Noobie Clutch Problems

Hi everyone! I just bought my first bike, a 1978 XS400. It was missing the forward clutch cover so I bought a replacement. I hook it up to find the clutch is not dis-engaging! Trying to push the pushrod but it does not do anything, it does not move, nothing appears to be working inside the case. It is easy to remove, it just slides out of the housing. It just seems to be butting up against the other side of the case. I assume I'll have to be taking the motor apart, but has anyone else had this problem and if so, what's the issue?

There is a small single ball bearing that goes in first before the rod, that must be there or the rod becomes too short to work the clutch. There is a clutch pusher in there too that has to be present to push on the clutch inside to work it.

There should be a ball on the worm actuator. Also a ball at the clutch end of the rod that goes between the pressure plate plunger. Those are often missing when the rod gets removed for a long time and the bike is moved around. Make sure you also have the cable holder for the case. If that is missing nothing will work.

xschris said:

There should be a ball on the worm actuator. Also a ball at the clutch end of the rod that goes between the pressure plate plunger. Those are often missing when the rod gets removed for a long time and the bike is moved around. Make sure you also have the cable holder for the case. If that is missing nothing will work.
View attachment 36023 View attachment 36024 View attachment 36025 View attachment 36026

Click to expand...

Thanks! The weather out here is terrible but I'll check the next chance I get. I'm pretty sure there isn't one on the worm actuator.

There may or may not be 2 balls, that guy knows his Yam twins.

Most designs only have 1 though. The way to know is with 1 ball and rod you will still have loose adjustment of you need 2 because the working length is too short. Your adjusting screw or whatever there should hit some resistance showing the length is right and you still have some adjustment left to do yet. The adjusting screw can serve as second ball too by being rounded off on the end.

Dunno about this one either as in the hole size for ball, some have the passage get bigger with a step at the ball inside clutch and the only way to add it is to yank the side cover and pull the outside pusher plate back off to get to the hole to put ball in. Other designs allow the ball to be same size as rod and it can go in the other side easily. If the ball is same OD as the rod you are in luck.

Update: I just got all the parts for the clutch cable and related mechanism. Upon pulling the clutch I get a fair amount of resistance but the clutch does not disengage. I’ve read elsewhere soaking the clutch plates in good oil (the current oil smells like bad gas) can work miracles and get it working properly. Regardless I’m planning to inspect the clutch assembly this weekend when I have time to disassemble the bike some. I’ll look for the bearings then.

Make sure you adjust the lower cable adjustment first before you adjust the one at the handle bar. The manual has this procedure in it. Also there’s threads in the forum on this.

I went ahead and did that, definitely improved the situation. I went ahead and opened up the clutch cover. This bike shows 4500 miles on the odometer and I believe it. Absolutely pristine gears and insides. The clutch is moving when I pull the lever however the plates are sticking and not disengaging. If I manually push the plates while the lever is pulled it disengages correctly. I went ahead and removed and cleaned all the plates as well as applied new oil to them. I did an oil change while I was at it but after I reassembled the bike the same issue came up. I started the bike and let it idle for a while but it still didn't work after I turned the motor off. Do I need the weight of the bike to get the plates to slip past each other? I've been doing this by turning the rear wheel by hand. I'll see if the new oil soaking in all night helps.

Unrelated issue: my left carb leaks gas like a strainer out of the intake and the same cylinder backfires when I rev the bike. I assume the mixture is wayyyyyy too rich, where's the adjustment for the mixture?

Your clutch cable might also be stretched out. Make sure you assembled the clutch correctly. There are two arrows, one on the basket and one on the outer plate. Those need to be aligned. It's all in the manual. Make sure your using oil designed for wet clutches. To test the clutch for dis-engagement, put the bike on its center stand pull the clutch in and kick the engine over with the kick lever. The kick lever should have no resistance. This also unsticks the plates and pads. If your looking to roll the bike are you putting it in neutral or trying to pull in the clutch? It should be in neutral. Does the bike move when you put it in gear and let the clutch out? (bike running of course) As for the carb issues sounds like a bad float valve or float. The carbs might need an overhaul. Post some pics of the bike.

Update: I let the engine sit with new oil in it and it worked! The bike runs and drives as it should! Thanks for all the help! Now just to adjust the timing...