clutch problems 1983 interceptor

so ive got an 83 vf750f and i could use some advice on clutch work. the bike starts in neutral but lurches forward and dies as soon as i put it in gear. if i try to start it in gear it lurches forward and dies immediately. this is all with the clutch lever in. there is not really any resistance in the clutch lever either. i went ahead and bled the system several times releasing any air that i could and then went about replacing the slave cylinder. new piston, new seals, new spring. upon disassembling the old slave cylinder, i suspected piston corrosion and a difficult time getting the piston out of the housing, but it came right out as it should with a little compressed air. the old slave cylinder components seemed fine and in good shape. i replaced them anyways figuring why the hell not. --- no change.

now ive turned my attention to the master cylinder. i took it apart and noticed that the piston set is recessed into the cylinder and would not come out with pliers. the springs function when depressed and the can be seen moving through the hole in the reservoir. there is also small evidence of fluid leaving the cylinder through the banjo bolt hole but i havent been able to find the weak link. im wondering if the pushrod (which also seems to be fine) is not getting enough pressure or putting enough pressure on the pistons/springs because they are compressed and/or worn. still no resistance on the clutch lever...

any suggestions? the bike has been down on that side and there is evidence of the clutch lever having touched down... seems to have held its form though.

thanks for any help!

 

Time maybe to inspect the clutch itself. If your plates are not worn out or warped they might be oil soaked. A DIY fix is to soak the fibre plates in a petro solvent. Springs could be shot too.

 

Pinch the line just below the master and and pump the lever to see if will build pressure, these can be a bitch to get pumped out and operating correctly again.

 

If the master is not bled completely, you will have this problem. Most master cylinders have the banjo bolt kind of pointed up. Higher than the piston. This will trap air in the mc at that point. Loosen the mc and point it downward in the front to get the banjo lower gravity wise. This will force the air back in to the mc and get bled out thru the little hole in the bottom of the mc reservoir.

 

You can test the mc pressure by putting an appropriately-threaded bolt into the end, subsitituting for the banjo bolt. If mc is working properly, you won't be able to squeeze the lever back to the bar, and you'll feel the pressure.

Similar to TOE'S suggestion but a little different.

When bleeding slave cylinder you don't want it moving in and out, so it's best to remove it from the sprocket cover and fully retract it and hold the piston using a C-clamp while bleeding.

 

Ive had luck with loosening the three bolts that hold the slave cylinder in place out a few truns then bleed the system again. when done retight the bolts and give her a test. let me know if this works for?

 

Is the return hole in the m/c clear? If not you can get this symptom as well. There is a small "plate" that sits over it. Remove it - just pulls out - and use a small piece of wire or toothpick to clear it. It will plug up if there was/is crap in the m/c. Beware though, with the cover off the return hole when you actuate the clutch lever fluid will shoot back at you. Cover all painted surfaces and move lever slowly.

 

You know, that sounds just like what happens when something inside the clutch basket breaks. It might not be a bad idea to pull it apart and check everything. I'm guessing the hub will be fractured at the base of the clutch pack.

I think you would know if there was a problem with the slave cylinder or air in the system. It would make the lever feel funny, or at least have a really short throw. It's worth checking anyway I suppose.

 

thanks to all and happy holidays!!! unfortunately, im away from the bike for the next week visiting family, but its back to the grind as soon as i get back and im sure with all of the tips i will come up with a solution!