Fork maintenance failure

[gixxerjasen]

Well, back to the real drama.

Just got off the phone answering the tech's questions. I was happy to hear the guy's name when I answered the call because as one person on the local forum posted

If there is anyone that can fix it, then it is Dean over at Stadium. He is the only guy that will ever touch one of my bikes other than me.

Anyway, he had a bunch of questions about how this happened. I answered truthfully and he said he'll take a stab at it but that I need to be prepared to buy new fork upper and lowers. He's never seen one stuck this badly.

Off to the online shopping to get prices. Best I've seen for upper and lower is about $380. Ugh.

 

[MCRIDER007]

That middle bushing is a duplication of the upper bushing, and I don't see where it does much of anything... UNLESS you buy into what MCRIDER007 suggested, that the lower fork tube is what is flexing and is what they are trying to restrain.

Just looking at the structure of the lower fork tube (especially as compared to the upper one) I completely reject that theory.

Fred, for the record, I totally reject your complete rejection of my flex theory but you are correct that RaceTech does not install the middle bushing. I saw that with my own eyes when I helped disassemble a set of forks at the last tech day. However, the owner of those forks was rather pissed at RaceTech since he said he was charged for the middle bushing.

 

[08FJR4ME]

Poor mans press, This heavy duty ratchet tie down did do the trick for popping the bushing and seal but oil poored out all over everything. Cost me a quart of oil too since I aready trashed the oil I took out. I went back to Ed's method on the second shock.

Bushing Pic's of wear.

2008 / GenII, First fork service for me at 59K miles.

 

[Fred W]

Fred completely missed the point and rather than get into a bunch of childish name calling I'm just going to let him believe whatever. By the way I was a Physics major at University and have a passing knowledge of Newtonian Mechanics.
And with that I'm outa here

Now where is that ignore button?

For the record, I'm not sure where I did any "name calling" as was inferred in your post.

I'll just try to take note the some people have a hard time discussing things (even technical situations) without getting all emotional about it.

That middle bushing is a duplication of the upper bushing, and I don't see where it does much of anything... UNLESS you buy into what MCRIDER007 suggested, that the lower fork tube is what is flexing and is what they are trying to restrain.

Just looking at the structure of the lower fork tube (especially as compared to the upper one) I completely reject that theory.

Fred, for the record, I totally reject your complete rejection of my flex theory but you are correct that RaceTech does not install the middle bushing. I saw that with my own eyes when I helped disassemble a set of forks at the last tech day. However, the owner of those forks was rather pissed at RaceTech since he said he was charged for the middle bushing.

Your rejection of my rejection is duly noted. As I mentioned, you might be right here.

Charging for a non-existent bushing is what I was referring to when I said: "I think they are just guys that have a clue about what's going on and how to make (more than) a few bucks selling suspension parts." I should have added, "whether they actually install them or not!".

Poor mans press, This heavy duty ratchet tie down did do the trick for popping the bushing and seal but oil poored out all over everything. Cost me a quart of oil too since I aready trashed the oil I took out. I went back to Ed's method on the second shock.

Oh my gawd man, no!! You cranked that strap on the top of the rebound damping adjuster?

Oh the humanity!! The horror!

Bushing Pic's of wear.

Them are some darn good pitchures of bushings that ain't bushing so well any more. You could easily have left them in for another 100k miles. The suspension would have behaved l;ike crap, but they would have still been in there.

 

[gixxerjasen]

Also, as Dean guesses at this point, the washer bent and became oblong and is jammed inside there. Not entirely good.

 

[HotRodZilla]

Also, as Dean guesses at this point, the washer bent and became oblong and is jammed inside there. Not entirely good.

AND this is why I don't take my forks apart. Sorry Jasen...Good luck, and let us know how it turns out.

 

[Fred W]

Alright. Let me stop all my jabbering about the middle bushing and see if I can actually be of any help...

So, when you are trying to bang the bushings and seal out, the lower bush hits the middle which hits the upper, which hits the washer, which hits the oil seal. The washer is on the outside (top) of the three bushings. I don't think that the washer is the hold up.

Much more likely that the (smaller diameter) middle bush is/was being jammed into the upper one, spreading it out and causing it to clinch the outer tube even tighter. So the trick will be to unjam that first somehow and then try again, or else get the top one out from above.

Can you get the inner tube to move downward from the locked state with some forcefull coercion? Not hammering on the rebound adjuster, but the top of the inner tube with a nice block of softwood as a buffer maybe?

 

[08FJR4ME]

Fred,

NO,NO,NO,NO I put a piece of aluminum tubing I had over the adjusters to protect them. All was good.

Yep, I figure I can do the next rebuild when I hit 120K miles. Remember I live in the land of flatness.

