New BMW G650X (merged) threadfest...

Discussion in 'Thumpers' started by mr moto, Oct 9, 2006.

  1. Max Kool

    Max Kool Xtankteam™

    Joined:
    Jan 19, 2004
    Oddometer:
    3,451
    Location:
    Los Angeles
    Yes I understand. Even at 5'10" the DR felt cramped.

    The X is not overly long geared like the DR for example, but I feel it could do some better still in the really tight and steep stuff with a tooth less on the front (and I never ride 100 mph anyway). I have a deal with my BMW dealer on a 14 tooth front sprocket. We both feel like the front sprocket from an F650GS will fit, but we both don't know for sure. he's sending me one just to try. If it fits I'll take it, if it don't I can send it back.

    So far I really like the bike, it has around 400 offroad-only miles. I've read on a German forum about a guy that had his X-moto on a Dyno. The X seems to be very susceptible to exhaust and especially inlet modifications. (don't look at the absolute figures btw, these could have been corrected crank hp, it's the gain that makes my mouth water).

    stock: 51.5 hp at 7046 rpm.
    Torque: 61Nm.
    With a diffrent exhaust: 54.1hp at 7425 rpm
    Torque: 63 Nm.
    same exhaust but with airbox modifications: 58hp bei 6714 rpm!!!
    Much more power over the entire rpm range!!
    Torque: 68 Nm.

    As you can imagine I'm especially interested in the airbox modifications. The gain per € is best, and the power delivery is lower in the rpm band, which is where you want it. I'm working to get the details of this modification and will keep you posted.

    Max
  2. jack splash

    jack splash Two Sheds

    Joined:
    Jun 5, 2004
    Oddometer:
    2,573
    Location:
    Pt Pleasant, NJ USA
    Hey: You work on the motor, I'll work on the frame etc. If I can get a couple of those foam air filters, I'll send you one.

    Crank: I don't have a machine shop, but maybe we can work on some ideas for mods.

    Jack
  3. Some Dude

    Some Dude what attitude problem???

    Joined:
    Dec 2, 2003
    Oddometer:
    4,770
    Location:
    Woodstock, GA
    Due in mid next week, I'll throw a new post up in the Vendor's section and if you're willing to help Max out with shipping to him I'll hook you up on an "intro" order pricing for the two of ya's. However I will ask you provide your feedback on the forum (good or bad) as I'm sure you'll be honest and using the bike as it's intended.
  4. Max Kool

    Max Kool Xtankteam™

    Joined:
    Jan 19, 2004
    Oddometer:
    3,451
    Location:
    Los Angeles
    Hey guys,

    I did some empirical experimenting with the airbox tonight. As some of you may know, the airbox consists of a few parts:

    1. The airbox itself, which encloses the throttle body and is draped from under the front of the seat all the way to the headstock.
    2. The airfilter element, which slots into the the top/front of the airbox. This is where the airbox gets sealed.
    3. Next there is the cover for the air filter element, which job seems to be mostly to reduce air intake snarl.
    4. And finally the faux tankcover that makes the bodywork on the front fit, and which in its turn is locked up by the white side covers.


    When I unbolted the side panels and the faux tank cover I found out there is very little room to breath through. The inlet duct, which is formed by the top of the airbox (1), and the inside of the air filter cover (3) is around 1" x 2" , maybe even smaller.

    I figured the next.
    • The way engine breathes is decided by many parameters of which the shape and volume of the airbox are very important.
    • On the G series the airbox is sealed with the air filter element, which in its turn sort of chokes the air that enters the airbox.
    • I don't want water and dust to fall directly into the airbox. So I do not want to open up the faux tank cover with metal mesh or something.

    The easiest way to see how the engine would respond to more air was to simply leave the air filter cover (3) off and leave the rest as it is. So the faux tank cover will stay in place, and leave the bodywork near the left fork leg as it is. All very stealth, and nothing got destructed. The airbox is still completely sealed by the air filter element.

    Anyway, bolted the rest of the pieces back together. Btw, mr BMW designer will you please explain to us why the side panels are fitted with hex-head bolts, and the faux tank cover with torx head bolts. They are even interchangeable!!! Aaaarrgghh!!!!!!!!!!! Why!!????

    Ok I fired up the bike and somehow expected the same behaviour as leaving the airbox sidecover off on my DR. Hard idle and no pick up on the revs because of a too lean condition. Not so on the G. It idled completely normal and gave a nice sweet "murbling" sound. Left it standing for a few minutes to get it warmed up a little. Took my jacket/helmet and went for a ride.

