Last Thing I Need

[paul_stuart]

hi everyone after practising on my bike something always breaks hahaha

but now the linkage on rear suspension is gone , where do you buy them ( link me if poss )

i hear this is a hard job and costs lots how true is this ?

thankyou

[richt]

If you mean linkage bearings it's not difficult but a bit expensive. A kit from 'All Balls racing' is about £60 includes Bearings, Bushes, Shims and Seals.

[aussiechris]

Hi Paul,

Virtually all of the kits sold by dealers include bearings with separate seals. In my opinion these are rubbish. And yes, I know that's what comes from the factory.

The original bearings are HN1516 which is a full compliment needle roller with a 15mm ID, 21mm OD, and it's 16mm wide. The supplied seals are the same dimensions but 2mm wide. That makes for an overall width of 2+16+2= 20mm.

There are a number of reasons why they fail early. Firstly, the needle rollers have little tits on each end to locate them in the housing as there is no cage. For some reason, in our application, those little tits break off and get in amongst the bearings causing failure. But the main reason is water ingress. Those 2mm seals have a steel shell and that doesn't seal too well in the dog bone as it is so thin.

Furthermore, sometimes the seals just plain fall out of the dog bone. The reason is quite simple. The overall width of the bearing and seals is 20mm, but if you measure the dog bones you'll find they are only about 18.8mm wide. This means (assuming the bearing is perfectly centered) that the 2mm seals have just 1.4mm to seat in. And since the seals have a bit of a radius on the inside, there's bugger all holding them in place.

The bearing you want is a HK1520-2RS (contact a local bearing supplier with that number). That bearing is a caged roller with in-built nitrile seals. It is 20mm wide but even though it is slightly wider than the dog bone, it is all one piece. I've been running these bearings for about 10 years now in various bikes. You can expect 5 to 10 years life out of them compared to less than a year from the standard ones. Price is about the same. Even though the original bearings have more rollers that doesn't help if they're full of rust and mud.

This only applies to the four dog bone bearings. There's another two in the underside of the swing arm with two 3mm wide seals. You can't use the HK1520-2RS in there as the total width will be too wide (40mm vs 38mm total). But those bearings a well protected and don't give as much trouble.

Also, you may have to get the inner rings (bushes, sleeves) off your dealer as the bearing shops seem reluctant to hold them. Gas Gas part numbers are BT27712014 (20x15x8mm) 2 required and BT27712005 (20x15x10) 2 required.

I've just replaced the bearings in my 2011 Raga. The originals lasted 11 months and we don't do much mud and water here.

I hope that helps.

Chris

Brisbane Australia,

[aussiechris]

Oh, I forgot to mention... You can use a couple of appropriate sized sockets and a bench vice to press the old bearings out and push the new one's in. They are tight but not that hard.