New crank for KX125: OEM or rebuilt an old one?

HighPlainsSquid
Edited Date/Time 7/28/2019 4:33pm
Blew up the crank on our '04 KX 125 and am in the process of rebuilding it. Should I:

1) get an OEM crank and pop it in?

2) get an OEM crank and send it to someone to have them true and balance it? If so, who?

3) get a good used crank off eBay and send that to someone for a rebuild?

I _was_ thinking about getting the Wrench Rabbit kit until I pulled the bike apart and found...one main bearing is moving but super stiff. The crank bearing is toast. To be fair, though, we had at least 78 h riding on this crank (unknown before that) and I was JUST about to replace it for preventative maint. But those hours are 14 year old learning and 57 yr old Vet riding. Anyhoo.... here we are. OEM.




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stavendirtbike 7/23/2019 6:19am
7/23/2019 6:19am Edited Date/Time 7/23/2019 6:23am
Send your crank or a used OEM one to mrcrankshaft. Always sent my cranks to him for rebuild. Great guy and quick turn around.

Those Hot Rods cranks aren't too bad. If it was a Wiseco I'd immediately throw it in the dumpster
kb228
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kb228 7/23/2019 6:24am
7/23/2019 6:24am
Get the OEM one rebuilt or buy a new one.
Avoid that hot rods and wiseco crap.

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DB97
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DB97 7/23/2019 9:41am
7/23/2019 9:41am
Pretty sure a new oem was about $230. I threw away the hotrod crank that came in mine.
HighPlainsSquid 7/23/2019 10:34am
7/23/2019 10:34am
I talked to Mr. Crankshaft and upon his recommendation bought a decent looking used one on eBay which I'll send to him for a build. It'll come in a little cheaper or the same as new, but will be true and balanced and also already heat-tested.

I might get TWO like this, just to keep one on the shelf in case my grandkids want to experience the Mighty 2004 KX 125 in the future.
stavendirtbike 7/23/2019 10:40am
7/23/2019 10:40am
HighPlainsSquid wrote:
I talked to Mr. Crankshaft and upon his recommendation bought a decent looking used one on eBay which I'll send to him for a build. It'll...
I talked to Mr. Crankshaft and upon his recommendation bought a decent looking used one on eBay which I'll send to him for a build. It'll come in a little cheaper or the same as new, but will be true and balanced and also already heat-tested.

I might get TWO like this, just to keep one on the shelf in case my grandkids want to experience the Mighty 2004 KX 125 in the future.
Good move with mrcrankshaft. Never had issues with several cranks both 2 and 4 strokes that he rebuilt for me.
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Markopolo400
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Markopolo400 7/23/2019 11:20am
7/23/2019 11:20am Edited Date/Time 7/23/2019 11:21am
I had https://www.cookseycrank.com/ rebuild the OEM crank from my 06 KX250. Did a great job would definitely use him again.

Edit: Crap guess he's not doing cranks anymore.
1
HighPlainsSquid 7/23/2019 4:02pm
7/23/2019 4:02pm
Markopolo400 wrote:
I had https://www.cookseycrank.com/ rebuild the OEM crank from my 06 KX250. Did a great job would definitely use him again. Edit: Crap guess he's not doing...
I had https://www.cookseycrank.com/ rebuild the OEM crank from my 06 KX250. Did a great job would definitely use him again.

Edit: Crap guess he's not doing cranks anymore.
He would've been my first choice, but... not doing them anymore.
Jim in VA
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Jim in VA 7/23/2019 7:48pm
7/23/2019 7:48pm
Slightly off topic, but when did Wiseco products go to shit? I used their pistons all through the 90’s, nothing but great luck with them. I had to quit riding from the early 2000’s until now, so a little out of the loop. I’ve been hearing they’re crap now, like other brands that used to be great. Probably all made in China now...
Matt Fisher
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Matt Fisher 7/24/2019 3:43pm
7/24/2019 3:43pm
Wiseco pistons still have an excellent rep, it's their cranks that rate only slightly better then Namura pistons (garbage in the shape of a piston).
Jim in VA
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Jim in VA 7/24/2019 3:51pm
7/24/2019 3:51pm
Cool, thanks for the info. Glad to hear their pistons are still good. So much low quality stuff with good marketing out there these days, you don’t know who to trust! Everything is hyped as the best it seems.
1
HighPlainsSquid 7/24/2019 4:40pm
7/24/2019 4:40pm
Jim in VA wrote:
Cool, thanks for the info. Glad to hear their pistons are still good. So much low quality stuff with good marketing out there these days, you...
Cool, thanks for the info. Glad to hear their pistons are still good. So much low quality stuff with good marketing out there these days, you don’t know who to trust! Everything is hyped as the best it seems.
Or the ads don't tell you _anything_. We've got 4 different kinds of Klotz oil on the shelf and they all say the same thing. I wish they'd just have a little statement or chart like "Best for enduros", "Best for high-revving motocross", "Best for Vet riders".

I'm so tired of informationless ad copy B.S. in descriptions.
Jim in VA
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Jim in VA 7/24/2019 5:00pm
7/24/2019 5:00pm
Yeah, don’t even get me started... I used to love reading Dirt Bike magazine and any motorcycle magazine in the 90’s and early 2000’s for real content, and real stories... love of the sport and education. Then it just became 90% ads, and the stories were all pretty much how to bling out a bike. Story title = Affordable $800 05 YZ250 build... “well we installed xxx brand triple clamps, a billet fuel cap, anodized bolts, and $12k later took it to the track.” Thankfully there are places like this for people to share actual unbiased information on products. Didn’t mean to rant, just don’t like weeding through hype.
1
HighPlainsSquid 8/13/2019 6:40am
8/13/2019 6:40am
Update!!!

Got the motor back together, using a new OEM crank, every bearing and seal that I encountered on the way in/out, and new V-force reeds (replacing some chipped/frayed ones). Plopped it in the frame, pipe on, etc. Started 1st kick.

Also threw on a new chain I had sitting around, a new front sprocket I had, and a new rear sprocket/bolts that I bought. Calibrated my torque wrench and tightened the sprocket bolts in a secret inverse pattern.

Rode for 45 minutes yesterday and motor feels really smooth. Pulls good, revs easily, sounds nice. I'm happy.

Also running a bottle of Klotz Beanol I have until I use it up. Smells nice.

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