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Ossa Mar Clutch Basket Removal


martin 305
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Hi there i wonder if any one can help me with the removal of the clutch basket on my 1974 mar as i need to replace the crank seals and primary chain . Done the flywheel side and the cush drive is loose ready to take off but i cant get the basket off , i have removed the nut but not sure if the basket just pulls off with a puller :banana2: its got a sort of washer/ nut thats round behind the nut and locking washer that looks like it needs to be un screwed ???? thanks for any help you may have . cheers martin :rotfl:

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hello there, haven't done this job on my own MAR but from looking at my Clymer Ossa Workshop Manual you just remove the clutch nut as you have , but the manual does say

"if there is difficulty in removing clutch hub , caused by previous applications of Loctite , heat the region where the hub joins the main shaft with a torch "

using a torch sounds a bit drastic, i would try a puller first. anyway good luck , hope this reply was helpfull

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Once you've taken the nut off the basket/hub there is nothing holding that assembly on the gear shaft.

The reason it won't come off (unless someone has altered the way it is secured from standard) is probably because the hub is tight or stuck on the gearshaft splines. You can gently lever the basket outwards with something appropriate like tyre levers with curved ends (obviously gently without damaging casing mating edges or anything else) as it won't be seriously tight, not like a taper. Or, better, you can use a puller behind the basket if you have one that will fit. Pulling/levering the basket off will bring the hub with it.

The basket has a needle roller bearing which sits on a sleeve that slides onto the shaft. As well as this sleeve there is a shim and a distance piece. All these should remain on the shaft when the basket is removed, it's unlikely the sleeve will come off inside the needle roller but check it doesn't. The other two pieces will remain on the shaft.

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Thanks for your help Woody and DJR :banana2: seems like it`s just a tight fit then ;) , dont fancy the heat option so i will try with a puller as i cant get any thing strong enough between the hub and basket to lever the hub off . Thanks again i will let you know how i get on :rotfl:

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You need to lever behind the basket itself, not the hub, you won't get anything between the hub and basket.

You need two 'instuments' with curved or L shaped ends pushed behind the basket so that you can push the basket outwards by levering between the back of the basket and the casing. I use two 12" long car tyre levers with curved L shaped ends although it can be done with one. This allows the lever to roll on the curve when levering against the basket and no part of the lever other than the curved part touches the casing so there is no risk of damage to it. Pushing the basket outwards will push the hub off with it. A couple of jolts normaly moves it.

Just be careful what you are levering against, particularly the mating face where the clutch case fits.

If you have a puller whose legs will fit behind the basket, that would be the better option.

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  • 7 years later...
 

I'm guessing you mean that when you have the bike stationary in gear, with the clutch in, it lurches when you slip the clutch out as opposed to moves off smoothly?

 

One possibility is warped plates, another is a sticking cable, another is the slots in the basket where the friction plate 'fingers' slide are badly ridged causing the plates to stick rather than move in and out smoothly. The cable and/or the ridges are the most likely although there may be other reasons.

 

Remove the cable and pull the inner through back and forth, if it is notchy just buy a new one.

 

To examine the basket, you'll have to remove the clutch case. You can see the ridges without having to remove the plates. If it is ridged they can be filed smooth again after removing the plates but it takes a lot of patience.

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anybody advise a novice on why my Ossa Mar lunges into gear when i slip the clutch ?

I had a similar problem where it seemed my clutch adjustment was changing every 5 minutes. Had a couple of occasions sitting waiting to enter a section with the clutch in and the bike would just set off as if I'd let out the clutch.

It turned out to be the fibre clutch plates delaminating. New plates fixed it.

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