Front sprocket play and chain question. - Wrist Twisters
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post #1 of 14 Old 07-15-2018, 06:09 PM Thread Starter
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Front sprocket play and chain question.

Because another member recently had a drive chain failure I thought I would carry out an inspection on mine. I've noticed a few things I'd ask about.
First even though my front sprocket nut is tight I have a small amount of play. Is this bad? I see on a drz400 forum that front sprocket play can cause front counter shaft seal failure. The fix is to use red loctite on the splines to hold sprocket on firmly. Any thoughts?
I also noticed that the last time I had my chain off to clean I've accidentally reversed it putting it back on. Is this a problem? Or should I take it back off and flip it around?

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post #2 of 14 Old 07-15-2018, 07:04 PM Thread Starter
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I should add more details regarding the front sprocket play. There is no play forwards/backwards. The play is in/out and less than a mm. So should the front sprocket bolt and washer tighten up against the front sprocket or only into the countershaft? Thanks.

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post #3 of 14 Old 07-15-2018, 07:21 PM Thread Starter
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Ahh, found this.
https://www.wristtwisters.com/forums...ead.php?t=9014
Fuck it... I'm going back to 16t OEM.

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post #4 of 14 Old 07-15-2018, 08:30 PM
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Quote:
Originally Posted by Islandboy View Post
Because another member recently had a drive chain failure I thought I would carry out an inspection on mine. I've noticed a few things I'd ask about.
First even though my front sprocket nut is tight I have a small amount of play. Is this bad? I see on a drz400 forum that front sprocket play can cause front counter shaft seal failure. The fix is to use red loctite on the splines to hold sprocket on firmly. Any thoughts?
I also noticed that the last time I had my chain off to clean I've accidentally reversed it putting it back on. Is this a problem? Or should I take it back off and flip it around?
1
There is supposed to be a small amount of end float of the sprocket.

2
YES flip that chain around so it's as it was!
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post #5 of 14 Old 07-15-2018, 08:49 PM Thread Starter
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Thanks mcromo. I won't panic about the freeplay in the front sprocket. But will most likely go back to OEM when current set is worn. I've read that the OEM 16 front sprocket is slightly wider and has less freeplay. Also couldn't help but notice that DID have an endless 114 link chain so no master rivit. That's gotta be good, right?
Also thanks for the advice on the chain reversal. I've actually put a few miles on before noticing I had accidentally reversed it. Hope I haven't done too much damage. I will take off and turn it back around, now.

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post #6 of 14 Old 07-16-2018, 07:28 AM
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Quote:
Originally Posted by Islandboy View Post
Thanks mcromo. I won't panic about the freeplay in the front sprocket. But will most likely go back to OEM when current set is worn. I've read that the OEM 16 front sprocket is slightly wider and has less freeplay. Also couldn't help but notice that DID have an endless 114 link chain so no master rivit. That's gotta be good, right?
Also thanks for the advice on the chain reversal. I've actually put a few miles on before noticing I had accidentally reversed it. Hope I haven't done too much damage. I will take off and turn it back around, now.
A properly staked Endless is far better than a clipped Master.

I doubt any damage will have been done to your chain for short time of use, and low(er) power levels are a part of that.

I noticed my stock chain displayed visibly higher loading on the rollers slightly to one side.
It could not be felt, the roller was nice and smooth right across the surface, but you could see how the chain found a place ever so slightly off set and ever so slightly unevenly loaded the rollers accordingly.
The pins will see the same effect.
That's why the chain should always be kept running the same way.
The sprockets and chain components all bed in to each other based on how they line up respective to each other on the bike, even with correct rear wheel alignment.

I'll get at your lube and cleaning question later today.
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post #7 of 14 Old 07-16-2018, 10:17 AM Thread Starter
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Well you've answered more than one question for me. My chain also has found a place slightly off center and I had wondered what was going on. Everything line up perfectly but still the chain ever so slightly run too one side of the rollers. It could only be seen as a clean mark in the lube and not felt.
I owe you one, thanks mate.

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post #8 of 14 Old 07-16-2018, 04:33 PM
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Islandboy - I do remember the topic of undersized sprocket hub thickness from several years ago. At that time I had tried a 17 tooth front just to see if I like the ratio change. For my riding I didn't like it and I went back to the original. But the 17 tooth sprocket I tried was the same hub thickness as the 16 tooth OEM and it mounted tight to the shaft with no freeplay. The OEM design is not intended to have freeplay, and a proper replacement should have the same thickness and have no freeplay.

So I (respectfully) disagree with Mcromo - by design intent - there should be no play of the sprocket on the shaft. The shaft itself has a bit play but the sprocket is intended to be held tight to the shaft.

But I do understand that many people have used aftermarket sprockets that have a thinner hub than OEM and have not had objectionable issues. I do imagine that the freeplay could cause the chain to wear differently. That might not be a big issue either. And I have heard others say that different bike manufacturers have sprockets mounted with freeplay. I don't have any first hand knowledge about that.

