OSSA MAR - NO GEARS

[poor1]

I've got an Ossa MAR with a lovely alloy tank which has been little used. I bought it about 10 years ago completely disassembled (everything including the engine, gearbox, rims and spokes - everything to it's last component). I put it together very carefully and had everything either polished, powdercoated and replaced with stainless.  I don't remember much of the detail, but am now trying to get it finished.  The engine is installed in the frame but moving the gear lever up or down does not select a gear and does not seem to engage with anything.

Two questions:

Am I going to have to take it all to pieces to get at the gear selectors  and

Contrary to my experience with the old British bikes when I operate the kickstart lever and disengage the clutch this has no effect and the kickstart which will still turn the engine over. I see from the workshop manual it is what it describes and a constant mesh gearbox.  Is this something to do with it?.

I've got a workshop manual. 

I would be grateful if someone could point me in the right direction.

 

[flinryd]

Hi poor1

I had a similar problem with mine, but only after changing the gear lever. I realised I had pushed it on slightly to far. Pulled it back a bit.  Let the shaft slide back into the gear box only 3mm. Then put a washer and Jubalieclip on the other end of the shaft. All was good after that. Mine might not be shimmed  up correctly.  Just my experience.  Hope this helps.

[djr]

2 hours ago, poor1 said:

I've got an Ossa MAR with a lovely alloy tank which has been little used. I bought it about 10 years ago completely disassembled (everything including the engine, gearbox, rims and spokes - everything to it's last component). I put it together very carefully and had everything either polished, powdercoated and replaced with stainless.  I don't remember much of the detail, but am now trying to get it finished.  The engine is installed in the frame but moving the gear lever up or down does not select a gear and does not seem to engage with anything.

Two questions:

Am I going to have to take it all to pieces to get at the gear selectors  and

Contrary to my experience with the old British bikes when I operate the kickstart lever and disengage the clutch this has no effect and the kickstart which will still turn the engine over. I see from the workshop manual it is what it describes and a constant mesh gearbox.  Is this something to do with it?.

I've got a workshop manual. 

I would be grateful if someone could point me in the right direction.

 

Hello, Yes unfortunately the kickstart  procedure should be the same as an old Brit Bike - it  has to be put in neutral for starting,

BUT the clutch is probably stuck so although pulling in the clutch lever should stop the kick start turning over the engine it wont if clutch is stuck/dragging

Have you started the engine and actually tried the gears/clutch ?

I have an MAR and the clutch is always stuck every time I start the bike from cold, however after 5-10 minutes of running it frees off and works fine

( I have tried all the different gear oils / clutch plates / adjustment methods etc. but none have cured this so I just live with it )

 

[woody]

Fit Barnett friction plates, they don't stick. And because they are higher friction, the springs can be backed off a bit to help lighten the clutch pull.

As mentioned in the first reply, the gear shaft can slide sideways slightly to the left meaning that the selector forks lose contact with the drum. Tap the end of the shaft to make sure it is fully home. Inside the clutch casing there is a circlip on the gear shaft and sitting against that on its outer side is a wave washer and shim. I'm not sure if this is supposed to stop the shaft disengaging from the drum as the washer should sit against the inside of the clutch case, but I don't think it does as it still seems to be able to move a little. Without it, it moves a lot more. A jubilee clip on the other end, as mentioned in previous post, stops movement.

If this isn't the cause of the problem, it is a strip down as the selector mechanism is inside the cases. Possible causes are incorrect shimming, weak spring on the selector fork, worn or broken tips on the selector fork etc.

[poor1]

OK that's very helpful. I'm relieved that my posting has caught your eye.  I will follow your suggestions.

With the passage of time I don't remember exactly how I assembled the engine and gearbox, but am I correct in assuming if I need to get at the selector mechanism the whole engine has to be split at the crankcases and that it cannot be accessed without removing the engine from the frame.?

No it has not been started, I simply assembled the engine and gearbox very carefully, or so I thought, and put it in the frame.  I wonder whether starting the engine, which requires further work to complete the wiring, would stir the thing up?. 

