Author Topic: IPB race "walking"  (Read 1331 times)

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Offline koko3052

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IPB race "walking"
« on: February 14, 2018, 08:54:23 AM »
Installing a DD6 yesterday, & pushing in the S&S IPB race got me to thinking of all that I've heard about this race walking inward. Is it internet hype or is it truth? What "forces" are at work to make this race move? I have never seen one moved. I hear hi hp. engines is what causes it, but HOW does it cause it to move....if it does? It is only a "support" bearing, not taking any side thrust. How can a roller force anything to move?
 Somebody please try to explain & enlighten me....by the way...this is not my first rodeo.  :potstir: :scratch:

Offline kd

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Re: IPB race "walking"
« Reply #1 on: February 14, 2018, 08:59:28 AM »
Mainshaft flex.  :scratch:
KD

Offline Nastytls

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Re: IPB race "walking"
« Reply #2 on: February 14, 2018, 09:06:45 AM »
Iíve wondered this myself.

Offline koko3052

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Re: IPB race "walking"
« Reply #3 on: February 14, 2018, 09:20:58 AM »
Mainshaft flex.  :scratch:

Wouldn't the flex have to be in the length that the race covers? I don't know, I'm far from an engineer. :missed:

Offline kd

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Re: IPB race "walking"
« Reply #4 on: February 14, 2018, 10:00:10 AM »
I believe the flex would begin at the last point of support (transmission main brg) and end at the last point (IPB).   An even marginally bent mainshaft could act like flex or cause flex at higher rotational speed when the clutch basket assembly's off center weight starts to influence the shaft stability. Marginal or minimal flex would not likely impart memory into the shaft. If you can imagine the flex being at the inboard end of the race sleeve position, the flex could influence the position of the race by causing it to move out. That is probably the intended function of the lip inside the S&S race, .... to grip the shaft beyond the flex point.   JMO and guessing.
KD

Offline jeffscycle

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Re: IPB race "walking"
« Reply #5 on: February 14, 2018, 10:51:21 AM »
    A good reason to go with the S&S race, it ain't going nowhere.
'01 FXDXT, '99 FXDL/XRD, '76 FLH

Offline les

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Re: IPB race "walking"
« Reply #6 on: February 14, 2018, 11:32:47 AM »
I've seen my share of that race walking inward.  Note that H-D has observed this too because the newer cruise drive tranny's have a mainshaft that has a shoulder on it so when you press the race on the shaft, it comes to a stop (rather than measuring a gap of .100" - .200" from the maindrive gear and manually stopping pressing the race on).

Offline smoserx1

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Re: IPB race "walking"
« Reply #7 on: February 14, 2018, 12:10:55 PM »
I don't know what makes it happen but it sure does.  Twice to me.  The first time I was able to get a bearing separator behind it and move it enough to fit the horseshoe on.  The second time no way, it was all the way into the seal.  Had to grind that one down and split it.  Got an S&S race after that.  Lesson learned.  Oh BTW my bike is not a high power one.  Andrews 21 cam & 95 inch but that is about it.
« Last Edit: February 14, 2018, 03:21:58 PM by smoserx1 »

Offline jsachs1

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Re: IPB race "walking"
« Reply #8 on: February 14, 2018, 03:57:05 PM »
Either belt or primary chain adjustment/alignment. Mainshaft flex from clutch assy. :nix:
John

Offline Deye76

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Re: IPB race "walking"
« Reply #9 on: February 14, 2018, 04:34:02 PM »
Don't know what causes it, but my OD6 walked. It took a beating for about 70,000 miles before it moved.
East Tenn.
2014 CVO RK, 2015 RGS, 1992 FXRP

Offline Ohio HD

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Re: IPB race "walking"
« Reply #10 on: February 14, 2018, 04:45:23 PM »
My thought is that John is right, the main shaft flexing. Higher torque motors, and riding style using the torque will flex the shaft. I pulled the inner primary when taking the 117 out of my '08 bike, and the race walked in to about 0.080" from the pulley retaining nut. I had to cut it off as my puller wouldn't get behind it.
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Offline koko3052

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Re: IPB race "walking"
« Reply #11 on: February 14, 2018, 06:19:12 PM »
Seems as tho we are fixing something other than the cause. :potstir:

Offline shovelinabox

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Re: IPB race "walking"
« Reply #12 on: February 14, 2018, 06:27:54 PM »
It happened to me! I installed the Jims upgrade bearing for somewhere around $35.00. It's a sealed roller bearing type. Jims part# 8960. My auto tensioner had the primary chain very tight with no play at all. I figured that is what caused my race to walk.
I cant decide if I want to ride to work or call in sick and ride all day...

Online N-gin

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Re: IPB race "walking"
« Reply #13 on: February 15, 2018, 12:41:02 AM »
I would think that the rotation and harmonics coupled with the rolling of bearing to make it walk. flexing a tempered main shaft, IDK
I'm not here cause of a path before me, Im here cause of the burnout left behind

Offline koko3052

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Re: IPB race "walking"
« Reply #14 on: February 15, 2018, 07:34:02 AM »
I would think that the rotation and harmonics coupled with the rolling of bearing to make it walk. flexing a tempered main shaft, IDK

Yea, that's not much distance between 2 bearings.
Now why doesn't it ever "walk out"...or is it against the clutch hub then, I haven't measured. :scratch:

