Clutch Won't Engage, Bike won't move, Clutch Slave Bad?

[Del16]

I am having a similar issue to yours. When I ride the bike (98 intruder 800) all is fine for about 15 minutes then I notice clutch slippage which progresses from slight to near complete disengagement in about 10 minutes time. I made the mistake of using automotive oil which was not for wet clutches so I removed the clutch and cleaned all plates with brake cleaner, cleaned all oil residue from crankcase with brake cleaner as well. First ride after that was same result so I replaced the clutch. still have the same issue, all runs fine for about 15 minutes, then it starts slipping again. If I let bike cool for a few hours it will run fine again with no slippage until warmed up. I also have not heard the fan come on and was thinking maybe the oil was getting too hot and causing the clutch to slip. I never see a temp light or oil light come on while it is running but both do come on when ignition is turned on so they do work and engine does not seem overly hot. I'm new to bikes so some of the obvious stuff is still new to me. I appreciate your sharing your experience. Did your bike ever have difficulty shifting from neutral to first when this clutch issue was acting up? Mine does that and after about a dozen tries it will go into gear and work fine again. I will try opening the slave bleeder next time this happens to see if there is any change in clutch engagement after relieving pressure that way.

[navigator]

Clean the small hole in the floor of the master cylinder with a small wire. That is where your problem lies.
Bleed the system again to blow out any debris.
Your fan will rarely come on unless you are sitting in traffic on a VERY hot day.

[Herb]

I have been using automotive oil in all of my bikes for over 50 years and have NEVER had any oil-related issues because of it. Whoever told you that running car oil would hurt the bike lied to you.

Navigator is probably correct about the problem.

[hillsy]

Whoever told you that running car oil would hurt the bike lied to you.

Some car oils have friction modifying agents which can damage a wet clutch. That's why it's a good idea to stick with bike specific oil unless you know what you are doing.

[YoDude]

8. Clutch worked again, worked great in garage. Went for a ride - after 30 minutes (I guess after it got hot) it left me stranded.
9. Moved bike to a sidewalk, let it cool for 15 minutes (tried to look cool sitting on the sidewalk - but felt like an idiot). After 15 minutes, clutch barely started working again - got the bike back home. I knew it would do this, so I only rode around the neighborhoods - at least i wasn't far away.

This is the exact symptom of a brake or clutch line that only works intermittently.
Replace the clutch line. It's swollen inside. Engine heat may cause more swelling to be encouraged. This would be especially true if, once warm, you cannot squeeze the clutch all the way to the handlebar. I have seen this type of symptom in a couple cars that I've owned in the past. Two different cars, same symptom. Drive it for a while and one of the brake lines swells up and blocks fluid flow.. In my instance, the affected brake would stay on, preventing the car from moving. After sitting for some time about 10~15 minutes, then pressure would SLOWLY release and the car could be driven again, until the brake line got pumped up again. it happens in the flexible part of the line.

Yo-

[94szki]

Clean the small hole in the floor of the master cylinder with a small wire. That is where your problem lies.
Bleed the system again to blow out any debris.
Your fan will rarely come on unless you are sitting in traffic on a VERY hot day.

I can confirm that the bike is still running fine post taking off the master and cleaning out that small hole. See my post from "Oct 29, 2019." It's June of 2020 and the bike and clutch are still running fine. In hindsight I guess I didn't need to replace the slave down below, but I guess it didn't hurt on an old bike. I think the aftermarket piston could have been part of the overall issue. The serrations appeared visually thicker than the serrations/swirls on the original piston. Put the original piston back in and bled the system and it worked then (in Oct of 2019) and the bike still works fine today.

Thanks,
Emmanuel

[94szki]

I am having a similar issue to yours. When I ride the bike (98 intruder 800) all is fine for about 15 minutes then I notice clutch slippage which progresses from slight to near complete disengagement in about 10 minutes time. I made the mistake of using automotive oil which was not for wet clutches so I removed the clutch and cleaned all plates with brake cleaner, cleaned all oil residue from crankcase with brake cleaner as well. First ride after that was same result so I replaced the clutch. still have the same issue, all runs fine for about 15 minutes, then it starts slipping again. If I let bike cool for a few hours it will run fine again with no slippage until warmed up. I also have not heard the fan come on and was thinking maybe the oil was getting too hot and causing the clutch to slip. I never see a temp light or oil light come on while it is running but both do come on when ignition is turned on so they do work and engine does not seem overly hot. I'm new to bikes so some of the obvious stuff is still new to me. I appreciate your sharing your experience. Did your bike ever have difficulty shifting from neutral to first when this clutch issue was acting up? Mine does that and after about a dozen tries it will go into gear and work fine again. I will try opening the slave bleeder next time this happens to see if there is any change in clutch engagement after relieving pressure that way.

Navigator was right on my bike. It seems like a very similar issue. I replaced the slave cylinder which I probably didn't have to do. That didn't fix my problem. I was lazy and didn't want to take off the master and clean it like navigator suggested - but that was the fix. You can replace your clutch cable for added reassurance if you want to (as YoDude suggested) but I bet a good clean of that little stubborn hole will fix the problem. I took the master off the bike, took the piston apart and cleaned it that way. I did not get the same results when I tried to clean the little hole while the master was still on the bike.