When (if) I get to the stage that i am able to rectify the gearbox I will look at replacing the clutch plates as suggested.

[trialsrfun]

Steve Sell at Marlimar OSSA supplies a shim pack of varying thicknesses to enable the crank to be centrally positioned and all the gear box workings have the right amount of end float. Steve also has the Barnett clutch plates, when my bike was finished the clutch would not free, the old plates seem to swell then will not function. The Barnett plates just work with less lever effort and a much better feel and action.

[poor1]

1 hour ago, trialsrfun said:

Steve Sell at Marlimar OSSA supplies a shim pack of varying thicknesses to enable the crank to be centrally positioned and all the gear box workings have the right amount of end float. Steve also has the Barnett clutch plates, when my bike was finished the clutch would not free, the old plates seem to swell then will not function. The Barnett plates just work with less lever effort and a much better feel and action.

Thanks for the extras bit of information

[poor1]

1 hour ago, trialsrfun said:

Steve Sell at Marlimar OSSA supplies a shim pack of varying thicknesses to enable the crank to be centrally positioned and all the gear box workings have the right amount of end float. Steve also has the Barnett clutch plates, when my bike was finished the clutch would not free, the old plates seem to swell then will not function. The Barnett plates just work with less lever effort and a much better feel and action.

Thanks for the extras bit of information

[poor1]

I'm delighted to say that a tap on the end of the shaft seems to have been the solution.  It moved inwards by about half an inch and (without starting the engine) the gears seem to be selecting OK.  I've also freed the clutch and it seems to working as it should.   It may well have had the clutch plates replaced with Barnett but I ould not know without taking it to pieces again.

Trialsfun speaks of Marimar Ossa.  When I googled it comes up as a Spanish site but not able to find any products.   Is there a good British supplier.  I know now that I will require anew rear drive chain. 

Any recommendations as to grade and type of oil for the gearbox please?

I need to get on and complete the wiring so that I can start the engine.  I have a full lighting set than I intend to install. Can this be installed with or without a battery?.

You have all been so helpful and I'm most grateful.  I think I shall back here for more advice as I press on. Thanks very much for your help so far.

Edited January 24, 2017 by poor1

[djr]

Hello, Steve Sell / Marlimar is in the UK {somewhere in the south I believe}

Las time I called him {a couple of years ago}  his phone no. was - 02392 593120 or 07800 778048

you may have to leave a message and be patient as I think he is a busy man, and Ossa spares probably not his main occupation,  its worth the wait as he is helpful and very knowledgeable about these bikes.

Inmotion also do some parts, both of them may well be at Telford off road show

hope this helps

 

 

[poor1]

22 hours ago, trialsrfun said:

Steve Sell at Marlimar OSSA supplies a shim pack of varying thicknesses to enable the crank to be centrally positioned and all the gear box workings have the right amount of end float. Steve also has the Barnett clutch plates, when my bike was finished the clutch would not free, the old plates seem to swell then will not function. The Barnett plates just work with less lever effort and a much better feel and action.

Thanks for the extras bit of information

[poor1]

Ive now located a chain thanks.  Will certainly go to the Ludlow show in february

[pmk]

Woody and others offered good info.  I suspect that you may have forgotten to install the snap ring (I guess Jubilee clip is another name for it) and the thrust washer on the clutch end of the shaft.

With those parts missing, the shaft is able to move left, and will see the same problem again.

The others posting are well versed in these OSSA machines.  I learned about the shift shaft end play when I removed the clutch cover.  You mentioned. 1/2" of movement on the shaft.  With my clutch side cover removed there is that much end play.  With the snap ring and thrust washers fitted correcty, the shaft end play is zero.

Try moving the shift shaft outboard, if it can be drawn out of the side case, you may want to remove the side cover and ensure all parts are installed.

[trialsrfun]

3 hours ago, poor1 said:

Ive now located a chain thanks.  Will certainly go to the Ludlow show in february

Telford search google for classic bike shows

[trialsrfun]

pmk in the Uk jubilee clip is a brand of hose clip