Linkage and bearings

Fred T

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#1
It seems that the bolts that are at both ends of the dog bones on my rear linkage worked loose a bit and after tightening them up there is still some play when I have the bike on a stand. The bike is new just this year and I've already greased the entire linkage twice so that I don't wreck the bearings but it seems that riding with the linkage losened has worn at least one of the bearings on the front out. (I can see the play in that area and the rest looks tight) I guess I will replace the bearings at both ends of the dog bones and maybe the dog bones too. What do these parts cost and are the bearings hard to remove? Is there a way to check them for wear?

Does anyone else have a few MM (5-6mm) of play in their suspension? Mine is not too bad but I'd hate to take out more parts if the bearings have gotten beaten to death.

Just looking for anyone with linkage experience. I'm frustrated because I was so careful to not destroy the stuff and did anyway! Argggggg!

Fred
 
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BRush

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#2
Let me ask you a few questions to get a handle on things. When you say "play", what/where exactly do you mean?

Up and down?

Side to side?

Fore and aft?

Is the play in the linkage bearings or the swingarm bearings? If it is the linkage bearings, can you tell which ones? When you installed the dog-bones, did you use a torque wrench to tighten?
 

DANIEL JOSEPH

Damn Yankees
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#3
Mine has a little play up and down. I believe it's coming from the area up by the frame. I've replaced the bearings and have not been able to get rid of it. I don't think it's anything serious or has any effect on suspension or handling.
 

Fred T

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#4
Originally posted by BRush
Let me ask you a few questions to get a handle on things. When you say "play", what/where exactly do you mean?

Up and down? - Yes.

Side to side? - no

Fore and aft?- no

Is the play in the linkage bearings or the swingarm bearings? If it is the linkage bearings, can you tell which ones? When you installed the dog-bones, did you use a torque wrench to tighten?
It seems to be from the two ends of the dogbones, mostly the front one. Everything is tight. It's a knock when you pull up on the swing arm. I will do a teardown tomorrow to see if the dogbones have wear on them. Jeez, I only have 500 miles on the bike and have greased this stuff twice and I still have problems. I ordered 2 bearings for both ends of the dogbones just in case, eventually I will need them anyway. $18.00 each! Ouch.
Fred
 

BRush

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#5
Mine does not do that to the extent that you describe (all new bearings last year). The bearings would have to be *really* bad to cause that. The bearing that is most likely to be destroyed is the small one at the bottom of the shock, but your bike is so new, that would be strange. If it was me, I'd closely inspect the holes in the dogbones to see that they are not ovaled out or something.

BTW, I presume you mean $18 per pair of bearings (92046-1216)? OEM bearings are pricey, but $18 for a single bearing is twice what it should be.
 
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#6
Since you pulled your linkage apart and greased it twice in 500 miles there may be a chance that you put the bearings in backwards and damaged them in the process. The service manual shows the bearings needing to be installed with the numbers facing outward. If not, they can be damaged when you press them in. Also a slight amount of play is considered acceptable. I don't have my manual with me as I write this so I couldn't look up the tolerances.

Another possibility is that you didn't tighten the linkage to specs when you put it back together. Loose bolts will definitely wear things out. The bolt that connects the rocker link to the frame is kind of difficult to tighten.

Your linkage getting slop in 500 miles isn't considered normal. I neglected to grease my linkage until around 500 miles and it was in perfect shape. There was not a lot of grease, but that is normal for a new KDX.
 

Fred T

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#7
Originally posted by rockrider
Since you pulled your linkage apart and greased it twice in 500 miles there may be a chance that you put the bearings in backwards and damaged them in the process. The service manual shows the bearings needing to be installed with the numbers facing outward. If not, they can be damaged when you press them in. Also a slight amount of play is considered acceptable. I don't have my manual with me as I write this so I couldn't look up the tolerances.

Another possibility is that you didn't tighten the linkage to specs when you put it back together. Loose bolts will definitely wear things out. The bolt that connects the rocker link to the frame is kind of difficult to tighten.

Your linkage getting slop in 500 miles isn't considered normal. I neglected to grease my linkage until around 500 miles and it was in perfect shape. There was not a lot of grease, but that is normal for a new KDX.
I never removed the bearings, just cleaned them up and regreased them. No, I didn't put a torque wrech on them and that's the problem. I never had the problem the first time I greased them and didn't torque them and maybe I didn't get them real tight for some reason the second time. A torque wrench doesn't fit under the bike very well. Maybe next time I will lay it on it's side and torque them down. I'm taking it apart Tuesday to check the dogbones, I think they may be ovaled and that's all the problem is. They probably cost a fortune and will be on back order. I can ride it like it is until they come in if I have to. Thanks for all the suggestions.
Fred
 
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#8
I have the answer to your 'problem'

Well..I think so. I cruised thru the responses pretty quick..maybe I missed it.

For one...5-6 mm is HUGE!!! If this is really what's slopping around, you have a major problem. Nothing that would be considered 'normal' in any way, shape or form.

I'll betcha that when you put the dogbonz back on, you tightened the fastener AGAINST the shoulder of the bolt...that the shoulder of the bolt was NOT INSIDE the dogbone. It would seem tight..but after just a bit of riding, it would come loose.

I did that the first time I took mine apart to grease it. Noticed it right away, took the fastener apart..used a C-clamp to compress the assy to correctly fit the bolt into the dogbone (I'll call it a 'pull rod'..that's what it is).

After the assembly is taken apart and greased it is difficult to get the pull rod correctly centered. Part of that is all the grease you just put in keeping the seal from 'collapsing' flat enough.

Devol makes a great set of pull rods. They are adjustable (length). Stock length is 112.5mm (I recall). Lengthening the pull rods will: 1. Lower the bike (mine lost about 3/8" seat height on the 'long' setting), 2. Increase the trail angle in the frontend geometry. That will 'slow' the speed of handling, but also increase stability at high speeds.

Be advised that Devol does NOT include the KX250 bolts/shims REQUIRED for their pull rods. They must be purchased separately. Expect to pay a lot...the bolts run about $13 US each!!

BUT..the Devol rods DO look cute!! Polished. Machined. 'Devol' name machined into each rod.

IF you tightened the fasteners AGAINST the shoulder, the edge of the shoulder will cut into the stock rod, the shoulder AND the rods will be damaged. If you rode it much at all, the pull rod hole will be out-of-round..so if it's assembled correctly, it will still be 'loose'.

Oh..one more thing. It may SEEM that the 'slop' you are seeing is coming from the pull rods. The mount to the frame (front) is more likely to be the cause of movement (in a correctly assembled pull rod assy). These bearings have been weak spots in kawis for years (sez a local shop owner..not me).

re: Can you take them out yourself? Maybe. There are threads on this forum about guys spending DAYS working on theirs. Torches, penetrating oils, big hammers etc. Sometimes it can be a big hassle!!!

Oh..the Devol rods are something like $80US. With the kx250 parts, the job will run you about $100 in parts.

Did I already say they are CUTE!!!! :)
 
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Fred T

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#9
coast is clear...

I got a helper to move the swingarm for me so I could see where the play was and after tightening everything there is almost no play at all so I just needed to get everything tight and that solved it. Nice that it was a simple fix, I guess I'll check them after every ride to make sure they stay tight.

Thanks all......have fun riding!

Fred