Poor Crankshaft Service

KTM Two Stroke
Edited Date/Time 12/29/2018 11:38am
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








2
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KTM Two Stroke 12/19/2018 10:55pm
12/19/2018 10:55pm
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

barnett468
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barnett468 12/19/2018 11:03pm
12/19/2018 11:03pm Edited Date/Time 12/19/2018 11:06pm
KTM Two Stroke wrote:
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...
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

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"?

KTM Two Stroke 12/19/2018 11:14pm
12/19/2018 11:14pm
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
Jrewing
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Jrewing 12/20/2018 12:07am
12/20/2018 12:07am
Check runout and if it’s next to nothing don’t worry.
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DynoDan22
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DynoDan22 12/20/2018 7:03am
12/20/2018 7:03am
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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kb228
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kb228 12/20/2018 7:15am
12/20/2018 7:15am
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.
KTM Two Stroke 12/20/2018 11:47am
12/20/2018 11:47am
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
m1ke20012
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m1ke20012 12/20/2018 12:57pm
12/20/2018 12:57pm
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.
barnett468
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barnett468 12/20/2018 2:33pm
12/20/2018 2:33pm
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 in the...
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
"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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Hcallz5
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Hcallz5 12/20/2018 5:40pm
12/20/2018 5:40pm
If anything is "send it to the right guy" it's definitely a crank rebuild.
mx317
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mx317 12/20/2018 6:39pm
12/20/2018 6:39pm
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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Jrewing
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Jrewing 12/21/2018 2:45am
12/21/2018 2:45am
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 get them...
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.
That would have been sweet. I’m guessing there was no one around to brag/show off too?
1
coastlinecascot 12/21/2018 3:03am
12/21/2018 3:03am
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 get them...
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.
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
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mx317 12/21/2018 3:46am
12/21/2018 3:46am
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 get them...
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.
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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mx317
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mx317 12/21/2018 3:50am
12/21/2018 3:50am
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.
coastlinecascot 12/21/2018 7:10pm
12/21/2018 7:10pm Edited Date/Time 12/21/2018 7:10pm
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...
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.
Thanks, what do you use to press them back together. I mean jig if any
mx317
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mx317 12/22/2018 4:42am
12/22/2018 4:42am
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.
coastlinecascot 12/22/2018 7:03am
12/22/2018 7:03am
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...
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.
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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harescrambled
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harescrambled 12/22/2018 1:39pm
12/22/2018 1:39pm
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 in the...
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
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.
2
KTM Two Stroke 12/23/2018 3:17am
12/23/2018 3:17am
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 workmanship was that poor...
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.
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
2stmark
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2stmark 12/24/2018 7:23pm
12/24/2018 7:23pm
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
riv187
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riv187 12/26/2018 5:06pm
12/26/2018 5:06pm Edited Date/Time 12/26/2018 5:09pm
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.
Jrewing
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Jrewing 12/26/2018 8:07pm
12/26/2018 8:07pm
What do you mean outside clearance?
mx317
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mx317 12/26/2018 8:19pm
12/26/2018 8:19pm
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.
Jrewing
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Jrewing 12/26/2018 9:47pm
12/26/2018 9:47pm
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
barnett468
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barnett468 12/26/2018 10:46pm
12/26/2018 10:46pm
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...
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
It doesn't work that way, and the critical clearance is between the rod and crank halves.
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Jrewing
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Jrewing 12/27/2018 3:12am
12/27/2018 3:12am
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...
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
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.
mx317
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mx317 12/27/2018 7:31am
12/27/2018 7:31am
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.
riv187
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riv187 12/27/2018 7:44am
12/27/2018 7:44am
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.
barnett468
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barnett468 12/27/2018 8:15am
12/27/2018 8:15am
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...
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
barnett468 wrote:
It doesn't work that way, and the critical clearance is between the rod and crank halves.
Jrewing wrote:
If one of the worlds best two stroke designers says it does I ain’t debating it.
I'm not sure exactly what statement you are referring to, but the way it works is that there is a minimum and maximum clearance spec that the side play of the rod should be set to. If this clearance is too small, the thrust washers and/or bearing can get damaged. The clearance between the crank and the clutch side of the case will be whatever it will be after that.

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