UPDATED WITH PICS ON PAGE 2 (2/20/2012)




So I'm at the point where I feel a better shock would help a bunch. So far I've come up with the following options and I want to keep this under $500.

Here's what I know about the shock:
305mm or 12" from eye to eye. Spring is a 14.2 kg/mm or 800 lb/in. I weigh in at 165-170 so I need about a 900-950 lb. These springs are pretty common, they are a 2.25" ID, 6" length and come in all weights up to over 1000lbs in 25lb increments.

Here's a great site I found with lots of shock lengths http://www.worksperformance.com/pdf/...ide/street.pdf

1) Ohlins/Penske/Fox F4i shock - If I can find one under $500. Pretty much must have an external reservoir otherwise there might be fitment issues.

2) Adapt a better shock that is approximately 12" from eye to eye and put spacers on it if it's a little shorter, or if it's a tiny bit taller it's okay because I need a slight increase anyway. Must have external reservoir although some configurations of shock mounted reservoirs might work ($200-500)

3) Racetech gold valve kit (apx $160), spring ($80+$5 collars), +oil and nitrogen and do it myself, or send it to Jamie Daugherty who specializes in adapting these shocks for other bikes (apx $300+).

4) Just put a new spring on it.

Option 1 would be great if I could find one.

Option 2 sounds like fun but the shock would have to meet a lot of criteria. I already know of a couple models that would probably work.

Option 3 sounds like the most viable, and I am not scared to do it myself, although I'm not sure where to get the nitrogen charge at, and it seems like it would be about the same price to send it out to him. I am concerned about whether the upgrade will be substantial enough to warrant the price.

Option 4 doesn't sound too bad either, but I'm concerned whether there will really be much of a performance improvement.



Any info you guys could spit out, particularly regarding just the spring and or racetech gold valve upgrade would be great.

 

I think you can get the nitrogen charge at a local bike shop. Why are you upgrading, is it your track bike? If it was me I would just change the spring, but I really can't tell you what kind of improvement you would see. Have you tried emailing the spring manufacturers to see what they have to say?

 

I would go with the Penske sport shock, its over your budget ~625 and no external reservoir but I think it would more then meet your needs.

On the street youll never work the shock enough to need an external reservoir, its rebound ride height and pre load adjustable, but the internal low an high speed compression can be set for your type of riding/body weight/bike when you order the shock

and lastly you can always upgrade it later to add the external reservior


full disclosure: i have a penske double click, ride almost all track

 

I'm an I level track guy but the bike is both street and track.

 

For the price your looking at your choices are either a used shock or rebuilding your current one with new valves and spring. I've heard people say over and over how bad the stock shock is yet I seem to have good results with it. I'd think the valves and spring rebuild would be plenty. I know valves and springs made a world of difference in my forks.

 

I feel ya, and I'm leaning heavily in that direction but I'm seeing Penske units for other bikes that are in the same price range that I could adapt to the bike. I just wish I knew someone who upgraded the shock with racetech internals so I could know if it's worth it since it's still using the stock body.



I found this link which shows the shock eyelet diameters.

My thought is that with a slightly shorter shock, I could add a spacer to the top bolt and weld it together with a longer bolt, but I risk the stroke being a few mm shorter, while with a longer shock I wouldn't need any more spacers, but either way I'd have the get the eyelet size right.
Here is an example



r6 shock is 12.13" while ours is 12" so that's about perfect (especially with adjustable ride height), but I think our eyelets are 10mm on both ends while theirs is 10/12mm, so I could just drill out the mount a tiny bit and use a 12mm bolt. Problem is most aftermarket shocks use a piggyback reservoir that may not fit.

Also the 954 shock is about 11.5" but I think the eyelets and all that match up, so just an extension would have to be made, but the stroke is 57mm vs 60mm.

Also our stock spring is an 800lb spring, so I could re-use it in whichever application. After reviewing my numbers I think 850-900 would be more ideal but 800 would do if whatever used shock on fleabay was under/oversprung.

If the bike weighs 420 semi wet and the rider weighs 165, the stock spring is actually almost perfect, assuming it isn't progressive or anything.

 

Just want to update some more information. It is unfortunate that the design of our bike requires such a high spring rate, as many bikes use springs in the 500-600lb range. It is also unfortunate I only see a used fox shock for our bike in the $700+ range on ebay, so I'm going to take the risk with a different shock.

The Aprilia RSV / RSVR shock up to 04 was around 305mm, depending on who made it. A little taller for Ohlins and a little taller than that for Penske.

Brand Model Year - Aprilia RSV 1000 R 2004
Öhlins shock absorber
Part No. AP 351
Type 46PRCLS
Length 313 +3,5/-2,5 mm
Stroke 63,5 mm

Unfortunately the spring rate is around 550 lb but after looking up the part number (1091-31/95L490), it is a 6.3" 2.25"id spring so I'm pretty sure an f4i stocker would work. The good thing is that this shock is all over ebay and the eyelets look about closest to what would work for our bike aside from a 929/954 shock.


I have finally decided to go with a Fox double clicker from an r6 off ebay that was very recently rebuilt by traxxion. It appears that most shocks use a 1/2" OD bearing/bushing for the eyelets, so upon arrival I will verify, pop them out and make or order the size that I need. Also the spring is only like 550lb so I will just reuse the stock spring @ 800lb.

Many of these shocks are a piggyback design, but after closely examining the bike, it appears that a piggyback that is perpendicular to the shock but sticks out to the left side (shock body on top, piggyback on underside) would fit. Conversely, the shock could be mounted the other way around, with the shock body on the bottom, piggyback on the topside and it just appears that the stock little mud flap on the undertail would need to be cut. It is preferable to mount the shock body to the bike with the rod end on the wheel for less unsprung weight (first option). Again if you can find an aftermarket shock with an external reservoir, that would always work assuming you got everything else right.

Here is a pic of the fox r6 shock


Hopefully this information helps someone in the future - and if i get this to work, I will post it up.

 

if your gonna spend 700+ on a used fox shock for an r6 why not get a double clicker penske since you ride both track and street, its 875 and can be rebuilt at any time and adapted for any bike out there, i asked about fox shocks and my guy told me they went out of business and parts are becoming harder to find. Best of luck though

 

Have to see how this works out. Would also like a new shock..... Subbed

 

Penske is probably a better unit but still it was $325 for a fox r6 shock that was recently refreshed by traxxion (who may have upgraded it) as opposed to the one aftermarket fox shock on ebay for the f4i that is going for $800. Yes I could buy new but that $1000 is way out of my budget which is why I am going this route. There is also a WP competition 3-way adjustable shock for under $250 but it would probably need to be freshened up. I would probably be able to sell this shock again if it doesn't work. I'm sure the Penske could be adapted for most bikes but it would still require quite a bit of work being that the bottom mount on our bike is so wide and that a 12" shock is pretty uncommon these days. I think the r6 shock would require the least modification aside from of course stumbling across a shock actually made for the f4i.

Another reason I went this route is because I emailed racetech a bunch of times regarding their valve kit and or pricing on a new g3-s and they never responded. Also Fox is still in business, just not for sportbikes.