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Noisy Ossa Factory 300 What Parts Should I Get Coming?


bigmark1972
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My green baby is sick and has a lot of bearing noise.

 

I believe the top end is fine the bike has a ton of power 
and not a ton of time on it. 

 

Assuming it's only the lower bearings can anyone help me out and tell 
me what parts are needed to swap out the crank bearings?

 

Anything else I should do / buy when in there?

Best place for parts? LewisSport is out they are at SSDT for 2 wks.

 

Input appreciated.

 

 

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You sure those are top end bearings? Might be something else too if your bike hasn't got much hours on it. My 280i is nearing 300 hours and while running the 2013 very high compression head (even higher than the red "Racing" head mod) no top end bearing replacements done, it's got a lot of abuse but still the heart of it going strong, running GRO Gear Extreme 75W oil, replacing every 20 hours or so.

 

Haven't done this but looking at the manual you need a rather shallow type of a bearing puller.

 

For parts you can try European OSSA dealers, a good bet is Joa International or someone from UK (but they probably are at the SSDT too I reckon).

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I could post a video of the noise tomorrow but have run several trials

with it and almost everyone agrees it sounds like lower bearings.

 

Checkers commenting saying they could hear me coming.  :chairfall:

 

I put a dial indicator on the flywheel and have .008" in and out play

and .010" lateral play (when considering both opposite directions)I am pretty sure that is not good.

 

Here is some video what say you?

 

 
First video was in and out, second was lateral, could have gotten more if I pried
harder but did not want to damage the flange in the case.

 

 

 

 

Edited by bigmark1972
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Yup, sounds like the big ends to me now too. The magneto has apparently too much play(?) When you open up the case you should see how are the conditions of different bearings by observing them or rotating them with your fingers - a rough or loose fiddly movement means a bolloxed bearing.

 

Good luck on replacing 'em, let us know how hard job is it. Most of us have to go through this one day anyways I reckon.

Edited by tsiklonaut
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The later Ossa's have a very tight interference fit for the RHS bearing to crank case housing. It took me 22 hours to strip out a crank shaft and replace the RHS bearing then re-fit everything, probably the longest time I have ever taken to replace a crank bearing, longer than a Tiger 100 rebuild even. Remember to remove the RHS bearing locating pin (allen head) first.

You can make a puller to extract the crankshaft from the casing, quite simply from a flat bar 20mm x 40mm that spans the LHS mag housing using some pieces of hardwood to prevent damage to the housing from the puller. Drill and thread the centre for an extraction bolt. (Hi tensile)

I used a hot air gun set to max to heat the RHS bearing housing with a lot of tension on the puller, when the shaft and bearing let go about 1mm with a mighty crack, it is really tight there. Massive heat and tension finally got the crankshaft out.

You need a good bearing puller to withdraw the clutch drive gear from the RHS of the crankshaft, it's fine to re-use 2-3 times without losing too much interference.

The RHS bearing has an integral VITON seal, same as per GG Pro, except the outer casing of the bearing has a slot milled in to locate the locating screw.

Replace the RHS bearing and gear and re-assemble.

Have the crankcase baking in the oven at approx 110C for an hour or so, keep the crankshaft in the freezer overnight. Use welding gloves to fit the two together without force.

You should use a permanent marker to mark the position of the locating pin in the housing on the inside of the crankcase, and on the bearing, and on the flywheel, so you can use the mark as a guide as you slide the now loose fitting crankshaft into position, make sure you have got the right position by inserting the locating pin, I think I used a torch to see if the hole lined up with the slot.

Good luck.

Bye, Peter B.

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  • 2 weeks later...
 

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