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Aprilia RS660 Tech Discussion

Discussion in 'Tech' started by Monsterdood, May 2, 2022.

  1. Monsterdood

    Monsterdood Well-Known Member

    So I just got an RS660 and it’s about ready to hit the track for the first time and I have a few questions.

    1) Are other racers running the cooling system as is or making any mods? There’s a higher flow water pump available and I saw someone looking at a secondary radiator but I don’t know if it’s being used. Cooling fan left in or removed? Thermostat left in?

    2) Traction control and engine mapping settings? I was going to start with all settings at a 1 and wheelie control off. Curious what others have found that works well.

    3) Do you turn up the traction control setting in the wet? What’s your experience in the wet or with the traction control in general?

    4) I’ve seen some references to needing to extend the forks to avoid the front wheel / fender crashing into the radiator guard / radiator. Any direct experience with this?

    5) Any direct before and after experience with the Rapid Bike race tuner? I’ve got the race ECU from HSBK (there seems to be different versions and capabilities of the race ECUs and I can’t tell which ones are which to be honest) but was curious if the Rapid bike tuner would add anything more. If the O2 feedback loop is turned off in the race ECU (which I thought it was), it seems like the rapid bike approach wouldn’t work. I don’t know, it’s not clear what works with what.
     
  2. Busdriver02

    Busdriver02 Well-Known Member

    1. Stock. I'm heading to a track day this next weekend at Chuckwalla. Temps are supposed to be in the 90s, I'll be re-assessing the Jet Prime pump after that.
    Robem did post a picture of an aux rad setup a while back, and the more recent pictures of their bikes appear to have them mounted.
    It looks like a dirtbike rad made to fit.

    4. I would suspect people smashing the radiator have dropped the front end a bunch. Stoppies at stock height don't hit anything.

    Beyond that, I'm a new racer with nothing to offer you.
     
    Monsterdood likes this.
  3. Lance Molnar

    Lance Molnar Aoxomoxoa

    1) Have run 2 team challenge races, a few sprints and a few track days...no cooling issues
    2) TC off, Everything else 1 except AEM (essentially throttle repsonse) = 2
    3) haven't run in wet...
    4) front end height maintained (though looks raised due to aftermarket triple design) - no issues with full front suspension stroke
    5) No
     
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  4. swetngblts

    swetngblts Well-Known Member

    The bike runs on the hotter side, even in cooler temps. I put the fan back on, higher bar cap and gutted the T-Stat.
    Time attack - settings all the way down or off has worked for me
    We dont race in the rain
    Yes, extended the forks.
    No
     
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  5. nlzmo400r

    nlzmo400r Well-Known Member

    Certainly not an expert on the RS660 in particular, but if the front wheel is contacting the radiator, move the radiator, not the front wheel. Get the geometry that works best and make other stuff work around that.
     
  6. Monsterdood

    Monsterdood Well-Known Member

    Thanks for the thoughts. I did put on a higher pressure cap and I wonder if the street bike is designed for coolant and when you switch to our water only spec, if the lower boiling point contributes to the issues too. I wonder how much engine power the larger water pump option uses. A fraction of a hp I would guess.

    I recalled seeing the picture but wasn’t sure if they actually used it or not. I think removing the thermostat coupled with the aux radiator could be a good solution if I have over heating issues.
     
  7. Busdriver02

    Busdriver02 Well-Known Member

    Can someone explain the lengthening the carts to not smash the radiator thing to me?
    If you're smashing the radiator, the controlling factor is compressed length of the forks and where they sit in the triples.
    If lengthening the forks successfully avoids this, then you're not using the full travel of the now longer forks, so what is the difference to just moving the normal length forks in the triples?
     
  8. swetngblts

    swetngblts Well-Known Member

    That certainly is part of the solution. The radiator can be pushed back at the lower mount, redrilled and bolted for an additional 1/4"-1/2" at the mount which is less where the contact point is.
     
