Ducati Monster Forum

I picked up my forks after they recieved an Ohlins 20mm valve kit and new springs. I installed the left side first, 4mm up (to improve handling) and snugged the triples. I then installed the right side about the same and proceeded to align it to the left using the axle. I could hardly get it the axle installed. By the time I got it to rotate freely I had to drop the right fork to about to where it was from the factory. The forks are dead even in length from the bottom of the lower triple to the bottom of the fork. However, the left is about an 1/8" higher out of the upper triple. This 1/8" is evident in the amount of chrome showing out of the bottom. It's almost  like the right is not fully extended (or the left is over extended).  I've read that after alignment the forks will probably not match in the triples, but is this excessive?

(http://farm7.static.flickr.com/6194/6054771754_09fdba2836.jpg)

(http://farm7.static.flickr.com/6077/6054771998_e405c02796.jpg)

(http://farm7.static.flickr.com/6067/6054222403_b7acf28648.jpg)

That would drive me crazy!

You've done it correctly.

Don't worry about it.

The forks on my S2R sit lower in the top triple than your lower fork.   They are right about at the groove on the top of the fork (about 1mm lower than your lowest fork).  So does lowering the forks help the big older monsters in terms of handling?   I've always wondered if I should lower mine....
Either way, that offset would drive me kinda nuts too.   Seems like alot of offset, but I'm no expert at all. 

I wouldnt let that go. If they were the same when you sent them out, they should be the same when you get them back. I think something inside each fork was done differently. And therefor, one of them is wrong!

(unless they are asymmetric forks, but I dont think so)

Originally (factory) they were both aligned in the upper triple to the groove cut in the tube. I'm not sure if the lowers varied in extended length  before, but I suspect they did....at least a little bit. I do know the axle needed to be persuaded out with a brass punch and hammer so I do suspect it was off a little. I did not think to take measurements then from the lower triple to the axle, just thought it was a tight fit mixed w/ some road grime.

LT Snyders book states they will most likely be different..just not how much.

The service manual gives a dimension from the top of the fork to the top of the lower triple (or something similar) this could result in a  misaligned axle.

While it looks like shit, I'll take function over form.  I'm going to call the guy who did them and see what he thinks. I wanted to see if others had similar experiences.

He suggested I raise them 4mm to reduce running wide in turns, high speed wobble (that he attributed to the front end becoming unloaded at speed b/c of the wind on the body due to the the upright seating position) and just giving it a little more sport type handling. I read a post on here recently that some one did it as well. I thought I'd try it and if it seemed to twitchy I could always change it back. But now...?

OK, so from the factory the forks height was lined up with the groove at the top of the forks.  That makes sense being the groove is there.
I've wondered about lowering mine a bit...
 
I agree with previous posts that the forks must not have been done the same because I would think they should be closer in length than those appear to be.

Just talked to the guy who did them, he stated he had to use a different tube from another set of forks as the one in mine was damaged either from original install or while removing it.  He went back and measured my tube vs. another spare and sure enough 1/8" difference. He said a mm or two is normal when aligning axles but this is excessive and wrong. I need to pull them off again but he'll take care of it. I'm not real worried as he is very reputable. Shit happens...just glad to know I wont have to look at this while riding.

Yeah I think the grove is probably an alignment mark for the assemblers....I cannot find the other post of who dropped theirs the 4mm but they seemed to like it. I think they may have raised the rear a bit as well.

Just to check something.....

Tighten (gently!) the rebound damping screws on both forks; perhaps does the screw on the 'long' fork go 4mm deeper?

The pic below is stolen from He-Man's shock rebuild thread for illustration...Thanks

Took the forks back in yesterday and we believe we have figured out what is going on but are currently not sure why.

The reason the left fork was longer...he had issues with the dampening rod becoming misaligned during re-installation. Originally he thought the little cup (not shown) that fits on the end of the damper tube (shown on left side of pic) had a fitment issue so he substituted it with  a spare tube he had in the shop. This tube was an 1/8" longer, not sure why but he thinks maybe its actually out of an early s4r, which essentially over extended the fork.

So he cleaned up the original tube with some light sanding and the dry fit looked good. After  reassembly, as  the compression screw was adjusted  he could feel the aluminum piece (sticking out in pic, right side) come out of the tube. There is a little circlip that is supposed to hold this in. As of now I am not sure if the tube is out of round or circlip groove cut to deep. Could anything else cause this (i.e. is it loaded from above being pushed past the clip)? Anyone seen an issue like this? Anyone have a spare tube from a gutted 07 S2R1k fork? We may try to machine spacers to replace the circlips that will fit between the aluminum piece and bottom of the fork.