Just my two cents...
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post #9 of 14 Old 07-16-2018, 05:05 PM Thread Starter
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Thanks for the input Mark. Even though I'm not overly concerned about the freeplay now, since there doesn't seem to be much history of issues with aftermarket front sprockets, I still would like to go back to OEM sprockets. I personally would like no freeplay, or at least reduce it. I also like the idea of a DID endless chain with no master join link. I'm also hoping by going back to the stock gearing it will shift the vibes I'm getting into a different speed range. While I like the 17/44 gearing I'm getting vibrations in my left foot peg at a speed I most cruise at. Buzzing, uncomfortable and distracting for long periods.
I'm about to order some OEM sprockets from Partzilla. They have 919 parts at 30% discount. Might get some cush drive dampers as well. They are cheap and mine are over 15yrs old.

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post #10 of 14 Old 07-16-2018, 05:37 PM
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I agree with your logic. There should be no urgency with the sprocket play concern. It also just bugs me when replacements are not quite the same as OEM.
I think you will appreciate the molded rubber on the faces of the OEM sprockets. No question the rubber bumpers dampen some of the chain noise.
I would be surprised if the ratio changes makes any improvement on the foot vibrations at speed. A characteristic of the I-4 engine that I don't really like either. But no bike is perfect.
For years I didn't use ear plugs when I rode and buzzing along with all the other noises bothered me. That totally goes away with ear plugs.
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post #11 of 14 Old 07-16-2018, 07:53 PM
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Quote:
Originally Posted by Mark919 View Post
Islandboy - I do remember the topic of undersized sprocket hub thickness from several years ago. At that time I had tried a 17 tooth front just to see if I like the ratio change. For my riding I didn't like it and I went back to the original. But the 17 tooth sprocket I tried was the same hub thickness as the 16 tooth OEM and it mounted tight to the shaft with no freeplay. The OEM design is not intended to have freeplay, and a proper replacement should have the same thickness and have no freeplay.

So I (respectfully) disagree with Mcromo - by design intent - there should be no play of the sprocket on the shaft. The shaft itself has a bit play but the sprocket is intended to be held tight to the shaft.

But I do understand that many people have used aftermarket sprockets that have a thinner hub than OEM and have not had objectionable issues. I do imagine that the freeplay could cause the chain to wear differently. That might not be a big issue either. And I have heard others say that different bike manufacturers have sprockets mounted with freeplay. I don't have any first hand knowledge about that.

Just my two cents...
Historically, I always operated on drive sprockets being end clamped with no float.
I really should correct myself now, some are end clamped with no float, some are not.
Certainly, my old Norton Commando and SOHC CB750s had end clamped drive sprockets.
My recollection is that my OEM 919 drive sprocket had a hair of float.
The 520 Renthal I put on about 10 years ago had more end float, to the point I did some head scratching and fishing around which ended up with me being able to sleep with the end float left alone.
Earlier today I did a super fast rip and found a website about some Honda cruiser types whose OEM drive sprockets have end float.
I didn't note down particulars, but saw enough to satisfy myself that there are some end float OEM drive sprockets in use.

From an engineering perspective, I'll make the following observations.
1
An end float sprocket/shaft spline class of fit can be enhanced to provide more, and more even, contacting load areas.(sort of like % of thread engagement for male/female threading in the face loaded state)
This is because any end face error will not be attempting to incorrectly load the sprocket's spline faces against those of the shaft.
This could allow a higher power rating and/or service life for the combination of the sprocket/shaft.
2
A end clamped sprocket will place the entire shaft in strain axially, in other words induce a stress.
This could result in a lower power rating for the shaft.
This could result in being forced to use a lesser class of fit for the sprocket/shaft splining, and a reduced power rating and/or service life.

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post #12 of 14 Old 07-16-2018, 08:13 PM Thread Starter
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Thanks mcromo. What your saying makes perfect sense. I wonder if there is an acceptable range of free float, a tolerance? So not enough and too much. I'm keen to get my hands on a OEM front sprocket now and check it out myself. Wish I hadn't been so eager to bin my old worn out one. I'll keep running my aftermarket for now and get some more miles out of it but will order a OEM set and put aside.
Cheers mate.

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post #13 of 14 Old 07-17-2018, 01:52 PM
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Quote:
Originally Posted by Islandboy View Post
Thanks mcromo. What your saying makes perfect sense. I wonder if there is an acceptable range of free float, a tolerance? So not enough and too much. I'm keen to get my hands on a OEM front sprocket now and check it out myself. Wish I hadn't been so eager to bin my old worn out one. I'll keep running my aftermarket for now and get some more miles out of it but will order a OEM set and put aside.
Cheers mate.
I can't say with any authority.
For the nature of the assembly, and allowing for a theoretical cummulative tolerance stack of the shaft spline working length and sprocket widths, my thinking is that a min of 5 thou to a high of 15 thou would bracket it nicely. (1 thou = 0.001 in.)
But I won't be surprised if I hear of, or find, numbers in excess of 15 though.
Be it before or during this winter, I should check the Renthal and OEM axial fits and report back.
And research the topic some.
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post #14 of 14 Old 07-17-2018, 07:16 PM
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Quote:
Originally Posted by mcromo44 View Post
I can't say with any authority.
For the nature of the assembly, and allowing for a theoretical cummulative tolerance stack of the shaft spline working length and sprocket widths, my thinking is that a min of 5 thou to a high of 15 thou would bracket it nicely. (1 thou = 0.001 in.)
But I won't be surprised if I hear of, or find, numbers in excess of 15 though.
Be it before or during this winter, I should check the Renthal and OEM axial fits and report back.
And research the topic some.
I just happened to have my front cover off the front sprocket and did a feeler gauge check, 11 thou' re the Renthal.

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