Timing hole B44vs

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madsundaysurvivor
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Timing hole B44vs

Post by madsundaysurvivor »

I'm building a B44 with miscelaaneous parts, and I have a doubt about the timing hole in crankcase.
In the t120 the flywheel have a slot to use this timing tool, I want made one for the bsa, but isn't see the mark in the flywheel, I this hole of the pic? Or it Will only for equilibration, I think Doesnt match straigt with the hole:
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Re: Timing hole B44vs

Post by kommando »

That's the timing hole, not like the 650 twin which is a slot.
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Re: Timing hole B44vs

Post by minetymenace »

kommando, do they use the same tool though? (£10 - £15 on ebay)
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Re: Timing hole B44vs

Post by kommando »

No idea but I doubt it, I use a 4mm allen key as it fits the hole and you can accurately get the hole aligned by looking at the key as you slightly move the crank. When the key is perpendicular to the flywheel you are spot on, all the holes I have checked using a crank disc have been accurate so no longer bother checking.

Same hole in a B44 crank

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Re: Timing hole B44vs

Post by madsundaysurvivor »

It is not the same, the twin t120 engines are the same diameter but different thread and the rod in t120 tool is about 6mm
i think BSW for t120 pre66 and UNC for bsa unit singles 69
I don't know if in post 66 or oil in frame of T120 models the thread will be the same.
It is very simple to manufacture, it is a rod, inside a drilled screw to keep it centered and when it coincides with the hole of the flywheel it blocks it just at the moment of static timing
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Re: Timing hole B44vs

Post by madsundaysurvivor »

This is why I love British motorcycles, nothing ever goes right on the first try. :roll:

I was checking the degrees of advancement of the hole in the flywheel, so I expected to find there 28, but I see that around 33 or 34, the tdc I have calculated with a dial gauge (I have no cylinder or piston) I may have mistaken 1 or 2 degrees, but not 6 degrees.
What is wrong with me?
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Re: Timing hole B44vs

Post by minetymenace »

I would have thought that with the peg in the flywheel, you should be at tdc, but clearly not! Try changing the wooden box the crank case is sitting on, it is obviously the wrong one, apart from that I have no idea!
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Re: Timing hole B44vs

Post by madsundaysurvivor »

:laugh :laugh Onthe opposite side it says BSA, I have tried but it still indicates the same degrees :roll:
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Re: Timing hole B44vs

Post by kommando »

Unless you have a good way of finding TDC like using a stop against the piston top then you are wasting your time checking at this stage.
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Re: Timing hole B44vs

Post by madsundaysurvivor »

Yes I agree with you.
As I am not sure this crankshaft is from this crankcases. out of curiosity I wanted to make sure everything was ok.
What is the difference in view between a b44 crankshaft and a b50 crankshaft?
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Re: Timing hole B44vs

Post by kommando »

B50 flywheel s are the same width, B44 flywheels have different widths, timing holes are different by a few degrees, both cranks will fit B44 cases.
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Re: Timing hole B44vs

Post by madsundaysurvivor »

Thanks, then I have a doubt .... the next monday I will solve it
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Re: Timing hole B44vs

Post by kommando »

Looking at your first photo of your crank its a B44, the flywheels are of different widths, plus the driveside mainshaft has full length splines not the short splines of the B50, because of the extra driveside main bearing. Now the mainshaft could have been changed but the different flywheel widths say B44. Trouble with finding TDC without a piston is accuracy, there is so little up/down movement of the big end at TDC you need to use a single point say 30 to 40 degrees below TDC and move the crank degree disc until you get the same reading going from one side to the other. Without this method you could be out by 10 degrees.
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