A forum for owners of Yamaha TTR250 trail and enduro bikes!

TTRfan wrote:

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Hi Ian

Sorry to hear you have had a problem. I really should have bottomed it out the issue the last time but the trail sort of fizzled out.

All Balls is an American concern and most of their TTR250 kits are advertised as being for the blue plastic-tanked models which are the only models officially imported there. I have always assumed that the linkage kits would fit both blue and white TTRs and, to date, that has been my experience.

I have looked up the part numbers for the blue and white (metal tank) models and they are different but I think that is because the white TTRs have the provison for grease nipples. It doesn't necessarily mean that the diameter of the bolts are different.

 

Brian

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 Just to clear up some confusion: I can tell you for sure that the plastic tank model linkages are exactly the same as the steel tank models. I have got the 93 linkage bolts installed in my 1999 linkage as we speak with no movement whatsoever.

I did use the 99 collar but it did'nt seem any different either.

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Jarrah.

Hi all,

I picked up a broken, tired open enduro last week. While going over the bike writing up what I needed to order I notice the rear suspension was notchy. Took the rear wheel and shock off and yep, its all siezed up.

Received an all balls kit that I fitted today, after putting it all back together I checked the action and now there is a good amount of up/down play on the likage. I didnt have this before.

I just gathered up all the old bits and measured the old bushes. The old ones have a slightly smaller internal diameter compared to the all balls ones. The bushes fit tightly on the roller bearings, but the bolts are loose.

I did a search and found this chap had the same issue but there is no resolution in the thread:

http://ttr250.activeboard.com/t49827851/linkage-rebuild-problem/

I have gone over the diagram in the manual and I am sure I have it all the right way round etc. Has anyone else had this before?

Here are some pics to show what I am getting :


New Sleeve 1

Old Sleeve1
New sleeve 2

Old sleeve 2

pics of the bolts :

 

 

boredus wrote:

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Hi Jarrah,

I have fitted several all balls kits in the past and never had this issue before. I am not blaming the kit at the moment, this is a 20 year old bike we are talking about after all.

I used all balls kits to do all the bearings from back to front on a 2005 KXF250 that had been standing for a year. No issues at all with that build.

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 Oh....Fair enough. I was going to measure my spare linkage for you but i cant seem to find my micrometer  It'll turn up. If you you want me to do this i can though.

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Jarrah.

Hi Brian,
you are right! just been back outside to check it again, cleaned some muck out of the bush. ( changed the battery too and then watched the cover ping off over the work bench and down the back.....darnit! )


To be sure its not the top shock bearing I have wedged a socket above it against the frame but still getting the same play.

I have torqued each bolt up 1 at a time ( leaving the other 2 on the linkage off) checking which one it could be. by hand they all seem tight.

Once I put it all back together and test it, there is again 2-3mm of play.

I am going to clean up the 2 old bushes in the morning and do a test fit.

Hi Brian,

I found the 2 missing bearings! sorry , in my haste to clean the garage to start work I put them in a drawer!

Have fitted those bearings as well now, after a quick trip to Wickes for a bigger hammer!

unfortunately that hasnt solved the play in the linkage. Here is a vid I took on my phone. It looks like the problem is with the  2 large bearings in the linkage arm. I just dont understand why though. They are a very tight fit within the linkage arm when I pushed them in.

I also measured both the old and new bushes, although the ID is smaller on the old bushes, the outside is the same. I have put the old bushes in to the new bearings and the play is still there. I am stumped now.

-- Edited by boredus on Sunday 6th of January 2013 03:57:44 PM

-- Edited by boredus on Sunday 6th of January 2013 04:19:16 PM

It really does'nt look like there is play there but can hear the noise. Are you sure that noise is not your rear caliper jumping up & down on the swingarm??? I'm pretty sure that you have one of the grease nipples the wrong side. The front bolt & the swingarm bolt is the only bolts that has the nipple on the left side as in pic below...

 

 It would'nt cause it to wobble having it installed incorrect but your chain may destroy your grease nipple.

 

 

 

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Jarrah.

 

-- Edited by barra8 on Tuesday 22nd of January 2013 05:42:09 AM

Just a thought, has a needle roller fallen out of the new bearing while you fitted them? This may give you more internal clearence between the bush & the bearing?

boredus wrote:

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barra8 wrote:

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It really does'nt look like there is play there but can hear the noise. Are you sure that noise is not your rear caliper jumping up & down on the swingarm???

