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Thread: Specs and Horsepower Numbers for the 250 2 stroke 3 wheelers

  1. #1
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    Specs and Horsepower Numbers for the 250 2 stroke 3 wheelers

    I've recently splurged and bought a ton of Specification manuals for the different manufactures and Kawasaki has the best books so far for the amount of detail they give. I can't find an offical statement for what Honda claimed the ATC250R had for horsepower and torque (including service manuals, spec books, etc), the Kawasaki book gives the numbers though.

    I would be interested to know what the ATC250R and YTZ250 were claimed to produce, any source material? I heard the cert of origin has this info?

    My Kawasaki book collection only go back to 1985, but I have coverage for all models (including motorcycles) up to 2004, and 2005 I have atv's only covered. I'm slowly putting this info on my site so everyone can find it easier, so I want only documents related by Honda, Kawasaki, Yamaha, etc. I'm not after what a magazine says, or someone else's dyno numbers.


    Below is the 1985 Tecate A2. PS is real close to HP, 37 would convert to 36.5hp.

    I can look up specs for other models, but check on my site first to make sure I don't have it already posted up.


    https://atvmanual.com/


    Quick list of interesting machines:

    Tecate:
    1985 A2 - 37PS
    1986-1987 B1-B2 - 42PS

    Tecate 4:
    1987-1988 A1-A2 - 42PS




    I made this thread since google results seemed to not give any solid info, just people guessing, figured I'd post some real numbers =).
    Last edited by ps2fixer; 02-11-2020 at 02:33 PM.

  2. #2
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    Wow, I would not have thought the torque was that high on that 2-stroke.
    Is that at 7,000 rpms?
    MrC.

  3. #3
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    Yes, the pic is max hp @ 8,500 rpm, and max torque at 7,000 rpm. International standard for numbers, they don't use , or . because different area's of the world it means something different, so they used just a space aka 7 000, looks weird but makes more sense than seeing 7.000

    Some countries write their numbers reversed to what we do, so instead of 1,234.56 they write 1.234,56

    Kind of funny they still write decimals though, they just don't use a normal thousands separator ex: 1 234.56


    EDIT:

    Just got more books in the mail, Honda ones this time. Sadly the Honda spec book I got doesn't have HP spec for any machine. I think I have Honda spec books now from 1959-2009. Kind of went all out on buying books lol.
    Last edited by ps2fixer; 02-11-2020 at 03:01 PM.

  4. #4
    6bt's Avatar
    6bt is offline At The Back Of The Pack Arm chair racerAt the back of the pack
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    Not 3 wheeler related, but do they say what a 2001 kx500 and a 2003 zrx1200r put out ho and tq wise?

    Sent from my moto z4 using Tapatalk

  5. #5
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    2001 KX500 the hp/torque values are blank sadly. Know of anything else with the same engine? Like the Tecate 3 wheeler and Tecate 4 wheeler used the same engine or very similar atleast. Is the EX500 anything similar? I don't really know motorcycle models like at all, just a few Honda motorcycles.



    The ZRX1200R I guess is the name of the machine, partzilla shows that, then the actual machine code as ZR1200 A3 which my book has.

    100 PS @ 8000 rpm
    83.8 ft-lb of torque @ 8500 (USA, Canada, California marketed machines)

    Also, no problem about the non-3 wheeler request, I have the data, so why not share what I can around. Only thing that I haven't quite figured out is how the data is sorted lol. It's like by engine size and model a-z, but it jumps around a bit, almost like 2 letter code machines first, then 3 letter code machines, but sometimes there's 3 letter code machines mixed in with the 2 letter code machines... really weird sorting lol. FYI, these books are huge, they have all the common tech info for all models, each book is 200+ pages and normally covers 2 years each book, last few books cover 3-5 years and are closer to 600 pages.

    Here's a photo of some of the books, got a lot more lol.

    Last edited by ps2fixer; 02-12-2020 at 01:24 AM.

  6. #6
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    The EX500 is (was) a twin cylinder, four stroke Ninja. Nothing like a KX500.

  7. #7
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    I see, I saw it had bigger hp numbers and figured the kx was a higher output model so was hoping they were similar lol.


