Shock Swap with 99-02 R6

[mr-fabricator]

I only had half an hour so it was just enough time to see if it actually went in ,

Im 73kg / 160lb on the scales + 10kg / 22lb of gear .

My bike track side weighs 147 kg /330lb

I went onto a suspension calculator and it suggested 0.8 springs for the front , its race only and i push hard so will probably go 0.9 or 0.85 front and some 7wt oil , its cool here in oz at the mo 20deg c but i hit the track in the summer at high 30's low 40's and obviously theirs a bit of heat to contend with from the exhaust .

For rear spring ill ask my suspension guy but looks like something between 12-15

New to all this suspension stuff but keen to do as much as i can myself and knowledge is good so we dont get stuffed from the shop thinking we will take whatever . Some bad people out there who earn a living from unsuspecting sustomers .

Will try to put the stock spring on the r6 shock just to get it rolling . As mentioned before the front is shocking when u actually have damping at the rear .

 

[mr-fabricator]

99-02 R6 Weight:
Dry Weight: 167.5 kg / 369.3 lbs
Wet Weight: 197 kg / 434.3 lbs
Stock shock rating: 9.8kg/mm

RC390 Weight:
Dry Weight: 139 kg / 306 lbs
Wet Weight: 154 kg / 339.5 lbs
Stock shock rating:*variable 8.8kg/mm to 17.7kg/mm


So with the stock r6 bike being a full 30kg heavier than my bike but adding that i want a firmer spring for the track That the stock r6 may just do , but i know theirs the ratio to contend with ... im just getting confused now ! Lol

 

[Ryanthegreat1]

I think we are also over looking the fact that the R6 has a rising rate linkage in the rear suspension and the RC has no linkage.

 

[mr-fabricator]

I think we are also over looking the fact that the R6 has a rising rate linkage in the rear suspension and the RC has no linkage.

Yep , sussed that as soon as i posted ...

On a plus i stayed behind at work today and jumped on the machine shop lathe

Found some 316 stainless 12mm ground bar , run a 10mm hole through the center and parted it off , i now have the correct size top and bottom eye for a straight fit to the rc ,

Hitting the track saturday on my other bike so the RC Will be looked at sunday . Gonna try and swap the springs stock to New shock and test ride at next opportunity before i do any more . For those on an extreem budget and to see how it handles with just a spring swap .

 

[SPG]

The R6 has a relatively flat "rising" rate linkage while the RC accomplishes a similar function by the change in shock to swingarm angle as the suspension compresses. I would suspect that the R6 nets close to a 2:1 while the RC is 2.8:1 (against the shock). So, with extremely quick and dirty estimation, if you liked a 500lb spring on your R6, you'd likely want a 700lb spring on your RC...

Again, grossly simplified estimation to make the point

-Sean

 

[Formula390]

The R6 has a relatively flat "rising" rate linkage while the RC accomplishes a similar function by the change in shock to swingarm angle as the suspension compresses. I would suspect that the R6 nets close to a 2:1 while the RC is 2.8:1 (against the shock). So, with extremely quick and dirty estimation, if you liked a 500lb spring on your R6, you'd likely want a 700lb spring on your RC...

Again, grossly simplified estimation to make the point

-Sean

I picked up my shock at the post office this morning, and called RaceTech. Waiting on a call back to talk with a more senior tech who can help a bit more with the complexity of figuring out what a good spring for rider weights will be, and what oil should be used for changing that out if necessary. Sure enough, the knob on the bottom of the shock is the rebound adjustment, which has 40 clicks, and isn't a ride height adjustment as I'd initially thought it might have been... so it seems that the +4/-2mm range specified must be the preload, and not a means of changing the eye to eye length as I had initially hoped. Still, it's a bit taller than stock, at 305mm, so that'll help with clearance some. I will whip up a 10 to 12mm bushing on the lathe later today (gotta do my initial service oil change and valve adjustment first) and try to mount up the shock probably tomorrow or Saturday... just for my own test fit piece of mind, and then put whatever spring RaceTech sends me. I'll probably pick up a set of cartridge emulators while I'm at it... either that or just some springs and TRY that route first. Dunno. Decisions decisions. The shock looks like it'll be a piece of cake to get working really well on the RC tho.

