The spring is a 700 lb/in spring (12.3 kg/mm or so) and I am about 150 without and 170 with gear. My free sag is a little on the low side, so I might be well served with a 725-750lb spring, but the 700 seems to work pretty well.
Stock R6 spring is about a 400-450lb spring and would be pretty awful...
-Sean
Stock R6 spring is about a 400-450lb spring and would be pretty awful...
-Sean
mr-fabricator
New Member
Im 180 ish in my gear so trying a 12.5 first . Should be close .
psych0hans
Member
How would one go about refurbishing this shock, as it doesn't come with a valve for the Nitrogen... I'm planning on doing an oil and seal change, but am worried about the nitrogen charging.
There is a means of grinding away the rubber cover on the reservoir. There is then a circlip, a seal, and another circlip. Basically you remove the first circlip, remove the seal, and save the second circlip. Then you insert a new seal, which is placed under the old 2nd circlip, which has a schrader valve on it, and recharge with that. You now have a fully rebuildable shock. Racetech sells the hardware necessary to do the who's change. If you don't have the equipment necessary to charge the nitrogen (you're going to need to recharge to 150psi-165psi) then you need to look at having someone familiar with rebuilding shocks do it most likely. The equipment (Nitrogen tank, adjustable regulator, hoses, and fittings) will run a few hundred bucks at least. You may be able to do the full rebuild for everything, except the nitrogen recharge, and have a shop do just that for you. In general tho, probably best to just have a shop who does this sort of this do it all for you if you are gong the full rebuild route. The alternative is do just the spring, and see if/how long that shock lives. If you pop it, or it needs recharging, then you can look at getting another shock and doing another shock swap, or doing the full rebuild then at that time. I would NOT go that route if you were racing, or doing trackdays, but it might be a viable option for a street rider who needs the time to rebuild funds up to do the shock rebuild...
Also remember, you will NEED to do the front end (at least springs, spacers, and oil) at the same time you do anything to the rear... or that front end is gonna be something you are quickly REALLY unhappy with once that rear end starts working so much better!
psych0hans
Member
There is a means of grinding away the rubber cover on the reservoir. There is then a circlip, a seal, and another circlip. Basically you remove the first circlip, remove the seal, and save the second circlip. Then you insert a new seal, which is placed under the old 2nd circlip, which has a schrader valve on it, and recharge with that. You now have a fully rebuildable shock. Racetech sells the hardware necessary to do the who's change. If you don't have the equipment necessary to charge the nitrogen (you're going to need to recharge to 150psi-165psi) then you need to look at having someone familiar with rebuilding shocks do it most likely. The equipment (Nitrogen tank, adjustable regulator, hoses, and fittings) will run a few hundred bucks at least. You may be able to do the full rebuild for everything, except the nitrogen recharge, and have a shop do just that for you. In general tho, probably best to just have a shop who does this sort of this do it all for you if you are gong the full rebuild route. The alternative is do just the spring, and see if/how long that shock lives. If you pop it, or it needs recharging, then you can look at getting another shock and doing another shock swap, or doing the full rebuild then at that time. I would NOT go that route if you were racing, or doing trackdays, but it might be a viable option for a street rider who needs the time to rebuild funds up to do the shock rebuild...
Also remember, you will NEED to do the front end (at least springs, spacers, and oil) at the same time you do anything to the rear... or that front end is gonna be something you are quickly REALLY unhappy with once that rear end starts working so much better!
thanks Matt, I'll look around for someone who works on shocks. Alternatively I'll just use it as it is and pick up a brand name shock when I can afford it. I'm in touch with YSS but still waiting for a reply. I called their Thailand office and they asked me to mail them, but no reply yet.
as far as the front is concerned I have some 7.5w oil and a set of .85kg springs off a zx6r for the front end. This apart from the rc8 internals and fork lowers.
psych0hans
Member
Hi, how did you add the valve? Did you drill a hole in the original cover and screw one in? Also, can you provide. Link or part number for the seal head? What other parts might be needed to make the shock rebuildable? Thanks
Race Tech sells the parts for the shock, the new seal head, an adjustable preload collar, and the reservoir cover with schrader valve. The cover that is already there can be drained filled with a nitrogen needle, so it is already serviceable. The schrader valve just makes it a little easier. I was in a hurry, so I made a new res cover on the lathe instead of ordering one, but they are reasonably priced from RT.
-Sean
-Sean
psych0hans
Member
Thank you (y)
psych0hans
Member
Any idea how many shock bushes I will need? I'm buying one of each - reservoir bladder, shock bush, seal head.
OldVet
New Member
Well I'm not happy with the stock rear shock so I'll be keeping an eye on this thread, thanks...
Hunterbear
Member
Also remember, you will NEED to do the front end (at least springs, spacers, and oil) at the same time you do anything to the rear... or that front end is gonna be something you are quickly REALLY unhappy with once that rear end starts working so much better!
Formula390 what is your recommendation for the front? What spring weight or spacer size and oil weight combo needs to compliment the new rear? I average 175 geared up. As far as the rear goes, if I just order a rear spring from Racetech for my geared up weight, then that should be the only thing I need to swap off the Yamaha shock to get the rear rocking? Just want to clarify a few points before I go ahead with the swap out. Thanks for your insightful help!
gbabyracing
Member
How much preload in mm do you have on that 700lb spring?
I'd have to double check, but about 12-14mm. I was running the spring on the 9/10 setting on the stock shock (with 3 mm added length, so somewhere between 7/10 and 8/10 on an unmodified shock). On the R6 shock I'm running it on about the lowest preload setting which gives me 164mm of total length on a 178mm spring. If I go with a heavier spring, I'll need to install a threaded preload adjuster.
-Sean
psych0hans
Member
theres only one way to find out. Lol
AirRsq
New Member
I'm doing the R6 shock swap right now and I'm gonna say "no". The reservoir being vertical will definitely interfere with the exhaust. The R6 shock has a horizontal res and barely fits. And if you mounted it backwards with the res facing the rear, it would definitely hit the airbox. I can say with near certainty that this pictured shock will NOT fit.
Alex no, sorry. Most likely it won't. The 99-02 shock reservoir is oriented horizontally, but just enough that it still clears. The shock you found there MAY work if you have an Akropovic or Arrow exhaust, but with stock exhaust, no chance. Sorry. The only shock swap candidate that made the cut, out of WAY too many I tried, was the Gen1 R6. Others came close, but didn't meet all the criteria for fitment. Even the aftermarket Gen1 shocks typically don't work it turns out... just ask the others in this thread who tried other possible candidates.
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