349 Cota s/arm bushes

[heavywrecker]

I have a lot of play in the swingarm bushes on my 349 Cota.

Is there a conversion to needle roller bearings available/possible?

Does the sleeve in the frame/pivot bolt wear, giving similar symptoms to shot bushes?

Cheers

[feetupfun]

Yes the steel sleeves (inner bushes) can wear. They can also rust.

With enough time and money, it is possible to convert your 349 to rolling element swingarm bearings but why would you when it is so much easier to just replace whatever is worn?

[michaelmoore]

Needle bearings are very intolerant of dirt getting into them. Plus you've got the problem of the races brinelling from the oscillating motion. Needle bearings often seem to have a perceptable amount of "shake" in them, and if you are careful you can set up a bushing with a very close fit and still have it free-running.

Compared to a well fitted bronze bushing that gets a squirt of grease once and awhile the needle bearing seems like a very poor idea for a dirt bike.

Unless of course you like to work on them a lot.

cheers,

Michael

[toofasttim]

Plus you've got the problem of the races brinelling from the oscillating motion.

That's a point. Never thought about it that way.

[heavywrecker]

Thanks for the help guys, going to tear it down and have a good look. Shall forget about needles.

Cheers

[michaelmoore]

I suspect trials bikes aren't going to see enough use where Brinelling of the races/needles would be a big concern. But most OEM needle bearings I've seen in bikes have been pretty well trashed, and even a small bit of dirt and water seems to make them pretty unhappy. I presume they are often chosen because it eliminates a machining operation for the manufacturer -- they just buy a box of standard bearings and push them in and send them off.

cheers,

Michael

[jimbo349]

Bushes are not available but a off the shelf oillite bush is available that is smaller in the id meaning either ream them out or have the metal spacer machined down which is what I have done on the MH so if they need changing again a couple of quid for the bushes and job done.

[woody]

In Motion / Bultaco UK have Montesa swingarm bushes. Worth a try to see if they have the size you need

[heavywrecker]

Thanks again for the help guys, much appreciated.

I have discounted the idea of a needle roller conversion.