Help! - Broken Valve on lower end of Fork Cartridge (Gen II)

[RZ350]

First of all, I "borrowed" this picture (#18) from an old thread, so thanks to Scoobyvroom for posting it: https://www.fjrforum.com/forum//index.php/topic/127506-race-tech-gold-valve-and-spring-installation/?p=723251

I just changed out the bushings and seals on my 2007 and I ran into a problem upon re-assembly of the stock cartridges in the fork tubes. I had the inner tubes with bushing all back together inside the outer tubes, no problems. Next I slid what Yamaha calls the SPINDLE, TAPER (shown in the upper left corner of Picture 18 above) onto the bottom of the cartridge and then slid the cartridge in the fork (fork was lying down). I wiggled the cartridge around a bit until I felt the end drop into the matching bore in the bottom of the outer tube. I installed the allen screw and copper washer into the end of the outer tube and everything seemed fine. But when I attempted to hit the required 25 ft-lb of torque, it seemed to turn way too much before the torque was met. The first one held together, but right before I reached 25 ft-lbs on the second one, it went pop... the threaded boss on the cartridge snapped off. The last sound you want to hear!!! Anyway, I got it back apart without the broken tip getting hung up on the allen screw, luckily, and it was time to search for parts.

Cartridges are pricy, so I opted to buy a set of Race tech valves to provide a replacement for the broken part. I figured a performance increase couldn't hurt either.

SO MY QUESTIONS... I don't want to repeat this goof on the new valve/cartridge assembly and was hoping you guys can offer advice. Did I have something out of place? Did that SPINDLE, TAPER need to go in before the inner tubes were installed or just slid in with the cartridge afterwards?

In my opinion, it felt like small boss of the cartridge (valve tip) wasn't bottomed out completely in the outer tube and as the screw was tightened, it stretched the valve until it broke. I say this because it took more turns than it should have to reach the torque compared to if it was seated tightly together in the first place.

Any help would be greatly appreciated.

 

[Bounce]

https://www.fjrforum.com/forum//index.php/topic/150102-avoiding-doubletriple-postings/

 

[Fred W]

No idea how you broke it. I’ve had the cartridges out of several FJRs and although fitting that bottom cup is a little fiddley, it seems pretty clear when it’s inserted correctly. Can’t visualize what you did wrong to break it.

Not sure that the valves are the same, but I have some used stock compression valves from my old 1st Gen if you can use one of them. Sounds like you already bought some aftermarket ones, which will be a nice upgrade for you. Might as well do the rebound valves and new springs while you are in there then you’ll really be good to go.

 

[RZ350]

Thanks for the offer Fred, I will keep it in mind. Its a bit baffling to me too. Here are some close up pictures to explain it better. The valve snapped at the necked down portion, of course.

This picture shows the broken valve end held in place by the screw.

The following exploded view suggests that item 16 goes onto the cartridge and then the cartridge goes into the inner fork tube (which I did).

But then this assembly instruction shows item 2 going in on after the cartridge is slid through the bottom of the inner fork tube.

It seems as though the small cap should fit through the opening in the bottom of the inner fork tube, but I haven't checked it yet. The other fork tube that is completely together is compressing okay, it seems

 

[Fred W]

Looking at the parts, only way I can see breaking off the threaded neck of the valve is if it were cross threaded? But it would have taken a lot of torque to do that. Seems a mystery.

I recall that the oil stopper #16 seats in the lower fork leg then the valve on the cartridge bottom fits into the stopper. I dont recall the spacer piece you have on the bottom of the cartridge. Where did that come from? Is that a stock valve or aftermarket?

 

[RZ350]

Luckily it didn't cross-thread and break off as you mentioned... that broken end and screw would have been captured in the bottom of that outer fork tube for eternity!!!

What you see is all stock parts, the valves have not arrived yet. The spacer piece you mention is, in fact, item 16 oil stopper in the figure (maybe Gen I is different?). I'm pretty certain the taper on the outside of the stopper performs the cushion effect at the collapsed end of fork travel, progressively limiting the flow of the captured oil squeezing out of the void between the inner tube end and outer tube "end cup". In effect, a hydraulic cushion to avoid a clunk when bottoming out.

The only theory I have been able to come up with is that installing the spacer (#16) after the inner fork tube was installed caused the lip of the inner tube to get sandwiched between the space and the outer fork tube seat, causing a small gap there and also where the valve extension seats in the small counterbore in the outer tube. The screw was trying to stretch the valve down into the gap, and SNAP!

