Starter clutch failing on my KZ750 H LTD

I saw in another thread a member stating the new sprocket surface was 1.663" dia. I just polished mine down and it mics out at 1.6635-1.664"

Can anyone confirm that this is a good measurement and I can just toss mine back in now that the dimples are out of it with new spring/roller pack?

Thanks,
-Paul

Here's a NOS KZ650 starter gear. Ed

Ed please tell me I'm reading that wrong and it doesn't say 1.764.

My new one measures 1.663 maybe 1.6635 both confirmed with my good quality slide caliber and a 1 to 2 inch mike.... Don't have the old one out yet or I'd give that one too.

Edit ....... Didn't see the question by twilight so it must be 1.6635 ..... not sure if its the dimention (as long as its within a ,001) you need to worry about and more the lines and the hammer marks from the rollers you need to worry about?

Yes (good news) you are reading it wrong. It says 1.664" Ed

That certainly makes my morning! Now If only my slough of gaskets would show up. Thanks Ed!

KZB2 650 wrote: Ok I know I'm gonna get grief for this but according to the "Clymer" manual it says you don't need to remove the circlip and gear at the 3 minute mark on the video and you can just tap the assembly (gear and bearing) out and back home both without removing it....

...I have a factory manual too and it shows removing the gear (once its out and on the bench) with the special puller and putting it back on with the pusher after bottoming out the bearing in the housing. I know A few of you have done the job and would like to here from you if you've done it without removing the gear.

You don't necessarily need to remove the secondary shaft gear to pull and reinstall the secondary shaft, but I think it's a good idea to do it.

In order to pull the shaft you have to remove the bearing bracket behind the gear - for this you will definitely need an impact screwdriver of some sort. I have a hammer driven one and had to remove the gear to avoid the body of the screwdriver hitting the gear and possibly chip the teeth.

Removing the gear isn't a big deal, all you need is three standard pitch 8 mm bolts like shown in the pic below (obviously long enough), just alternate between the bolts 1/2 - 1 turn at the time and it'll come right off.

Reinstalling is a lot easier than removing, once you clean the gear and shaft of the old oil and dirt that caused the gear to get stuck in the first place you can usually just push the gear back on - if not just use a socket or a piece of pipe to tap the gear back on, doesn't take much force.

Btw, I agree with Ed, definitely replace the starter clutch gear while you're in there - I didn't the first time, just replaced the springs and plungers. Lasted a couple of years, then it started acting up again, mostly when cold. Then I found a NOS starter clutch gear and redid the whole thing, now it just grabs the first time, even after winter hibernation, time and money well spent.

Hey thanks OnkelB but I just came in from removing it not a half hour ago and I desided to keep it on.

My Sears impact (absolutly right about needing one .....were tight!) was able to sneak by the gear and the shaft and bearing taped out very easy.

Am going to pick up some Loctite 243 for the oil pump screws and the 6mm allens on the clutch assembly in the morning and should have it all back together in no time. I swear I worried so much about this and it was such a piece of cake....... maybe I better wait till I get it all back together before I celibrate but I see no problems at all.

I agree too with replacing the gear (had a problem finding it but with help here I finally did) and I desided on the clutch assembly too....... the rollers were a little marked up along with the gear (chatter marks) and the springs were weaker too with one of them noticeably weaker then the new on so I'm felling really good about it working out.

Have the motor out so it might take me a little while to get it back in but like I said am feeling like a million bucks right now.

KZB2 650 wrote: Hey thanks OnkelB but I just came in from removing it not a half hour ago and I desided to keep it on.

My Sears impact (absolutly right about needing one .....were tight!) was able to sneak by the gear and the shaft and bearing taped out very easy.

Am going to pick up some Loctite 243 for the oil pump screws and the 6mm allens on the clutch assembly in the morning and should have it all back together in no time. I swear I worried so much about this and it was such a piece of cake....... maybe I better wait till I get it all back together before I celibrate but I see no problems at all.

