Electric start engages while engine is running

Hello,

I have a MKIII with 17k miles. The e start has always worked fine. 3 days ago I e started the bike and the starter did not turn off. I turned the ignition off and the starter turned off. I then kickstarted the bike and the starter engaged while I was kicking the engine through. Solenoid checked out ok. Wiring all ok. Bike worked fine for 2 days and it happened again. This time the starter died. I took it apart and found the insides trashed. Figured I'ld fix it during the winter, so I removed brushes, and put the starter back in to cover the hole and I would just kick start the bike. Starter engaged again while I was kicking it.

Is this a sprag clutch issue?

Has anyone else had this experience?

I'm going to buy a new starter, and I note that there are serval options...any comments would be appreciated.

Thanks

my guess it the sprag has failed. if so it will over speed the starter and destroy it. it will have to be fixed first or any starter you replace it with will also be destroyed.

The sprag has over-centered and locked. Time to replace the sprag and carefully measure the engine sprocket and crank gear and replace if worn. Most importantly check the anti-backfire device. It should slip at no greater than 50 ft-lb.
http://www.oldbritts.com/e_start_backfire.html

This may be what allowed your sprag to over-center.

Ron I don't think the sprag is going over center or it would stay permantlyt engaged.

Well, having sold over 550 starters, I tend to be a lightening rod for starter issues. I have been intensly studying the sprags stickyness. I have not come to a firm final analysis yet.
As reported to me, the sprag has stuck while running and therefore "should" be in freewheel mode with seemingly no particular reason to stick. But stick it does. This causes the starter to try and spin up to 45,000 RPM ...which it can not do and stay in one piece. The comutator simply explodes from centrifugal force. It will not do this if driven by 12v, even for extended period of time. So it is definitely NOT a warrantiable failure.
The sticking has happened without even using the starter to start the bike, I.E. after a kick start...I have been investigating the relationship of the 2 steel cages along with the preengagement spring between the cages. The issue of 14 dog bone rockers or 18 does not seem to matter..both do it. I suspect it happens more on new installations, but have no proof. Looking very closely at the sprocket race and the drive gear race I am almost positive the sprag normally runs/rides "with" the engine sprocket. The drive gear race seems to take the brunt of the abuse from kick backs or slip and catch which dents the race... out of all the ones Ive seen so far the drive gear race are the ones being deformed and the engine sprocket all seem like new.
More to come ....

dynodave said:

As reported to me, the sprag has stuck while running and therefore "should" be in freewheel mode with seemingly no particular reason to stick. But stick it does. This causes the starter to try and spin up to 45,000 RPM ...which it can not do and stay in one piece. The comutator simply explodes from centrifugal force. It will not do this if driven by 12v, even for extended period of time. So it is definitely NOT a warrantiable failure.
The sticking has happened without even using the starter to start the bike, I.E. after a kick start...I have been investigating the relationship of the 2 steel cages along with the preengagement spring between the cages. The issue of 14 dog bone rockers or 18 does not seem to matter..both do it. I suspect it happens more on new installations, but have no proof.

Click to expand...

They can certainly jam if the cages break up.

Remains of a jammed sprag!

["Quote" removed. (You appear to have disabled your BBCode setting again dynodave...any particular reason why?) - L.A.B.]


No arguement there....
however the ones I am trying to analyze are like one with brand new sprag (under the guise of "upgrade" to an 18 rocker) never used....kick started...then while out on a run, it catches...makes noise then gernades the starter. The owner never mentioned it was "breaking up" only that it was new and never even engaged once!

Thanks for all the comments......I'll be taking the sprag clutch apart today and will post the results. It is worrisome however, if one were to replace any damaged parts and still have a new starter engage and self destruct.

Your bike turned itself into an HYBRID :shock: I knew there was a lifeform in each bike, but to evolve like that is something I never considered :mrgreen:

Jean

OK, I took everything apart and the sprag bearing self destructed.

I noticed that the race on the engine sprocket has some small detents and the race on the starter drive gear has some scratches.

Has anyone every machined these parts to fir a new sprag......or do I need to bite the bullet and spend close to $500 for these 3 items (not counting the starter)?

Hi,

It was mentioned that Alton where looking at developing a system for the MK3, I for one would be VERY interested in a system that uses modern thinking/expertise & parts.

I think if my current starter system went kaput, I'd remove the starter system, blank off the hole & just struggle with the kickstart & wait for Alton to release a new system.

Sorry I don't have any useful comments about your current situation :roll:

Kevin

I don't have any good answers for you. I have always espoused prevention by using an ignition that does not kick back (esp boyer MKIII) and then hopefully not getting into this situation. I am starting to think that maybe gearbox oil getting into the primary may be a contributing factor to the skid and jam syndrome of the sprag. This would eventually damage the sprags working surfaces and break up the cages.

Other than a clutch rod seal and a rita ignition, my MKIlI with 50w oil in the primary works 99.9999% flawlless, has my starter and over 20K on the clock. I have been thinking of putting a gearbox cover on it with the kicker hole eliminated.

Hi Dave,

That's good to know. I have one of your starters and it works great, I just don't know if I would spend 5-700euro on replacing all the original parts if the starter system went kaput. , sorry if I'm hogging another posters thread, I'll shutup now!!

The 3 parts are 227 GBP without shipping from NA. However they NOW also list a starter, though I'd be curious to see what one looks like, for just under 1K GBP!!!

I just saw the harley version of the prestolite starters on ebay shipped for $95 USD.

bwolfie said:

I just saw the harley version of the prestolite starters on ebay shipped for $95 USD.

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Unfortunately the Harley Prestolite starter armature and adaptor end plate doesn't fit the Commando.

For now I think I am just going to put everything back together without the sprag and run it like that (using the kickstarter) for the rest of the season and do a proper repair during the winter. Just when I thought I had everything running great. Oh well....I should know better.

I put everything back together minus sprag and am using the kickstart. I have what I believe is an early Boyer and I guess along with everyhting else, I'll upgrade the ignition system, this winter. Any comments on Sparx, Boyer or Pazon would be appreciated.

Thank you all for help!!!

nberg said:

I put everything back together minus sprag and am using the kickstart. I have what I believe is an early Boyer and I guess along with everyhting else, I'll upgrade the ignition system, this winter. Any comments on Sparx, Boyer or Pazon would be appreciated.

Thank you all for help!!!

Click to expand...

Please search for ignition talk on the forum, there is plenty of great stuff out there.

Same as you I've put everything back together and using the kickstart only. Word from the Empire Rally is that there are newer systems in the works from a few sources so I'm just sitting back and waiting to see what develops.

dont walk away from the sparks, RUN RUN RUN sometimes you get what you paid for but in this case IMHO 2 cents is to much for this JUNK

nberg said:

I put everything back together minus sprag and am using the kickstart. I have what I believe is an early Boyer and I guess along with everyhting else, I'll upgrade the ignition system, this winter. Any comments on Sparx, Boyer or Pazon would be appreciated.

Thank you all for help!!!

Click to expand...