Wrong fork bushings installed at factory - heavy wear ensues

[rick]

My OE bushings were showing wear right at the gap at about 1200 miles. I'll be getting back inside mine in a month or so to do some upgrades to the Andreani cartridges. Should be interesting to see if the new bushings w/ smaller gap are also showing some premature wear.

[Guest ChicagoAJ]

My OE bushings were showing wear right at the gap at about 1200 miles. I'll be getting back inside mine in a month or so to do some upgrades to the Andreani cartridges. Should be interesting to see if the new bushings w/ smaller gap are also showing some premature wear.

I wonder what the bushings look like @jeffkisthename is running with. Nearly 30,000 miles on his bike. This is what I was asking you about in the PM Jeff, haha. 

[gregjet]

twf,
Funny you got that result. When I did mine there was a definite out of round with the original bushes. With the originals you could get the bush at right angles to the gap and push it inwards when it was mounted . With the replacements you could not

[twotone]

So the gap isn't the problem, but the quality of the bushings are questionable.

[Guest ChicagoAJ]

So the gap isn't the problem, but the quality of the bushings are questionable.

Well, maybe once hundreds of bikes come in with problems related to this (if that ever happens) we'll see a recall. Doubt it though if it takes tens of thousands of miles. 

[twf]

twf, Funny you got that result. When I did mine there was a definite out of round with the original bushes. With the originals you could get the bush at right angles to the gap and push it inwards when it was mounted . With the replacements you could not

Maybe I don't know how to measure I have 3 fork tubes here, each one is from different set of forks. Also have 2 new bushings and 1 used. I just measured them all and swapping around as well. They all within 1 thou. I can not push them any tighter. They sit on tube exact, not to tight or loose. For comparison 2nd gen sv bushing Matt mentioned is loose fit, looser than it is on sv tube. And for comparison 1st gen sv uses gap as well and fit is same as fz07. This is because this bushings with big gap are like spring, they want to close.
 
 
 
 

[pattonme]

the battle of electronic calipers will commence. Gentlemen, to your stations!
 
I have a FZ07 to do so I can provide another sample. To @twf's point the OE bushing is bloody tight and isn't going to spin. I'm not sure I would characterize the "correct/SV Gen2" one as loose though. I don't have a super-accurate pull gauge or anything. The SV Gen1 as I recall wasn't so tight as the FZ07 one nor have I ever witnessed anything other than proper, even wear; nothing remotely like the FZ07 can produce in a single digit thousand miles. I have a few pairs of Gen1 forks lying about so I guess I'll need to bust them open.
 
Stay tuned. At least this saga is more interesting than the 5-ring circus, ya?

[norcal616]

Who are the judges

[twf]

[twf]

Try that. If you put one finger on gap you can spin it easy. And no, I am not spreading it. You can actually take small flat screwdriver, put it in that gap 90º to tube and against end of bushing, it will spin very easy.
Put fingers on bushing 90º from gap and you will never spin it.
 

[rick]

Well, something is clearly going on here that's not right. Every pict of relatively new bushings that's been posted here has shown some wear right at the end gaps - mine included. For that to happen, the bushing is either not perfectly round as it sits (btw, twf, judging by the cracked screen, yer calipers have obviously see better days) or something is causing that bushing to lift at the end gaps putting more pressure there.
 
My new(small gap) bushings will have a few thousand miles on them by the time I get in there. If those show no wear, well, seein's believin'.

[norcal616]

Possible the other lower fork parts are not machined properly??

[tommyquest]

the battle of electronic calipers will commence. Gentlemen, to your stations! 
I have a FZ07 to do so I can provide another sample. To @twf 's point the OE bushing is bloody tight and isn't going to spin. I'm not sure I would characterize the "correct/SV Gen2" one as loose though. I don't have a super-accurate pull gauge or anything. The SV Gen1 as I recall wasn't so tight as the FZ07 one nor have I ever witnessed anything other than proper, even wear; nothing remotely like the FZ07 can produce in a single digit thousand miles. I have a few pairs of Gen1 forks lying about so I guess I'll need to bust them open.
 
