" it behaves normal and holds the bike in place when put into gear.

Quick update, I came to the conclusion that something was wrong internally and I was not comfortable removing the clutch.

I took it to a shop and he confirmed my suspicion. He was able to identify a loose bolt behind the clutch. He applied Loctite and should be good.

I am kinda OK with loose EXTERNAL bolts, and have lost/replaced 4 of those. Internal loose bolts are another story and make me really question how long till the next bolt loosens and I have to crack the engine :-(

I got lucky this time and it was just behind the clutch so cracking was not required.

Assuming it was the shift drum index plate screw that came loose, it's a common problem with all the Honda horizontal engines and clones. Loctite should prevent it from happening again.

That is what you called on the first reply ;-)

I might pick his brain tonight if I see him.