  9. swetngblts

    swetngblts Well-Known Member

    Suppose it may have to do with the upper triple being used as well. What about fork cap extensions?
     
  10. Busdriver02

    Busdriver02 Well-Known Member

    Fair point.
    As a reference point then: I have GP carts (w/ cap extensions) and a woodcraft upper. The seam between the caps and tubes sits about 1mm below the top of that triple. That's the stock fork tube location. (I swapped all the fork guts over and reinstalled them prior to swapping the upper triple just to make sure I could start from the stock setup.)
     
  11. tgold

    tgold Well-Known Member

    Water may have a lower boiling point but it's more efficient at transferring heat than coolant is, so I wouldn't think that it would make the situation worse.
     
  12. swetngblts

    swetngblts Well-Known Member

    I was at stock height as well, with proper spring rate and still smashing up against the radiator guard, but not quite smashing the radiator yet. We extended the forks and raised the rear. I am now just rubbing the radiator guard which im fine with. I dont know jack about suspension so as to the question about extending forks internally and using full travel thats best suited for someone that knows. I can say the bike feels taller, much more stable and on rails.
     
  13. Busdriver02

    Busdriver02 Well-Known Member

    Weird.
    Probably an internal bump stop difference between the different cartridges I'd guess.
     
  14. metricdevilmoto

    metricdevilmoto Just forking around

    "Stock height" is subjective if you're just looking at where the fork tubes are in the triples. Most aftermarket cartridges can be "stretched" internally to add stroke and the position of the outer tubes in the triples would be "stock", but the motorcycle could be 5-15mm taller in the front.
     
  15. Busdriver02

    Busdriver02 Well-Known Member

    Yes, but hitting the radiator would depend on where the fork bottoms out internally, not on total stroke.
     
  16. Monsterdood

    Monsterdood Well-Known Member

    If someone is using springs too light and bottoming out, then that would be worst case and if someone is over sprung for their weight, they may not have issues with bottoming and contact with the radiator guard.

    I’m sitting around 185lb without gear right now and I’m starting with .95 fork springs in Ktech IDS cartridges. I’m quite curious now if I might or might not see any issues with the wheel hitting my radiator guard.
     
  17. TWF2

    TWF2 2 heads are better than 1

    His was same as stock. We extended forks so they don't go bellow top of upper triple.
    Internal bump location can be changed. Example if 10mm travel is added bump stop can be moved 10mm as well keeping travel same as stock. Or you could have extra 10mm of travel but never use it.
    You have cap extensions which is another way of doing it. His cartridges don't come with extended caps so we just extended cartridge instead.
     
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  18. Busdriver02

    Busdriver02 Well-Known Member

    Gotcha.
     
  19. swetngblts

    swetngblts Well-Known Member

    Same setup.

    Not sure if its just someones opinion or not. I did read somewhere that the Aprilias engine is positioned more forward having more weight on the front or more transfer weight to front so most people are finding out they are undersrpung from their normal spring rates. Bullshit or Not, i dont know.
     
  20. kman0066

    kman0066 Well-Known Member

    Sounds a bit like a self-inflicted problem for those with aftermarket upper triples. Aftermarket upper triples are being used which sit higher on the forks (to allow room for really big clip-ons at stock fork height), requiring you to lengthen the forks internally once you find out you need to be sitting taller vs. just dropping the forks lower. I don't think the stock forks with standard aftermarket carts have stroke length problems that I've heard. But there could be, dunno. The stock upper triple works just fine BTW, you just unscrew the bars from it, then you can drop the forks quite a bit for more length, and you have plenty of room for triple clamps. All without having to do internal fork modifications, buying an upper triple clamp, etc. But it does leave the lugs for the old bars on the upper triple, which may not be pretty enough for some people. I suppose you could saw them off as well, sand, and paint it if you really cared enough.

    Those aftermarket upper clamps sure are pretty though :D
     

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