Unique Mk III Feature

I recently acquired a '75 E-Start, and noticed a plug on the right hand crankcase below the timing cover at about the 5 o-clock position. I've never noticed this plug before on my previous Nortons ('70 Fastback, '65 N-15, '61 650). Could this be a provision to install a timing pin as I've seen employed on BSA Twins? If so, any further info would be appreciated, as I've never come across any references to timing tools, part numbers, procedures, ect.

Thanks,

Some (Most ? ) Mk111 cranks have a slot machined for initial timing setting at 28° I have never seen a tool to lock the crank in position.

I have had two Mk111 cranks with no slots or marks. I don't know how common this is, but don't be too alarmed if you don't find one

jumpjg said:

I recently acquired a '75 E-Start, and noticed a plug on the right hand crankcase below the timing cover at about the 5 o-clock position. I've never noticed this plug before on my previous Nortons ('70 Fastback, '65 N-15, '61 650). Could this be a provision to install a timing pin as I've seen employed on BSA Twins?

Click to expand...

You are correct, the plug is for checking the 28° BTDC timing position and is only found on the 850 MkIII cases.

If there is an actual 'timing tool' then I have never seen one!

Anyway a tool isn't really necessary as the timing slot (at the 28° position) is quite easy to see. And of course if an electronic ignition like Boyer Bransden is fitted then that needs the crank setting to 31° which means moving the crank by about half the width of the slot.

But at least the timing hole/slot can be used to check the accuracy of the primary side timing scale plate.