Fasteddy
Member
Interesting, but, my RC shock is sitting in my garage and does measure 300mm and when compared to the RC8 spec'ed at 290 I measure 10mm difference. I did see the spec given as 304 in the manual for the RC and there is no KTM part number on the RC390 shock...
Fasteddy
Member
Yes, I have both service manuals opened at this moment, I do not dispute what the manuals, shop or owners are saying but My measurement of the shock is closer to 300 then 304 like 301. I could loosen the jamb nut and give the lower eye a turn to see how much difference it makes, what would be more interesting is to see what part numbers are on the Duke shock, my RC has a 100235 U-023, and what appears to be two different date codes, one close to the part number I would assume is the design date 07 12 2007, above that a 2015 manufacture date. curious if the dampening is different?
On Ebay I found an excellent pic of a Duke shock showing the part number, same, but says USA after it, mine has a USA sticker on the top eye, interesting stuff...
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The RC eye to eye length is 300mm. Period. That's measured by a machinist (me) and the R6 eye to eye is 304mm. It could be you got the numbers mixed up. I regularly measure parts to 0.001" (or 0.01mm) and that 300mm eye to eye is dead nuts. {shrug} Sometimes manuals get stuff wrong. Errata exists because of these "bugs" in the documentation.
psych0hans
Member
I finally have the R6 shock fitted and ready to go. I measured the sag today and it's too high. Going to need a new spring, sooner than later. Here are my numbers -
Rear static sag - 542-532= 10mm
Rear Rider sag - 542-498= 44mm
Preload - Max
still need to set the front preload on the RC8 forks, but I realised I didn't have the needed socket to adjust the nuts. Will source it asap and adjust.
Rear static sag - 542-532= 10mm
Rear Rider sag - 542-498= 44mm
Preload - Max
still need to set the front preload on the RC8 forks, but I realised I didn't have the needed socket to adjust the nuts. Will source it asap and adjust.
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Ktm rc 390 yamaha rear suspension swap
I just did this swap today and it makes a HUGE difference with the ride quality, I recomend it to all of you, plus a buddy of mine gave me a spring from I think a newer yamaha because it is black in color and I just replaced the spring too. Last photo is when it had the stock spring and shock. Next upgrade will be the Arrow GP2 exhaust, love that sound.
I just did this swap today and it makes a HUGE difference with the ride quality, I recomend it to all of you, plus a buddy of mine gave me a spring from I think a newer yamaha because it is black in color and I just replaced the spring too. Last photo is when it had the stock spring and shock. Next upgrade will be the Arrow GP2 exhaust, love that sound.
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Even though they may have different part numbers, I believe the RC and Duke are fitted with the same bargain-basement OEM shock. The R6 conversion fits both variants equally well, and does indeed perform immensely better than the OEM piece. I do not think it is at all consequential that the R6 shock is 304mm eye-to-eye, vs 300mm for the stocker: The R6 conversion is a great, cost-effective mod for which we have Matt to thank.
DeathFromAbove
New Member
Where or what did you guys search to figure out that the R6 damper/spring assembly's eye to eye, mount type and spring rate would work for our bikes?
I ask because my NSR250 needs some help too. It's a lowly MC16 and won't see much beyond the occasional spirited ride so I'm looking to get it done on a budget.
Back to the RC...
Read the thread and from what I understand the R6 stuff will work fine with my 150lbs. Or did I miss something?
I ask because my NSR250 needs some help too. It's a lowly MC16 and won't see much beyond the occasional spirited ride so I'm looking to get it done on a budget.
Back to the RC...
Read the thread and from what I understand the R6 stuff will work fine with my 150lbs. Or did I miss something?
to answer your second question first: Your 150# on a RC390 would work with the upgraded 10.7kg spring. The stock spring would be a little light for you... Once you are in gear you are going to be pushing closer to 170# or so, so you'd need more spring to get your sag set correctly... Now, as to how that might work for an NSR... no clue! The MC16 is certainly going to weigh less than the RC390. I don't remember what the eye to eye length is on the NSR shock, and it's been a LONG time since I've held one of it's shocks in my hands. On my MC18 racebike I had fitted a fox shock, I BELIEVE off of a CBR 600, but I've no idea what generation. For that swap, I pulled the NSR shock and went digging through a pile of shocks at a local suspension shop to see what might fit and we reworked the shock for my specific race application. We changed the valving a few times before we got it dead nuts on. Honestly, your best approach for the NSR is to contact Paul at Tyga ([email protected]) and see what they say. They are THE NSR experts, so if a swap candidate is out there, they'd know. There is also a NSR listproc you can join and email to. Most of the owners there are 21 and 28 riders, but there are the small handful of 16 and 18 riders still.
