Discussion in 'General' started by Gorilla George, Aug 9, 2014.

  1. Smilodon

    Smilodon Wannabe

    Plumbing the board's Grom wisdom again... I'm not getting to use the Groms as much as I would have hoped for a number of reasons, so try to commute on one every now and again to keep them "exercised". I don't need to go on the interstate or anything to get to work, but there is some 4 lane, different roads depending on what route I take, but folks go along at a pretty good clip on whichever one I use.

    Essentially, I'd like a little more top speed when using the Grom in this way, and was thinking of doing some performance mods on one of the Groms to achieve this. Yes, I know I can swap in a Panagale engine, run nitrous, supercharge, go 8 valve oval piston or whatnot, but this isn't a "superbike"-spec project. I was just wondering if something like a pipe/rejet/intake modification would make any worthwhile gain, or is this a hopeless task without spending "just buy another sportbike" money.
  2. Sabre699

    Sabre699 Wait...hold my beer.

    @Gorilla George will be right along.
    Gorilla George likes this.
  3. Past Glory

    Past Glory Well-Known Member

    Short answer: No.
  4. Smilodon

    Smilodon Wannabe

    Well dang. Kind of figured, but thought it might be intentionally restricted in some way I could bypass. I don't think it could pull any more gearing.

    OK, will I be less skairt because I *think* I'm going faster because of the pipe and intake noise? :D
  5. SuddenBraking

    SuddenBraking Tire collector

    I believe with a big bore and some other oohs and ahhs you can get to the mid teens in terms of horsepower, but reliability is pretty spotty (and the tranny can't keep up with that powah). If you love the little chassis and want more power than that, you need to do a 250/300 swap. They're for sale (and/or the parts you need for the swap are for sale) all day on this group:

    I'd assume you could have some fun on this one :D


  6. aftriathlete

    aftriathlete Well-Known Member

    TB Parts cam and CJR ECU reflash. If you already have an intake and exhaust, the cam and ECU is literally $200, and good for about a 50% hp increase over stock when you put those 4 things together (8ish rwhp stock to a little over 12). Moves the power right in the RPMs but that sounds like what you are looking for anyway for highway speeds.
  7. Past Glory

    Past Glory Well-Known Member

    All you'll end up with is noise. That extra 4 hp isn't going to get rid of the dreaded speed loss that even the slightest of inclines brings. If "getting along at a good clip" is what you want, I second the suggestion to do the CB300F engine swap. That gives you all the HP of a GROM engine based "superbike" build with all the reliability and easy operation of a bone stock engine. Either way though, it takes $$$ to make that speed possible.
  8. wiggeywackyo

    wiggeywackyo Well-Known Member

    All this talk and no one has asked a simple question: what is a "good clip" in mph?
  9. Funkm05

    Funkm05 Dork

    Tree ... maybe tree-fiddy.
  10. SuddenBraking

    SuddenBraking Tire collector

    Seeing as the stocker goes 55-60, I'm assuming he wants something that can get to 70-75ish.

    You're using the plural of Grom - how many do you have?
  11. How fast do you want to go? Or how much are you willing to spend to go that fast?

    The Grom is capable of getting into the mid 20's HP, but you will spend more money than the bike cost itself, to get there. Well, you might can get it cheaper, but it will not be reliable.

    As they always say...


    You can only have 2.

    The little things like exhaust intake, power commander, ceramic bearings, etc will give you a couple of HP, and a small increase in MPH, but not enough to transform the bike into something that is comfortable on a 4-lane highway. To get that, you are going to have to go into the motor.

    Mine has a 183cc motor with 4 valve head, and external oil cooler. Which meant it needed an aftermarket clutch, and drastically different gearing. I believe right now I am running +1/-3 gearing (420 chain kit).

    Then once you get into Ohlins suspension, brakes, rearsets, quickshifter, bars, ignition module, exhaust, intake, so on and so forth, you can easily end up with a $12-14,000 Grom that has to run off race fuel all the time. It is a lot of fun, but you could just as easily go get a 600cc that would be even better on the highways.

    So it really comes down to, how much are you willing to spend, to make your Grom that fast? It can be done, but it isnt cheap.
  12. dtalbott

    dtalbott Driving somewhere, hauling something.

    Can he just get the Grom stuff you bought early and then upgraded again?
  13. TurboBlew

    TurboBlew Registers Abusers

    On my scooter its ~95mph. Same sized tires as the grom. Thats with a rubber band transmitting the power.
  14. I do need to sell a bunch of that shit. I’ve got 2 brand new Power Commanders for The Grom, still in the box, because I forgot I had already bought one and bought another one......twice.
    dtalbott likes this.
  15. DBConz

    DBConz Registered Idiot

    Might be interested in some of your parts you’ve upgraded.

    I’ve got -1/+3 gearing, suspension, speedo recalibration , SS brake line, slip-on only (I think), and looking for an intake.

    I’ve considered a cam & ECU flash for some torque, but it seems to only improve top speed.

    Sent from my iPhone using Tapatalk
  16. Smilodon

    Smilodon Wannabe

    I have two Groms (mentioned way back in this thread but now that it is more than 140 pages...! who would know?). They were bought to give my wife something she feels comfortable with that essentially works like a normal motorcycle (to learn on). I got one so we could both have some fun with it, rather than me standing around like an MSF instructor all the time. It was a Christmas gift to each other.

    She is still interested, but we have reduced our spare time lately. So, I try to ride them to work occasionally (I don't live that far from work) just to keep them "exercised". With me on one (about 200 pounds with gear), I don't think I'm going 60. Plus, I have a small trunk in the back for commuting which increases drag a little. Maybe 50-55 in a tuck. But on some stretches of the commute that is a little uncomfortable (speed difference to cars).

    I'm in Florida, so it is straight and flat. The speed limit on the faster area is 55, but that isn't even close to real speeds. The "normal" morning speed is more like 70. f I could go 65-70 on the Grom, I'd be happy. Right now, I've figured a convoluted route using back roads that limits the exposure to US-1, so that is a bit of a work-around. For *that* trip, putting the Michelins on might be a better upgrade as the OEM tires (different ones on the two Groms oddly) are kind of rim protectors.

    But, what I was looking at was similar to what you often do to any streetbike. Open up the intake and exhaust, and adjust the fuel to match in order to get greater rideability and increased power. Figured I'd ask here, since you all have so much experience with modifying them, and pretty much got my answer. I'm not looking to do anything like swap a 300 motor in one. Sounds like fun, but would rather spend the money on another project. Not looking to build "Super Grom".

    A scooter was mentioned earlier. Oddly, my Kymco 125 (with practically the same engine as the Grom) seems to be faster top-end wise. Aerodynamics?
  17. Past Glory

    Past Glory Well-Known Member

    You're not getting that speed out of GROM in a sustainable, reliable engine build. It would be horribly impractical. Time to buy her an R3 or the like.
    TurboBlew likes this.
  18. DBConz

    DBConz Registered Idiot

    any feedback on the Chimera air intake? does it add any torque, or just top speed? is it noisy and did you need a tune to keep it from running rich?
  19. Technically, not accurate.

    He could, but he needs to be prepared to spend about $6,000 on the motor and transmission.
  20. TurboBlew

    TurboBlew Registers Abusers

    kymco makes a 200 thats fuel injected and will do an easy 60 out of the box. Msrp is less than a used grom. Take the added savings and buy a variator or a fuel controller... and its the same 12" tires as a grom and 2yr warranty.
    Of all the bikes Ive owned... my vespa is really one of the more entertaining rides. Its just as comfortable on i95 as it is on A1A. Its like a scapel for commuting.

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