 

[RoninJames]

I picked up my shock at the post office this morning, and called RaceTech. Waiting on a call back to talk with a more senior tech who can help a bit more with the complexity of figuring out what a good spring for rider weights will be, and what oil should be used for changing that out if necessary. Sure enough, the knob on the bottom of the shock is the rebound adjustment, which has 40 clicks, and isn't a ride height adjustment as I'd initially thought it might have been... so it seems that the +4/-2mm range specified must be the preload, and not a means of changing the eye to eye length as I had initially hoped. Still, it's a bit taller than stock, at 305mm, so that'll help with clearance some. I will whip up a 10 to 12mm bushing on the lathe later today (gotta do my initial service oil change and valve adjustment first) and try to mount up the shock probably tomorrow or Saturday... just for my own test fit piece of mind, and then put whatever spring RaceTech sends me. I'll probably pick up a set of cartridge emulators while I'm at it... either that or just some springs and TRY that route first. Dunno. Decisions decisions. The shock looks like it'll be a piece of cake to get working really well on the RC tho.

Hey Matt if this works out you think you could whip up a few more of those bushings for sale here? for those of us who are without access to a lathe?

 

[reenmachine]

McMaster-Carr

12mm x 10mm bushings in 12mm & 15mm widths

 

[Formula390]

Hey Matt if this works out you think you could whip up a few more of those bushings for sale here? for those of us who are without access to a lathe?

You can order them from McMaster-Carr, or me, whichever. I ordered 5 more of the shocks this morning and will be rebuilding them and making them available for those who don't have the means to do the work themselves. I never got the call back from RaceTech so I'm going to call them again in a few minutes and see if I can reach their tech sales guy successfully this time...

 

[reenmachine]

McMaster-Carr

12mm x 10mm bushings in 12mm & 15mm widths

You can order them from McMaster-Carr, or me, whichever. I ordered 5 more of the shocks this morning and will be rebuilding them and making them available for those who don't have the means to do the work themselves. I never got the call back from RaceTech so I'm going to call them again in a few minutes and see if I can reach their tech sales guy successfully this time...

I wasn't trying to step on your toes -- just found those on McMaster & posted up since you had mentioned finding them online earlier. I'd certainly prefer to have a 1-piece bushing cut to the correct length.

 

[Formula390]

I wasn't trying to step on your toes -- just found those on McMaster & posted up since you had mentioned finding them online earlier. I'd certainly prefer to have a 1-piece bushing cut to the correct length.

Not a worry in the world dude! I'm pretty easy going, and the entire purpose of the thread was to let folks know there are options. I do plan on building some shocks (why do just one when I can do six back to back) and making them available, in case others don't want to do all the footwork themselves to figure out the right spring and oil and valving et all for themselves, but if somebody wants to take the preliminary info to their suspension guy, or get parts elsewhere, I ain't worried in the least!

I put the info out there because I intended all along for this to be an open-sourced project. I'm gonna get enough help from others on the forum, for things I don't have the knowledge myself on how to do, that this is one way I can give back.

I did hear back from one of the Racetech product development guys. I've gotta take some sag and spring measurements and send him that info. On Monday he'll compile that and figure out the correct rate spring, and if we need to look at an oil change and/or different valving to make it work on the RC390. There are also options they already have like a threaded preload adjuster and an alternate reservoir cap with a schrader valve for nitrogen recharging... at which point the shock becomes completely rebuildable. When I was talking to him on the phone he said he LOVES that model years of the R6 shock, because it's so versatile and the damping is terrific for adjustability. He said we couldn't have a better platform to build from... so things are looking VERY promising here for this being a really good shock for us for a much cheaper price than the Ohlins or WP options. Some will always go that route, and hey, that's fine... but some will want the adjustability at a more economical price point.