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You really cant see the linkage remaining fairly still while the swing arm bracket moves?Its definatly the swingarm moving, I am lifting it with my hand so can feel the little knock   

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 With the camera moving around i can't see much. Did have a look for the tenth time & yes i can see the movement now.

I guess i won't be helping you anymore

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Jarrah.

Hi,

I replaced my rear bearings with the All Balls kit this Summer and I've got excessive play too. It's probably 1/2" at the axle. It's hard to pinpoint exactly where the slop is coming from, but I think that's because every bearing has a small amount of play. I can feel the linkage arm shifting a little at each bearing. It was no better after replacing the bearings than it was before. I did not replace the top bearing at the time, but I don't think it's moving enough to give that much free play.

I measured the new collars and the ID was .007" (.18mm) larger than the original collars I pulled out. I cleaned and reinstalled the old collars and there was less slop than with the new parts, but it's not great (it was sloppy before, hence the need for servicing). It does seem that my parts were either machined with poor tolerances, or I got the wrong parts. There's no way the new bushing should have that much play in it compared to the old. That is with the new bolt as well, so it's not just a matter of the new bolts having a larger diameter. I think I ended up just using the new bearings from the kit, IIRC.

I don't have any advice for you since I never got this resovled.

I am wondering if the shock itself can attribute to the suspension slop? I know my shock is probably farted out as it has little dampening control so I will be getting that rebuilt this winter. I'll revisit this then. Please keep us posted on what you find.

-Kent

my thoughts, for what they are worth,

It would appear that the tolerance bands on the various items are not really working for you, will try to explain;

All bearings are designed with built in slop, (internal clearance) as Brian calls it, if it wasn't there, they would seize, this is controlled by international standards and for 'general' bearings, including these, the internal clearance is classifed as C2 C3, C4 and is measured in microns (0.001mm) relative to the internal bore of the bearing.

Normally, needle roller bearings for this sort of application should be C2 clearance, this means that the upper & lower limit of the internal clearence will be roughly 5 microns, (min) to 35micons (max), for this size of bearing - 0.005mm to 0.030mm

C3 & C4 classifications have larger internal clearances, these sometimes used for higher loaded applications, where for example, the bearing may get hot (& therefore reduce the internal clearance & seize)

The bearing also relies on the fit on the outside diameter, to squeeze it down so that it is within the internal tolerance for the clearance mentioned above, so ideally, before it is fitted, it may be 'sloppy', but when fitted ,it is squeezed down and the internal clearence somewhere in between 5 & 30 microns.

Going back to my first point about tolerance bands, all of the items will have been machined with an upper & lower limit, therefore;

if the bore of the linkage housing was machined at the upper limit of its tolerance, (large) the outside diameter of the bearing machined at the lower limit of its tolerance (small), the rollers are machined at the lower end of the tolerance (small) and finally, the sleeve/bush has its outside diameter machined at the lower end of it tolerance (small)
Then it may end up with too much internal clearance especially if the bearing has been made with a C3 or C4 class of internal clearance, instead on a C2 clearance

In my engineering experience,this can happen and it quite a normal problem, as there is a large amount of 'human error' when measuring stuff. Also if the bearings you are using are not from a reputable supplier (SKF, FAG etc), - these days a lot of poor quality bearings are coming out of China, being repackaged & sold on as 'good quality'

Apoligies for boring you all to death with this.

Swapping linkages around may help if you can get a spare, packing it solid with a heavy grease may 'help' it pass a mot, as the grease may reduce the clearance, maybe talk nicely to someone that owns a machine shop with a small grinding machine, to make you a slightly larger bush?

Rob

I removed the bearings from the all balls kit this week and fitted 2 new IKO bearings.
The IKO are on the left. The bearings feel very loose ( if I can say that) in that there is a fair amount of play in the roller. Once fitted the play in the swingarm was worse.


I have removed them and refitted the all balls bearings

I have fitted a kit to the top of the shock tonight so I dont believe there is anywhere else for the play to be.

The rear suspension is back together now so lets see what the MOT man says once the engine is sorted.

