Starter, Gears and One Way Clutch Inspection

[74Nitro]

I don't recall these being 7mm, but I could be totally wrong.
Why not just make your own? Start with a more common bolt and run the correct die over it.

 

[MEL]

I have considered that I am looking for a 7mm 125 pitch hex die now. I'm not sure if I run a 100 pitch bolt which is a finer thread I believe through a 125 if the threads will be strong enough. But I think at this point the worse that can happen is the bolts may strip when using the puller. I
don't think the flywheel would strip. Otherwise maybe take a 8mm and go down a size.
yeah 7mm is on in it's self but a 125 is even more obscure.
Thanks a lot for your help!

 

[74Nitro]

I wish I had one here in front of me.
I've had these apart before and I don't recall ever using a 7mm dia x 1mm pitch bolt here, because I don't think I have any of those bolts.
Maybe you already know this, but the pitch is the distance in mm between the tops of the threads.

 

[MEL]

I have a friend who has a UTV had the same issue trying to find a 7mm-125. Lire 1000 back a few posts said it was a 7-125.
A 6 slides through the hole an 8 is too big wont even start. a 7mm-100 will start in the hole but binds as it goes in. Thanks for the explanation I only
know enough to be dangerous. I too could still be wrong. Thanks again for your help.

 

[MEL]

ended up using a 2 jaw puller and a little heat. With a few wacks she was off.
Next question after replacing relay, starter clutch, flywheel gear, idler gear and starter. I finally started it today and the starter wants to hang in the fly wheel for about 4 tenths of a second causing a high pitched whine. normally I would let it ride for a while to see if all wears in but with all the starter and gear issues they've had I'm a little hesitant to put it all together. Has anyone seen this issue before? Thanks for any information..

 

[cannondale27]

Your starter is always engaged. No Bendix. That’s the reason for the One-Way bearing/Starter clutch.

 

[MEL]

Thanks Cannondale27 I thought of that during during my sleepless night. Any idea what would cause that noise and or do you think I should be concerned?

 

[cannondale27]

I think it’s common if I remember right. Must just be the one way dragging a little. Once miles are on I think it goes away. Others will hopefully chime in here.

 

[MEL]

Thanks again for your input. I was thinking that as well but I don't have any experience with it. The noise is definitely coming from the starter when I listen to the stethoscope. Cant hear it any where else. Unless someone has any other info I was going to keep an ear on it and see what happens. The new design clutch was a lot beefier for sure. Thanks again for your help.

 

[Josh Hugel]

I have a low mileage 2005 RS Vector in the garage that came in with a starter issue and for a chain tensioner update.

The starter was still capable of starting the engine but it acted as if it was kicking out or skipping teeth on the gears. The starter was removed and a bench test performed which indicated that the starter worked but sounded a little rough so a new one was ordered. To inspect the gears the stator cover was removed but no obvious failures could be seen so the flywheel was removed to inspect the one way starter clutch. The hub on the flywheel gear that the clutch bearing locks to during startup had noticeable wear which I suspect was causing the problem so a new idler gear, idler gear pin, one way clutch and flywheel gear was also ordered.

When replacing any one of these starter component on the Yamaha 4-stroke engines I recommend that all the related parts are replaced. The good thing about replacing all the starer parts is that there have been updates to the gears to make them stronger.

Stator cover removed to inspect starter gears (flywheel also removed):
View attachment 134159

Starter flywheel gear with a bad one way clutch hub:
View attachment 134145

New updated idler gear. Notice that there are no webs in the gear and the teeth that the start motor's small gear runs on are now wider:
View attachment 134147
View attachment 134148

New updated one way clutch looks to be stronger than the old one:
View attachment 134149
Old one way clutch installed on flywheel:
View attachment 134150

New one way clutch installed on flywheel:
View attachment 134151

I didn't notice any significant changes made to the large flywheel gear that locks to the one way clutch but I thought after all the Viper starter gear failures that Yamaha switched them all to chromoly for additional strength.

I am looking at doing this right now. I have finally got the stator cover off after more messing around than I care to admit... Everything at a glance looks fine, I tried pulling the flywheel but stopped before I got too carried away and wanted to check here first. Judging by your pictures it could possibly be the one way clutch slipping causing my issues. Are these updated parts the replacements for the old OEM parts? Where would I look at purchasing these? I bought a new starter motor from Yamah parts house.

 

[MEL]

I totally agree with Grizztracks. I replaced everything when I replaced the starter. I also replaced the tensioner. Unfortunately I didn't know about the starter issues when I replaced the tensioner. If I had it would have been much easier to do both at the same time. I used all OE parts hoping the starter would be better than the original. Lots of people put in after market. Mine had a whine after I replaced as it was disengaging but went away shortly after and all has been well since. If your going in I would recommend a stator as well as those also had issues. due to the age of the sled I had to get parts from several different company's. Ona I had to order directly from Japan. Which was the flywheel by the way because I didn't use the correct puller to get it off . Be sure to use a good puller. Take your time.