I'm guessing this is going to get expensive...

This is my beloved 2011 Raga 300. After the usual weekend practice and a thorough clean, I discovered both crankcase halves have broken around the lower rear engine mount. These are magnesium cases. I know there has been a reported issue of misaligned holes at this mount but I checked it about a year ago and it was perfect (no drilling necessary). Obviously this is what we have to expect to have a lightweight bike.

Anyway, new magnesium cases appear to be unobtainable. I'd be happy to replace them with the standard aluminium ones hoping they might be stronger. The problem is that the local dealer appears to only have one half in stock and I thought they were sold as a matched pair. Looking at the Gas Gas Future thread, I'm guessing the factory won't be shipping any parts soon. So I might be testing my welding skills (I can weld aluminium but never tried magnesium).

Do some serious homework before you try welding Magnesium, I suspect this is the stuff that flares up on you when it gets hot!

This should not have to be expected from riding a light weight bike.

Magnesium alloys are not ideal for use in engines.

I would do a little research before starting up the welder,if you do have some dry sand on hand.

I had a repair done on some aluminium crankcases. It was all ok but it warped the cases and I ended up buying new ones.

Your dealer should be able to order them as the parts dept is still open if this article is correct.

http://www.dealernews.com/dealernews/article/gas-gas-suspends-production-it-awaits-financial-restructuring-plan-approval

Wow, there shouldn't be stress on a case like that or if it is intended to be a structural member it should be beefier than that. I would suspect there are cases available at least from importer stock somewhere. All the talk about parts shortage isn't that relevant now. Interesting break pattern that stayed all in the same plane.

Anyone with a pro should compare their skidplate shape with a new one. If it has been flattened you are prone to breaking the case or brackets. Luckily the bracket broke on mine before the cases. I am able to hammer it back to curved with a 16lb sledgehammer and put in some new rubber cushions.

Have heard of them being successfully welded,I would search out a company with good experience of welding magnesium .I don't think new cases would line up with the frame,do you have access to another bike you borrow the engine from to try it in the frame to find out?Ive only heard of the magnesium cases breaking never the normal ones.Good luck with it

There are 3 problems welding this case. 2 of them specific to magnesium.

1) The casting may be porous and may have absorbed oil which makes a good weld impossible. Warming it with a blow torch and flushing in brake cleaner usually gets rid of sufficient oil.

2) Magnesium shrinks a lot on solidification and a further 1.5% on cooling to room temperature, this causes cracking.

3) Some magnesium alloys are flammable (porsche wheels for example) but bike parts generally are not. Test for this by melting a portion of the broken off piece the pulling the TIG gas shield away sharply.

To repair this I would not try too weld the broken piece back on. I would butter the broken surface with several layers of 4043 using minimum heat input pulse / intermittent technique, Then I would weld heavy aluminium straps across the surface, at 90 degrees to the bolt. The straps would be something like 12 wide by 6 thick flat bar.

I've heard of a few of these mag cases break now. I think I'm going to look and do some mods to prevent it happening to mine.

I hate paranoia, especially when these cases are so expensive.

Looking at the right hand side of the broken piece, it looks like it may have taken a hit from the bashplate.

Is there a mark on the plate relating to that point?

Thanks folks for all your replies,

I am aware of the fire risks with welding magnesium but it seems to relate mainly to OA gas welding. The argon coverage from TIG welding mostly negates the problem. Fine shavings and dust are still a hazard. I agree that the main problem would be distortion. Given the amount of work involved in rebuilding the engine I think I'll play it safe and throw new cases at it. Looks like my dealer can source them ok.

I think the main problem is that the rear bash plate rubber was worn through and, as Steve suggested, there has been contact between the bash plate and the mounting lug on the case. I need to replace these rubbers maybe every year.

Chris.

I undo the bash plate from time to time and put it under the press to make it fit without a lot of force on it (takes some goes, and is quite scary because its quite bendy so you need to go quite far with the press). And check or replace the rubbers.

Checked mine today and all is fine at the moment, There's hardly a scratch on my bashplate and I've noticed it's got anti slip teeth on the bottom.

I know what you mean, Crazybond, I have done loads of them in the press on various bikes, mainly customers not my own, Some of them do need a lot of pressing past the point of no return as they spring back.

Hell fire pal that's really bad luck you have there. You could try getting or asking for ally cases from another country and get them shipped . You can also get a better quallity bashplate from off ebay . I saw them recently for £120 . You can bet they will be more effective than the standard GasGas one. I get parts with no problem on the whole despite the press etc from GasGas UK . Don't think that GasGas arn't in production. Gas Gas UK got 80 bike's delivered last week and i heard that from Andy Hippwell so it's not bull dust .That's for my 15 year old TXT 280 too by the way . Give them a shot as a last resort .

Good luck .

Edited February 2, 201511 yr by shyted

bloody hell, just bought a 2011 raga and have now seen this, great