Offline jeffscycle

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Re: IPB race "walking"
« Reply #15 on: February 15, 2018, 09:38:54 AM »
   Short of having a bike  on a dyno without a primary cover on, we can only assume that the mass of the clutch doesn't always run true, plates shifting around on top of not really being balanced. So for argument sake, say the main shaft is flexing, the primary bearing wants to keep it straight, but the race is pushed on harder on the inside. Throw in some extra heat on the that area, and the race loosens, eventually walking inwards. I've never seen one walk outwards, but the hub is less than 1/8" away to stop it.
    I've been victim/witness of it almost since the beginning of them being used in '84, so why didn't HD do something, $$ of course. But the S&S race is THE cure, even if its a bit pricey, But in my world if that race is coming off, an S&S is going on.
'01 FXDXT, '99 FXDL/XRD, '76 FLH

Offline les

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Re: IPB race "walking"
« Reply #16 on: February 15, 2018, 10:14:01 AM »
I would think that the rotation and harmonics coupled with the rolling of bearing to make it walk. flexing a tempered main shaft, IDK

Yea, that's not much distance between 2 bearings.
Now why doesn't it ever "walk out"...or is it against the clutch hub then, I haven't measured. :scratch:

Although I've never seen it first hand, some on this site have said they have seen it walk out.  But it appears that these are in the minority; it usually walks in.  There have been postings about putting snap rings on the outside so that if it does walk out, the snap rings hit up against the clutch hub and stop the race from moving too far out.  The snap rings just act like spacers, they don't have grooves cut.

Online rbabos

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Re: IPB race "walking"
« Reply #17 on: February 15, 2018, 10:23:13 AM »
The race walk is caused from angular loading pressure from the rollers transferred to the race. This means the whole race is not under the same pressure from the rollers since there is needed clearance in the assembly. This slight clearance can tilt the roller in operation. It's only about .001 or so.  The angle pressure comes from shaft deflection, starting at the main drive gear. Under high loads the inside of the race gets more pressure then the middle and outer end from the rollers. This tries to force the race outward. Witness marks on the race will bear this out.  Fact of life. Needs a good press fit or means to lock the race up from moving out ward.
Ron

Offline kd

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Re: IPB race "walking"
« Reply #18 on: February 15, 2018, 01:29:34 PM »
Well said Ron. That's kinda what I was trying to describe back in reply #4 but I had never examined a sleeve that had moved.
KD

Offline tdrglide

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Re: IPB race "walking"
« Reply #19 on: February 15, 2018, 03:17:32 PM »
Happened to me after I read about it here on this site. Hmm..
Moved in and took out the main shaft seal. Leaking trany fluid was my first clue. Replaced with S&S

Online N-gin

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Re: IPB race "walking"
« Reply #20 on: February 16, 2018, 12:53:55 AM »
The race walk is caused from angular loading pressure from the rollers transferred to the race. This means the whole race is not under the same pressure from the rollers since there is needed clearance in the assembly. This slight clearance can tilt the roller in operation. It's only about .001 or so.  The angle pressure comes from shaft deflection, starting at the main drive gear. Under high loads the inside of the race gets more pressure then the middle and outer end from the rollers. This tries to force the race outward. Witness marks on the race will bear this out.  Fact of life. Needs a good press fit or means to lock the race up from moving out ward.
Ron

So according to this one could say that it will walk one way and one way only.
But, What about the ones that walk out?
Could it be that maybe some of the shafts were made on a Monday? or the boring of some of the cases.
 :scratch:
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Online rbabos

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Re: IPB race "walking"
« Reply #21 on: February 16, 2018, 06:01:25 AM »
The race walk is caused from angular loading pressure from the rollers transferred to the race. This means the whole race is not under the same pressure from the rollers since there is needed clearance in the assembly. This slight clearance can tilt the roller in operation. It's only about .001 or so.  The angle pressure comes from shaft deflection, starting at the main drive gear. Under high loads the inside of the race gets more pressure then the middle and outer end from the rollers. This tries to force the race outward. Witness marks on the race will bear this out.  Fact of life. Needs a good press fit or means to lock the race up from moving out ward.
Ron

So according to this one could say that it will walk one way and one way only.
But, What about the ones that walk out?
Could it be that maybe some of the shafts were made on a Monday? or the boring of some of the cases.
 :scratch:
I got my explanation of the  pressure points backwards and didn't get a chance to correct it as the post timed out. Most should pull IN more so then out, with the most pressure on the Outer end of the race. Either way, basic cause is shaft angle, roller pressure is uneven on the race. If pressure was even on the whole length of the race from the rollers, it would just sit there and not walk. Bearing alignment could alter which end of the race sees more pressure also and direction of race movement.
Ron
« Last Edit: February 16, 2018, 06:05:47 AM by rbabos »

Offline Nastytls

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Re: IPB race "walking"
« Reply #22 on: February 16, 2018, 07:51:06 AM »
Does the Baker Hi Torque bearing eliminate the IPB race altogether? Does it slide right on the transmission shaft?

Online rbabos

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Re: IPB race "walking"
« Reply #23 on: February 16, 2018, 08:25:36 AM »
Does the Baker Hi Torque bearing eliminate the IPB race altogether? Does it slide right on the transmission shaft?
Yes but doubt it has the load capacity of the large OEM rollers in regards to life span. Mind you, I've never run one to find out so my assessment is based on bearing contact area only. Keep in mind shaft deflection is the root cause of IP race walk but the bigger issue is the amount of press of the race on the shaft. If the interference is enough the angular forces will not overpower the press fit, so no race walk. Some of these races do not have a lot of interference , while some, you can barely get on or off.
Ron

Offline koko3052

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Re: IPB race "walking"
« Reply #24 on: February 16, 2018, 08:26:23 AM »
I haven't installed the Hi Torque but it should not eliminate the ipb race. IPB race is on the input shaft, Hi Torque is on the output. Input shaft is supported by 1 ball bearing in the trap door, 2 needle bearings inside of the output shaft & the IPB, clutch pack basically hangs off the end.
Yes, hi hp is making that input shaft & those little bearings, do a lot of work! :emsad: