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Countershaft front sprocket question...

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I have an 86 XR600.

What is the best (strongest) front sprocket to use for this machine?

I know there's a ton of posts about this subject but to be honest all the varied opinions and mention of different models and such is baffling and I can't figure it out.

I'm a big guy putting a lot of stress on it and I want the sprocket that is the least likely to damage my splines. I don't mind doing some slight mods to make something fit.

Can someone please give me the straight answer

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I wasn't really asking about brands of sprocket as much as I hear about using sprockets off of other models that are thicker and don't wear out the splines as much.

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Don't think there's an option to use a different sprocket with the 86 XR or XL..Both of them use the wider spline gap and less splines than the more

modern 600..After I'd say 90 they changed the shaft and gave you more splines closer together as they did with the 650L. Only way out of it would

be to swap the shaft over to the 650L or later model XR600 one..Then you can use the 650R sprocket. I certainly wouldn't be taking a good gearbox

apart to do that..If you needed to go in for some other reason fair enough,,otherwise forget it.

Edited by Horri

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Moly paste the heck out of the one you have. Make sure the keeper is in good shape, and the groove the keeper locks into.

Sometimes the drilled holes in the sprocket are in slightly the wrong place and the keeper doesn't lock in to the countershaft properly.

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This paste is 70% Moly,  Honda recommends at least 60% for splines.

 

The idea with splines isn't to lubricate in the conventional sense, but to prevent fretting corrosion, which will greatly accelerate wear once it starts.

 

The most effective material is molybdenum.

 

It takes very little of the paste to do the job, clean the splines and then burnish in a thin layer.

 

 http://www.guarddogmoly.com/gd570.shtml

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........fretting corrosion............

Fantastic!

Now we know the name of the beast.

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Looking at a few materials-science and tribology pages, looks like harmonics often play a large part of the process.

That is, it's likely not just the hammer of a 650cc thumper lighting off that causes the fretting, but how that thump 'rings' through the entire drivetrain.

 

Since small changes resulting from choice of tire, chain, and gearing could change the harmonics, and this could give a logical explanation why some bikes can go 30,000 miles with no wear, and others that strip out in mere thousands.

 

And, I wonder, is it perhaps not (as some suspect) gross shock absorption the rubber on the factory sprocket is supposed to absorb, nor noise, but perhaps dampening of the harmonics that lead to fretting?

Maybe bolting a big lead puck to the sprocket would turn the trick (but greasing is much more practical...)

Edited by XR650L_Dave
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