Jetting advice: CPR air filter on 950

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by randel, Sep 7, 2012.

  1. Grinderman

    Grinderman Been here awhile

    Joined:
    May 26, 2011
    Oddometer:
    150
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    Chico CA, Where the NUTS come from!!
    Hey thanks for the quick reply. My last setup was not the h2w setup in any way. When I initially set up my cpr filter I pulled all of the jetting that was set up for the pre filter and put all stock items back on. What I am trying to improve on is..
    42 pilots
    175f main, 180r main
    3 clip stock needle
    cpr air filter
    I have the remote for the fuel screws, but from what I understand these are more for the air/fuel at idle then anything. Is that right?

    It sounds like these fp needles are the way to go in the less restrictive environment, and I am trying to follow your lead because you know what's up. I like the idea of 2nd position on the clip because it can cover a wider range in elevation. I just don't know what direction to head at the moment. I am at sea level and it's hot here in Nor Cal. Maybe I well try 3rd position and see if that makes a difference. If it is still flat in power I well throw the stock needles back in and compare. I screwed up by changing two things instead of just one. I should not have touched the floats until after changing the needle and riding it. Believe it or not this crazy bike that I spend all of my time on is what keeps me sane:rofl
    #41
  2. Sporting Wood

    Sporting Wood I

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    Thanks for the compliment. Anything I know about these things is gleamed from a lot! of practice not getting them right. :lol3

    FP needles are totally different! I'd say that if its better in the 3rd clip for you on the stock needle, might stick with it...or spring for the fp needles which are totally the way to go imho. Stock needles are fatter/leaner with much less taper... making flatter transition to wfo power. All it changes moving clips down is the transition to main comes slightly earlier and there will be a bit more bleed through into the low circuit...which is likely why you had a leaner float before and probably a bit less on the screws. Shouldn't make so drastic an effect on elevation performance, if any at all. The greatest factor I have found in that regard is the 45 slow jet.

    I'm east coast, our air is humid...your's is dry. I have my valves adjusted tight, yours may be loose. I left the plugs in my Akras... Whats working for me might not be so great for you. Esoteric I know, but these carbs are really fickle.

    Best thing is to get the other stuff close, especially the float height, then top speed it to dial in the mains. Set those and leave them alone. Then figure out if it runs better in clip 2 or 3, 42 or 45 slows.... Small singular adjustments from there. I know its not that helpful but...:freaky
    #42
  3. Goss

    Goss LC8 Adventurer

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    This new run on the CPR set up has many of us becoming carb apprentices to you gurus.

    I have installed the CPR with Ken's jet kit for 500 ft elevation. I have a hanging idle issue now but had to leave town and could not finish tweaking to remedy that. Ken thinks I need to check my floats again and if they are both at 3mm then set them to 4mm. The kit did come with FP needles and they were set at the 3 clip. Can't wait to get home and get the thing dialed in.

    Looks like a good thread to interact with if one needs advice thanks to Sporting Wood and other experienced tuners.
    #43
  4. Sporting Wood

    Sporting Wood I

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    Oddometer:
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    I heard sporting wood was considering laser cutting a bunch of these here air filter plates out, saving the perspective buyer a whole bunch of cash...

    i mean, wtf? Its only a $75 filter and the plate is an easy thing to make. You guys spending $300 got too much money! :D


    Here is the filter (Ok, so its $90 now, price went up)

    You'd also need a couple of Dzus connectors the folks there sell for $2.15 each.

    All else you need is a scrap of 1/16 or .080" alloy... I used a 1/8" piece of 6061 but just about any decent quality aluminum sheet would do... old road signs, legal size clip board, etc...

    I didn't use the X-ring attachment as CPR. It looks as though it'd create an opportunity for vibration as evidenced by their first version self destructing. Instead I located some large Buna-N Grommets that isolate vibration to the plate and more firmly affix the plate to the carb bodies imho.
    [​IMG]

    [​IMG]

    Jigsaw and a drill is all a guy needs to make this thing. I can provide a tracing, or even could lend out a 1/4" plexiglass template. I made this one with a Bosch woodworking router with a bearing mounted flush cutting laminate bit... :eek Even cut a bevel on the side that clips to the filter flange with a bevel cutting bit.