Now, as to your first question... The swap candidates were narrowed down by drilling through tons of sources for shock sizes and lengths... from pretty much any and all manufacturers. Forums were a great location for me to search for this information, and basically I distilled the initial list down to shocks which were approximately the correct length and had the correct mounts with eyes on both ends. Once I had it narrowed down to the top 8 candidates, I then ordered the cheapest version of each and started trying to do fit-up. This took a few months in all to locate all the shock candidates and fit everything up. Once I had the final best candidate in hand (I had a strong indication it was going to be the Gen1 R6 I posted here I had a final candidate possibility. The valving was one of the key questions. If the shock was going to require revalving, then it might have put it outside the realms of a cheap swap candidate... but as it turned out the thing fit NEAR perfectly. The rear brake reservoir requires a little relocation is all. Then, it was down to spring rates and availability, and if it COULD be rebuilt... RaceTech offers a kit, so I ordered up the parts, rebuilt one, fit the estimated spring for my weight, and took it for a ride. It worked! Some of the other foum riders also on the indication that a candidate had been found also tried it, all to pretty much universal favorability. For track duty, the damping is not quite there. One might be able to get away with just changing the shock oil from 5w to something more like 7w or 8w, but really it's just not all that well suited for race applications. For canyon carving, street use, and the occasional track day, it'll work well enough... and WORLDS better than the stock shock.
The swap candidate took a LOT of time and work, and money, to get it all narrowed down to the available options. I then released all that information to the forum / rider community as Open Source information as my means of giving back to the community that puts groceries on my table. If folks want to order a shock from me, terrific. If they want to order the parts from me and do the work themselves, I can do that too. If one is just changing the spring, it's perfectly possible to do oneself... it's not the EASIEST thing in the world, especially if you have rudimentary tools, but it's possible and links to videos showing how to do it have been provided in the thread along the way. I built a special setup for removing and installing the springs, and also have all the equipment to rebuild the shocks, refill the oil (oil has to be pulled at vacuum to degass or you end up with an emulsion shock still), as well as recharge the nitrogen. The bleeder to pull vacuum, and the vacuum pump, as well as the various fittings and such, plus the nitrogen recharge setup, was probably about $500 in all to assemble... so it took my rebuilding a few shocks for forum members before that investment broke even, but I've done enough now that the equipment to do the work is paid off. I think it's been a good investment in the community, and was also something I feel helped build my reputation on being a good forum and RC390 community supporter.
I know that both myself and Chad at Commonwealth Moto feel that the best community supporters, not just forum sponsors, go the extra mile in terms of customer service and giving to the community. The both of us work together, and we share common values on how we demonstrate our support of the community...
DeathFromAbove
New Member
Thanks for taking the time to write all that up. Looks like I've got my work cut out for me to find something for that bike. I've heard about the CBR600 shock being an option but no idea on which generation.
I've got an R6 shock on its way over to me for the RC. I'll probably toss it on just to see if the damper needs a rebuild and order up the spring kit (and rebuild if necessary) from you over winter.
I've got an R6 shock on its way over to me for the RC. I'll probably toss it on just to see if the damper needs a rebuild and order up the spring kit (and rebuild if necessary) from you over winter.
Matt you are one of the best guys here. Stellar standup guy. See you next year at MOTOGP COTA
Edwardp33
Member
Matt is good people. Buy stuff from him. He has been great for me and others in Austin to work with. Matt rocks!!!
CDN Duke
Member
Quick question, for a bike requiring a lowering kit (wife is 5'2"), is the R6 shock still an option? Perhaps with shorter spring?
CDN Duke
Member
Update - I've ordered a T-Rex Racing lowering kit, which simply offsets the top mounting for the shock so the R6 would still be an option it seems. (as compared to other lowering kits that replace the lower shock mount on the stock unit)
Fasteddy
Member
Yes and yes...
Ok Thanks !
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