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Play In The Dog Bones


serious3
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should there be any play in the dog bones when the bike is resting on its skid plate and the rear wheel is at full droop? bike feels good but noticed it the other day while changing the chain and sprockets. thanks and a merry xmas to you all!!

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I presume that when the bike is on a stand you're trying to lift the rear wheel and feeling some play. Unless all the dog bone bearings and shock bushes are brand new there's bound to be some play because the total of all the little clearances add up and are then magnified by the length of the swinging arm; however if its overly 'clunky' its time for a service. If you've caught it in time a clean and re-grease may suffice.

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if your bike is not new then it would be "normal" for there to be some play in the dog bones as what lowbrow has said, just try and keep them well greased and cleaned and serviced regularly and the amount of play will be minimised, putting new bearings and bushings inot the dog bones can reduce this though if there is alot of play there. i wouldn't bother trying to get the play out as i have tried and trust me you cannot get it out at all.

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aaaarggghhh one says leave it the other says fix it! what's a man to do?? had another poke at it yesterday and there is about half an inch vertical free play in the linkages at the back wheel so thats a small amount at the dog bones themselves. think i will keep an eye on it over the next few weeks and see what happens

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Depends how OCD you are! Once I know something is broken i HAVE to fix it, its a horrible expensive habit of mine. That said I rode for a year with half an inch play in the rear with no problems that I noticed. It was only when I measured the amount of play I realised the bearings were shot. Not even sure I can tell the difference now I've done it BUT I know its fixed :rolleyes:

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  • 2 weeks later...
 
 
 
 
Have any of you mont riders tryed These.service free dog bones.

got to be the way to go.....

That uses multiple sealed ball bearing units, right? I'd guess that the balls will work fine, though you do have to ask why Honda/Montesa didn't go with with the (lower cost) sealed ball bearing solution in the first place. In theory the standard needle bearings should take **much** more load than the ball bearing kit, but stock needle load carrying ability rapidly goes to nil when the grease washes out. The 100,000 question is why the grease washes out of these in the first place - the seals should do a fine job keeping the grease in for years, but they obviously don't.

I'm in the process of rebuilding my 315R suspension right now. One thing I did was measure the bores on the wishbone. The lower one was out of round by .1mm - definitely enough to distort the needle bearing housing and possibly enough to distort the seal. I'm going for a new dog bone. It did make me wonder - how long does a brand new set last, compared to a rebuild set? Are these OK new, but not so easy to rebuild properly?

I'm thinking about taking the old dogbone and boring it out, putting a close fitting plain bearing there instead and adding grease fittings. One pump of grease every trial and I'm willing to bet it will last forever w/o taking it apart again.

Sam

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Here's what a expert in both Trials and the bearing business here in SoCal had to say about ball bearings being used to replace needle bearings in the Montesa linkage;

"They apparently machine out the stock dog bone, but it couldn't be much - by looking at the photo maybe one millimeter? And assuming they used the stock 10mm bolts, then the new sealed bearing would be a 10mm x 22mm. If so, that is a model #6900 with a load rating of about 200 Lbs. The needle bearing that Montesa uses has a load rating of over 2000 Lbs - a huge difference, which is why you don't see ball bearings being used in shock linkages. The next larger bearing would have an outside diameter of 26mm, a width of 8mm with a load rating of 440 lbs. Even if you stacked in three, the total load rating of 1300 Lbs is a far cry from the factory set-up of over 4000 Lbs.

Servicing the dog bone is a pain, but at least the Monty one removes quickly."

The problem I've experienced with the needle bearings is a lack of space within the bearing to retain any real quantity of grease. I use a sticky chain lube to coat the bearings and a coat of water proof grease on the seals and bolts to keep water out. Living in dry Southern California certainly helps! :thumbup:

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Here's what a expert in both Trials and the bearing business here in SoCal had to say about ball bearings being used to replace needle bearings in the Montesa linkage;

"They apparently machine out the stock dog bone, but it couldn't be much - by looking at the photo maybe one millimeter? And assuming they used the stock 10mm bolts, then the new sealed bearing would be a 10mm x 22mm. If so, that is a model #6900 with a load rating of about 200 Lbs. The needle bearing that Montesa uses has a load rating of over 2000 Lbs - a huge difference, which is why you don't see ball bearings being used in shock linkages. The next larger bearing would have an outside diameter of 26mm, a width of 8mm with a load rating of 440 lbs. Even if you stacked in three, the total load rating of 1300 Lbs is a far cry from the factory set-up of over 4000 Lbs.

Servicing the dog bone is a pain, but at least the Monty one removes quickly."

The problem I've experienced with the needle bearings is a lack of space within the bearing to retain any real quantity of grease. I use a sticky chain lube to coat the bearings and a coat of water proof grease on the seals and bolts to keep water out. Living in dry Southern California certainly helps! :thumbup:

This is what I suspected all along, when all the bike manufacturers use needle roller bearings in the linkage there's a good reason. I saw a bike at the SSDT that had collapsed it's lightened linkage plates, not only did these break but the shocker snapped at the same time. Now I'm not saying that a collapsed bearing could cause this damage but who knows? I for one would be sticking with what the manufacturers supply. Regular maintainance prolongs bearing life, I use a Molybdenum Grease in my linkage as it does seem to repel water. When I've owned a Monts I also changed the dog bone when it came time to replace the bearings.

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