Posted: 03/21/2011 8:20:54 PM
I frequently examine the countershaft splines on my XR650L. However, I admit, my eyes aren’t as good as they used to be. Advancing into middle age, I’ve acquired presbyopia. The last time I inspected the countershaft splines, they appeared quite good to my unaided eyes. Therefore, after I greased the countershaft splines, I took a few photographs, and went riding.
However, I had noticed a hint of rust on both the countershaft, and the sprocket. Rapidly approaching 10,000 miles on my bike’s odometer, my nagging conscience prompted me to examine the photographs I had taken. Closely examining the macro photos, I thought I detected some countershaft spline wear.
Therefore, I went outside, removed some grease, and examined the countershaft with a magnifying glass. Indeed, I discovered the countershaft splines were beginning to wear.
Closely examining the Parts Unlimited sprocket I had just removed, I believe I also detected some wear on the trailing edges of the inside teeth.
Previously, I drank the XR650R, countershaft sprocket, Kool-Aid. I had planned to wait until my current countershaft sprocket needed replacement before making the switch. However, I now decided to act immediately!
I had shortened my drive chain to 108 links with my current 13T/45T sprocket combination. Therefore, I needed to acquire a 13T, XR650R, countershaft sprocket as quickly as possible. I did some research, and discovered I could obtain a 13T, PBI sprocket in 24 hours. The XR650R countershaft sprocket has 60 percent more contact area with the countershaft than the XR650L countershaft sprocket.
Mounted backwards, the sprocket teeth of the XR650R sprocket are 2.5 mm farther from the engine. Based upon the experience of others, I don't think this will present a problem. In any event, I am perfectly willing to accept greater sprocket wear, and/or greater drive chain wear, rather than any additional wear on the countershaft splines.
I needed to tap lightly on the PBI sprocket with a hammer to allow me to install the sprocket retainer. Heeding Dave's admonition regarding PBI sprockets, I examined the alignment of the sprocket retainer. The alignment isn't perfect, but it should be robust enough.
I went for a ride, and everything felt good. I will routinely inspect the drive chain, and both sprockets for unusual wear. More importantly, I am going to routinely inspect the countershaft splines under magnification to ensure I have stopped the wear.
Reply by jrsride2002 on 03/22/2011 11:13:24 AM
Good Idea Spud! I hadn't thought of using the 650R sprockets before.. Imma have to look into this now! I have already replaced on counter shaft, and my current one has a chip missing from it right now, so it's going to need replacing sometime soon.
Keep up up dated on this post, I can see the potential of a lot of man hours or cash savings just from this simple replacement!!
Do you guys think that the counter shaft itself could be a replacement part for the 650L?
Good work dude! ~Junior
Reply by SpudRider on 03/22/2011 6:16:42 PM
Thank you, Junior. I'm just following the lead of others who have experimented with the XR650R countershaft sprocket. Everyone who has tried the XR650R countershaft sprocket has given good reports on it, so I have been converted! I will certainly keep everyone updated.
I might be wrong, but I don't think the XR650R countershaft will work as a replacement for the XR650L countershaft. However, I think the XR650L countershaft splines will not suffer damage if one employs the wider, XR650R countershaft sprocket. Spud
Reply by SpudRider on 03/26/2011 01:27:26 AM
The following manufacturers produce 13T countershaft sprockets for the XR650R motorcycle.
- Moose Racing: Part #M602-20-13
- AFAM: Part #20517-13
- Sprocket Specialists: Part #617-13
- PBI Sprockets: Part #50-386-13
Reply by Lancester on 03/26/2011 10:02:34 AM
When I went to my Moose 14 tooth sprocket, it was obviously wider. I was worried at first that it might be the wrong part, but now it makes sense. They must have seen the advantage to a wider sprocket & that's what they sell as a XR650L piece.
Reply by dusty trail on 03/29/2011 7:03:30 PM
When I rebuilt my xr650l a couple of years ago with over 40,000 miles on it, I HAD to replace the countershaft. That meant splitting the case. The splines had worn down to only about 1/32" or so thick. My xr is the only bike I have ever noticed any countershaft wear on at all. I must say this is the first time I had seen anyone put grease on those splines. What purpose does that serve? Would seem to me that having grease there would attract more grit in that area and accelerate wear. DustyOriginally posted by jrsride2002
Do you guys think that the counter shaft itself could be a replacement part for the XR650L?~Junior
Reply by SpudRider on 03/29/2011 8:01:23 PM
Dusty; Many XR650L owners believe rust accelerates wear on the countershaft splines; therefore, they recommend greasing the splines. I now believe rust is a symptom of countershaft wear, and not the cause. Therefore, I no longer grease my countershaft splines. I'm convinced small spline area, engine torque, and the lack of a cush drive are the causes of XR650L countershaft wear. I'm also convinced the XR650R countershaft sprocket is the cure for this ailment. Spud
Reply by dave_cl on 03/30/2011 08:38:50 AM
Grease will still help to alleviate wear, even if rust is a symptom not a cause. Metal moving around on on metal with a load on it, lessen the friction, lessen the wear, the movement per-rotation or per-whatever isn't much but it adds up, especially as the torque transferred is pretty high. Dave
Reply by SpudRider on 03/30/2011 10:17:53 AM
That's seems logical to me, Dave. I guess a little grease on the countershaft splines certainly can't hurt anything, and probably will help as you stated. I never heard of anyone else greasing the countershaft splines on another motorcycle. Do other riders employ this practice, or are the XR650L owners unique in this respect? Spud
Reply by bbultema on 03/30/2011 7:38:42 PM
Every time you hit the chain with a little chain lube I think you should hit the splines on the front sprocket. I always try to get some in there. On the farm they recommend that chains that run under severe conditions get oiled after the day is over to let the oil pass through the dirt to where it needs to be.
