Primary drive brand rear sprocket- 2300 miles- TOAST - Kawasaki KLR 650 Forum
2008+ KLR650 Wrenching & Mod Questions For repair, maintaining or modifying discussions related to the newly updated 2008 and beyond, Generation 2 KLR650 Motorcycle.

  • 1 Post By GoMotor
LinkBack Thread Tools Display Modes
post #1 of 7 Old 08-22-2016, 04:08 PM Thread Starter
2nd Gear
Join Date: Jul 2014
Location: Seattle
Posts: 113
Primary drive brand rear sprocket- 2300 miles- TOAST

So 2300 miles ago, I replaced a worn out rear sprocket with a new one from Rocky Mountain, primary drive brand. Now half the teeth are busted off, and the rest look ready to go too. WTF? Now I didn't change the chain out at the time, since it didn't seem to need it. And I'll readily admit that I ride aggressively commuting back and forth to work in heavy traffic. But still! Worn out between oil changes? When I install my new rear tire this week, I'll be putting on a new chain and both sprockets. Going with Sunstar sprockets this time, hopefully they last longer.
So is this the kind of life span I can expect with my style of riding or is it just what I get for going with cheap parts? Maybe it was just a fluke? What do you think?

Sent from my SM-G920V using Tapatalk

2013 KLR- klx needle, EM doohickey, EM fork brace, EM drill through subframe, UNI air filter, 16 tooth front, thermo-bob, SW-motech crash bars, JNS skidplate, Tusk panniers, Wolfman Explorer tank bag, Acerbis front fender, Russell Seat, Barkbusters, doubletake mirrors, Cogent suspension
BigRed is offline  
Sponsored Links
post #2 of 7 Old 08-22-2016, 05:21 PM
4th Gear
GoMotor's Avatar
Join Date: May 2014
Location: Texas
Posts: 1,260
I think a good clear photo is needed. Maybe a couple rom different angles.

I also think Rocky Mountain would like to have that sprocket back and would most likely send you a new one.

I bought a new Shinko 270 rear tire from and it lost about 11 center knobs in 500 miles. I asked how that could happen. They asked for a photo of some missing knobs and a drill bit through the tire and sent me a full credit. So, I am still buying things from them. Be polite and ask them how they think this could have happened and see what happens.
shinyribs likes this.

Last edited by GoMotor; 08-22-2016 at 05:30 PM.
GoMotor is offline  
post #3 of 7 Old 08-22-2016, 05:50 PM
5th Gear
Join Date: Aug 2010
Location: Kelowna, B.C.
Posts: 2,619
Most probable cause: bad chain. Order another set and replace both this time. The Primary Drive stuff from RMATV is decent according to all reports I've read.

2 cents,
DPelletier is offline  
post #4 of 7 Old 08-22-2016, 06:01 PM
1st Gear
Join Date: Jun 2016
Location: Monroe, MI
Posts: 57
I've never had an issue, if the old sprocket was worn, it's most likely that the chain was worn as well.

Sent from my Nexus 6 using Tapatalk

'82 XV920: Soon to be tracker --'00 KLR685:adv -- '04 DRZ400E --'12 Super Tenere --'13 Versys (wife)0X DRZ400S (wife)
verboten1 is offline  
post #5 of 7 Old 08-22-2016, 07:37 PM
klr4evr's Avatar
Join Date: Mar 2007
Location: Fort Sask , Alberta, Canada
Posts: 3,545
Send a message via Skype™ to klr4evr
How many miles on the chain?? I'm thinking the chain caused the excessive wear. Recommended to change the chain and sprockets together. Like to see what Rocky ATV would say about it. I've got about 8000 miles on a Primary Drive chain & sprocket set and they still look great.

My Kaw Barn - 2004 KLR, 2006 Concours (sold), 1997 Bayou 400.

"It's a friggen motorcycle, it's not supposed to be comfortable, quiet or safe. The wind noise is supposed to hurt your ears, the seat should be hard and riding it should make you shit your pants every now and then. "

<--- Please fill in the 'Location' on your personal profile page. User CP/Edit Your Details

This information makes it much easier for other members to answer/comment on your posts.
klr4evr is offline  
post #6 of 7 Old 08-25-2016, 05:19 PM
3rd Gear
shinyribs's Avatar
Join Date: Aug 2016
Posts: 527
I agree with the others here. A stretched chain can easily knock the teeth off a rear sprocket.

I don't know if you ride off road much, but I've crunched gravels between chain/sprocket and pooched gears that way. It stinks, but it's just part of the game.

A worn out cush drive with a bad bearing in a gear carrier could result in this as well.

Also, and not to be rude, but you really should be able to easily tell if a chain is stretched to the point of where it would wreck a gear. It would be clicking and popping trying to force-fit itself. If you didn't notice this, then definitely take pics of the gear and contact the seller. The world isn't perfect and there could be a batch of gears that didn't get machined properly. Sellers and manufacturers would love to know about this, but likely will never find out unless you help them.

Sprockets don't shed whole teeth when you wear them out. It's definitely not a premature wear issue, something is destroying the gear, or faulty manufacturing is at hand.

Last thing, are you positive the new rear gear was the correct pitch to match your preexisting chain?

Last edited by shinyribs; 08-25-2016 at 05:23 PM.
shinyribs is offline  
post #7 of 7 Old 08-25-2016, 11:05 PM
4th Gear
CheapBassTurd's Avatar
Join Date: May 2009
Location: Indiana/ Michigan line at the Lake
Posts: 1,585
Good point, Ribz.

Is a non 520 sprocket accidentally on?

I just came off a similar episode. Rock-twisted chain got replaced with a
used one. I didn't realize how used. On a 1200 mile round trip the chain was
getting HOT. Stops for gas and a shot of WD-40 on the chain made the stuff
kinda steam off !! Got to NY, the halfway point/ destination and the chain and
sprockets were shot in 600 miles. Reversing the sprockets and a new chain got
me home babying it. Spare front and a new rear sprocket are on now.

(The teeth were shark-finned but all were intact, and some flattening at the tips.)

I've been with D.I.D. chains and Sunstar sprockets 30 years.
A matched new driveset should last 20,000 miles on minimal care and hard riding.
30,000 for a clean, wet chain.

This is my son, with whom I am well pleased." ----God

Last edited by CheapBassTurd; 08-25-2016 at 11:14 PM. Reason: Forgot to answer BigRed
CheapBassTurd is offline  
Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the Kawasaki KLR 650 Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Similar Threads
Thread Thread Starter Forum Replies Last Post
Front drive sprocket? larry31 2008+ KLR650 Wrenching & Mod Questions 8 08-05-2015 04:40 PM
rear sprocket question 3rdaavbn KLR & Other Motorcycle Related Discussion 1 08-09-2014 06:07 PM
drive sprocket rubber Scrapper 2008+ KLR650 Wrenching & Mod Questions 17 03-28-2014 09:45 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome