BASTOK

Hi all !

I want to change the original rear shock of my '99 XX. Here in my country putting a Olhins it's almost impossible, we are talking about U$S 2000 o maybe more.

I will buy something used but in good shape in the US, but I need to know if someone knows which models of rear shock could easily fit the XX (the 99 or upper).

Here I know someone adapt a cbr 600rr 04 and it works fine. But was on the XX '98, carbs, so there are differences in the space available to put the new one, especially the gas bottle.

Did someone have some experience on this ??


Thanks in advance!

Bastok

Nutter67

Another alternative is to fit the rear shock from a pre '95 CBR900RR. Just needs a heavier spring (and a rebuild/overhaul). It will bolt straight in - just need to find somewhere to mount the remote reservoir. I upgraded to a longer braided line and fitted the res under the seat.

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Paul

Never let a motorcycle take you somewhere your brain didn't get to three seconds earlier

CanadianBird

You could ship your shock to Jaws during the "off season" for a rebuild. You could try Penske, maybe it's more affordable than Ohilins. The above advice is probly better.

smurf211

Here are some notes:

Penske Shock Installation problems....

CanadianBird

I remember that tread and I bought my Penske from Tripledigets. Is he still on the board? I had my tech do the install it's mounted near the left side grab rail. Bike can still go on the centre stand and now the rear wheel is closer to the ground. I confess I do throw a lot of dosh at my bike parts and labour, and I'm able to. I recognize others are very skillfull and prefer and are able to do their own work. My hat's always off to them. I also am aware not everyone has "unlimited cash" to throw at their Bird. Which is why this forum is so excellent. Advice, alternatives, pictures(except me) abound. The skill level is very high on our forum. Good luck on you search for a new rear shock. Of course then you'll have to re-build the front. lol

BASTOK

Thanks you all for the quick answers.

I will look if I find some 900rr on ebay in good shape, because I think the 900rr '95 we could find maybe there are quite old and no in 90-100% working condition!

Living in a country where you have to pay 100% of duty taxes to import things from other countries is dissgusting. If you tell me a Penske for U$S 600 or an Olhins for U$S 1000, well maybe I'll think of it, but U$S 2000- 2200...........

I think something used and in good shape for the rear ando maybe some Hyperpro for the front (new) I'll be wasting near U$S 700-800 and improving the front and the rear ...

I will continue in touch!

Banshee

I got a cheap 900rr, then had it rebuilt, revalved with Gold Valves and a new spring to suit my weight & riding style. Made a fantastic difference.

On my last BB, I just had the OEM rebuilt with Gold Valves and that alone was a fantastic change.

As long as you don't need to be adjusting the rear a rebuilt OEM BB rear is fine. If you need to make adjustments for 2 up/single or road/track days, then an overhauled 900rr or aftermarket would be preferable.

lois

Questions.

Was that a pre 95 like Nutter stated?


What make of shock is it?

Lois > aka, man of many questions.

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Banshee

Yes, it is a '94 900RR. That's one of the main reasons I went with full rebuild.

Brand is Showa, same as the stock BB rear.

Mykl > aka, man of as many answers as I have. And a few extra questions, as well...

lois

Thanks guys.....I will try and locate one.


Lois

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shewie

There is something brewing on this topic. Stay tuned for another of smurf211's excellent write-ups. BTW, you may want to hold off on that, Lou, unless your Gixxer is boring you and you want to take your bird to the track.

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smurf211

So far from all the research I have been doing this recommendation is dead on. I talked to John at Jaws and the economical way to go is the BB stock rebuild with a heavier spring and look into the possibility of having it converted to oil over oil instead of gas over oil, which is optional. But if you want the adjust ability as stated above, the 900rr is the way to go. The heaviest spring for the stock 900 is 15kg/mm. Race tech calculator for me is 17kg/mm. which isn't far off. Motion-Pro has a spring for about a $130 that is a lighter mm rate but progressive (PDS). I also found some ballpark numbers to get an idea of cost: $150 rebuild, $50 re-valve, ~$100 re-spring, total about $300. I just won a bid on eBay for a '93 for $40. So for approx 350 +- plus the extension for the reservoir, we are at about half of what a Penske would be and about a 3rd of an Ohlins. Again this is all personal pref. I think with reasonable effort and cost you can upgrade and then adapt to your components and learn their limitations. The best bang for the buck for the front, according to John, is the kit they have with the longer springs, shorter spacers and 10w oil. Apparently they have put a lot of time into evaluating this and they feel the gold valves and the golden (price) shocks are marketing hype and ridiculously expensive. To some extent I have to agree. Again, this is up to the individual and is subject to personal preference, and what your requirements are. You can always upgrade in stages. I did a part number comparison if anyone wants to see it from Ron Ayers and the 900rr shock list the same number all the way through 93 - 97, but when you start spec-ing out the 900 shock on Race techs page they list from 92-94 in a group. I won't post all that but I think it is safe to stay with a 93 or 94 year shock.


Here's a link. There are plenty of others. I tried to look at Eibach and all I could manage was dirt bikes. I must be missing a link on the page.

Moto-Pro Suspension


I am going forward with my RT Gold valves for compression, rebound, and the springs. I am getting a clunking sound when I go over the railroad tracks by the house. My confidence factor is limited right now. When I had the Triumph and the Pilot Powers I would not hesitate to lean over, but I'm just not there yet with this machine. I feel my tires are adequate, and the shock will do for know, but my front end is suspect so I haven't gotten to frisky with it in the corners. Hopefully we're going to change that next week. I am also putting a 47t on the rear, total error correction for that is -11.75% on the SH. ... // smurf

Banshee

Damn, the post I wrote earlier didn't stick. Have to type it again.

Ok, I have an Eibach spring from this page Eibach Springs - Performance Suspension, Lowering Springs, Shocks, Sway Bars, Coil-Overs and Wheel Spacers!

I selected motorsports, then used the application selector link. Then North Am, Coil Over, Main, Imperial, 2.25, 6.0. The one used for my rear was the 0600.225.0950. Whish is 6" length, 2.25" ID, and 950 not sure of the units, lbs/ft? Don't remember. That is for a rider ~85kg (~187lb) on the bike with bag for street, not track, riding. They also put in a spacer ~ 5-10mm thick as the spring is shorter than the OEM Showa one.

smurf211

Ok, not having the specs from you I would have NEVER found this. Is it safe to "assume" that the 950 designation is kg/mm?


And haven't some of the heavier riders been going with the 1100 kg spring rate?

I'll add this to my info collection. I should probably summarize and place this over in my suspension tracking thread. Thanks, Banshee. Also 1 kg Racetech fork springs are not to be found so I ordered the .95 kg for the front. I believe X1 has these and if it's good enough for him it will certainly do for me. // sm

Eibach Springs - Performance Suspension, Lowering Springs, Shocks, Sway Bars, Coil-Overs and Wheel Spacers!

Attached Images

Eibach Spring rate.jpg (25.7 KB, 20 views)

Banshee

I think you may be correct with that, smurf. Although 950 kg/mm would sound more like a bar than a spring! kg/cm perhaps?

I used the calculator on the Racetech site to work out what spring weight would suit me and then picked the closest from Eibach. RACE TECH PRODUCT SEARCH

For 75kg rider (no gear), I get ~16.6kg/mm = 923lb/in. So it is lb/in after all and the heavier guys are using an 1100lb/in spring.

smurf211

This is what I've come up with. My question next is adapting the heavier spring to the 900rr shock. When I get the 900 shock in I'll supply some photographs for comparison. It's kg/mm but a beer sounds great right about now.

