Poor Crankshaft Service

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12/19/2018 10:45 PM

Sent out my Crankshaft(KTM 150) to a local Dealer for a revision.
He is a Yamaha Dealer but i know him for years.
He did the Crankshaft Jobs not by himself he had an external Engine Mechanic.
Yesterday i pick it up but do not check at the Dealer?‍♂️ when i come Home i found this


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12/19/2018 10:55 PM

Think this Guy worked with Hammer, Vice ,Grindig Machine ?
Can this have any negativ affect on the Performance.
Write an E-Mail to the Dealer Yesterday evening
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12/19/2018 11:03 PM
Edited Date/Time: 12/19/2018 11:06 PM

KTM Two Stroke wrote:

Think this Guy worked with Hammer, Vice ,Grindig Machine ?
Can this have any negativ affect on the Performance.
Write an ...more

No, the dents and scrapes won't affect it whatsoever, however, they shouldn't be there. If it was me, at the very least I would take it back to them and have them put it on the truing stand so I can see the run out. If it is excessive, it is a problem. I would also check the side clearance for the rod.

What do you mean by "revision"?

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12/19/2018 11:14 PM

I mean a New Connection Rod with the lower Bearing
I want to save some Money KTM Dealer 400€ Conrod+Work
Here i spend 200€ ProX Conrod + Work
Was the wrong decision

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12/20/2018 12:07 AM

Check runout and if it’s next to nothing don’t worry.

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12/20/2018 7:03 AM

As stated, take it back and have them show you the runout. If it's more than .001-.0015" I would be extremely mad. The dents and scratches wont hurt, but beating the hell out of my crank halves with a steel hammer (supposed to use a brass hammer) is just poor worksmanship. That is atrocious!!!

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12/20/2018 7:15 AM

If the runout is ok then it will work. Id probably find a new crank guy. IIRC, ken oconnor said he doesnt even use a hammer at all to rebuild cranks.

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12/20/2018 11:47 AM

Talked to the Yamaha Dealer today and he told me KTM Crankshafts are very hard to Balance because the Pin is pressed so hard in the Crankshaft halves??
He say don’t worry about the marks

Can beliefe it or not tomorrow i Go to my KTM Dealer to let the runout Check.

What makes me nervous is that he grind off a little on each side.
I work the last 15 years as a Machine Mechanic and know this is not the right way to work

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12/20/2018 12:57 PM

Yea if the rod is out true then you have a problem but the dents shouldn't affect anything and was probably applied from the truing process with a hammer.

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12/20/2018 2:33 PM

KTM Two Stroke wrote:

Talked to the Yamaha Dealer today and he told me KTM Crankshafts are very hard to Balance because the Pin is pressed so hard ...more

"Talked to the Yamaha Dealer today and he told me KTM Crankshafts are very hard to Balance because the Pin is pressed so hard in the Crankshaft halves??"

This makes no sense to me.


"He say don’t worry about the marks"

Of course, what does he care.

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12/20/2018 5:40 PM

If anything is "send it to the right guy" it's definitely a crank rebuild.

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10' 200 XC-w
96' XR600r

12/20/2018 6:39 PM

I always used a straight edge to get it started and check it again when it is about halfway pressed together. I usually can get them .004 or less before I even begin the dial indicator trueing process. The last one I did I put it in my trueing stand to check and when I spun it the indicator didn't move. I thought it wasn't touching but it turned out to be dead nut on .000 using the straight edge alone! I always use a brass hammer to align it so you don't have those marks like the one pictured here.

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Take it to the limit, one more time!

12/21/2018 2:45 AM

mx317 wrote:

I always used a straight edge to get it started and check it again when it is about halfway pressed together. I usually can ...more

That would have been sweet. I’m guessing there was no one around to brag/show off too?

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12/21/2018 3:03 AM

mx317 wrote:

I always used a straight edge to get it started and check it again when it is about halfway pressed together. I usually can ...more

What press setup are you using. I want to start doing my cranks in house. I have a fleet of bikes I take care of.

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12/21/2018 3:46 AM

mx317 wrote:

I always used a straight edge to get it started and check it again when it is about halfway pressed together. I usually can ...more

Jrewing wrote:

That would have been sweet. I’m guessing there was no one around to brag/show off too?

Unfortunately not, but I still bragged about it.

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Take it to the limit, one more time!

12/21/2018 3:50 AM

coastlinecascot wrote:

What press setup are you using. I want to start doing my cranks in house. I have a fleet of bikes I take care of.

I have a 50 ton press and an old car rear bearing removing tool to slide between the crank halves as I press it apart. I sometimes have to use shims to hold it straight as I press. I press off one side and then turn it over and press the pin out of the other half. I have seen a jig setup that holds then straight as you press them back together that looks sweet. I think Motion Pro has one.

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Take it to the limit, one more time!

12/21/2018 7:10 PM
Edited Date/Time: 12/21/2018 7:10 PM

mx317 wrote:

I always used a straight edge to get it started and check it again when it is about halfway pressed together. I usually can ...more

coastlinecascot wrote:

What press setup are you using. I want to start doing my cranks in house. I have a fleet of bikes I take care of.

mx317 wrote:

I have a 50 ton press and an old car rear bearing removing tool to slide between the crank halves as I press it apart. I ...more

Thanks, what do you use to press them back together. I mean jig if any

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12/22/2018 4:42 AM

coastlinecascot wrote:

Thanks, what do you use to press them back together. I mean jig if any

No jig. I press the pin in one crank half, install the rod parts and start pressing. I use a straight edge to get me started and check it again after I have it pressed part way down. It moves a lot easier before it is pressed all the way together, so I try to have it as close as possible before I use the dial indicator. I use a lathe with live centers to spin it on to check it.

