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Thread: DIY dyno

  1. #31
    Join Date
    8th December 2014 - 14:39
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    1980 Suzuki Gs1100E
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    SWPA
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    145

    dyno roller size

    I'm planning to build a bike dyno and I need to come up with a size (inertia wise) for the roller wheel. I want to be able to dyno a 150 hp bike.
    thanks, jfn2

  2. #32
    Join Date
    12th February 2004 - 10:29
    Bike
    bucket FZR/MB100
    Location
    Henderson, Waitakere
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    4,194
    I ran my bike on a Dynajet 150 I think it was and it was OK. 175hp. If you can find what their setup is it'd be a good start. If I remember correctly we spun the roller to something like 130mph in 3rd gear

  3. #33
    Join Date
    18th May 2007 - 20:23
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    RG50 and 76 Suzuki GP125 Buckets
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    Auckland
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    The DynoJet has a number on the drum, not sure what it means, inertial weight maybe because it was part of the information needed when installing updated software. I will take a photo tomorrow.

  4. #34
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    18th May 2007 - 20:23
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    RG50 and 76 Suzuki GP125 Buckets
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    Auckland
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    Click image for larger version. 

Name:	Dyno Drum Info.jpg 
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Size:	762.6 KB 
ID:	329821Click image for larger version. 

Name:	DynoJet Drum Number.jpg 
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ID:	329822

    DynoJet 150
    Drum Mass 13.82
    Drum Circumference 4.67

    I have no idea if the units are in Kg's meters lbs feet or good old American slugs and ergs. Google - US common system of units.

  5. #35
    Join Date
    2nd July 2013 - 11:52
    Bike
    GPR150
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    palmertson north
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    Quote Originally Posted by TZ350 View Post
    Click image for larger version. 

Name:	Dyno Drum Info.jpg 
Views:	158 
Size:	762.6 KB 
ID:	329821Click image for larger version. 

Name:	DynoJet Drum Number.jpg 
Views:	176 
Size:	831.5 KB 
ID:	329822

    DynoJet 150
    Drum Mass 13.82
    Drum Circumference 4.67

    I have no idea if the units are in Kg's meters lbs feet or good old American slugs and ergs. See US common system of units.
    im shore my dyno jet was lined in lead
    i'm over buckets

  6. #36
    Join Date
    12th February 2004 - 10:29
    Bike
    bucket FZR/MB100
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    Henderson, Waitakere
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    4,194
    What software is anyone using on a home built inertial dyno?

  7. #37
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    8th December 2014 - 14:39
    Bike
    1980 Suzuki Gs1100E
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    SWPA
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    145

    dyno software

    I'll be using the Performance Trends Datamite system.

  8. #38
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    2nd July 2013 - 11:52
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    GPR150
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    palmertson north
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    Quote Originally Posted by jfn2 View Post
    I'll be using the Performance Trends Datamite system.
    same here..
    i'm over buckets

  9. #39
    Join Date
    8th December 2014 - 14:39
    Bike
    1980 Suzuki Gs1100E
    Location
    SWPA
    Posts
    145

    dyno units

    I believe 4.67 is in feet and the 13.82 is in kg/m*2. The new DynoJet roller seems to work out very close to those numbers.

  10. #40
    Quote Originally Posted by TZ350 View Post
    Click image for larger version. 

Name:	Dyno Drum Info.jpg 
Views:	158 
Size:	762.6 KB 
ID:	329821Click image for larger version. 

Name:	DynoJet Drum Number.jpg 
Views:	176 
Size:	831.5 KB 
ID:	329822

    DynoJet 150
    Drum Mass 13.82
    Drum Circumference 4.67

    I have no idea if the units are in Kg's meters lbs feet or good old American slugs and ergs. Google - US common system of units.
    A bit of napkin math suggests that I/r^2 (Inertia/(radius of drum squared)) would be equal to about 1.5x the mass of the bike to achieve accelerations similar to on track in each gear.

    That would suggest that a bucket would accelerate about 3 times faster in each gear on the dynojet compared to the track. Does that sound about right from your experience TZ or way off the mark?

  11. #41
    Join Date
    18th May 2007 - 20:23
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    RG50 and 76 Suzuki GP125 Buckets
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    Auckland
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    10,473
    Yes I agree with you, they do seem to accelerate quite a bit quicker on the dyno than the track.

  12. #42
    Join Date
    8th December 2014 - 14:39
    Bike
    1980 Suzuki Gs1100E
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    SWPA
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    Moooools:
    My bike with me on it weights 548.5 kg. Lets say that in top gear it takes me 10 secs to accelerate on the track. Using your equation ( I know it's right) I come up with 28 kg/m*2 with a .457m dia roller. Using TZ350's dynojet number of 13.82 kg/m*2 and a dia of .457m (which I also think is right) I need roughly twice the kg/m*2 to get the same acceleration. So I need to be turning 2 rollers like the dynojet one. If TZ350's dynojet roller measures somewhere around .406m long I'll need one around .816m long. Am I correct? Thanks

  13. #43
    Join Date
    26th June 2005 - 21:11
    Bike
    Honda NSR300 track hack
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    Pukerua Bay
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    4,089

    Anyone want to buy a cheap DIY dyno???

    I'm selling up as we've bought a section and got to move house, so for sale is my beloved dyno.

    It's a humble little inertia chassis dyno that was designed for doing bucket bikes, it has since been used for tuning many bikes, including a lap record setting NSR300.

    It comes with everything ready to go minus laptop for screen (or can include for addition $200). That includes cooling fans and exhaust extraction as well as data acquisition module.

    if you are interested I can arrange getting some photos and techinical specs sent though.

    As for price i'm not sure, if you're interested get in touch 022-089-3234 or G.skachill@gmail.com

    Cheers,
    Glen


  14. #44
    Join Date
    5th April 2013 - 13:09
    Bike
    zuma50
    Location
    illinois
    Posts
    372
    Looking for recommendations on a manual hydraulic brake master cylinder for inertia drum braking. 900lb drum.

    Going to use a car disk and caliper, but having a hard time sourcing a master cylinder that offers fairly easy mounting and isn't vacuum assist

  15. #45
    Join Date
    13th June 2010 - 17:47
    Bike
    Exercycle
    Location
    Out in the cold
    Posts
    5,624
    Outside the US there are still a lot of British Lockheed non assisted brake masters in scrapyards.

    Inside the US, I'd look at aftermarket race car stuff - Wilwood probably. Dirt car applications would be a good starting place.

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