Hi, Due to being on a tight budget ive decided to try and do my own main bearings as they are grumbling badly.

Im wondering if its really difficult or not and if anyone has the sizes of the bearings.

I have access to a good bearing supplier but obviously sizes would help.

Any advice very welcome.

Thanks

If you have never split a motor it could be difficult. The Beta comes apart pretty easy. I would not recommend doing it if you do not have air tools. You need a flywheel puller. I would pull off the flywheel, clutch and primary gear off the crankshaft first. Then the cylinder, After that pull the engine from the frame. The parts diagram has the bearing sizes. I would recommend getting the main seals from Beta. Good luck!

Like lineaway says you need air tools or a fit for purpose impact driver and buy the time you buy it you could have got it done for as much if not less, unless you want to do it of course then that's another matter! when I attempted splitting my cases I couldn't undo the clutch basket nut or the primary drive bolt by hand and had to take it to a shop.

I was quoted £400 by one trials shop with engine out, fly wheel, top end and inner clutch case off!

I ended up getting it done in a motocross shop for £70 with me supplying the parts.

Again like lineaway says If you do go for it yourself don't take the top end off before the primary drive bolt or you have to hold the con rod back as your undoing it, not pretty!

You need some way of holding the flywheel and clutch inner while you undo the nuts.

One of these works well, it's what I've used on many rebuilds and it will work both ways around, studs to hold flys one way and tangs to hold the teeth of clutch inners the other.

http://www.ebay.co.uk/itm/Motorcycle-Clutch-Holding-Tool-Lockable-Clamp-For-Gear-Hub-Basket-Flywheel-/221523009997?pt=UK_Motorcycle_Parts&hash=item3393cce1cd

A puller is needed to actually remove the flywheel from the crank as it sits on a taper.

http://www.ebay.co.uk/itm/FLYWHEEL-PULLER-30-x-1-5mm-BETA-EVO-BETA-REV-3-SHERCO-TRIALS-/161275881184?pt=UK_Motorcycle_Parts&hash=item258ccaa6e0

Once the cases are split, DO NOT bash the mains out of the cases, gently heat the cases around the bearings, often boiling water (arrange a rag around the bearings to hold the water to the cases) or heating them in a oven is enough to expand the cases enough to push the bearings out.

Again, gently heat the cases to fit the new, with a very gentle tap with a socket (around the outer bearing race) will see them seated properly.

The main bearings are 30x62x16 in size (6206), use a good quality one, like FAG, SKF not an Ebay spanky****y special.

Note: Not any old 30x62x16 will do though, main bearing need to run a certain clearance and it's usually C3 that are the minimum standard needed, though often C4's are fitted to modern engines as well, check the numbers on your old bearings.

I believe the main seals are viton 25x40x7 both sides.

I have done my REV3 a Sherco 200 several Bultos BSA and AJS'S and never owned an air tool I just used the correct tools and pullers

I have done my REV3 a Sherco 200 several Bultos BSA and AJS'S and never owned an air tool I just used the correct tools and pullers

I've done a few as well and, despite all this stuff about heating the casings and watching the bearings fall out with a tap on the bench, nobody I know has not had to resort to a reasonable hammer. I'll believe it when i see it - maybe there's a video somewhere?

If you try it with out real tools, you have a good chance of messing something up. A while back a friend broke a clutch basket, just trying to change a shift shaft on a Sherco. 30 minute job which cost 4 times as it should. I`ve done loads of bikes. I learned right away that a rattle gun was the way to go. But then again I worked at a shop.