sounds like mines doing the same thing, a bit nosy and

a bit of play in the flywheel, I can see this being a dear do 

 

...if you can get parts?

Ye of little faith Nigel!

 

Mine just went from butter smooth to rough as hell within 500 yards at the Scottish.

 

Pretty sure a couple of 50p Chinese bearings have given up.

 

Surprisingly I have a friend who can fix these things and don't expect the bill to be high even by the exacting standards of the tightest man in Fife.

 

 

 

Is it the same bearing left and right side?

 

/Christian

I really don't know I have a man that knows these things  so I'll ask him tomorrow and get back.

 

He started talking about cranks and casings, bearing removal when I took it too him and I just glazed over.

 

I do remember him mentionong some sort of special tool is required;

 

At this point I made an excuse and left.

 

 

There is a special tool to pull the crank out but you can make one just as easily

Hi Christian,

The older Ossa's have a needle roller bearing on the left side, a special made for Ossa to a close tolerance.

Later motors have a conventional ball race, you can retrofit the newer ball race (which has better endfloat control than a needle roller) if you can get hold of the later inner bearing plate.

The right side bearing is the same as a GG Pro with the same integral viton seals, except that the outer bearing casing has a radial groove machined in there to locate the bearing position screw.

The later crankcases have an extremely tight interference fit for the right side bearing to prevent possible crankshaft endfloat, should the bearing begin to move in the housing under stress (high revs).

The crankshaft bearings don't have a history of giving up so quickly. It may well be that the gearbox has taken in water, either externally or from the water pump shaft/seal and if this happens, there is every chance that the water can get into both crankshaft bearings and begin rusting up the bearing surfaces.

Also, it is important to change the gearbox oil often on these bikes.

Bye, Peter B.

Mine is around 275 hours of abuse, still going strong. I'm having the 2013 very-high compression head which is even higher comp than the special red racing head, hence the crankshaft is getting a lot more abuse. At 200+ hours most 2Ts are blown to bits thus I think OSSAs are very good quality engines considering mine's still running like a minter nearing 300 hours.

 

I'm replacing oil (GRO Gear Extreme) every 15 to 20 hours and putting in 450-500 ml instead of 350 ml the manual says.

 

Not sure if my 2013 model has the needle or regular main bearing. I need to get there first to see since the thing just doesn't wear through no matter how hard I abuse it... (most other trials bikes would have been blown to bits already )

Edited May 23, 201610 yr by tsiklonaut

Mine is also a 2013 Factory with high compression head.

I rode this bike a LOT at least 130 hrs.

 

When I got it (used) the clutch was adjusted incorrectly and slipping. It had already

eaten a clutch by the time I got it. 

 

Clutch fiber running through the mains is probably not a good thing who knows

if previous owner changed the oil, it looked very bad. 

 

I also went 20 hrs or so between oil changes, looking back I would

have decreased that to 10 or even less.

 

I also have an hour meter on my bike now to be able to watch 

things more closely for maintenance reasons.

 

 

 

Edited May 23, 201610 yr by bigmark1972

On the gas gas the entry hole for oil in the bearing case on the ignition side is tiny so I doubt anything will get in. It's about 1mm. However I think the drive side is open, is the ossa the same ?

On the gas gas the entry hole for oil in the bearing case on the ignition side is tiny so I doubt anything will get in. It's about 1mm. However I think the drive side is open, is the ossa the same ?

There are more openings towards the gearbox.

Hi baldilocks,

The left side does narrow down to approx 1mm dia or less when the oil passage ways reach the bearing plate. The right side is open to the gearbox oil as per GG.

Bye, Peter B.

I've had it confirmed today that mine have gone, so its off

back to Birketts this weekend to get sorted