Author Topic: M33 1955 - Starting Issues  (Read 914 times)

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MBULLYB

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M33 1955 - Starting Issues
« on: 02 April, 2017, 19:40:08 »
Hi, I have a 1954 B33 500cc fitted with a Lucas MO1 Mag/dyno. Once started the engine runs fine without missing a beat but it really difficult to kick start. It will push start but even that takes a few a goes. Ive had the Magneto rebuilt by Priory Magneto's, Its had a full carb rebuild, and has been timed and tuned. Ive had a number of people try to kick start it but were all strugling. 

Any ideas what this could be as im getting desperate.....

Thanks
Mark

TTJOHN

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Re: M33 1955 - Starting Issues
« Reply #1 on: 03 April, 2017, 09:36:45 »
Do you have an unsupressed plug cap on the bike? it should be for a magneto, I know sucking eggs etc but sometimes new leads are fitted with caps attached also check you have the correct plug and not a supressed one.
I have a B33 and if I flood it, I have to wait some time before it starts, yet if I just turn the petrol on, without flooding it will start okay.

MBULLYB

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Re: M33 1955 - Starting Issues
« Reply #2 on: 03 April, 2017, 18:57:46 »
Hi John, yes its fitted with an NGK LZFH cap, the HT lead was replaced at the time of the magneto rebuild. Ive measured the lead with a meter and its 0 KOhms . Im also using a Champion (non resitor) L82C plug which is new.

One thing worth mentioning is that the kick start occassionally slips, im not sure if thats affecting it but i expect thats because its taking such an hammering  >:(

Does anyone know a trusted BSA Mechanic in the East Yorks / Hull area that could fix this?




JulianS

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Re: M33 1955 - Starting Issues
« Reply #3 on: 03 April, 2017, 19:57:35 »
These engines are usually very easy starters.

More likely that the clutch is slipping rather than the kickstart.

Check that there is a little clearance between the clutch pushrod and the adjuster on the arm on the gearbox.

If it still slips you will need to strip the clutch and check the plates and springs.

Is the valve clearance set correctly? Are you using the exhaust lifter to ease the engine over compression before giving a good swing on th kickstart?

MBULLYB

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Re: M33 1955 - Starting Issues
« Reply #4 on: 03 April, 2017, 20:17:06 »
Hi Julian, ive been told it should be easy to start but its not, there's clearly something wrong..... I went to a VMCC meet yesterday and no-one there could kick it over either, we could only get it started with a push.

Yes im using the valve lifter, far too much compression otherwise. Will check the clutch tomorrow and will also try the valve clearance. Thanks


MALCOLM.JOHNSON

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Re: M33 1955 - Starting Issues
« Reply #5 on: 03 April, 2017, 20:57:43 »
It is very easy when you have had these singles a long time and CAN start them, forget how b... difficult they can be when you first get one and need to master the art. So my reply is based upon the supposition that you may be new to this machine - apologies if not the case.
My method is set the advance/retard lever partially retarded, fuel tap on. While the carb is filling take the engine to compression and if one is fitted, use the de-compressor to ease the piston just over TDC. If bumping off, put the gearbox into second and pull the bike backwards until you meet compression resistance. Doing either of those will put the piston near the start of the power stroke and will, when set in motion allow 3 strokes or 1 1/2 revolutions before the piston meets compression again, when the kinetic energy stored in the flywheels will be enough to take it past TDC and hopefully fire and hopefully run. Now when that is done, I then give the carb a light "tickle", but not to the point of flooding. This raises the fuel level slightly above normal and will help the engine to "catch". With the throttle only slightly open give that kick, or bump start to set those flywheels in motion. All things being equal it should at least fire if not burst into life. Good luck!

JulianS

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Re: M33 1955 - Starting Issues
« Reply #6 on: 03 April, 2017, 21:01:12 »
As you have replaced the mag I would also double check points and pickup and  that the ignition timing is correct - should be 3/8 inch before TDC mag set on full advance.

MBULLYB

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Re: M33 1955 - Starting Issues
« Reply #7 on: 04 April, 2017, 13:07:19 »
Hi Malcom, yes i'm new to this bike and classic bikes in general so thanks for the advice. Its pretty much the process im following.

Julian, the timing has been set but i'll check it again, along with points and pick up.

MBULLYB

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Re: M33 1955 - Starting Issues
« Reply #8 on: 04 April, 2017, 19:36:53 »
Timing seems OK, points appears to be .10 inch rather than .12 but its difficult to get in there with a feeler gauge and see exactly? Tried Malcolms method and still no joy

MBULLYB

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Re: M33 1955 - Starting Issues
« Reply #9 on: 23 April, 2017, 20:22:49 »
Still having trouble starting the damn thing. Ive reset the points and timing and it still wont start. if i pull the ignition lever towards me is that advance or retard?

Thanks
Mark

JulianS

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Re: M33 1955 - Starting Issues
« Reply #10 on: 23 April, 2017, 21:17:53 »
Full advance when the wire is slack, providing its got the correct magneto.

MALCOLM.JOHNSON

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Re: M33 1955 - Starting Issues
« Reply #11 on: 24 April, 2017, 21:45:10 »
With the bike on the centre stand, remove the sparking plug, put the bike into 2nd or 3rd, push on the rear tyre in the road direction and when you look at the contact breaker rotor, it will be turning clockwise. Operate the advance retard lever and check what you have to do to move the cam ring in the opposite (anti clockwise) direction. That will be the way to move the lever to full advance - opposite direction to achieve full retard. So now you will know whether you have a "tight" or "slack" cable advance. The other way to check is to look at the contact breaker and if the adv/ret cable is on the right of the CB, then it is a tight cable advance - on the left a slack cable advance. It would be nice if all were the same, but over the years swaps take place, incorrectly as Julian mentions. Extremely important information to know about your bike, both for starting and running.

Now push slowly on the tyre again, with a finger over the plug hole  and when you feel compression you know the engine is with the piston rising towards TDC awaiting a spark. Lets check this is happening at the right time? Using a thin rod of some sort, one end resting on top of the piston, SLOWLY continue moving the rear wheel until you reach the highest point the rod travels and mark the rod with some reference point to the outside of the engine. That is TDC. Once found carefully recheck and then with your adv/ret lever in the fully advanced position, turn the engine backwards a little to send the piston partway back down the bore. Once done, this time moving the engine slowly forwards again, mark the rod at the point the contact breaker JUST opens. Measure the gap between the two marks which should be in the order of 7/16 inch. If not the magneto needs re-timing correctly.

MBULLYB

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Re: M33 1955 - Starting Issues
« Reply #12 on: 14 May, 2017, 18:28:54 »
Hi Malcom, thats a really good explanation, much appreciated