Dave

 

[gixxerjasen]

I had all the innerds out of the fork. As I was tapping it slowly went down back in but so slowly that I didn't realize it till I was done. Not sure what is going on in there and we won't till the tech can get them apart, one way or another.

As of right now, it's out of my hands and at the shop though, so we'll see what happens and I'll report back.

 

[MCRIDER007]

That middle bushing is a duplication of the upper bushing, and I don't see where it does much of anything... UNLESS you buy into what MCRIDER007 suggested, that the lower fork tube is what is flexing and is what they are trying to restrain.

Just looking at the structure of the lower fork tube (especially as compared to the upper one) I completely reject that theory.

Fred, for the record, I totally reject your complete rejection of my flex theory but you are correct that RaceTech does not install the middle bushing. I saw that with my own eyes when I helped disassemble a set of forks at the last tech day. However, the owner of those forks was rather pissed at RaceTech since he said he was charged for the middle bushing.

Your rejection of my rejection is duly noted. As I mentioned, you might be right here.

I have noted your noted............and my offer to give you an opportunity for a real world test to demonstate the superiority of the 3 bushing design stands.

 

[Redfish Hunter]

I am completely dejected over the hurtful rejections.

Perhaps the poor bushings could use some inspections.

And the deflection of the flexing,

Resulting in the wearing and tearing,

Of the cushioning bushings,

Makes me want to start swearing.

Perhaps all this knowledge,

Here at FJR college,

Needs a hard shove,

Towards happiness and love.

I find it funny as Hell that you all sound so damned smart but you can't agree on anything. You all make great points and as I am reading each of your posts I find myself completely in agreement with what I am reading at that time. For now, I am going to follow the lead of Yamafitter and shut up and get the heck out...

 

[Fred W]

I have noted your noted............and my offer to give you an opportunity for a real world test to demonstate the superiority of the 3 bushing design stands.

That particular test would be greatly appreciated. More because it would be fun to ride a 3rd gen, than a 3rd bushing. As I mentioned before, the differences between gens are too many to attribute any "seat of the pants" improvements to the 3rd bushing. The only way to accurately make that analysis would be to remove the bushing on a 2nd/3rd gen and do before and after on the same, identical test mule.

And, fret not, Redfish Hunter. I don't think those rejections are as hurtful as they may appear. MCRIDER007 and I have a relationship which can stand a few hypotheses rejections. We have privately had some technical discussions about suspensions, and their modification, and I will confess publicly that I have a great deal of respect for his level of suspension knowledge, expertise and experience. Especially his understanding on how the combined bits and pieces translate into actual road performance. Most of my blabbering comes from the theoretic side, with only a limited amount of practical first hand experiences.

I'm pretty sure that Billy Fitter is not really upset either. He just needed some time away to gear up for the new season

(Hockey of course! What other season is there?) He's probably still sore about the Bruins knocking out the Habs a couple years ago, though.

Nice poem, though. You really showed us your sensitive, creative side there...

And now, back to waiting to hear how (or if) this forking drama comes out.

 

[ionbeam]

I am completely dejected over the hurtful rejections...Towards happiness and love.

I find it funny as Hell that you all sound so damned smart but you can't agree on anything. You all make great points and as I am reading each of your posts I find myself completely in agreement with what I am reading at that time...

Nice impromptu poem, did you ever think about a career in English?

If everyone is agreeing, nobody is learning. It is even possible for everyone to be mostly correct, yet mostly in disagreement with everyone. 'Tis the way science moves forward, hypothesis abound, trials are run, facts are accrued and converted into information, new questions are discovered and the cycle repeats. It all works until someone gets hung up on 'it has to be my way, my way only and my mind is closed to any other options'. You can't fill a closed container.

 

[gixxerjasen]

Hey Ionbeam, don't forget the other possibility. You know, that mostly everyone is incorrect.

Hey, it happens. In fact, sometimes those are the best arguments. :

 

[RaYzerman19]

Bushing Pic's of wear.

2008 / GenII, First fork service for me at 59K miles.

OK, I'll fuel the fire..... I see the wear on the bottom bushing because the teflon is gone and copper showing. The wear on the uppers would be on the inside surface where all the sliding occurs, yes? Regardless, the FSM doesn't provide any time/mileage interval for fork oil or bushing changes, except to check for leaks and roughness at recommended periods. So how often should you service your forks, bushings and/or oil? I've seen high mileage forks with moderate wear and low mileage forks with more.

Back to the problem at hand, when you can't get your forks apart, it is possible the lower bushing has not dislodged the middle bushing and has slid inside the larger middle bushing. Best not attempt to pull the inner tube out at this point and leave the middle bushing in there as it will be a bear to get it out later.

Meanwhile, it is counter-intuitive to me to leave the middle bushing out as I believe more bearing area is better. No point in starting a poll as we won't agree. And it escapes me how the cast lower fork tube flexes to anything significant.

