Katana Owners Club U.K.

Guys,

I need some info on the 650 clutch assembly.

I've built it all up and put it together with a new friction plate set, and I can still turn the inner drum by hand with the springs in and the bolts tightened up!

The old clutch had a bit of slip when ridden hard, but the new clutch is far more meaty (obviously). And the old clutch didn't do this.... There is obviously a problem!

The basket and oil pump drive has all gone back together as per the manual (ie the dogs on the oil pump drive gear are locked into the groove etc).

Something is very wrong here.....

But what? I do have a page missing from my factory manual scan (3.65 is missing) detailing the centre nut tightening torque etc, but installing a clutch is hardly rocket science. There are the same number of new friction plates as there are old ones, so I'm not a plate short.

The only thing I can think of, is that I didn't soak the plates in oil... I just dunked each one in oil before putting in. I wonder if they need time to swell?

The only other thing is the springs - I'll measure the free length when BSB qualifying has finished, but there wasn't a problem before...

Any ideas you can throw at me in the meantime would be appreciated!

I want to get it done for Wimbotsham tomorrow, but it's looking like we could be double Triumph mounted at this point

J

you checked for wear ridges on the basket? did you put enough metal plates in? cos it sounds like youre missing one! soaking the plates in oil wont make any difference. finally, did you use the spacers under the bolts on the springs? im pretty sure the 650 has them like the 1100 and all gs series motors.

John,

I've given up for the time being!

All the driven plates are there. From looking at various info sources, there should be 8 friction plates and 8 driven plates. 1 of the driven plates is held in place with a "piano wire" clip, which leaves 7 in my hand - So should be the right amount!

One thing you mention is spacers: I have washers that fit on top of the springs, but looking at the exploded parts diagram for the 650, I can see nothing else that resembles what I already have.

It's obviously something that I haven't done right - In theory, it should be better as it was working fine (albeit with a little bit of slip when given some welly) before I stripped it and changed the gearbox internals, and the new friction plates have twice the meat on them that the old ones have!

I'm just wondering it it is the springs? But having measured the free length as per the manual, they are within tolerance - And surely they won't go from hero to zero within a couple of weeks of being out?

I'm confused....

Short of having the clutch assembly off (again) and treble checking, I'm at a loss!

J

It's still giving me grief....

Have installed new heavy duty clutch springs, and still just as bad!

This is what I have done so far:-

Installed washer on the end of shaft, fitted space and needle bearing for oil pump drive (with relevant washers).

Offered up clutch basket, locked into place on crank gear. Made sure the 2 tabs on the oil pump drive gear are locked into the back of the basket (turn the oil pump drive with a screwdriver until it clicks into place).

Fitted inner drum, tightened up retaining nut with lock washer on.

I have 8 driven plates (one held into place with the "piano wire" clip, which incidentally hasn't been disturbed). And I have 8 friction plates. Soaked in oil for a good couple of weeks.

I initially suspected a difference in length of the mainshaft that I put in, but measuring from the bearing inner race to the end of the shaft is 72mm, exactly the same as the old shaft.

Something is going quite badly wrong here (and it's probably my doing), but I have no idea as to what.

Every bike I have come across, I have not been able to turn the inner drum by hand, with the springs in and tightened up.

It's almost as though it needs another couple of plates - But I have the same amount as specified. The friction plates are new, and have much more meat on them than the old ones... It worked before (albeit with a bit of slip), but won't work now!!

Just about ready to ring the scrap pikeys now... Had enough of the chuffin thing!

J

Update:

I've had the verniers on the new plates, and have measured between 2.80-2.89mm thickness.

I've since hunted down one of the old plates (that looks visibly worn), and it measures 3.06mm in thickness.

Multiply that difference by 8, and there is one hell of a gap!

I've been on to the clutch plate manufacturer, asking for technical specs and basically got told to sod off, as it was Friday afternoon!

I think we may have found the problem..

J

Blimey. What a nightmare hope you get it sorted now. I would have burnt it by now

Pete