(http://kuixihe.com/gallery3/var/resizes/Tutorials/forks/10%20compression%20valve.JPG?m=1303653130)

He subbed a part out?? Go find the original part and find way to make it work. Otherwise, it's just wrong. If he tossed it, he should buy you a new one.

You better all ready have a suspension guru on-hand before you go making your own spacers, and by the sounds of it....not so much?

Well,
there are a few things I´m not sure about here... first, a 1/8th inch (or 3 mm) difference in fork length is easily arrived at if not care is taken to put the fork top nut on both legs at the same height on the cartridge rod.
Seems this is not the case here, but you have experienced what I also learnt some time ago to my expense: There are quite a few cartridge versions around, with slight differences in cartridge tube length. Very annoying, actually  [bang]

I´m not sure what you mean by this statement: "as  the compression screw was adjusted  he could feel the aluminum piece (sticking out in pic, right side) come out of the tube"... is this while adjusting the compression damping with the adjuster at the bottom of the assembled fork?
     

Originally he used a spare cartridge as he felt there was something wrong with mine. This cartridge was approx 1/8" (probably closer to 4-5mm) longer. Which in turn made the fork longer. At least that is the way it was explained to me.


Yes...After I returned with the forks he put back  in my original cartridge tube and reassembled everything.  The forks were back to equal length.  When he gave them back to me I asked where everything was set. He stated the compression was 8 clicks out and then proceeded to verify it in front of me. He adjusted 8 clicks back to zero and as he was putting it back to 8 clicks out he said he felt it "give". Meaning the aluminum compression valve holder pulled past the circlip in the cartridge toward the bottom of the fork.  We did not have time to take it apart again for me to see that in person.

Good morning.

Well, this sounds very strange to me. Take a look at this picture:

(http://i855.photobucket.com/albums/ab117/Monsterhpd/Kompmojkomplett1.jpg)

At the left is the bottom plug in the lower fork leg, it has the slotted adjuster screw in the middle where you adjust the compression damping (or at least can try to, see my previous posts on the subject).
This plug goes thru the hole in the fork leg and connects with the internal thread in the aluminium comp stack holder to the right. This, in turn, sits inside the cartridge tube and is held in place with said circlip / lock ring.
When assembling the fork, the plug is torqued to 40 Nm against this circlip /lock ring, and if ever the comp stack holder would come past the lock ring, this is the time.

The slotted screw you turn from the outside when adjusting the damping only turns, it does not move axially.
On the inside, it has a slot which mates with the blade of the the threaded part in the middle; the not-so-needle-shaped tip on the right is the compression adjuster needle.
As you turn the screw on the outside, this needle climbs (or descends depending on which way you turn) on the internal threads in the bottom plug and has no physical contact with anything else. Especially, no interaction whatsoever with the circlip.
Also, when assembled the fork spring pushes the fork apart; this circlip is what prevents the forks from falling apart.

There is a remote possibility that the slot-and-blade connection between the external adjuster and the internal needle thingy has a problem; with everything properly assembled the tolerance should not allow them to come apart, though.

I hope I managed to make this reasonably understandable; if not let me know.

Kind regards and good luck [thumbsup]  

  

MonsterHPD - Thanks for the response it was quite helpful. It also reinforced what I was thinking, that when the plug is torqued the comp. stack holder moves then or not at all. I'm wondering now if the needle backed all the way out of the stack holder during adjustment, and thats what he felt "give". If so, perhaps it shifted and he wasn't able to turn it back in because the needle and stack holder became misaligned?? I would assume the pieces should be machined in a way that this cannot happen. I should know more tomorrow, they are closed today.

Thanks again

alright alright, i dont want to start blowing holes in your buddy's theories, or throwing wrenches around... but he's got some stuff wrong here. dropping your front end 4mm (or raising the forks 4mm up into the triples) will certainly increase your bike's willingness to turn-in. It will become "twitchier." The reason this happens is because you reduce your rake (angle of your forks). This ALSO reduces your wheel-base length slightly (distance between two contact points of your tires). Unfortunately for your pals theory, no matter what your seating position, a shorter wheelbase equals less straight-line stability at high speeds. Quicker turn-in, shorter wheel-base, less straight-line stability. That's the trade-off. If you're having front end wobble problems at super high-speeds, this likely isn't the solution.

putting more weight over the front end will help, but i don't think this small geometry shift is going to get you there. you'd need to install some clip-ons, raise your rear-end, things to that effect.

the monster is a rear-biased bike, so it's going to feel light in the front... with this geometry change, i WOULD be wary of how twitchy the bike gets. if you notice a lot of wobble, you may need a steering damper... dont want the dreaded tank slapper...

hopefully this is somewhat insightful...