Starter Ring Gear

Hey folks.

My starter was acting sickely so I took it apart and found I needed some new brushes like nobody's business. I replaced the brushes and cleaned up the insides generally. I put her back together and she spun but the second I put a load on it, it would stop. I subsequently found out about the ring gear and how there must be pressure on it so that it only turns with a lot of torque applied to the armature. The starter now turns the engine, but not with enough umph to turn her over. How tight do that starter screws have to be to hold the ring gear and prevent slip? The screws are kinda stripped and the metal are soft was hell.

Thanks
CSB

what kind of bike are we talking about here?

duh... sorry. brain back fire...

its a 76' 750 twin which I want to have my children

The starter has a sprocket on the end of it that drives a chain that in turn drives the sprocket that actually engages the crank and makes the engine turn over. The starter clutch is attached to the back of the rotor by three screws, and those screws "must" be tight, if they are not then the starter will snap them right off.

A picture would be a lot better, so I'll see if I can snatch one from kawasaki.com.

If this works, the top pic is 76-77, the bottom one is 78-79.

steell,

Yes. Everthing you say is correct. However, I have already checked al lthat out. Along with there being a starter clutch, there is what I call a 'slip gear' or 'ring gear' or 'oh shit gear'. It is a ring gear inside the starter (see part #12 on diagram you pasted). Two planetary gears normally rotate along this ring gear and turn the external shaft.

However, if, for some reason, the shaft is torqued quickly (such as a backfire) or stopped while under load (such as, ummm, if you jammed a screw driver through the sprocket), the 'ring gear' turns inside the starter (part 12) instead of messing up the armature or other parts of the starter.

This ring gear is held stationary by the pressure of the front and back of the starter as bolted together by the two long arse screws. If These screws are not tight enough, the starter will turn, but the slightest pressure of the external shaft will stop it and engage the ring gear which will spin freely. I have tightened the screws as much as I can, and it now turns the engine, but it seems to hit hard spots and instead of cranking up steady and it seems to hit a hard spot in each cycle. It still startedd after a few gut wrenching groans off a car battery, but...

If I understand you correctly, you are saying there is a planetary gearset inside the nose of the starter?

I have not had any reason to dismantle a 750 twin starter so far, I haven't run out of spares yet, so I am not familiar with anything inside it. I assumed (wrongly it appears) that the armature shaft stuck out the end and had the drive sprocket mounted on it.
The only slippage problems I have had were related to the starter clutch mounted on the back of the rotor.

If you take it apart again, I am really interested in seeing pics of it.

Steell,

It is actually interesting how it works. And I am hoping to get a new starter rather than fix this one. But the armature does not stick out. It fits, like you said, into the nose cone which has two planetary gears which are mounted on shafts on a rotating platform that is connected to the external shaft which connects to the sprocket. Then, there is a gear with inside teeth on which the planetary gears run. Normally that ring gear stays still. But if too much torque comes thru the external shaft, the ring gear slips instead of torquing the armature around.

I need to fab. some sort of shim to get the ring gear pushed tighter I think. I also ordered some bolts with hex heads so I can tighten it more.

I run across double posts fairly often, but that's the first time I have seen a sextuple post

Your description sounds like a planetary gear reduction (although you didn't mention the sun gear in the center).

I don't think that ring gear is supposed to slip under any circumstances, if it does then it will eat away the metal surrounding it fairly rapidly (ie: self destruct). The chain and the large sprocket are both much weaker than the armature shaft, so they would be the "fuse", and I have seen the teeth stripped off the large gear. I would be inclined to use some LocTite with a high shear strength to lock that ring gear in place.

If that is the case, then is it posible that a diagnosis of a slipping starter-clutch may actually be the slipping ring-gear?

Post edited by: loudhvx, at: 2007/04/07 12:17

loud;

Well, I'm still learning myself, put perhaps... I know that was atleast part of the problem on my bike. The starter didn't work. It would spin really fast but I put it in the bike and it wouldn't turn the chain. So I pulled it and did some research and tightened the bolts. This time it would start to spin the chain but then it went out and wouldn't spin but made a whirring noise.

I added a make shift shim and tightened the bolts as tight as I could. I put it in and it actually turned the engine. Still sounded sickley, but turned it. Then it quit again. I had to go back to school so I haven't been able to take it apart again.



, then I added a spacer (don't ask how I improvised this...) and tight

This describes what I see in the 76 twin starter. I think the dropped this design very soon

www.drpiston.com/81_83_Starter_Paper.html

DamN! This is it! This is the starter on my Kawa

www.drpiston.com/81_83_pix.html