    The two little holes I put in there were to affix the template to the metal ... and a mistake in placing one so close to the grommet. Welded'em up though so its no biggie now. Next time, it'd be in a better spot, and likely just riveted over once the cutting was done.

    Beat the crap out of it traversing some Colorado passes last week and viola, no cracks! :lol3 No leaks, no cuts to the Grommets... nothing.

    Better - Cheaper - Just as Fast!

    [​IMG]


    Also... as an aside... Those dern weirdly sized 1.3mmX6.3mm carb o-rings that like to leak, I sourced a bag of 1000. Anyone who needs some, pm me. SASE and the promise of a beer might get you a fresh set. :freaky
    #44
  5. Goss

    Goss LC8 Adventurer

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    Installed CPR filter setup on 04' 950S, elevation 510 ft, Akras with inserts in place.

    180 main in front
    185 main in rear
    65 idle air jet front and rear
    45 low speed jet front and rear
    4mm float set
    FP needle at 3rd clip

    Idle hangs slightly so to attempt correcting this my IMS are 3.5 turns out but still having idle hanging.
    Going in on the IMS makes the hanging idle worse.

    Bike cruises fine with no surging but does not have real crisp throttle response like it did with air box and pre-filter.
    Seems down on top end power as no power wheelies are happening. No bogging or stumbling.

    Any suggestions on where to go from here ?
    #45
  6. Johnf3

    Johnf3 Long timer

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    I am not sure on your jetting--you have a bunch of variables that I don't. I do know that something is wrong with your set up because mid and top end power are noticeably increased with the CPR set up. Your float level seems lean, your slow jets too rich, and your mains richer that what I run. If the FP needles have a thinner taper then the stock needles, that will make the mains even richer. I have no experience with FP needles though. These are just my observations based on what is working for me.

    My experience with the CPR filter set up is that only the mains need to be touched. 170/175/180 are all sizes I have used with good results. Stock pilots, stock idle airs, AS 1 3/4, stock needle in 3rd clip. I run FMF Q mufflers with spark arrestors. My float height is 3mm last time I checked. I am at 3.5K in elevation.
    #46
  7. mousitsas

    mousitsas Long timer

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    Like John said, you are way off from what everybody uses. Set your carbs according to the H2W jetting as a starting point, then just change the mains.
    #47
  8. Goss

    Goss LC8 Adventurer

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    Thanks gentlemen.

    The jetting is what Ken at AdvMachines sent me to start with when I bought the CPR setup from him.

    I have 160 & 165 mains I could use but none in the 170 range so I have contacted Ken about those.

    I do have the stock 42 slow speed jets and the 50 idle jets.

    I figured since my bike ran so well with the jetting he sent me for the pre-filter on the stock air box that this would be very close as well but as you guys are saying it seems to be way off. Just glad the CPR setup allows for such easy access to make the changes. Will update when I have made progress.

    Many thanks.
    #48
  9. Goss

    Goss LC8 Adventurer

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    Had some time this morning so I pulled the carbs, set the floats back to 3mm. Put in the 42 slow speed jet and the 50 idle jet. Then put the needle at the second position from the top. Left the 180/185 mains in. IMS screws 2 turns out.

    Bingo ! Went out for an hour ride. Idles greats with no hanging throttle. Nice pull to redline. Much crisper throttle. I think possibly the mid range could be better when you get on the throttle but it cruises with no surging at 4k-5k rpm.

    Will wait to hear from AdvMachines master to see if he has a cure for a little stronger midrange.