Stay tuned. At least this saga is more interesting than the 5-ring circus, ya?

Matt, if that's my bike up next, it has 3225 miles on it for comparison.

[rick]

Possible the other lower fork parts are not machined properly??

yep, but that doesn't account why those low mileage bushings are worn only at the gap

[pattonme]

it's not correct to say that they are *only* worn at the gap. they are worn on both sides, 180 deg apart.

[twf]

(btw, twf, judging by the cracked screen, yer calipers have obviously see better days) 

Would you prefer more expensive caliper without broken glass? Here it is If you don't like electronic one I have dial as well and few micrometers. 
 
 

 

 

 

[twf]

Well, something is clearly going on here that's not right.

Yes, something is going on and I think I know what it is. Bottom line is I am not finding any of things mentioned here.
- Bushing with gap is not incorrect bushing used by factory as stated. Gap is there by design. Incorrect bushing is the one without gap.
- I am not measuring them out of the round
- I am also not measuring them at 41.1mm as mentioned in first post, 1.653 = 42mm.
- They do spin around, look at picture of cut out tube I posted, at 8 o'clock you can see multiple lines going up/down the tube. That is bushing gap rotating. 
- Outer tube I have here is not out of the round
 
 
 
 
 

[gregjet]

Hmmm, curiouser and curiouser...
Well mine got changed a fair while ago and Matt's internals are now in so it can rest in peace. But I am interested to see if any more stuff comes to light.
Remember my bike is the Australian MT07 ( not even the HO version which is every other countries FZ/MT). And a first release at that. But Mine definitely did have the big gap and OoR and was better with Matt's suggested bush. Many others have had the oval wear pattern on this forum.

[twf]

Many others have had the oval wear pattern on this forum.

That is only pattern it will wear. Smaller circle in bigger circle will never have full contact all the way around.  If you have wear 180º apart it tells you there is bending/flexing going on, which is normal and usually in direction of load.
And it is more than just fork tube, it is whole chassis/geometry that can play part. 

[gregjet]

Actually you have hit on a diagnostic I think. A too small bushing will bulge on both sides at right angles to the gap, regardless of orientation of the gap. It should also wear most at the right angle and taper away from that line across the bush on both sides.
Normal wear would almost always be in the front and back ( tolerence slump) relative to the fork/ motorcycle orientation. It also will be most wear on the edges of the bushes ( a parabolic shape I am guessing) and reduce as you go across the bush. Or at the very least taper across the bush. They would tend to the bottom of the lower bush and the top of the upper bush.

[twf]

Except I don't measure them too small, see my previous post.
The wear you guys see is normal. Regular forks in relative small diameter will flex more, reason bushings on those forks don't last as long as those in inverted forks.
Wear in fz07 is just to soon so there is something else going on. Like I said I think I know what it is, there is another pattern I noticed with this bikes that makes me believe it is related.
If I find some facts to my suspicion I will post it.

[twotone]

Twf,
 
I'm gonna guess and say it's one of two things:
 
1. Poor quality bushing
 
2. Or poor surface in the alloy slider.
 
(Maybe more options here)
 
The wear rate as reported here is way too soon as you and other pointed out.
 
And I agree that the wrong bush is one with no gap for oil flow, creating a vacuum between stanchion seal and a narrow gap bush.
It really is logical to drill holes for the latter.
 

[twf]

Drilling holes is option but if gap is not cause why do all that.
First you have to find what problem is than fix it.
If different bushing is holding up much better than it points to bushing itself.
 
1. Maybe, seems like coating is very thin compared to others I have here.
2. Surface is fine, I looked in to it.

[weazsel]

it's not correct to say that they are *only* worn at the gap. they are worn on both sides, 180 deg apart.

 
 
Hey Matt @pattonme how did mine look after a little over 5,000 miles?

[twotone]

Drilling holes is option but if gap is not cause why do all that. First you have to find what problem is than fix it.
If different bushing is holding up much better than it points to bushing itself.

 
I agree, but for those with paranoia re a gap, let them drill,
I would go easy route - gap :-)