Attached Images

racetech 250 # on a blackbird.JPG (71.6 KB, 20 views)

shewie

I'm so glad that you are doing all this, smurf. After our conversation I think I will do some fiddling with what I have, but I need to pick your brain some more and find out what else you learned about rebuilding the Showa unit.

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Banshee

When I had mine done, I took it to a bike suspension specialist. The drilled the unit to release the pressure, (there wasn't any, surprise, surprise), then stripped it down and cleaned it. When it was reassembled they put in a valve to repressurise it. (At least, that was what they needed to do for the OEM BB shock, I don't remember if they needed to do that for the 900RR, but I think so.)

Once stripped & cleaned, they replaced the OEM valve with a Gold Valve & shimmed to suit my weight. The made up a spacer to go on the end of the spring as the Eibach spring is shorter than the OEM 900RR spring (~1/4"-1/2") and is not tapered like the OEM. The also made a spacer which was fitted on the shaft of the shock internally that effectively lengthened the shaft so it doesn't need the 6mm shim on top. Refilled with fresh oil, assembled with a longer hose between shock & reservoir, (from memory they used a leftover Galfer SS braided brake line they had from when they sold them as well), & repressurised. A bit of fine tuning of the settings with a ride test or 2 & it was all good.

edit: Added a pic of the stock valve from the 900RR shock.

Attached Images

shockvalve1b.jpg (129.4 KB, 28 views)

shewie

Banshee, would you mind laying out exactly what you had done to the stock unit? I think I will keep using mine and just try to make it as good as it can be, so any info I can gather will be helpfull come winter.

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Where are we going and what am I doing in this handbasket?!

Banshee

On my '98 I had the OEM BB unit overhauled by a bike suspension specialist.

They drilled top of shock to let out pressure & disassembled shock. It was cleaned out & the valve removed. Gold valve was installed & shimmed for my weight & road bias (as against track bias shimming). As I very rarely ride 2up or track, a set & forget system was fine by me then.

They then reassembled it with fresh oil & original spring, as it was in the right range for my weight at that time. The put a schraeder valve in where they drilled the top of the shock & repressurised it with nitrogen. Put it on the bike with a 6mm shim.

I then took it out for a ride & they tweaked the preload & rebound based on what I told them. Practical upshot is that the ride is much smoother. If you look at the pic of the valve I put in the last post, it is similar to the BB valve, although that had fewer larger holes, they still aren't all that large. The Gold valve, however, ony has 3 holes each for compression & rebound, but the take up most of the face of the valve. Probably more hole than valve! As a result, when you hit a small sharp bump, the size of the holes in the OEM valve restrict the oil flow, so more of the inital impulse is transmitted to the frame. With the much larger holes in the Gold valve, more of the oil is allowedto flow through the holes with the shims doing the control of the response to that same inital shock. So the force transmitted to the frame is smaller, but over a longer time, smothing it out better.

In the pic, you can also see the OEM rebound valves. I had these done with the front on both my '98 & '07. It seems that for most road riding the OEM compression valves are fine with lighter oil (5wt). They replaced the rebound valves & shimmed as appropriate for me & used slightly heavier Racetech springs which, like Jaws spriings, are ~100mm longer with a shorter spacer. The Gold rebound valves also had much larger holes than the OEMs. Again, this lets the shim stack do the work of controlling the oil flow rather than the valve holes. Having said that, I suspect that the main improvement is from the springs & lighter oil. The lighter oil having the same effect as larger holes, by flowing through the compression valve easier, and it is the reduction of the inital impulse when you hit the small bumps that takes much of the harshness out of the ride. The springs then give you the better ride & cornering feel. It is usually said that the front, in particular, is overdamped & undersprung, which is why the basic conversion of Jaws springs & lighter oil works so well & is such good value for money. Once you go far beyond that, it becomes a matter of diminishing returns. Although some want that extra adjustability & use it, for most of us it is more likely that a single set & forget is the best value option.

Are you confused yet? I think I am!