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Take it to the limit, one more time!

12/22/2018 7:03 AM

mx317 wrote:

I have a 50 ton press and an old car rear bearing removing tool to slide between the crank halves as I press it apart. I ...more

coastlinecascot wrote:

Thanks, what do you use to press them back together. I mean jig if any

mx317 wrote:

No jig. I press the pin in one crank half, install the rod parts and start pressing. I use a straight edge to get me started ...more

Great info. I have a couple scrap cranks i need to mess with. It's not the money having someone else doing it. Ken occoner is good. It's the turn around time that makes it's hard

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12/22/2018 1:39 PM

KTM Two Stroke wrote:

Talked to the Yamaha Dealer today and he told me KTM Crankshafts are very hard to Balance because the Pin is pressed so hard ...more

They didn't balance it, they pressed it together and trued it. Was that perhaps a translation error? At any rate if their workmanship was that poor, I'd want them to replace the crank. That kind of work is unacceptable. I know the dings and grind marks won't hurt the operation of the crank if it's true and without runout, but it wasn't like that when you brought it to them. The "outside mechanic" they used probably charged them 25% of what they charged you for the work. And as far as the pins being pressed in so tight it's hard to work on, that's BS. A press fit is a press fit. Just the same as any crank by any other OEM. The clown that worked on it should have used brass wedges and a brass mallet to true it.

The Yamaha dealer should have been able to do that work in house.

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Many thanks to everyone helping me out this GNCC season: SRT Offroad, Acerbis, FCR Suspension, O'Neal Racing, Evans Waterless Coolants, Rekluse, Twin Air, Braking Brakes, Carbsport

Profile image credit Ken Hill Photography

12/23/2018 3:17 AM

harescrambled wrote:

They didn't balance it, they pressed it together and trued it. Was that perhaps a translation error? At any rate if their ...more

Yesterday I was at my KTM Dealer, he check the Crankshaft for run out and it’s OK.
It was my mistake to save 200€ and go to the Yamaha Dealer.
But he is Yamaha Dealer here in Austria since 1995 so I trust him to make a good Job

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12/24/2018 7:23 PM

The dumb mechanic should have used a brass or copper hammer
Obviously he didn't & although it spins true it makes him look like a hack

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12/26/2018 5:06 PM
Edited Date/Time: 12/26/2018 5:09 PM

I do cranks mainly for myself. I have had bad ones done before by "shops" with "good mechanics" with excessive runouts> I race my bikes hard,,so I want run-out 1/2 of factory tolerance. I got mad at paying good $$$ for BS work and got my own 32 ton press, and learned from some old timers. Contrary to thoughts...a BRASS hammer will leave dings like that in a steel crank. You smack it hard enough on the edge with a brass hammer and those divots will be there. I've done it too..Dressed them with a file and moved on,finished my rebuild and proved it was good winning races... That said- I use a Snap On lead shot hammer now,,that doesn't mark em up !.. The critical things is run-out and side clearance. I share this in case anyone wants to do there own as well....use a quality lead shot hammer...measure outside clearance and rod side clearances..write it down,,,press it together and true it.

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12/26/2018 8:07 PM

What do you mean outside clearance?

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12/26/2018 8:19 PM

Jrewing wrote:

What do you mean outside clearance?

Width of crank halves. Crank must be the same width (crank half to crank half outside). Measure before you press it apart.

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Take it to the limit, one more time!

12/26/2018 9:47 PM

Jrewing wrote:

What do you mean outside clearance?

mx317 wrote:

Width of crank halves. Crank must be the same width (crank half to crank half outside). Measure before you press it apart.

Thought that’s what it was . I’ve read a hop up tip is to keep a minimum of 1mm clearance with case and crank halves to limit friction of air fuel. Theory is that if clearance is closer it creates a friction/drag of the gas mixture at high rpm

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12/26/2018 10:46 PM

Jrewing wrote:

What do you mean outside clearance?

mx317 wrote:

Width of crank halves. Crank must be the same width (crank half to crank half outside). Measure before you press it apart.

Jrewing wrote:

Thought that’s what it was . I’ve read a hop up tip is to keep a minimum of 1mm clearance with case and crank halves to limit ...more

It doesn't work that way, and the critical clearance is between the rod and crank halves.

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12/27/2018 3:12 AM

mx317 wrote:

Width of crank halves. Crank must be the same width (crank half to crank half outside). Measure before you press it apart.

Jrewing wrote:

Thought that’s what it was . I’ve read a hop up tip is to keep a minimum of 1mm clearance with case and crank halves to limit ...more

barnett468 wrote:

It doesn't work that way, and the critical clearance is between the rod and crank halves.

If one of the worlds best two stroke designers says it does I ain’t debating it.

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12/27/2018 7:31 AM

barnett468 wrote:

It doesn't work that way, and the critical clearance is between the rod and crank halves.

If you measure your crank width and put it back the same your rod side clearance will be in spec if you have the right rod kit. You can’t make the crank wider or it won’t fit between the crank bearings without locking it up.

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Take it to the limit, one more time!

12/27/2018 7:44 AM

I will add,,,, there is a thing of tolerance stack up...I carefully check the rod and washers in the rod kit against the original...I have seen aftermarket kits where the rod or washers or both are different than stock,,a .0001 on this,,.002 on than,,.005 on the rod,,,and when you press it together it squeaks a little extra and is .001-.002 tighter than stock...you try your feeler gauge on side clearance and it's way too tight..Not checking this after wards,,,is why some fail and the person says "I put a new blank rod in it" They suck. I had a CR250 I put a Prox rod on and had to swap washers from another kit to get the final spec I wanted.

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