What causes the bendix not to engage?

[Quinc]

I have tried two oem starters, two oem bendixs, (both used) I replaced the washers and spring in the flywheel cover with new oem and every once in a while I hit the start button and the bendix does not engage. I just hear the spinning sound. What am I missing?

 

[OCD Solutions]

How's the teeth on the flywheel? Any burrs that prevent the bendix gears from slipping into the flywheel gears

 

[mikidymac]

Don't forget the little washer insice the bendix that separates whe weights. The tabs break off and the weights move around.

 

[augustaf]

The bushing in the crank case could be worn, permitting the Bendix to drop away from the starter - which may let the armature spin, causing the splines to strip on short order.
Otherwise, the problem would be with the Bendix not functioning properly

 

[iQRTurbo]

It has absolutely nothing to do with anything else than the back cut on the teeth of the ring gear and bendix. No manufacturer(including Parts sourced by Yamaha) of ring gear or bendix does enough back cut to reliably engage every single time. Look closely at the ring gear and you will see the teeth on this new MSD flywheel vs the ones I have cut more. This bendix has been cut properly too. If you look at your parts you will see there is likely no lead in on the teeth making it difficult for them to mesh on startup. It’s not rocket science to fix it and don’t be intimidated to try it. A steady and consistent hand with a thin blade cutoff wheel you can fix the bendix and ring gear so it will never, and I mean never, miss again.

 

[ScottS]

If you are running a Zeeltronics setup and did not weld the ring gear to the flywheel, check it to see if it's slipping

 

[E350]

It has absolutely nothing to do with anything else than the back cut on the teeth of the ring gear and bendix. No manufacturer(including Parts sourced by Yamaha) of ring gear or bendix does enough back cut to reliably engage every single time. Look closely at the ring gear and you will see the teeth on this new MSD flywheel vs the ones I have cut more. This bendix has been cut properly too. If you look at your parts you will see there is likely no lead in on the teeth making it difficult for them to mesh on startup. It’s not rocket science to fix it and don’t be intimidated to try it. A steady and consistent hand with a thin blade cutoff wheel you can fix the bendix and ring gear so it will never, and I mean never, miss again.

This makes sense to me. It would also explain how I made the non-engagement worse by occasionally misstakenly hitting the starter when the engine is running (because I am stupid and the stop/start switch orientation is different between our '94 SN SJ and our '95 FX1). Engaging the Bendix into the flywheel when the engine is running would have the effect of removing any Bendix leading triangular "forward cut" and flywheel receiving triangular "back cut" and making the engagement intermittent depending on where the Russian roulette wheel of the flywheel comes up against the Bendix when that starter/flywheel combination is engaged.

ICRTurbo: Thank you for posting and thank you for posting those pictures.

 

[OCD Solutions]

Posting video for [mention]ScottS [/mention]

 

[jetpilot36]

It has absolutely nothing to do with anything else than the back cut on the teeth of the ring gear and bendix. No manufacturer(including Parts sourced by Yamaha) of ring gear or bendix does enough back cut to reliably engage every single time. Look closely at the ring gear and you will see the teeth on this new MSD flywheel vs the ones I have cut more. This bendix has been cut properly too. If you look at your parts you will see there is likely no lead in on the teeth making it difficult for them to mesh on startup. It’s not rocket science to fix it and don’t be intimidated to try it. A steady and consistent hand with a thin blade cutoff wheel you can fix the bendix and ring gear so it will never, and I mean never, miss again.

so the flywheel teeth are worse when they're sharp like bran new in the box? and you grinded them down like in your first pic? in your first pic you're showing 10 flywheel teeth. going clockwise the first 4 teeth look new. and you grinded the nest 6 teeth on the pic? im about to pull my flywheel and replace bendix. and i wanna do this. just making sure.

 

[iQRTurbo]

so the flywheel teeth are worse when they're sharp like bran new in the box? and you grinded them down like in your first pic? in your first pic you're showing 10 flywheel teeth. going clockwise the first 4 teeth look new. and you grinded the nest 6 teeth on the pic? im about to pull my flywheel and replace bendix. and i wanna do this. just making sure.

I grind them all, I just took the pic part way through the process to show before and after

 

[iQRTurbo]

so the flywheel teeth are worse when they're sharp like bran new in the box? and you grinded them down like in your first pic? in your first pic you're showing 10 flywheel teeth. going clockwise the first 4 teeth look new. and you grinded the nest 6 teeth on the pic? im about to pull my flywheel and replace bendix. and i wanna do this. just making sure.

Note: that is the back side facing the bendix getting back cut

 

[jetpilot36]

Thanks man. Gonna grind mine down. Yup backside. No use in the front side

Sent from my SM-N975U using Tapatalk

 

[bored&stroked]

My ski just started doing this. It would crank for a sec, then starter spin noises without cranking, then it would crank again all without letting go of the start button.
Put a used oem bendix in and now it just makes starter noises with no cranking at all.

 

[E350]

I like iQRTurbo's explanation. The two surfaces need to mate -- the bendix and the back of the flywheel need to engage. You would want a bearing to match its race, so why wouldnt we want to check how the bendix mates with the flywheel?

 

[Sanoman]

Interesting thread.l have experienced this same thing a couple times since l changed over to my zeel set up.But my flywheel is welded

 

[Quinc]

I have the same issue on all of my skis that have stock flywheels. Only ski that doesn't do it has TL. Only thing I haven't tired replacing is the flywheel.. So might try that next.

 

[E350]

Have you held the bendix to the flywheel to see how well they mate/grab each other?

BTW, I have been meaning to ask you. Why does you avatar now say "Buy a Superjet" ?

And which Superjet?

 

[OCD Solutions]

This seems like a really good excuse to buy a fourth axis for my CNC.

 

[iQRTurbo]

This seems like a really good excuse to buy a fourth axis for my CNC.

Haha, 4th axis would be nice to have for sure! My mill is only digital readout and XYZ power feed, no CNC at all but my Menards CNC (aka, 4.5” angle grinder with cut off wheel) takes 20 minutes to fix any bendix and ring gear and I guarantee they won’t ever misfire again. Plus those teeth on a bendix are harder than woodpecker teeth. That operation is better for the work of an abrasive wheel than mill tooling anyhow.

 

[Quinc]

Have you held the bendix to the flywheel to see how well they mate/grab each other?

BTW, I have been meaning to ask you. Why does you avatar now say "Buy a Superjet" ?

And which Superjet?

I haven't taken them apart yet. I will probably ride rest of the summer and mess with them this winter. And because everyone should Buy a Superjet.