    First thing I noticed was a nice throaty snarl. Next thing was the engine pick up from low revs. Nearly too much in the rain, in second gear the rear wheel would simply spin if I gave it some throttle. Very rewarding! I could not find any downsides. no jerking, no bogging, no stalling no whatsoever. Just a very eager engine and a naughty snarl!

    As I was afraid my enthousiasm was mostly fed by the inlet snarl, I changed back and forth between with and without the air filter cover. The wet roads were the deciding judge. With the air filter cover fitted I had a very good accelleration, just as I was used to of course. Without the airbox cover though, the rear wheel would simply spin if I janked the throttle. First I though I was fooling myself, but doing repeated roll-on tests proved to me the midrange and especially the throttle response had improved. I cannot tell if the pure horsepower have improved, but the eagerness, the willingnes to pick up at opening the throttle (and the willingnes to lift the front wheel!) has improved definately.

    "Aren't you afraid your McGuyvering is leaning off the carburation?" Good question, I was asking the same myself. But I am not afraid I am. There are many sensors around the engine to deliver the best air-fuel mixture. The barometric pressure will be lower at 10.000 feet height for example, and a clogged air filter element has to be compensated for as well. The engine also uses a lambada sensor which is used to keep the mixture at the stoichiometric optimum. All in all, as long as I am on a steady throttle I'm not afraid the engine will run too lean. On accellerations the mixture simply isn't too lean, for then it wouldn't accellerate as it does now. Instead it would bog.

    All in all, I'm going to keep it like this for a while. When my rear tire is worn I will maybe do two dyno runs. One with, and one without the cover (choker??). Just out of curiousity.

    Btw, this bike needs no aftermarket exhaust. As it is, especially with the inlet snarl, it sounds very naughty. (which reminds me, I could ask a friend to cut open the exhaust, remove the catalytic converter and weld it back up again, totally stealth).

    Jack, Bobby,

    If we can work something out with the foam airfilter i would greatly appreciate it. In the meantime I've asked my local dealer and Touratech importer to see what he can do.

    Keep up the good work all!!
  5. Oni

    Oni Ronin

    Joined:
    Sep 13, 2006
    Oddometer:
    1,839
    Location:
    Pasadena - Californistan
    Max

    Can you take some pictures? Trying to visualize the covers and air filter setup...and it's not working. Do you think there is a greater chance of ingesting water from splashing during water crossings with the cover off? Think of any downsides to your modification?

    Gonna order one today (X Challenge)! :D Dealer has a demo and said he can get one for me in a few weeks.
  6. Max Kool

    Max Kool Xtankteam™

    Joined:
    Jan 19, 2004
    Oddometer:
    3,451
    Location:
    Los Angeles
    I promise to make some pictures this weekend, ok?
  7. Oni

    Oni Ronin

    Joined:
    Sep 13, 2006
    Oddometer:
    1,839
    Location:
    Pasadena - Californistan
    Cool Max Kool! :D

    Just got off phone with dealer. Think I'm pickin' mine up Memorial Day weekend. :evil
  8. lsellers

    lsellers a DSRIDER

    Joined:
    Dec 29, 2006
    Oddometer:
    1,612
    Location:
    Fresno, California
    Very exciting
  9. 91ctrk

    91ctrk Been here awhile

    Joined:
    Mar 31, 2005
    Oddometer:
    337
    Whats the ready to ride weight on the X's? Seems like a nice DS bike.
  10. sweetgrass

    sweetgrass Single Track Mind

    Joined:
    Jan 4, 2006
    Oddometer:
    199
    Location:
    Santa Fe, NM
    i really like the bike, was just down at my dealer to order a part for my GS and sat on the X once again.
    bad mistake, now i want one, again! but my only complaint with the X so far is the limited fuel capacity. not sure of any aftermarket fuel tank solutions but i think i would need to resolve that issue before taking this bike to baja.
  11. Max Kool

    Max Kool Xtankteam™

    Joined:
    Jan 19, 2004
    Oddometer:
    3,451
    Location:
    Los Angeles
    The chance of ingesting water in crossing has not changed. The airfilter and the airbox are still completely covered. It's just the duct that's gone. But wait till the pictures, they will explain.

    Max
  12. thumperdust

    thumperdust BRRRRAAAAPPP!!!

    Joined:
    Jul 15, 2006
    Oddometer:
    39
    Location:
    Seattle
    touratech will be offering some, there in new cat.
  13. Max Kool

    Max Kool Xtankteam™

    Joined:
    Jan 19, 2004
    Oddometer:
    3,451
    Location:
    Los Angeles
    I've been thinking a while about welding some sort of aluminium side tank that can be bolted onto the right side of the bike. There's plenty of room there. Something like an extra 1,5 gallons would be nice.

