How not to B33!

[Dan_B33]

Thanks Neil.
Will do the soldering when all set properly.
I have changed spark plug to NGK LZFH (1.5quid) spark is brighter.
Need to chec other things ....recheck timing and carb settings

[Dan_B33]

My calculations tell me I have been seating up timing wrong way.
Spark plug angle is around 60deg. I shall calculate new value using Pitagoras.....i did and it comes close to 11 mm before TDC.
Considering if the angle was straight it is 9.52mm....need to check tomorrow

[Dan_B33]

I have used sinus function of 60deg ...tomorrow shall see if any joy

[Derek996]

I don't know how you are calculating your ignition timing setting Dan but the timing for the B33 engine is 7/16" (= 11.11mm = 38º) before TDC.

[Dan_B33]

Is it 7/16" or  i have read on that forum it is 3/8".
7/16th is for B31 is that the same for B33?
Dan

[JulianS]

3/8 inch see attached from the BSA factory. But I suspect your would find not too much difference in use between 7/16 and 3/8 inch.

The Gold Star (with same stroke as the B31/33) maintenanace manual helpfully converts to degrees.

[Dan_B33]

When I have set it 3/8 looked like it is too late....black smoke (ortoo rich mixture) . I will try 7/16 and see how it goes...

[Dan_B33]

Answering questions what I do calculate?
I can't imagine stripping clutch cover to setup timing in the future.
I would like to use small "gizmo" into spark plug hole with gauge..
With descompresor lever pressed ....I get the reading on where is the piston . Can set TDC and then amount needed before TDC.
Calculate and explanations attached.
Since gauge is not dropping straight angle on the pisto but rather 60 degee...I need to know what is the new value...
Turns out for 7/16" (11.1125mm) my value is 12.83mm.
I hope that explains?

[Dan_B33]

Gizmo on the picture!
Please let me know abou that lazy Idea 💡.
What can go wrong ....with setting timing using that methodology?

[Derek996]

3/8 inch see attached from the BSA factory. But I suspect your would find not too much difference in use between 7/16 and 3/8 inch.

The Gold Star (with same stroke as the B31/33) maintenanace manual helpfully converts to degrees.

I stand corrected. It is indeed ⅜" = 9.53mm

[Derek996]

When I have set it 3/8 looked like it is too late....black smoke (ortoo rich mixture) . I will try 7/16 and see how it goes...

I wouldn't think the timing out by few degrees would make any difference to how rich or otherwise it runs.

[Dan_B33]

No matter what I do either 3/8 or 7/16....no joy!
Spark plug is wet after 3 kicks. And spark is so solid that it light remains of a fuel on spark plug if I kick it outside on cylinder.

Could it be too high fuel level?

[Rog1]

Okay; you have fuel and a good spark and so I suspect it's a timing issue. So here are some questions.

Do you always turn the engine forward to the timing position, not backwards? You need to take up all the slack in the drive to the magneto, by turning the engine in the direction it will run in. If you don't, the timing will be out.

Do you check the timing once set? You have to give the magneto pinion a sharp tap to seat it on to the taper, or else it will shift when you do the nut up. Just place a large socket against the pinion and tap the socket with a hammer; not too hard, but sharp. But still check it afterwards.

Is the advance/retard lever in the right position and is the cable properly adjusted when you set the timing? Does the mechanism work as it should? As you look from the left side of the bike, is the advance/retard cable to the left of the points (the cable should be slack) or to the right (the cable should be tight).

You might have been told all this already but it's late and I'm tired; I haven't checked the other posts.

A bit unlikely especially if you have good compression, but is the valve lifter properly adjusted and not holding the exhaust valve open?

[V500]

No matter what I do either 3/8 or 7/16....no joy!
Spark plug is wet after 3 kicks. And spark is so solid that it light remains of a fuel on spark plug if I kick it outside on cylinder.

Could it be too high fuel level?

So the spark timing is set correctly, there's compression, a good spark and enough juice to wet the plug. It should run given those conditions, but are you sure you set the timing on the compression stroke rather than exhaust stroke?
Sorry if it's been mentioned before.

[Dan_B33]

Hi,
All positions checked from Rog list !
I managed to run her when I have set timing 3/8" before TDC.
But just 2 or 3 times!
Now it is on 7/16"...not staring.
For sure I set on compression stroke...
After inlet valve goes down and before outlet lifts.

Compression is strong...I need to use decompression lever to force piston move past the compression stroke or jump full weight in kick-start
I will keep on trying...