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Messages - Steve.S

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Singles / Re: M21 gearbox
« on: 24 May, 2024, 20:59:13 »
Sorry, the oil seal runs on the boss of the sprocket.

Singles / Re: M21 gearbox
« on: 24 May, 2024, 19:21:29 »
You will need to remove the bearing again. Heat the case first.
There are 2 oil retaining washers, one either side of the bearing. The outer one sits centrally in a recess in the casing and is held firmly in place by the bearing. Yours is loose because the bearing has not been seated properly. When fully seated, the bearing will trap the washer. Although it doesn't matter too much with a seal fitted, this outer Oil Retaining Washer should be fitted with the recessed inner to the outside. The inner washer should be fitted the other way round. The oil seal runs on the sleeve gear which you have yet to fit.
It would be worth checking the end floats once assembled, and remember that the mainshaft kickstart nut should not be done up tight, as per the M20 Manual.

Change the oil now.
However, it would be helpful to know which models you own. For example, one could be a 1912 Model A and the other a 2024 Gold Star, which may need different oils.

Singles / Re: 1947 B33 Crank case assembly help needed
« on: 19 May, 2024, 15:03:02 »
I see no reason why you can't just make up a mild or stainless steel spacer of a thickness to allow the engine sprocket to line up with the clutch sprocket. I don't think you need to use Phosphor Bronze.

Singles / Re: Magdyno , driven gears , info required
« on: 19 May, 2024, 14:58:45 »
I think there may be some confusion here. Idie is correct in saying that the gear is lubricated by oil in the timing case, but this is the Magdyno drive gear, with a seal on the boss.
Bigsingle is referring to the 2 gears behind the triangular cover..
Lucas stated in one of their Instruction sheets that the Celeron fibre gear should be lubricated by the application of a small amount of grease, and not run dry.
Unfortunately, fibre gears that arrive in the UK by ship seem to be of poor quality.
Hope this helps.

Pre War / Re: B21 gearbox gaskets
« on: 18 May, 2024, 18:14:14 »
I don't know much about these modern gearboxes with internal kickstart springs, but I wonder if you could loop  piece of string around the spring hook and pull it tight to pre load it? You just judge the pre load by how it feels.
Regarding endfloat, assuming the gearbox was working OK before the spring broke, I wouldn't worry about it too much.
However, I would make the gasket about the same thickness as the old one. When it's all assembled, grab the mainshaft and push it in and out. If you have a DTI gauge, use that, turning the shaft through 360 degrees. (Endfloat will alter if something is bent). Otherwise just judge it by eye.
I don't think this need concern you at this stage, but it might be worth mentioning that endfloat would normally be accurately checked with the component clean, dry and free of oil.
Finally, if you can't select gears after you've reassembled it, it probably means the indexing of the teeth on the selector shaft is incorrect.
Best of luck, and let us know how you get on.

Pre War / Re: B2 pushrod seals
« on: 09 May, 2024, 02:01:47 »
Well, I use BMC Mini Rocker Cover Bolt Seals, Part No 12A 1358.
I cut off the reduced diameter bit, chamfer the top slightly to fit the flare on the push rod tubes and cut a flat on the OD to clear the barrel.
Have a look at them and see what you think. They're about the right thickness i.e quite thick.

Pre War / Re: MP42 Headlamp
« on: 05 May, 2024, 18:09:48 »
I've sent you a PM.

Twins / Re: A65 Spitfire mkiv needs choke ?
« on: 05 May, 2024, 12:55:13 »
I have heard these carburettors sometimes need cleaning thoroughly before fitting, so I agree with Dave Brady. Also, sometimes jets are loose.
Are you saying that adjusting the air screws don't make make much difference to tickover speed? If all is well, they should be quite sensitive.
I wonder if you might have a little bit of debris in your Pilot By Pass orifice?
A friend of mine once found a dead fly in his float chamber!
You are correct. The mixture adjustment screw is an air screw.

Twins / Re: Piston rings
« on: 05 May, 2024, 12:37:10 »
Cox & Turner Engineering 01935 826816 can make piston rings.

Singles / Re: M21 rebore
« on: 05 May, 2024, 12:34:12 »
If it were mine, I would have it resleeved back to standard.

Pre War / Re: Carb re sleeve
« on: 05 May, 2024, 12:32:14 »
The slide is 1 3/16" diameter.

Pre War / Re: Missing screws
« on: 05 May, 2024, 12:31:12 »
Surprisingly, they are 1/4" BSCY and the outer ones are 1 1/8" long.

Well, is it much easier to kick over when it won't start compared to normal? If it is, then it could be the exhaust valve sticking. Make sure the valve lifter is not holding the valve open. 75lbs sounds a bit low for 6.5:1 compression ratio. Is it gutless? I would expect nearer 100lbs or more. You  should add a little oil through the plug 'ole and see if the pressure increases. This will seal the rings temporarily (and to a degree the valves). Ideally you should carry out a cylinder leakage test, but the kits cost about 100.00. However I think this is separate to the problem you have.
So from what you have said, I would suggest possible magneto failure (which probably means it's the carburettor!)
It may help if you took a neon with you to fit when it won't start to see if you have a spark.
Regarding Lead Replacement Additives, it could be argued that the valve seats would have work hardened by now, so being unnecessary, but if you select one with an octane improver, you may be able to run more ignition advance before pinking sets in, giving you a little more power. I would recommend using the Castrol product.

Pre War / Re: Missing screws
« on: 04 May, 2024, 21:10:45 »
I think you will find that Hitchcock's Motorcycles sell a set of 10 Timing Cover screws with the correct fillister head and thread. The Part No. is 90209.
You will have to cut them to length. They're rather expensive, but they do look the part.

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