I fear those oil stoppers (#16) need to be installed in the outer tubes before assembling the inner tubes into the outers. If so, I will need to tear the tubes apart again, possibly damaging bushings and seals in the process. But hey, that's only a little more time and money right? I was just hoping to get confirmation from someone before I go through the extra work. Tonight I plan to test whether the stopper fits through the lower end of the inner tube. If so, total fork assembly should not be needed (crossing fingers!).

Luckily, its so hot and rainy in FL right now, its sort of my "off-season" with commuting to work.

Thanks again for your interest in my dilemma.

 

[Fred W]

I think #16 is the larger cup shaped thing on the far right of your top photo. I do not see the spacer ( thing between the Allen bolt and bottom of the broken compression valve in top photo) anywhere in the parts diagram. I sure do not remember fiddling with any spacer there, but I have only done 3 different 1st Gens. Or maybe it’s just the advanced CRS.

 

[RossKean]

I think the "spacer" is the broken off piece...

 

[RZ350]

Oops, yes the broken piece looks like a small spacer, but it was part of the original valve tip. I show it apart and then together in the 2 pictures. I edited the original post not to mis-lead anyone new reading this thread.

 

[Fred W]

Ah, yes. That is how I didnt remember it. Now that I know that I can see a shard of metal on the broken surface of it.

That is a strange break-off of the valve. No idea how on earth that happened.

 

[RZ350]

Another clue to this mystery (actually more like my nightmare!)... In the thread I linked to from Scoobyvroom in post 1, no where does it show the inner tube removed from the lower leg, but yet the oil stopper #16 is lying there on the bench. I think he removed the cartridges and stoppers from the forks, and then simply re-installed them later. This suggested the hole in the inner tube will allow the stopper to pass through it. Good news, I suppose, for me not needing to fully disassembly the forks again. But why the valve broke is still a mystery.

 

[RZ350]

Reaching a little bit.. but I guess there is the possibility my trusty torque wrench suddenly went out of adjustment and is over-torqueing things.

 

[RZ350]

I had a few minutes in the garage tonight and tested whether teh oild stopper did indeed slip through the end of the teh inner tube... the answer is yes, albeit tight. That is good news and means I don't need to worry about taking the forks completely apart or buying new bushings and seals in the event some of the newly installed parts were damaged during the second disassembly.

Other good news (I think!) is I found something drastically wrong with my formerly trusty torque wrench. I decided to give it a quick bench test.

Using the semi-accurate fish scale method with the torque wrench set at 25 ft-lbs, I recorded a pull of 29.8 pounds before it clicked. Even worse, this was at a 15" moment arm, so the actual torque being applied at a 25 ft-lb setting was 37.25 ft-lbs!!! Well, I think I found my culprit... that's about 50% more torque. Probably time for a new torque wrench, or at least a re-calibration. I just wonder if I have some other fasteners over-torqued elsewhere... eek!

When the new valves show up in the mail, I will get them installed and use the proper torque and see how that goes. My next challenge will be breaking the Loctite fitted valves free in the cartridges... sounds like it takes about 500 degrees to melt the red stuff.

More to come as a followup.

 

[RossKean]

Was your pull of 29.8 lb exactly one foot from the pivot? (Looks longer but that might just be perspective). I had a decent quality "clicker" torque wrench that worked perfectly up to the point when it didn't work at all!! One axle pinch bolt got severely over tightened before I realized what was going on. Thankfully, I caught it in time and no damage was done.

 

[Bounce]

Anyone have a source for recalibrating?

 

[Fred W]

Not worth the cost unless you have a lot of equipment needing regular calibration. Metrology labs dont want to be bothered with one time Cals. Plus, something is wrong with it to be off so much, suddenly.

Better off getting rid of it and buying a new one. Test it when you get it so you can return it if it isnt reasonably accurate.

 

[lonerider]

I use these for a rough check https://www.amazon.com/gp/product/B009GLISY4/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 . Definitely not laboratory accurate, but will detect large inaccuracies in the wrench.

 

[RZ350]

RossKean - good eye... it was actually 15" from the socket drive. So I did a little math: 29.8# x 15" = 447 in-lbs. Then 447/12 = 37.25 ft-lbs

 

[RZ350]

My workplace use to have a means of checking torque wrench calibration in-house, but I think we out-source it to a local company now.

There is a calibration nut on the end of the handle but the correct sized socket is too big to fit in the recess to reach it. Also, I would need a socket with a concentric hex key to adjust it. I guess I could just cut part of the handle off to gain access with a simple box end wrench.