 

[Redfish Hunter]

(Sigh) I cannot believe that none of you understand the reasoning behind the engineering change. Once again, I will have to set you all straight on this.

Yamaha designed the original FJR as a SPORT-tourer. A big sportbike with luggage carrying ability. It was intended to be ridden and played with in a lively sporty manner. Lots of wheelies, intense cornering and high speed riding. The fork damping was calibrated for high speed. The forks were expected to do a lot of flexing and the extra bushings would create stiction. Therefore, only two bushings were utilized.

The 2nd Gen was designed more as a Gentleman's Sport-Tourer. Longer swingarm, and a softer ride. The suspension calibration was aimed at the older more relaxed crowd, the ones who were actually able to afford this bike. The damping needed to be set up for high and low speed and fork flex was not supposed to be an issue. The use of 3 bushings would not create more stiction with the more relaxed riding style that Yamaha was expecting to see from FJR riders.

Of course all of that I just typed is 100% Pure BullShit. Don't believe any of it. I made it all up on the spot. But, looking back and reading it now, it almost makes sense.

None of which fixes our friend Jasen's problem. I know what will fix it though. The solution comes in Candy Red and will be at your friendly neighborhood Yamaha dealer very soon.

Oh, I almost forgot. Hugs and kisses my friends!

 

[Fred W]

OK, I'll fuel the fire..... I see the wear on the bottom bushing because the teflon is gone and copper showing. The wear on the uppers would be on the inside surface where all the sliding occurs, yes?

Exactly.

Regardless, the FSM doesn't provide any time/mileage interval for fork oil or bushing changes, except to check for leaks and roughness at recommended periods. So how often should you service your forks, bushings and/or oil? I've seen high mileage forks with moderate wear and low mileage forks with more.

Great question. Once the teflon is gone, the wear that occurs to the bronze bushings will be pretty minimal. You could ride around with worn out bushings for the remainder of the bike's life and things wouldn't get any worse. So why bother replacing the bushings at all?

The answer is that the Teflon layer keeps the sliding friction to a minimum. This allows the forks to be as responsive as possible to every little road irregularity. If you do not mind the increased stiction and rougher ride qualities of worn out bushings there really is no reason to ever change them.

Back to the problem at hand, when you can't get your forks apart, it is possible the lower bushing has not dislodged the middle bushing and has slid inside the larger middle bushing. Best not attempt to pull the inner tube out at this point and leave the middle bushing in there as it will be a bear to get it out later.

At this point the edges of the old bushings are probably pretty banged up. The middle bushing has most likely already been dislodged and it hanging up on the upper bushing. That is what other 2nd gen owners have reported (ref FJREd's nice post on rebuilding 2nd gen forks linked to earlier in this thread). I think getting them apart now is the only path. I'm betting the shop will be able to do it without destroying the forks.

Meanwhile, it is counter-intuitive to me to leave the middle bushing out as I believe more bearing area is better. No point in starting a poll as we won't agree. And it escapes me how the cast lower fork tube flexes to anything significant.

I agree that normally having more bearing surface is a good thing. This is a rare situation where more surface is worse because of the evils of increased friction. Those bushings are already quite large in surface area. There will be a considerable mount of drag sliding them even immersed in fork oil. Add to that that the inner tube does flex and having three (mostly) stationary bearing surfaces will increase the amount of friction.

The reason that we don't have all of this churn in the rear shock is that the diameter of the shock rod is so small, the amount of friction is also much smaller. Also, and probably more germane to this, there are essentially no lateral loads being applied to the rear shock (just extension and compression) unlike the role of the forks that have to also hold the front wheel in place.

 

[gixxerjasen]

The solution comes in Candy Red and will be at your friendly neighborhood Yamaha dealer very soon.

If I was in the financial situation to buy one of those, I wouldn't have been tearing into my forks myself. Sigh, but yea, that would be a sweet solution.

 

[08FJR4ME]

I will try and get some pic's of the inner side of the busings. I keep everything that comes off or out of my bike. Don't ask me why.

Dave

 

[Redfish Hunter]

The solution comes in Candy Red and will be at your friendly neighborhood Yamaha dealer very soon.

If I was in the financial situation to buy one of those, I wouldn't have been tearing into my forks myself. Sigh, but yea, that would be a sweet solution.

Just to let you know that in spite of the fun I am having with this thread, I am following it with great interest. I have never torn into a set of forks, my courage has failed me every time I consider it. I am benefitting greatly from the collective wisdom of the forum on this one. I don't even care how many bushings are necessary or who is actually correct. I appreciate the knowledge being shared.

Of course, my dealer probably appreciates it as well. The more I read, the more convinced I am that this is not a job for me.