Interesting info on clearances. I can certainly appreciate why some built in tolerances are acceptable, especially where heat is involved. That said, those types of allowable tolerances shouldn't be felt by hand or seen by the naked eye, so I can only assume (in my case) that something was either not put together prooperly (by me) or the parts are poorly machined. I can pretty much measure the slop in each joint with a ruler, so something isn't right.

Boredus, you said you have 2-3mm of play, what does that work out to at the end of the swingarm, where the axle is?

You've got me motivated to pull mine apart again so I can compare my measurements with yours.

-Kent

I am hoping the MOT man thinks that too. In that clip I had wedged a socket above the shock so it was locked. I have since fitted the top mount kit so no play there.

So I took mine apart last night and was able to isolate where most of the slop is coming from.

I do have some slop at the top of my shock, so I slipped a piece of wood in between the top of the shock and the frame, then put a bolt though the frame and tightened it down against the wood. It kept the shock in place when I was moving the swing arm and it did tighten things up some. Obviously that needs to be serviced too. It now looks like what Boredus has in his video.

After that, it looked like the majority of the play is coming from the front bearing on the linkage arm (where it attaches to the frame). I removed the other 2 joints, shock bottom bearing and swing arm connection, it and it was obviously loose. I could twist the linkage arm side to side quite a bit, indicating that the bearings/collar where not tight to the bolt. The other bearings looked better so I'm starting with this one.

I measured the parts and they are pretty close to what Boredus is showing. FYI, this is #26 in the parts diagram above.

The new collar measurements - ID: 16.28mm, OD: 19.94mm

Original measurements - ID: 16.13mm, OD: 19.94mm

Bolt OD ~15.85mm

The OD of each collar is the same, but the inner diameter is larger on the new All Balls one. Keep in mind that the old one is 13 years old, so it may have been smaller start with. It's only .15mm larger, so I'm not sure if that's enough to cause much play. However, I am running the OLD collar, so the All Balls one is not causing an issue there. I guess the next thing to check is the ID of the bearing, which will be hard to do since it's a needle bearing.

If the All Balls bearing has a larger ID than the OEM one, then that could cause some play too. I don't see where else it could be coming from.

Something else worth noting, the seals are deformed, indicating to me that the seal was taking some of the weight of the collar. If the bearing was not sized properly then surely it could cause the seal to wear improperly like this (below)? That's 500km after installation (all dirt riding). What are your thoughts?

-Kent

Yes, that's just like mine, if not slightly better. Of course if it's able to twist likle that, it doesn't stand a chance to hold the linkage in place fore and aft with the weight of the bike on it.

I think the next step may be to try a different set of bearings.

How are your swing arm bearings? I was taking a close look at mine last night and althought they seem smooth, I wonder if they are wrapping at all. Because of the geometry of it, even 0.5mm of play at the swing arm could result in ~2mm of play at the axle.

-Kent

That's interesting (the free play specs).

But I don't understand what they mean by "end" free play though, and I will explain why...

The side free play of the swingarm, measured at the axle is dictated ONLY by the swingarm bearing.

The vertical slack that I think we are talking about in this thread, which I checked by rocking the bike over on the sidestand and moving the rear swingarm up and down by hand, is dictated by the swingarm bearing AND a heap of linkage bearings, so you would expect it to be more.

To add to this, in the "chassis" section, when dismantling the rear suspension, the manual suggests that horizontal and vertical movement at the axle should be checked, and that the horizontal (sideways) movement should be less than 1mm, whereas for the vertical movement they just want you to check for binding. I guess this is understandable because without the shock installed you can't really check the play in the vertical.

[actually, the vertical play can be pretty hard to check, with the shock installed also - unless the preload setting is minimal]. 

I'm not sure where this leaves us as to tolerable limits in the actual linkage parts.

By the way, Yamaha Australia are STILL advertising the TTR250 in their new model offerings, so its not dead yet (although maybe they are just moving residual stock), and so if any Australian members just happened to be at a dealer who just happens to have a new/demo one on the showroom floor, they could check the vertical play on a new model.

-- Edited by brindabella on Thursday 17th of January 2013 05:48:58 AM

I spent some more time in the shop last night going over every piece and the only conclusion I can come to is the All Balls parts are poorly made. The OEM parts do show a little bit of play, and the All Balls parts are much worse. I suppose I can expect some play out of the original parts as they are 13 years old.

The All Balls collars (in my case) have the correct OD, so they fit nicely in the bearings. The play is all coming between the bolts and the collars, since I feel the ID of the collar is too large.