    Thanks again for the suggestions to go back stock except the mains.:freaky
    #49
  10. mountain eagle

    mountain eagle terrorist

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    Hmm, I had gotten the impression that with a CPR or open type air filter we no longer needed to have different main jets front to back. I'm currently running a 162 (5300') on both. Just monitoring the rear cylinder plug it looked lean with the 160 and was goodn'rich at 165........ seems happy and pulls pretty good with the 162. When I did pull the front plug it looked about the same.............

    :ear?
    #50
  11. Johnf3

    Johnf3 Long timer

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    Great. Glad you got it running better.
    #51
  12. fieldmechanic

    fieldmechanic n00b

    Joined:
    Sep 28, 2012
    Oddometer:
    4
    I just bought a 950 Adv, and shes running pretty sweet! I put a new air filter on and a uni pre-filter on and took her for a spin. I live at about 5000ft, and ride only up. At about 8500ft, and when hitting the throttle at about 4k it falls on its face. I have always had some light popping on deceleration. My friend says it smells a lot like gas while riding behind me, which confirms my suspicion of it running a bit rich.

    The bike came from somewhere's in AK so who knows what its jetted for. The previous owner has done tons to the bike so I'm sure that its not stock jetting. It currently has a hard time starting in the garage at anything below 50degrees outside temp, and I try and ride year round.

    This is what I'm dealing with:

    uni pre-filter
    Dual FMF cans with spark arrestors
    Canisterectomy
    5000ft and almost always ride higher
    Premium only


    That being said what would people suggest for jetting? I'm planning on getting a Factory Pro kit unless there is something better out there?
    #52
  13. mousitsas

    mousitsas Long timer

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    Try stock jetting with DNA filter.
    #53
  14. MudratinOz

    MudratinOz Nomadic motorcyle traveller

    Joined:
    May 15, 2007
    Oddometer:
    924
    Location:
    Lake Macquaire, NSW, Australia
    Thanks Sporting Wood for the details of your alternative set up :clap
    I've considered changing from the stock set up ( with Prefilter) on my 05 950 S to the CPR for a while know, but have been a little concerned about how it would go riding in Desert and high dust enviroments, water crossings are another cause of concern (to me).

    Interested to hear others experiences.

    I see that the ITG and CPR are held on by Dues fastners, but only on ones side, what secures the others side ?
    #54
  15. rossguzzi

    rossguzzi 990 Adv.

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    I like the look of that set up too. Is it possible to get some filter skins for those filters so on real dusty rides/change skins mid way?
    Interested !
    #55
  16. TcRulz

    TcRulz Been here awhile

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    Hi Ya'll, looking at doing the same thing but it looks like filter skins only fit the dome shaped filter:cry. Anyone know if the the dome filter fits the standard CPR base and anyone got an internal height of the dome filter (think it might be 65mm or 100mm but not sure). I see you have to cut the trumpets down to use it.:eek1
    #56
  17. blublapp

    blublapp Adventurer

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    Germany
    anyone been on the dyno with the 950 now?
    #57
  18. corndog67

    corndog67 Banned

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    In the old days , we'd snake one of moms stockings and put it over the Uni, Filtron or K&N filter. Keeps the birds and whatnot out of your nice clean filter and cheap too.
    #58
  19. randel

    randel Been here awhile

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    Can anybody suggest what to change?
    I'm running CPR airfilter setup with my 950SE
    175 main jets
    45 IAJ
    IMS 1,5 turns out
    Factory pro needle on 2 clip from top
    Floats 4mm
    Bike has great mileage and good power but when opening throttle from steady cruise 3rd/4th in city traffic it has maybe half second hesitation before accelerating strong. What can cause this? To lean IMS? Should I raise needle 1 clip? Change IAJ to 42? Raise floats?
    How to get rid of this annoying hesitation?
    #59
  20. wilso122

    wilso122 Been here awhile

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    I bought head 2 winds Baja race jet kit for the CPR and full GPR 2-1. Great setup but thirsty as anything, range gone from 100miles on the tank to 70.. So off to the dyno man as think its too rich. Will see what they say.
    #60