BTH Timing

ogrilp400

Well Known and Active Forum User
Non-VOC Member
Dear All,
How does one set the armature when the timing cover and hence the drive pinion are on and you can't see the arrow on the end of the shaft?
 

vibrac

Well Known and Active Forum User
VOC Member
You dont! I now mark the gear after fitting to help next time at least you can only be exactly 180deg out on the mag:(
 

vincenttwin

Well Known and Active Forum User
VOC Member
Put the shaft with the little arrow pointing up ,put the lock pin in and slide the gear on and mark the gear facing up and do not move lock pin and then easy to time.
 

vibrac

Well Known and Active Forum User
VOC Member
you miss the point he already has the gear on he cant put the shaft with the arrow pointing up.

Glen Bewley on jtan has the right idea (He usually does) pop in the pin time it as normall (you have a 50% chance of getting it right) if it does not start loosen pinion rotate mag 180 pop pin in lock up tight take pin out and job is done
 

deejay499

Well Known and Active Forum User
VOC Member
With the ATD cover removed and nothing disturbed, the arrow is visible (may need a torch) With the rod in place, arrow pointing up, undo the nut, turn the engine to your set up and redo the nut up. There seems to be about 6 to 8 degrees engine movement on the shaft with the rod in place. I have just done mine today and going for 32 degrees and the rod is free to drop in and out. Haven't tried it yet.
 

davidd

Well Known and Active Forum User
VOC Member
With the ATD cover removed and nothing disturbed, the arrow is visible (may need a torch) With the rod in place, arrow pointing up, undo the nut, turn the engine to your set up and redo the nut up. There seems to be about 6 to 8 degrees engine movement on the shaft with the rod in place. I have just done mine today and going for 32 degrees and the rod is free to drop in and out. Haven't tried it yet.

Deejay,

I found the same. It was 4.5 degrees either way, which one might expect in a threaded hole. I do not think this is a big deal, but I think it helps to do it the same way each time for consistency.

On my mag, I found that when I timed it with a strobe that the most accurate way to time it was with the rod in place and the rear wheel bumped forward so that the rod could not be moved. That is where the static timing and the dynamic timing yielded the same results. Again, I don't think it amounts to much. I did this work on the racer because I needed accurate and repeatable results, but I think it may be overkill for the street.

David
 

vibrac

Well Known and Active Forum User
VOC Member
the slop in the locking rod is no different than the clearance in the 4 tooth interfaces that the drive is transmitted through to the magneto the movment and must be allowed for consistantly when setting timing
 

deejay499

Well Known and Active Forum User
VOC Member
Thanks davidd. I did my 32 degrees with the engine going forwards. With your answer about the rod, it could be a degree or two later. Started it up today and it ticks over quicker than before, so may be better. 8.1 pistons fitted.
 
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