Again, I'm looking a difference of .43mm between the bolt and new All Balls collar. Same bolt and old OEM collar is .28mm difference.

The way it sits right now, the bearings do very little to assist in the motion of the suspension, because the bolt spins freely inside the collar.

I see my options as:

1) Run it, ignore it. Replace the top shock bolt, and maybe the swingarm bearings too for good measure (not All Balls parts).

2) Buy some new OEM collars to see if that resolves or improves it (old ones might be a few thou larger due to wear?).

3) Have some new collars machined with slightly smaller ID. Not that hard to do if you have friends in machining.

4) Have the bolt knurled to increase the OD, and make it a tighter fit inside the collar. At that point the bolt and collar should not slip very much and make the bearing do all the work. Might have to grease it and hammer it in...

Thoughts?

PS: it's not just the one joint, the centre joint is sloppy too.

- Kent

-- Edited by KentJ on Friday 18th of January 2013 08:37:07 PM

Brian,

This is correct, I started off this thread barking up the wrong tree so to speak.

Kent,

To test what Brian is describing above, simply take the sleeve on its own and bolt it between either the swingarm joint or the frame ( swingarm is easier to get at) and tighten/torque up the bolt. When tight, the sleeve and bolt cannot move as they are held in place by the fixing.

As described a few posts up, the only area where we can get this play is where the rollers push up against the sleeve and where the rollers press up against the outer bearing housing.

Raggis45 wrote:

All bearings are designed with built in slop, (internal clearance) as Brian calls it, if it wasn't there, they would seize, this is controlled by international standards and for 'general' bearings, including these, the internal clearance is classifed as C2 C3, C4 and is measured in microns (0.001mm) relative to the internal bore of the bearing.

Normally, needle roller bearings for this sort of application should be C2 clearance, this means that the upper & lower limit of the internal clearence will be roughly 5 microns, (min) to 35micons (max), for this size of bearing - 0.005mm to 0.030mm

The bearing also relies on the fit on the outside diameter, to squeeze it down so that it is within the internal tolerance for the clearance mentioned above, so ideally, before it is fitted, it may be 'sloppy', but when fitted ,it is squeezed down and the internal clearence somewhere in between 5 & 30 microns.

Rob

I see what you are saying, I guess I didn't fully understand what you meant before. I'll test that out and see what I find.

-Kent

KentJ wrote:

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Barra, thanks for the info. Much like boredus, I may have been looking at the problem from the wrong angle. The play is probably due to bearing clearances and not the bolt/collar sizing. When I get some time I'll reassemble everything and see how it looks (It's sub-zero in the garage right now, takes some motivation to get out there after the kids are in bed etc).

I usually use Bel-ray's waterproof bearing grease, I'm under the impression it's a qulaity product.

As for the seal, I think I must have buggered it when I reinstalled the bolt on the bike. The bearings are still intact, it's just the seal that's damaged. That's the spring you can see in the photo.

Here's a close-up of that seal.

Thanks for the help.

-Kent

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 I see it now lol. Atleast you know why there is different clearances for different bearings.

I'm sure it will be just fine for you aslong as that grease you describe is thick enough. If it's a waterproof lithium soap based grease chances are your sweet. Obviously the weather will play a part in what grease you use so you may be spot on

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Jarrah.

KentJ wrote:

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BTW, the mechanic at the Yamaha dealer said these bikes "always have a bit of play in the suspension". Take that for what it's worth...

-Kent

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 That seems correct but mine only has 1mm play (standard) Not enough for it to be noticable unless heaps of pressure is put on it. Maybe i use better grease though & have grease nipples fitted so i can get more grease in than usual.. I can understand any aftermarket parts having more play than usual though (which is'nt a problem but i prefer Genuine).

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Jarrah.

-- Edited by barra8 on Friday 25th of January 2013 03:30:13 AM

I put mine together with the 2-3mm play at the axle.

The engine is back together now and I am jsut starting to find out which bits and details I am still missing so its slowed down a lot.

Admitedly with the snow this last week I havent been out in the garage much!

BTW, the mechanic at the Yamaha dealer said these bikes "always have a bit of play in the suspension". Take that for what it's worth...

-Kent

Just an update on this thread, the bike went through the MOT yesterday with no mention of swingarm play etc.