Clutch basket run-out

[Mark Stratton]

Following on from my rebuild thread http://www.z1ownersclub.co.uk/forum/vie ... c&start=15 has anyone else experienced runout on the outer ring of the clutch basket? Mine is currently 1.1mm out although the inner part of the basket closest to the crank gear is only approximately 0.1mm out. The bike did have a vibration at around 3500rpm so I was thinking that this could be the reason.

[Garn 1]

Mark, I have noticed, not so much run-out, as an un-eveness in the large inner needle race and its bearing surface. When inspected, I could find nothing. This un-eveness was noticed when I had two Z1 engines side by side on a bench with the bottom half of the engine removed.... One was smooth and the other had a tight spot when spinning the clutch basket. I swapped the needle rollers out, however the un-evenness persisted. I replaced the basket complete. Later checked the bearingat surface... found nothing that would cause this problem.

I put it down to the fact that defective one had had its radial springs replaced at some stage and had become misaligned causing ovality in the bearing.

I have since regarded all clutch basket as a critical piece of equipment, that can cause vibration and noise that can often be attributed to both head and bottom-end noises. Looking at the relative size of the gears and the mass of the clutch basket, it must be spinning less than, yet close to crankshaft speed.
RegardZ.

[Mark Stratton]

Garn

The bearing appears to be okay it's just the outer part of the basket. This photo may explain it better


As you can see the problem is purely on the outer part of the basket. When the dial gauge is put onto the basket closest to the crank gear it's pretty much spot on with no runout. Really just wondered if this is the norm or if I need to replace the basket. The springs and studs were replaced last time the engine was apart and the studs welded into place by a mate. When it was assembled before welding it was checked close to the crank gear to make sure that it was aligned properly however I don't remember it being checked on the outer ring so don't know if it was like it prior to welding.

[Garn 1]

Mark, I understand that you are trying to find out if this 1mm run-out is acceptable and would cause the vibration noted.
I haven't at my disposal an assembled clutch basket. I would say the rim that you are measuring from, doesn't seem to be a precision point and in fact seems to be a very ordinary linished, spot welded mild steel strip. Perhaps that run-out may be acceptable for this genuine pre-fab'ed basket, not that I like it!
RegardZ

[zed1015]

Don't bother taking measurements from that strap, they are only pressed on and are all like that to some degree.
It's normal.
Sometimes they aren't even sat fully down in the groove on the basket fingers .
Working round the basket with the pliers or mini clamp etc to fully seat the strap might get it running truer but i've never found it made any difference.

Vibes are most likely caused by something else, out of balance carbs,crank etc or maybe it's just the usual Kwak 4cyl vibes through the bars that give you a numb hand (usually the throttle side made worse by the throttle tube resonating on the bars ).

[Mark Stratton]

Thanks Garn and zed1015.

You have put my mind at rest so I can get on with the rebuild.