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Discussion Starter #1 (Edited)
All,
I installed a zx6r shock on my 2007 sv650s over a year ago and I am really questioning my choice and whether or not my setup is close to correct. Here is where I'm at:
front forks: .90kg/mm Sonic Springs, preload is 2 1/2 graduations out
rear: '09 zx6r shock (ebay), compression and rebound are in the middle, I have backed the preload all the way out because I feel like the bike it trying to buck me off on the really bumpy stuff if I'm riding fast. It's not terrible but I suspect it could be better.
tires: all stock sizes (120/60/17, 160/60/17) Pirelli Angels fwiw. I had a 70 profile on the front but now I like the 60 after going back to it. I'm open to trying different setups though.

I see people changing the amount of fork visible above the triple clamp... I just have the caps visible (no fork tube). I also see differing opinions as to the rear shock length. Looks like the '09 is 339mm. Is this acceptable for a Gen 2?

No track days yet but I would like to. I really want to take my bike up to RaceTech if I can't get this figured out in my own garage. I probably will regardless but I would like to get this as sorted as I can with the equipment I have. I keep watching Dave Moss' videos and I'm trying to get this nailed down but I'd like some advise from the SV crowd. You all have been down this road before!

My specs: I'm currently about 166lbs. I was 200 when I installed all the parts though so it's been changing. My leathers are pretty heavy so I'm probably close to 180 with that, boots, helmet etc.
 

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rear: '09 zx6r shock (ebay), compression and rebound are in the middle, I have backed the preload all the way out because I feel like the bike it trying to buck me off on the really bumpy stuff if I'm riding fast. It's not terrible but I suspect it could be better.
Not sure if this your case or not but most people who find the bike too hard or stiff on road bumps are setting their rebound with too much damping, and try to compensate this with little to zero preload.

Have you tried to set the preload to get the correct rider sag and setting the rebound near to full open?
 

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Discussion Starter #3
I have not set the rebound to nearly open, no. I will definitely try that. It's just in the middle now. I set the preload for sag because I thought that was a good place to start but you may be right on the rebound, thanks!
 

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start by setting sag. if you cant get the right sag numbers out of the bike, everything else is not going to help. since you havent posted sag numbers, I'm betting you're way off.
 

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Discussion Starter #5
Well that's kinda my issue. I started with this video and Dave Moss' video on sag when I originally set this up. After feeling as though the bike wanted to buck me I started second guessing my rear shock choice (length and weight of the spring). That's when I started backing out my preload on the back to see if it helped. It seems to have helped some but Skywalker's comment has me thinking rebound, but my weight has changed a lot too. I'll have to re-check my numbers now.
 

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I concur with mad8vskillz: first of all you need to correctly set your preload for your actual weight.
More race or touring oriented your choice, but that's the starting point from which fine tuning of compression and rebound shall start, based on your feeling with the bike.

And, after setting the correct SAG, if you feel the bike is going to throw you off the saddle on road bumps, I'd start with an almost open compression and rebound, and then slightly increasing from there on trial-and-error basis.

Edit: I'm not completely sure about the rear shock lenght you quoted in your opening post. I was under the impression it should have been 335mm for a gen. 2 SV, but I might be wrong on this.
 

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Yup, preload for sag first, both ends.

Shock length is slightly longer than the stock 330mm, but that's not necessarily a bad thing, depending on how you want the bike to behave.

The bike 'bucking' over bumps sounds like too much damping - comp, rebound or both.

I wouldn't start dropping the front until you've set it up as is, then feel like you want it to turn even faster - you've already raised the rear with the longer shock. If you do that you then have to start from scratch with preloading for sag at both ends again.
 

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Discussion Starter #8
Well I checked my numbers again. Front is the same as I wasn't messing with it (it's in that 30-40mm range, about 35). I had set the rear to 35mm as well but it's more like 40 now after I backed it out. I think I need to get that back to 35mm and start adjusting my compression and rebound damping.

