Topic: 71 cb500 broken teeth on starter gear

[wjustinleigh]

When I got the bike the starter would make a terrible racket (and not start the bike) so I always just used the kick-start which works great.  When I decided to rebuilt it I figured I'd solve the issue.  I pulled the engine and then the starter and can see through the hole where the starter goes that there is a section of the starter gear which is missing teeth (photo).  I ordered a new starter gear and am preparing to split the cases to get at it (which I've never done before).  I'd really hate to replace the gear, put the bike all back together then break off the teeth again. 

Any ideas/experience on why it would have broken off the starter gear teeth?  The gear turns freely clockwise with a finger and not at all counter-clockwise which I read is correct.  The teeth on the actual starter are worn down a bit (I assume from banging against the broken teeth on the gear) but are surprisingly not too terrible (will be replaced).

[rb550four]

 I would guess that someone banged a starter in without lining up the teeth, then, upon realizing the starter was seized, changed it out with a different one. Just a guess.

[nccb]

I had an issue with my 750 like that.  The spindle piece on my starter wobbled ever so slightly and it broke the teeth of my reduction gear.  I got a starter and gear from a guy on the forum. 

[rb550four]

Did you find the broken teeth in the oil pan? just wondering. I saw the other thread leading up to this and left thoughts as requested.

[wjustinleigh]

Yep, I just pulled the pan this evening and all the teeth were sitting there.  I don't think I'll re-use them though!  Good thing they're heavy, those things could do some damage in there.  Tomorrow I'll see about cracking these cases.  Thanks for the advice.

[dave500]

if you knock the primary shaft through you can do it without splitting the cases,its a fiddly wrangle but it can be done,i think xsmooth did it once?

found it!he replaced the starter clutch,once thats out of the way you should be able to do that broken gear?worth a shot before you split the cases if you dont really need or want to,heres a detailed how to with good pictures.
http://forums.sohc4.net/index.php?topic=122084.0#lastPost

and this prelude to it.
http://forums.sohc4.net/index.php?topic=121832.msg1382676#msg1382676

[Bodi]

Possibly the starter clutch rollers are failing somehow. If the gear was spinning freely when trying to start and then the clutch grabbed hard, maybe that could break off some teeth?

[rb550four]

Holy crap Dave, I read xsmooth's thread , what a supreme PITA that would be.
 I can understand that in his case he didn't want to break it down because he didn't have the top end off, but this member's top end is off.
 When you say fiddle, you ain't just a kidding, so many things can go wrong, like having the needlebearings slip out of the basket,  or having part 12, 13 and 20 blow out into the rest of the lower cases then having to track that down....Holy $hit!
  I read that and went directly to the unheated barn an opened up a 500 case..... man , you better have some small fingers and a long fuse. If it wasn't in pictures I would never believe it would be possible.
  I 'll be the first to tell you that I don't know everything about the 500/550 even though I've been in a bunch of them, because there is always something else to be learned, some other way things can be done, but this looks even trickier than it should be especially for this member with the top end already off on a no known history engine.
   That was truly a work of art' but I'm a split the cases down kind a guy in a strange motor every time. It will be interesting to see what wjustinleigh will choose to do. Thanks for the link, I'm still amazed. Thanks for sharing.

[wjustinleigh]

I'm the broken teeth guy - yeah, I went through the post and was completely impressed and in no way convinced. 
We're going to try this cases open deal, I figure I've come this far, might as well see it through.  Will make it easier to get everything cleaned up too.
Appreciate all the advice!

[dave500]

yeah if you doubt your finnese and patience level itll be too hard,id just split that case being half done and unknown anyway to be sure all the teeth debris is found,youll really be able to clean it well as you go.

[dave500]

i just today replaced the timing belt and water pump on my wifes little 99 hyundai excell twin cam,ive done this before and a few others like toyota rav four and suzuki vitaras,id sooner do the honda starter gear job!

[bryanj]

OK I always said somebody somewhere will break one of everything and you got the only 500/550 starter gear i seen knackered in 40+ years----go get a gold star

[dave500]

yeah what happened to the guy who said he had a snapped primary chain in a 500/550?i thought he was going to post photos?

[wjustinleigh]

Thanks all, broken starter gear out, new one ready to go.  Never did see what caused the problem, hopefully a new starter and starter gear will cover the issue.  Glad to know I can provide the first broken starter gear for the archive!

[dave500]

good job,find any other debris?

[wjustinleigh]

I found the missing teeth and a some other small small metallic particles, about 20ish of them about the size of sand grains.  I had expected to see something else to indicate why the starter gear was broken and why the engine was smoking so badly before the rebuild.

[nccb]

see if the starter wobbles even just a bit.  I did the same to mine a year or so ago, apparently the 750 is way easier to take out?