I'm not so sure that greasing the output splines is such a good idea on a dirt bike. My experience with heavy equipment tells me that anything that runs in dirt wears better without grease. The grease will hold the grit and make a paste similar to valve grinding compound. Nate D from Dirt Tricks commented on how leaking engine oil does a similar thing: "In addition to a loose sprocket situation, one other thing often noted about Gas Gas is they tend to develop a leaky counter shaft seal. Is your seal leaking, or has your seal been leaking in the past? This condition creates a bad situation as it will hold abrasive material like sand to the area around the leak. This grit will eventually work its way between the sprockets and splines. It is more likely that a loose sprocket is the cause of your issue however."
Honestly, I can't understand what causes the damage on the splines. IMO it can't be a wear due to friction, because the sprocket can't move much laterally. As a matter of fact, the splines look dented to me; look at those pictures: http://www.cafehusky.com/threads/at-54-117-miles-you-might-want-to.39163/#post-375414 In that post, JonXX described them as «hammered» and I agree. Anyway, if the wear is due to friction, I don't think that greasing the splines is a good idea because of what Xcuvator just wrote. If you grease them, you should often wipe the old grease up and regrease, like you do with the chain. What confuses me is, above all, that I have a little play and neither the splines of my sprocket nor the ones of my CS look worn or dented.
Even thought there isn't a lot of room for movement, there still is movement. Lots of wear can occur in this type of "industrial" application without a lot of movement, such as fretting, false brinelling, and brinelling. A proper lubricant (such as a moly paste) can help by spreading out the contact area, reducing surface adhesion, and absorbing some of the shock. I believe that a lube that is heavy in moly, and frequently cleaned, is best. It seems like a sporadic issue, in any case. Every sprocket/shaft interface is going to have play, otherwise you would not be able to assemble them. Yet some guys seems to get a lot more wear than others.
Problem is when shaft to sprocket gets dry it rusts. Then riding rust rubs off then shaft rusts again,and again, and again. This is removing material from the shaft, over time the shaft has lost material this loss of material on the splines makes the sprocket loose makes it wear faster. I use JT sprockets as have found they are the tightest on the splines. Hardness of the sprocket has nothing to do with wear on the shaft it's the lack of tightness that has more effect on wear and rust. Once the shaft has started to wear/rust it just wears faster as it is wearing thru the case hardening. SM's are the worst for this type of wear when the chain finally gets lubed the splines never seem to get lubed. WD40 to keep rust from forming helps. But some oil the splines is best. Don't use chain lubes found engine/trans drain oil works better no tacky stuff to hold the grit (lapping Compound) sling off cleans off much easier than chain lube sling off WD40 and a rag it's off. Just try the drain oil trick it's free and you can see for yourself it lasts longer than the expensive spray lubes. Later george
Thanks George! My 630 is in for a countershaft change now and I will give the used oil a try, and make sure I use it often.
Yep, so the countershaft on mine was stuffed, nearly completely stuffed, when I bought the bike with ~15,500 km's (9,600 miles). I actually have the shaft lying around here still, might grab some better pictures of the wear for people since it's now out of the bike.
Locktite makes a retaining compound suitable for locking loose fitting sprockets on splines. Have used this with excellent results. Check it out! http://www.henkelna.com/industrial/product-search-1554.htm?nodeid=8797928521729
Excellent! Think I will give the 680 a go with a new sprocket and shaft. I really don't want to have to replace the shaft again! I wonder how difficult it will be to fit another CSS when the first needs replacing.
Thanks willie- this looks encouraging. Like Ken I'm wondering about how strong the bond is- i.e. how difficult it is to remove the sprocket once used.
I hope that the product can withstand the pounding and make sprocket removal difficult without the application of heat/puller and will be very pleasantly surprised if that is the case.
Personally, I wouldn't use a retaining compound like the 680. It is only a polymer and would have low compressive strength, hence after a few throttle on/throttle off cycles it compress to the extent that it wouldn't be there, or in the other case if it were to survive it wouldn't allow you to take the sprocket off, as it "replaces clamp rings, set screws and snap rings", in other words is able to resist shear (as in taking the sprocket off the shaft) but mentions nothing about being in a compressive working environment (like the stress the sprocket/shaft undergo).. If there were to be anything to help with this problem, a softer front sprocket would be the answer, as you should know hard materials will wear soft materials, and as there is only a sprocket and a shaft, one will need to wear, and I know which one I would want to replace more often
Some interesting bits in this thread as well: http://husaberg.org/mechanical/16836-fix-countershaft-spline-wear-husabergs-ktm-exc-models.html
What the iron man sprockets guy in the gas gas forum said sounds true, if there is no slop a difference in hardness shouldnt matter so much as there is no movement on the contact surfaces (therefore no opportunity for friction) and the spline will be much harder at that point. Unfortunately though I reckon once slop develops hardness of a sprocket will matter, even if the spline is harder a softer component will still wear a harder one, just the softer one will wear at a faster rate. Once wear develops all you can do to extend your splines life is to lube it before every ride and keep the lube/grease clean, blast the "dirty" lube away with WD after the ride and then lube it again. A soft alloy sprocket and a kush hub might not hurt either.
I have seen a few other people echoing ZipTy's comments with regards to the rust issue as being the main cause of wear. Keeping it corrosion free with a thinner and less 'tacky' type of oil (namely engine oil) on a regular basis might indeed work better if this is the major cause of the issue. Grease has some advantages, but the possible 'lapping' or grinding effect when combined with some grit is a serious trade off...
Mine too. Please, see the videos. So, should I forget about it? I've tried 3 different sprockets (14,15 and 13) and all have pretty the same play
Yeah, many of us have seen that play. The main thing, though, is that you need to look carefully at the splines on the counter shaft itself. You may not have appreciable wear on those. Can you post a pic of the splines? EDIT: OK- just saw your pic of the splines in the other thread. My response there is: You're good- splines look good. All you can really do is go with the brand of CS sprocket that offers The Least play, and keep things cleaned/greased. If you've got cash to throw at the issue (to avoid larger issues) then you're going to want to look into getting a cush hub.
How tightly do the Renthal sprockets fit? I have one in 14T on my workbench and planning to swap it in for the stock unit when I get some time. Now that I read George recommends JT sprockets, I may return the Renthal and find a JT though if the former has a history of fitting poorly.
Hi The second one (img 2224-15) is renthal. The others I think are OEM. May be you can take a conclusion by looking at the videos.
What about soaking the shaft in silicone spray instead of oil or wd. No oily residue left behind to attract any dirt.