I really just wanted to check with everyone here as far as if the shock I put on was close enough to really "working" length-wise. It sounds like short of a Penske I'm not too far off the mark. Also I should clarify that the roads I ride involve some pretty gnarly bumps/potholes/washouts etc. so I may be asking a bit much of the suspension. It has occurred to me that an XR650 may be better for this route at times :lmao:

and DarkHorse, yeah I agree on not dropping the front forks. I think I had seen that mentioned when people went to a 70 profile front which I've already done and I didn't care for it. I'm back to a 60 and prefer it. I only brought it up in case I was leaving any stones unturned.

At this point I'm just going to enjoy it and take it up to RaceTech when it's convenient.
 

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IMO your geometry is better with a 70 profile front and the rear raised enough to get rake/trail where you want it. the profile on the 70 is better for handling.

if ride height is an issue due to leg length, that's a different story
 

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Discussion Starter #10
IMO your geometry is better with a 70 profile front and the rear raised enough to get rake/trail where you want it. the profile on the 70 is better for handling.
That right there is why I went with the 70 in the first place. I figured it would even out the taller rear shock. While I'm sure it did, I found that I didn't care for the 70 profile when I was doing my parking lot practice sessions (figure 8s, tight weaves, u turns in the box etc.) When I went back to the 60 the bike seemed to "work" again. While the 70 handled better on the highway at 80mph I found it handled worse in the parking lot at 8mph. Since I quit commuting with this bike I'm more interested in the latter.

That's my long winded way of agreeing with your point! ;D
 

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Discussion Starter #12
busdriver
that is a spec I'm trying to nail down too. According to RaceTech's site the '09zx6r spring rate is 9.2kg/mm (sounds close to your number) and according to this thread I should be dang near that range with my fluctuating weight. Or at least between 8.95kg and 9.4kg/mm

Your point is well taken though, the zx6r IS stiff compared to my stock pogo stick at 7.697kg/mm. I am of course basing this all off of these interweb resources and I wouldn't mind getting confirmation from someone. I myself found the 9.2kg number for this zx6r spring and you found 10kg... which is a considerable difference in actuality! That leaves me wondering what I really have.

Thanks for google-checking me, my google-fu may not match your google-fu :ears:
 

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I pulled the 10kg/mm number from the racetech website. Racetech also recommends a much softer rear spring than Penske. I suspect the Penske numbers are meant for a competent racer.

I'm about 180 before putting on gear, I'm an intermediate track day guy, not a competent racer. I have a 8kg/mm / 450 lbs/in spring on the back end of the track bike.

Edit to add: I had a ZX-6R shock on the rear to hold me over while I was getting the Ohlins rebuilt. 2006 I think. In any event it was way too stiff for the pace I'm riding.
 

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Discussion Starter #14
That's very good frame of reference right there, and really the info I was looking for. I suspected this shock was just wrong from the outset so I'm pretty sure a RaceTech trip is in order next week.

Good news is I have almost no money invested in that rear suspension, just time. I had to replace it anyway since the stock shock blew out on my commute. Now that this bike is moving from 99% commuter to 100% fun canyon bike I need to get these things in order.
 

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That right there is why I went with the 70 in the first place. I figured it would even out the taller rear shock. While I'm sure it did, I found that I didn't care for the 70 profile when I was doing my parking lot practice sessions (figure 8s, tight weaves, u turns in the box etc.) When I went back to the 60 the bike seemed to "work" again. While the 70 handled better on the highway at 80mph I found it handled worse in the parking lot at 8mph. Since I quit commuting with this bike I'm more interested in the latter.

That's my long winded way of agreeing with your point! ;D
between the two, did you adjust ride height on either end to maintain the same trail with the two front tires?

if changing nothing else, it'll turn in faster with the 60 than the 70... but it won't have as much edge grip, the profile is lazier, there's a higher chance of denting a rim, etc.

you need more rear ride height with the 70.
 
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