 

[mr-fabricator]

Good work as always please keep us posted on racetech recomendations for spring etc ,

 

[mr-fabricator]

Found this , 675r is a ohlins TTX unit

Daytona 675 Shock Length: 293/295 mm (two different sources) Spring Rate: 12.6 kg/mm Shock Stroke: Top Bushing Mount Width: 30 mm Bottom Bushing Mount Width: 30 mm Street Triple Shock Length: 293/295 mm (two different sources) Spring Rate: 12.1-12.2 kg/mm (two different sources) Shock Stroke: Top Bushing Mount Width: 30 mm Bottom Bushing Mount Width: 30 mm

Thoughts , ??

 

[Formula390]

Found this , 675r is a ohlins TTX unit

Daytona 675 Shock Length: 293/295 mm (two different sources) Spring Rate: 12.6 kg/mm Shock Stroke: Top Bushing Mount Width: 30 mm Bottom Bushing Mount Width: 30 mm Street Triple Shock Length: 293/295 mm (two different sources) Spring Rate: 12.1-12.2 kg/mm (two different sources) Shock Stroke: Top Bushing Mount Width: 30 mm Bottom Bushing Mount Width: 30 mm

Thoughts , ??

That's going to be too short of an eye to eye. Stock at 300mm has racers easily hitting hard parts. They are getting shocks measured in the 310-315mm realms to get the ground clearance necessary. With the 99-02 shock being 304mm eye to eye it's not AS long as I'd like (310mm) but it's close enough I think it'll keep folks from hitting hard parts still.

 

[Formula390]

OK, here's some photos from the mounted 99-02 R6 shock on my RC390:

The shock clears the stock exhaust, tho I did have to pull the exhaust and the rear tire to get the OEM shock out, and the R6 shock it in there:

The only interference issue there is, and it's REALLY minor, is the rear brake fluid reservoir hits the shocks nitrogen tank:

I dealt with this by just ditching the bolt, and using a zip tie to hold it in place. I may ditch it altogether and just change over to a long clear tube with a cap to hold fuild. That's what I always did with my racebikes previously. Can't see why I couldn't/shouldn't do that with the RC390 too.

For the sag with the stock spring any my weight, it's going to need a new spring to be sure. My sag with the preload set at max (8.3mm) was 42mm. That's WAY not acceptable... I suspect something in the 10-12kg/mm with the Racetech threaded preload will get the spring where it needs to be. The compression and dampening settings seem like they are going to be quite adequate. I set both in the middle of the range and will see how the test ride goes once I get a correct rated spring for my Big Boy weight.

 

[RoninJames]

Good stuff Matt! Look forward to ride results.

 

[Formula390]

Good stuff Matt! Look forward to ride results.

That will probably be once I've gotten the new spring. I'm considering pulling the stock spring off and swapping it onto the R6 shock. I don't know if I'm up for screwing about with that until the Racetech guy gets back to me on Monday or Tuesday tho with the new target spring and we get that ordered and sent this way. I've got enough other projects currently in flight that I'll probably just leave it be for now and concentrate instead on the exhaust development and let the shock just sit there for a while. Any riding it'll be doing in the interim would just be on the dyno anyway. LOL

 

[Treachery]

You might be able to get a Rizoma rear reservoir and mounting arm that will let you reposition it such that it'll clear the shock.

 

[Ryanthegreat1]

I am measuring the shock bushing on the RC390 to be 32mm and the R6 to be 30mm. Turned a 12mm to 10mm sleeve tonight.

The stock R6 spring seems about as stiff as the stock RC spring. Probably just fine for a street rider. Going to ride to tomorrow and see what I think.

Lots of rebound can be dialed in on the clickers. You can crank it all the way down so it rebounds in 7 seconds or you can back it off so it rebounds too far and bounces.

Compression does not seem to have as much range but still seems to adjust slightly.

Might be the the best $20 upgrade ever.

 

[Hunterbear]

This is one thread I've been lurking and watching for quite a while. Very impressed with what you've turned up Formula390. Eagerly looking forward to the final results and verdict. If all is a 'go', I plan to duplicate this for my bike ASAP. Thanks for putting in the time and effort to sort something like this out for us. Really appreciated!