    Also, just discovered that the certificate of origin has the machine's horsepower rating on it! Now I'm on a search for photos of the certificates since I'd think those numbers would be the most accurate and least likely to have mistakes.

    Here's a couple I've found so far....


    1986 Tri-Z 250 - 32.9hp

    1985 ATC250R - 38.4hp
    1985 ATC350X - 28 hp (service manual says 26.6hp)

    2000 TRX400EX - 34.2hp
    2004 TRX450R - 43.4hp


    From specs books:

    1985 Tecate - 36.5hp
    1986-1987 Tecate - 41.4hp


    Pretty interesting, not sure if the 86 250r got more power than the 85, but seems like the tecate is the king of the 250 2 strokes for pure numbers sake.

    Would be awesome if I could get a pic of every model and year to validate numbers. Any idea why the 350x service manual and the cert are so far off?

  8. #8
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    Quote Originally Posted by ps2fixer View Post
    Any idea why the 350x service manual and the cert are so far off?
    Might be because no two dynos will register exactly the same reading on the same engine and production tolerances between two "identical" engines will have varying performance.

    Dynos are meant to be used for tuning, so unless results like what you're posting were made on the same dyno under the same conditions they don't mean a lot. Manufactures lie because numbers sell. The only way to know the true power of an engine is to look at the fine print on the humbling little paper slip they give you at the tower on your way back to the pits.
    Last edited by El Camexican; 02-13-2020 at 12:49 AM.

  9. #9
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    I figured there was a margin of error, but it's about 5% off, figured they'd be closer to a 1% tolerance. Very valid point though.

    I did find a atc200e cert and it's a perfect match, 13.0hp. I figured any published numbers in specs books would be averages or "typical" numbers, while the title would pull from the same data set, I wouldn't think every machine is tested for HP output before being sold and logged on the cert, but maybe it's a quality control thing.

    Either case, having something for a document to say what the power should be about is better than nothing or guessing the figures. Honda didn't publish the ATC250R hp specs that I can find, so the only stock, non-modified, and new condition numbers I can think of to get the spec is the cert of origin.

    I wonder how big the margin of error is. In the electronics world, cheap parts are normally around 10% tolerance, so assuming 26.6hp is the "average" figure, then real numbers should be something like 24-29.3hp.

  10. #10
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    Just came across this thread, pretty interesting. Guess really it's just a taxable hp rating, not a true number or anything. Based on a couple places, it's just based on bore size & # of cylinders. I guess the 2 strokes got a different formula since the tecate has the biggest bore (70mm), 250r close behind it 66mm, and the tri-z doesn't make sense with that logic since it's 68mm bore unless they messed up and rated it as a 4 stroke.

    https://www.camaros.net/forums/15-ta...te-origin.html

    https://www.corvetteforum.com/forums...-question.html

  11. #11
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    I know modern 2stroke 250cc dirtbike engines range from 44-49hp
    Pretty sure the kx and CR 500 were in the 62-64hp range

  12. #12
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    93-94 kx250 shows 53.6ps which converts to 52.9hp.

    oh looks like the 93 KX500 gives a hp spec, 64.5ps, converts to 63.6hp. Pretty crazy from a 250 to a 500 there isn't a monster difference for some reason. In the 4 stroke work, double the displacement, and you get roughly double the hp from my understanding.

  13. #13
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    [QUOTE but seems like the tecate is the king of the 250 2 strokes for pure numbers sake.

    [/QUOTE]
    What was that Barnett used to say?
    As for the KX250/KX500, I think the biggest difference between the two was the amount of torque that the KX500 had compared to the KX250.

  14. #14
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    36 vs 49.2 ft-lb of torque, bit of a difference, but it's about 27% increase for a 100% increase in engine size. Pretty interesting in either case. I suspect the 500 has a lot more upgrade potential, maybe power output was restricted for better mpg/fuel econ or to keep the machine more "safe".

  15. #15
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    My memories of the 80s is a little foggy for reasons I really don’t want to get into here, but I don’t ever recall hearing anybody complain about the fuel economy, or lack of power on their 500 2 strokes back then.

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