Specs and Horsepower Numbers for the 250 2 stroke 3 wheelers

[ps2fixer]

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


https://i.gyazo.com/15fdb0ad493cac1e429715e0d205a4e6.jpg

I made this thread since google results seemed to not give any solid info, just people guessing, figured I'd post some real numbers =).

[MrConcdid]

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

[ps2fixer]

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.

[6bt]

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

[ps2fixer]

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.

https://i.gyazo.com/cf1a50a3f8cc579b69bccc7ec0915c8a.jpg

[350for350]

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

[ps2fixer]

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?

[El Camexican]

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.

[ps2fixer]

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.

[ps2fixer]

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-tag-team/77351-hp-rating-certificate-origin.html

https://www.corvetteforum.com/forums/c1-and-c2-corvettes/2892435-tank-sheet-question.html

[Pryme]

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

[ps2fixer]

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.

[350for350]

[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.

[ps2fixer]

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".

[El Camexican]

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.

[ps2fixer]

Yea, I wouldn't think the motive would be fuel econ either, there was the big oil crisis of the 70's, but I wasn't even alive then xD.

[bkm]

A 10hp and 13ft lb difference between the 250 and 500 is huge in a machine that weighs 200ish lbs. Having owned a modern 250 KX, I can tell you that it's all the power I've ever needed and having ridden a few KX 500's, I can tell you it's all the power you'd ever want unless you were an expert rider.

[ps2fixer]

Yea 50hp+ on a bike is pretty crazy.

Just for fun I grabbed the machine weights.

kx250 is 213lb
kx500 is 220lb

Only 7lb difference, that's quite amazing, almost would suggest to me the same frame was used, just the engine was the difference (know nothing about this model besides specs in the book lol).

Pretty crazy weight to power ratio too.

kx250 is 4.01lb of weight per hp
kx500 is 3.46lb/hp

That is a huge drop, guess I was just looking at the wrong numbers lol. Just for context, the service manual says the 350x has 26.6hp and weighs 320lb so the weight to power ratio is 12.03lb/hp. that must be one crazy bike to ride.

[yaegerb]

A 10hp and 13ft lb difference between the 250 and 500 is huge in a machine that weighs 200ish lbs. Having owned a modern 250 KX, I can tell you that it's all the power I've ever needed and having ridden a few KX 500's, I can tell you it's all the power you'd ever want unless you were an expert rider.

To dogpile onto this thoughtful comment I would also like to add that I once heard a qoute from a pro racer that the 250 tuned to a 265 when properly used is all the power a racer ever needs. Later I decided to race my 250r with a shaved head and can tell you it’s a lot of power to handle effectively. I honestly couldn’t imagine effectively handling a 500.

[El Camexican]

Yea 50hp+ on a bike is pretty crazy.

Just for fun I grabbed the machine weights.

kx250 is 213lb
kx500 is 220lb

Only 7lb difference, that's quite amazing, almost would suggest to me the same frame was used, just the engine was the difference (know nothing about this model besides specs in the book lol).

Pretty crazy weight to power ratio too.

kx250 is 4.01lb of weight per hp
kx500 is 3.46lb/hp

That is a huge drop, guess I was just looking at the wrong numbers lol. Just for context, the service manual says the 350x has 26.6hp and weighs 320lb so the weight to power ratio is 12.03lb/hp. that must be one crazy bike to ride.

Weight is another area where the factories fudged with the numbers. At one point it got to where they were draining the forks, shocks, radiators, transmission, fuel tank and probably filling the tires with helium before giving out what they called “dry weights”.

Read through all the old dirtbike magazine and time and time again you’ll see where they put the vehicle on a scale and it was considerably higher than the advertised weights.

[ps2fixer]

Yep dry weight by definition is weight with no fluids so it would make sense it's all drained, or more likely assembled and never filled with any fluids. Now if they were removing parts to reduce the weight, then I could see it being a problem. I'm sure the tires sold on stock machines are as light as possible for this spec as well as for the benefits of having lighter suspended parts.

Newer machines have "curb weight" as the true weight with a full tank of gas etc. Still doesn't account for rider weight and such, but we all don't weigh the same. I think dry weight was used because it was a consistant value, didn't matter if the tank was full or not, the raw machine weighed the same, curb weight requires all fluids to be the same as stock level to get the same weight.

A good example of a manual that has both weights is the 2003 TRX650FA service manual (Rincon).

Dry weight is 600lb
Curb weight is 631lb (31 lbs of fluids)

Oil capacity is the same way, there's a total when rebuilding an engine vs just draining the oil and changing it. Same machine:

3.0 US qt after draining
3.1 US qt after draining + filter change
4.1 US qt after disassembly

That means, about 1 qt of oil is left behind in that engine when changing the oil. Some engines are only 0.1 qt difference.