    The Touratech 16 liter tank looks too bulky for me now.
  14. sweetgrass

    sweetgrass Single Track Mind

    Joined:
    Jan 4, 2006
    Oddometer:
    199
    Location:
    Santa Fe, NM
    i've looked on touratech's site and havent found any aux tanks for the X, just for the F650GS.
    hopefully that will change very soon.
  15. sweetgrass

    sweetgrass Single Track Mind

    Joined:
    Jan 4, 2006
    Oddometer:
    199
    Location:
    Santa Fe, NM
    that could be the ticket!! :D
  16. Max Kool

    Max Kool Xtankteam™

    Joined:
    Jan 19, 2004
    Oddometer:
    3,451
    Location:
    Los Angeles
    ok, a more pictoral description of what I did to the airbox. Once you see it you will know it's not worth the name "modification".

    First you need to remove the seat:
    [​IMG]

    Next we're going to remove the two 4mm hex head bolts and pull the "studs" from their bushing (grease those bushings!). This is more than enough to get access to the airfilter, no need to completely remove the side covers:
    [​IMG]

    Remove the two torx 25 bolts in the front of the faux tank cover (here's where that utterly useless bitdriver I bought to get to my DR's pilot screw comes in handy):
    [​IMG]

    After you've removed the faux cover we're seeing this, the air filter cover alas the inlet snarl silencer (bolts already removed):
    [​IMG]

    And this is the straw the engine has to breathe through, not big izzit?
    [​IMG]

    [​IMG]

    Let's remove the air filter cover and see what's underneath:
    [​IMG]

    [​IMG]

    That's more like it! the airbox itself is still completely sealed, the air filter element is snugly in place and if you reinstall the faux cover all is stealth and protected from the elements:
    [​IMG]

    [​IMG]

    one happy G! Runs crisper and shows more bite that stock.
    [​IMG]

    now that we're making pictures anyway, I thought I'd show you my GPS mount "solution". It consists of seperate Touratech parts. One is a regular holder for my GPSMap276C, the other is some sort of barmount designed to use your GPS on the steering stem of a mountainbike. Together they look like this:
    [​IMG]

    [​IMG]

    [​IMG]


    Btw, fitting those barkbusters was hell. The clutch and front brake levers were too long. I sawed them off 2cm's and when we welded the "balls" back on we found out the levers were lacquered or plastified. No ground and once we had ground they badly discolored during the welding. Now that the levers were shorter it seemed that Mr BMW found it a wise idea to lathe the inside of the bars to a size too big for the Magura kit I bought with the barkbusters, but too small for a kit that is used on steel bars. . It looks like the inside is threaded. Of course to make fitting the genuine, not yet available BMW handguards a breeze..... Why mr BMW, why?!! What's wrong with the regular Acerbis/Magura/Barkbuster/Protaper sizing?

    Ok, so far this contribution.

    Max
  17. Max Kool

    Max Kool Xtankteam™

    Joined:
    Jan 19, 2004
    Oddometer:
    3,451
    Location:
    Los Angeles
    Somewhere around 350lbs. but because of the mass centralisation it feels much lighter once riding than for example a Suzuki DR650, which weighs the same.
  18. jack splash

    jack splash Two Sheds

    Joined:
    Jun 5, 2004
    Oddometer:
    2,573
    Location:
    Pt Pleasant, NJ USA
    Btw, fitting those barkbusters was hell. The clutch and front brake levers were too long. I sawed them off 2cm's and when we welded the "balls" back on we found out the levers were lacquered or plastified. No ground and once we had ground they badly discolored during the welding. Now that the levers were shorter it seemed that Mr BMW found it a wise idea to lathe the inside of the bars to a size too big for the Magura kit I bought with the barkbusters, but too small for a kit that is used on steel bars. . It looks like the inside is threaded. Of course to make fitting the genuine, not yet available BMW handguards a breeze..... Why mr BMW, why?!! What's wrong with the regular Acerbis/Magura/Barkbuster/Protaper sizing?

    Ok, so far this contribution.

    Max[/quote]

    Max: Cool, I try it own mine this weekend. You don't have to put the balls back on the levers, the bark buster will prevent any issues, once you cut down the levers.

    I used the acerbis pro guards and they went on with no problems.
    Jack
  19. 91ctrk

    91ctrk Been here awhile

    Joined:
    Mar 31, 2005
    Oddometer:
    337
    Thanks...lotsa places to ride in holland?
  20. Oni

    Oni Ronin

    Joined:
    Sep 13, 2006
    Oddometer:
    1,839
    Location:
    Pasadena - Californistan
    Thanks Max!

    Nice set up on the GPS too!