Peer Landa — Starter Sprag-spring

Starter Sprag-spring

[ click on image to return to index ]

The following modification might be looked at as a tiny fix, but hassaved me a few grand – and perhaps even more if I initially knew about the following:

One of the most annoying thing is when my Ducati refuses to start, as the starter slips and stutters. First I thought this might be a problem for bikes with a lightened flywheel since this startedto happen after I installed a very light race flywheel – the starter-sprag has ever since acted up… and it didn't matter how new the sprag was, soon enough it begun to slip – often making it impossible to start the bike at all.

As you might understand from reading some of the other entries on thisweb-site, I became compulsive and started to collect info about thesprag, (I even purchased a crank-shaft seal for a Chevrolet which lookedsimilar to the spring in the Duc-sprag, which is essentially the weak part).Anyways, when looking closer at the sprag I could see that the spring whichholds its rollers in place had an “opening” where the spring is “screwed”together (into its loop). I then cut the spring shorter and put it all backtogether, and boom… just like that – the bike started up as it had a new sprag.

But infelicitously less than six months later, my starter acted upagain. When looking at the sprag-spring again I realized that it could have beencut a whole lot shorter than I initially did – making it much snugger. So I did, and needless to say; now it works like a charm.. and this was almost four years ago.

If anyone has questions regarding a bad starter sprag, I'm happy to answer any question you have. The stuff you'd need in order to do a hack like this is a 30 mm wrench-socket for the flywheel, a tube of red lock-tie for the flywheel-nut – and then, most importantly, make sure to put the sprag and the stator (amateur for the alternator) back the same way as you took it off. Note that both the sides of the stator look pretty much the same which makes it tricky to get back the right way if you forget to put a marker (or something) on it to indicate which side is which… By the way, that Chevrolet crank-shaft seal-spring is too thick… nice try though, eh..?