I agree too with replacing the gear (had a problem finding it but with help here I finally did) and I desided on the clutch assembly too....... the rollers were a little marked up along with the gear (chatter marks) and the springs were weaker too with one of them noticeably weaker then the new on so I'm felling really good about it working out.

Have the motor out so it might take me a little while to get it back in but like I said am feeling like a million bucks right now.

Congrats bro!!! You know I'm expecting a step by step, with mucho pics, walkthrough write-ups!!!

Makes sense to replace the gear/sprocket if it's heavily flat spotted. I chucked mine up in the drill press and used some emery cloth to smooth it out then mic'd it. Good as new. I wonder how many other gears can be saved by a simple polish?

I followed the manual and didn't take the gear off the secondary shaft. It pulled out with a little brass tap nice and easy.

Hey Random am waiting on some 243 Loctite to do the 3 allens holding on the clutch starter and will be a while before I'm done. Gotta say between the video, manual and tips on here about what others have done there is not much I can add. The manual spells the steps out perfectly.

Didn't take any pics and want you to relax .......honestly it is easier than it sounds. Cleaning up the pan and gaskets will probaly be more time consuming than the other work but was pretty easy for me since I did it 3 years ago for the bore job and valves.

Forget removing the gear several others have not and me neither ..... plan on a impact driver for the screws and maybe a electric impact wrench from Harbor Freight (worked good for me) for the clutch nut and shaft nut (In your case).... you could do it with holding the brake in gear more than likely too?..... try it before with a big breaker bar if you want to save there.

I really wouldn't want to try it without removing the motor or at least flipping it upside down but that sounds like a lot of work too. You younger guys could and have done it crawling under the bike but it was so easy to get too with it out. Sure us guys can help you out as you go along if you have something your having problems with and I will add to this if I can think of more.

KZB2 650 wrote: Hey Random am waiting on some 243 Loctite to do the 3 allens holding on the clutch starter and will be a while before I'm done. Gotta say between the video, manual and tips on here about what others have done there is not much I can add. The manual spells the steps out perfectly.

Didn't take any pics and want you to relax .......honestly it is easier than it sounds. Cleaning up the pan and gaskets will probaly be more time consuming than the other work but was pretty easy for me since I did it 3 years ago for the bore job and valves.

Forget removing the gear several others have not and me neither ..... plan on a impact driver for the screws and maybe a electric impact wrench from Harbor Freight (worked good for me) for the clutch nut and shaft nut (In your case).... you could do it with holding the brake in gear more than likely too?..... try it before with a big breaker bar if you want to save there.

I really wouldn't want to try it without removing the motor or at least flipping it upside down but that sounds like a lot of work too. You younger guys could and have done it crawling under the bike but it was so easy to get too with it out. Sure us guys can help you out as you go along if you have something your having problems with and I will add to this if I can think of more.

I was being somewhat sarcastic, pretty much feeling good about doing it now, and glad urs is right!

I've still gotta order the clutch nut and thrust washers, prob order some new s clutch Allen's while I do that...

Gotta but a electric impact and impact driver...

Other then that, maybe a clutch removal tool? Did you use an extension on the driver to get around the gear? Link to the driver you have?

Thank man!

Awesome Random ....... The impact I have is a old sears model from I'd guess is from 1980-81 so I'm sure its not available anymore...... Correction I just punched up Ebay under Sears Impact driver" and they have one :laugh: The model number is 947641 and is .99 cents with 4 days left and 24.99 buy it now ...... 3 others watching it though. Maybe bid on it to get rid of the buy me and try to get it in 4 days ???

I saw a Vessel brand that's made like a screw driver with a built in impact that has a #3 JIS tip on it on Amazon and Ebay that gets good reviews (on Amazon) but that's all I know about it. It was around 20 bucks so that might be good too.

The clutch holder tool I got was 17 bucks shipped on Ebay and is a EBC brand .....pretty HD. Good luck.