whac-a-mole problems and alton e-start (alternator rotor) timing marks.

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joe czech

joe czech

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been having "on-and-off," intermittent problems with my 74 Mk2 for a month now. seems i would fix one thing, all would be good for a day or so, and then everything would turn to crap. fix another issue, and, same thing. it was like i was playing "whac-a-mole" with troubleshooting and repair. LSS, it seems i was having failure of my tri-spark ignition system. it was an early system that had a red potting material to seal up the internal electronics. whatever failed, or whatever happened, the hard, red plastic potting material bulged from internal heat. anyway installed a new unit, however, spent two days and couldn't get the bike running. SEEMS the alton timing marks are off by almost 90°. no way it was going to start using those marks. when i discovered the timing mark problem, the only way to set timing was with a degree wheel. found true TDC, set advance at 29°, and all is good. i know the alternator rotor is keyed, so either the rotor's timing marks are mis-marked or somehow the rotor plate slipped. really don't want to tear into the alton rotor right now - just glad to have a running bike. looking for some feedback from other alton starter folks.
 
joe czech said:
i hear ya! at my age, my hobbies are my life. problem is, too many hobbies and not enough time. but, in reality, i'm so busy doing nothing, i don't have time for anything. ;);)
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I hear that from every retired person I talk to.
 
still looking for input from other alton folks. sent an email to alton - waiting for a reply.
 
swooshdave said:
I hear that from every retired person I talk to.
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Another one I hear from us old timers is:
" I don't know how when I worked for a living , I had all the time to do the stuff around the house and yard that has become my new full time job now, in my supposed retirement. "
 
If the nut holding the rotor on loses tension the rotor can slip and smear the key around the shaft. If it is 90 degrees out then worth checking.
 
So the Alton timing mark was correct when you installed it and the bike was running fine and now the mark is 180 out? As suggested, the only way that can happen is the rotor slipping on the crank. Maybe the nut was not tightened sufficiently that the taper was not effective, allowing the woodruff key to shear.

FWIW the woodruff key in any taper fitting is NOT designed to take the strain - the taper does that. The key is just to ensure parts are properly aligned. If the taper joint is not sufficiently tight, the key can be sheared off.
 
MexicoMike said:
So the Alton timing mark was correct when you installed it and the bike was running fine and now the mark is 180 out? As suggested, the only way that can happen is the rotor slipping on the crank. Maybe the nut was not tightened sufficiently that the taper was not effective, allowing the woodruff key to shear.

FWIW the woodruff key in any taper fitting is NOT designed to take the strain - the taper does that. The key is just to ensure parts are properly aligned. If the taper joint is not sufficiently tight, the key can be sheared off.
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Does the rotor on the Alton sit on the taper because it doesn’t on a stock bike. Just the front sprocket is on a taper.
 
The Alton Rotor doesn't fit on a taper, it fits just as the original stator did on the plain end of the crankshaft. I think the secret to it not shearing the key is to make sure the large crankshaft nut is tight, as per Alton instructions.

Ref the timing marks. Mine were correct but I made them a bit more distinct with a bit of paint. Sounds like your rotor has moved. I think you're going to have to bite the bullet and take the rotor off to check the key is ok. If it has broken it needs sorting or at some stage your starter drive will probably fail.
 
Expanding on Nortoniggy's comment, the Alton relies on the crank shaft nut to clamp the starter components against the sprocket. Fricton/clamping force holds all in the correct place and transfers the drive from the starter motor, so lose the clamping force and carnage may follow when the starter button is pushed. The key only makes sure that the timing mark is in the correct spot initially.
Alton now recommend that the nut is loctited to stop it coming loose but my opinion is that it is better fit all, go for a good ride and get the engine hot then retorque the nut. If the sprocket eases slightly on the taper the clamping force will reduce. I got 1/8th of a turn when i did the retorque.
 
having emailed the alton folks, it seems that the sprag clutch/rotor assembly has somehow slipped on the crank. the only reasonable explanation is something with the woodruff key or keyway. i remember having two NEW keys, and don't remember having any spare parts left when completing the job, but then again, there's always murphy's law. if i find that i somehow f***'d-up, i'm taking that to the grave. anyway, thanks for the replies.
 
Your woodruff key may have slid out of its groove as you slid the Alton sprag/clutch assembly on. Mine did but I noticed and ended up trimming a bit off the woodruff key and it stayed in place. The timing marks on mine were spot on but before timing I take a sharpie marker to make them more visible.
 
Yeah, quite right - NO taper on Norton alternator rotor - I was thinking of a different application. Sorry! :(
 
Over the years mine had a build up of lock tight so when I torqued it up it gave a false reading and I had a similar problem with my Alton but easy to fix then no more problems
 
I seem to remember Yves posted a while ago about a modification he'd done to his Alton to provide a more positive location that didn't rely on the keyway. I don't remember the details but it required some minor machining (minor if you have the skills and machines) and was fairly straightforward. I remember thinking at the time that if I fitted an Alton I'd make the modification from the get go.
 
update - tore into my alton starter assembly to address the mis-aligned timing marks. turns out that i did not forget to install the woodruff key, but the key sheared and caused some minor crank damage. anyway, the sprag clutch/rotor was frozen to the crank - finally got it off. got things cleaned up, and i'm thinking the crank is OK, just need to get a new clutch assembly. Jack at Classic Bike Experience indicated excessive engine backfire can cause a woodruff key failure, but to be honest, i've never seen a key failure. damage to the crank is about .125" and 180° - got the remaining key out and things cleaned up. i think i'm good to go.
whac-a-mole problems and alton e-start (alternator rotor) timing marks.
 
Does the Altron sprag and E start drive parts on the crankshaft end depend on the rotor key to turn the engine ?
 
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