Reply by dave_cl on 03/31/2011 12:52:02 PM
I think there are just not many thumper that see street duty that don't have a cush drive that have a sprocket that is both 'loose' and 'narrow' like the XRL, so this problem simply does not occur on other bikes. With each power stroke the splines beat against the sprocket, whack whack whack whack. Dave
Reply by SpudRider on 04/06/2011 11:17:10 PM
Today I mounted a new Dunlop, D606 rear tire. At that time I seized the opportunity to remove my XR650R countershaft sprocket to examine both the sprocket itself, and the countershaft splines. Here is a photograph of the "front" side of my XRR sprocket, as mounted (reversed) on my XR650L, with 1,200 miles of wear.
Here is the "back" side of my XRR sprocket, as mounted (reversed) on my XR650L, with 1,200 miles of wear. My XRL sprocket actually exhibited more wear on the back side than this XRR sprocket, so I am very pleased.
Here is a photo of my countershaft splines after using the XRR sprocket for 1,200 miles.
Here is a comparison photograph of the countershaft splines at 10,000 miles, just before I installed the XRR sprocket.
My rear sprocket is in excellent condition; I did not note any significant wear. My drive chain is also in excellent condition. My XRR countershaft sprocket came off easily by hand, and reinstalled easily, by hand. The sprocket retainer is in excellent condition, and mounts securely to the sprocket and countershaft. So far, I am very pleased with my XR650R countershaft sprocket, and I intend to continue using the XRR CS sprocket. Spud
Reply by jrsride2002 on 05/02/2011 08:43:55 AM
Well i went for it Head first And it kinda hurt. I bought a JT XRR sprocket, the stock 15 tooth. And it was WAY to big. The sprocket would not go on the shaft deep enough for the retention clip to be bolted on, the clip it self would just sit on the very end of the counter shaft. The sprocket needed to modified to slide further down the shaft for the clip to be bolted in.
What I ended up doing was using a grinding stone on my drill press and slowly going at it. The fitted result looks like this:
The grinding also changed the color of the sprocket. Was a nice pretty silver, but now has the heated copper color to it:
I used some spray paint to tell me how much was metal was removed. I had to go and buy a grinding stone to do the job. The one I got is a "Craftsmen 1" rotary grinding point":
All in all, I dont think it was really worth all the time I put into it. Then again maybe there is a good reason, that someone else could see I that cant?? I don't know. I do have a working XRR sprocket tho! ~Junior
Reply by dave_cl on 05/02/2011 09:22:29 AM
You will still have a more spline-spline contact than the stocker. Dave
Reply by SpudRider on 05/02/2011 10:03:45 AM
I didn't need to grind my XR650R sprocket; when I met some resistance, I lightly tapped the sprocket onto the countershaft with a hammer. After riding 1,200 miles with the XRR sprocket, I easily removed it, and re-installed it by hand. I am very happy with the 60 percent increase in contact area the XR650R sprocket makes with the countershaft splines.
Reply by jrsride2002 on 05/02/2011 1:19:24 PM
Oh, don't get me wrong. I am TOTALLY down for the continuous use of the XRR sprocket. I have already had the shaft replaced once, for a costly some of $1200. But I also had some work don't to the motor and few other things so i'm sure just the replacement would have been cheaper.
What I was leaning more towards was, I don't think I will go with a JT sprocket the next time I have to replace it.
I get worried about how much "Tapping" is required to force the sprocket to move up the shaft just to fit. What I worry about is everything that is attached to the shaft. Like the bearings, and the transmission drum and all those goodies that i know absolutely NOTHING about. I get that the bike was designed to take a huge stress tolerance to abuse from the direction of the crank, but I don't know if Honda designed the motor to take abuse from a different direction. Does that make sense? That's why I didn't forcefully hammer the sprocket on in the manner you described.
Thanks for the other diagram! ~Junior