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Timing problems on the 450 Bomber

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royhall:
Now your asking a big question. From memory (it is quite a few years ago now) the K5 rotor and sprag clutch fits and the timing marks should be the same. That said, there are a few engines out there with a different crank configuration that were used mainly on the police specials. They are that rare I doubt you would have one of those.  So if the rotor is correct but still doesn't line up correctly something else is amiss. You didn't say what work has been carried out on the engine? Is it possible that the cam chain is maybe a tooth or two out that would put the cam out of sync with the crank. There are timing marks on the camshaft that need to line up, I would check that first. Also check that when the TDC mark on the rotor is set that the piston is actually at TDC.

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I used a "Charlies Place" electronic ignition, and to get the timing correct it was right at the end of it's adjustment. I never did get to the bottom of why that was as it ran well in that position. But there really was no adjustment left. Just a thought, is it possible to get back to the points setup and see if all is okay, or was it already running on points before you decided to fit the electronic. As I said, you didn't mention the bikes history before you attempted to fi the new unit.

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McCabe-Thiele (Ted):
I know nothing about black bombers but my casual observation is that in the first photo the two ignition sensors are in the lower quadrant, in Roys photo the sensors are in the upper quadrant - just looks so different even if neither is at TDC?

Could be different design of rotors - how do they compare to the original points base plate locations?

royhall:
Yes I noticed that. I think it's just a different decision on how to best fit everything. Sensor position doesn't matter as long as the rotor is keyed correctly to accommodate that position. My biggest problem was getting both cylinders timed, as you can see the sensors are actually touching and there was no movement left. I had to half the difference and this left it very slightly out but it still runs well.

McCabe-Thiele (Ted):

--- Quote from: royhall on November 26, 2023, 01:23:25 PM ---Yes I noticed that. I think it's just a different decision on how to best fit everything. Sensor position doesn't matter as long as the rotor is keyed correctly to accommodate that position. My biggest problem was getting both cylinders timed, as you can see the sensors at actually touching and there was no movement left. I had to half the difference and his left it very slightly out but it still runs well.

--- End quote ---

Oddly enough it took me ages to get the timing marks correctly aligned for 1/4 and 2/3 on my 400 - it was fitted with the Dyna system.
Even though the individual sensors are slotted for adjustment getting it right between the baseplate & the individual sensors took me ages.
It was easy to get 1/4 right but 3/4 would run out of adjustment so then had to move the baseplate a bit, re adjust 1/4 then check 2/3 and repeat as nipping down the baseplate would change the settings slightly.
Definitely worth my effort as the engine sounded quiter & smoother when I finally got it right.
It actually took me attempts spanning several days as I would leave it saying thats close enough only to go back to make minor changes.

royhall:
Yes that was my problem on the Bomber. Unfortunately I ran out of adjustment. I considered filing the sides of the sensor plates to get them closer together but it would have made little to no difference as it was so close anyway. Bit of a design and manufacturing problem I think.

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