Crankcase bearing

Information relating to the Matchless G2 or AJS Model 14 250cc Lightweight
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ade
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Joined: Sun Oct 02, 2016 7:34 pm
Location: Calne Wiltshire

Crankcase bearing

Post by ade »

Which side am I drifting this from? I will heat it of course. This is drive/clutch. Will a RSL7 from eBay for £5 be cheap and fail? I beleive I need two of these on this side don't I? I am a bit confused over the old bearing still attached tho.

Hang on do I have 2 options bearing wise? the casing out bearing is a RSL7 but the inner bearing is a ball bearing RSL7 or a roller bearing 012543? someone please put me right!
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Janet
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Re: Crankcase bearing

Post by Janet »

The one still attached is a roller bearing with loose rollers. As I haven't broken my engine yet, I don't know what it looks like inside but I think it may have something to do with the con-rod.

I couldn't tell you whether the bearing from ebay would do for your crankcase. Bearing ;) in mind that usual suppliers of parts to fit are considerably more expensive, and the amount of use they get when the engine's running,I suspect they may not do the job. You could ask the seller.
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cbranni
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Re: Crankcase bearing

Post by cbranni »

Your photos suggest everything came apart as it should.

If you heat the drive side crankcase up until it's spit hot, bang the case join side down onto two bits of wood the ball bearing and the breather stator plus the outer race of the roller will fall out. The inner race of the roller bearing and the breather rotor should pull off, remember the rotor has a small narrow keyway which fits a key in the drive side axle.
By all means spend a fiver on a bearing................ it's your choice, I know what I would fit, take a look at club spares and see the cost of drive side ball and roller bearings ...................£110 for the pair.

When you put the new bearings in warm the case again to spit hot (spit hot is when you spit on the heated case the spit boils n spits) drop the ball bearing in first, then the stator and last the roller outer race, do not hammer them in, you may break the end on the crankcase................... if you search the forum much has been said on this subject.

Colin
only dead fish go with the flow
Andy51
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Re: Crankcase bearing

Post by Andy51 »

Hi Ade, don't waste your money on cheap and often nasty products, especially given the importance of this particular one. I tried using cheap Chinese bearings on my G80 - they dropped in the heated crankcase nicely, but as the 'cases cooled the bearings tightened up to the point that the mainshaft would only turn with application of force - no free running there! The bearings did not have the right internal clearances, and no variations with different clearances were offered. Order good quality bearings and pay the money! If the bearings had gone in, they would probably have given other problems and they are b*****s to replace, don't take the chance. Luckily I found out the problem at the assembly stage, so they only caused me a short delay while I got good ones - main bearing failure after assembly doesn't bear thinking about. Cheers, Andy
ade
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Joined: Sun Oct 02, 2016 7:34 pm
Location: Calne Wiltshire

Re: Crankcase bearing

Post by ade »

Good advice everyone, thank you. I will buy the proper one from the club. I am not sure what a breather rotor and stator is! I wish there was a decent manual showing the bottom end in more detail.
ade
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Re: Crankcase bearing

Post by ade »

Is this the inner race and Breather Rotor?
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Janet
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Re: Crankcase bearing

Post by Janet »

ade wrote:Good advice everyone, thank you. I will buy the proper one from the club. I am not sure what a breather rotor and stator is! I wish there was a decent manual showing the bottom end in more detail.
I haven't any photos but I find this very useful. It's of an early G2 so you need to check the part number variations for later machines but it gives a good idea of what fits where. http://archives.jampot.dk/Book/Spares_l ... e_View.pdf The drawing is in some manuals but this is very clear even when blown up to a bigger size.
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cbranni
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Re: Crankcase bearing

Post by cbranni »

http://www.archives.jampot.dk/Book/Work ... .NEILL.pdf

http://www.archives.jampot.dk/Book/Owne ... n_Book.pdf

Here are two links which will supply all the info you need just needs to be read

Colin

PS
Yes that is the breather rotor, also acts a spacer tween bearings and it's keyed to the axle, you may need a puller to get bearing and rotor off some can be tight.
only dead fish go with the flow
ade
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Joined: Sun Oct 02, 2016 7:34 pm
Location: Calne Wiltshire

Re: Crankcase bearing

Post by ade »

Thank you both, very useful. It's so difficult trying hard to put something together you never took apart. particularly if it's been in boxes for 37 years and bits are missing. I have nothing at all on the ignition side apart from the casings. Even my pushrods are missing!
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