250R PUMA cylinder (399cc) dyno

[Buttermilk]

Here is some of the latest developments for the venerable Honda TRX250R.

This dyno chart is a stock stroke (72mm) with an 84mm bore, making it a 399cc engine.

www.cpindinc.com makes the cylinder, as well as other castings such as the Cheetah Cubs, Cheetah Super Cubs, Cheetah, Cheetah DM, and Cheetah DMX casting for the Banshee. Calving Pollet Industries also makes the Sphynx, and Sabertooth for the 250R. It is also my understanding that this is the same foundry that makes the Pro-X casting for the 250R as well.

This motor was built by Nate McCoy (www.mccoysperformance.com) and was dyno'd at a Sandtrax (www.sandtrax.com) in Tulsa, OK on the same dyno that I do my own testing and tuning on.

I think it's pretty impressive and gets my blood flowing.

I don't know what pipe, gearing, carb or any details of this motor other than the bore/stroke. I do know that this motor was dyno'd on alcohol.

Regards,

[All250R]

TRX400R

[Buttermilk]

http://www.cpindinc.com/pub/view_product/22?lm=2&name=7101-8571-1303

Here's the cylinder.....

[All250R]

Originally posted by Buttermilk
http://www.cpindinc.com/pub/view_product/22?lm=2&name=7101-8571-1303

Here's the cylinder.....
No valve train, oil filters... How can you not love the genius of the simplicity.

[8686]

Beautiful. Mid 80's hp and it's still giving up displacement to the 450 4-strokes. I love it.

[HmF300ex]

Originally posted by 8686
Beautiful. Mid 80's hp and it's still giving up displacement to the 450 4-strokes. I love it.
Ye it is pretty strong(to say the least lol) but I wanna see someone who is new to quads jump on a 85hp 250r and be able to use all 85hp and do the maintenance. 4 strokes are just so much realistic for the average rider and have more torque and a much more spread out power band.

[Buttermilk]

Here a chart comparing the 399cc Puma to a true 450cc (stock bore/stroke) 2005 Honda 450R that belongs to a friend of mine.

The Puma still has more torque than the 4 stroke 450R.....

[boosted3g]

It would be interesting to see if the additional revs will compenate for the lack of power of the 4 stroke. If the torque multiplication of the lower (numerically higher) gear ratios will even it out or is it as one sided as it shows. Ive owned both and i know my decision but i always like numbers.

any pictures of this beast? i really cant imagine that much power! that thing must whoop on everything

[brnrubr4ever]

what case mod would need to be done for this?

[josh_10_07]

those are some pretty good numbers. cant wait to see what my 437 puma does. What pipe do you have?carb?and on alky?

[josh_10_07]

sorry didnt read everything

[opdmize]

Lets see some pictures! :)

[lzyga05]

i am almost sure the 400 2 stoke has way better bottom end then any 450r , unless ur talking about 1000-3000 rpms. i have never seen any one rideing with those rpms any way so it doesnt matter imo

[RATPACK Z400]

What type of riding you do with that 399puma? And comparing a 399 puma to stock 450r is joke the puma has mega port,crank,etc work done thats like comparing a stock mustage motor to a nascar motor.

[deathcorefan2]

wow you have to be sand draggin or something...wow lets see some pics!:eek2:

[rancid]

i got to ride a 431 puma in a long travel 250r with a +4 swinger and wow that thing needs more than a +4. besides that i have had some built yfz450s and some nice banshees and im loving this thing im getting one to dump in my lt-r450. very good tq from this thing, i cant see any 450 4 stroke no matter how built even coming close to this thing. except mabey a turbo. very nice cylinder, he said this thing had a 4 mill crank to get that cc,s. i dont think it would matter how much porting and valve and even cam work you did no 450cc 4 stroke has got what this has.

[kiesta00]

Originally posted by RATPACK Z400
What type of riding you do with that 399puma? And comparing a 399 puma to stock 450r is joke the puma has mega port,crank,etc work done thats like comparing a stock mustage motor to a nascar motor.

Dude what are you smoking? Theres nooo way a stock 450r is making 61 hp...get your mind right

[RATPACK Z400]

kiestaoo, are talking to me ? if you are where did i say anything about hps?there are 450s that are putting 100hps but on some kind of induction system dont what it is, just was told by builder he done one, but the new 4-strokes are getting up there in hps as does the 250rs I wouldnt say one better than the other for dragging depends on money IMO!

[kiesta00]

Thought you were saying that the dyno chart was comparing a puma motor to a stock 450r motor my bad haha.

Drag racing is all about who has the most money..and its certainly not mee

[RATPACK Z400]

Yeah it all money ! but boring to me i live in MD and love trails went to dunes was bored of the dragging up the dune hills, gets old quick ! was different though ,and saw some insane banshees,rails.got to ride a bunch of different quads like 700r,yfz450,450r.

[slamdak8782]

isnt it funny how 450 guys loved to brag about beating a quad with over 20 year old technology but when a company makes a modern 2stroke cylinder they get all upset because they are no longer king. Hahaha 24 years of being the greatest quad and counting. I guess since Honda will never will make two strokes the R will always be the greatest.

[twincat800]

Yeah they wont ever be made like that anymore just like cars with all the hp they used to have. Now companys focus on reliability and have to meet certain regulations. I personally never saw a 4-stroke quad ran on alky but there out there. Did you guys know that top fuel drag cars only make 1000hp on regular gas? When ran on alky they make over 8000hp which is what makes them so fast and then they have to rebuild them all the time. Took me forever to figure this out and not 100% percent if its right but this is what i came up with... A 250cc bumped up to a 400cc is a gain of 37.5% of cc. If you bumped a 450cc engine size up 37.5% that would make it a 720cc which is hugee! And a 720cc high compression engine with the biggest bores everywhere ran on alky like your 400cc, im guessing would make more power than your quad. But realisticly its not possible to make a 450 that big, but if you want to compare it to an actual 4-stroke quad that can be around 720cc, and do everything possible to it to make more power and then run it on alky, imo would make numbers way up there like yours. Just something for everyone to think about when they talk about a fully modded to hell 250 2stroke compared to a 450 4stroke, we all know 4strokes dont make a much power as 2strokes congrats and get over it, they are there own classes which is why there named different, one more powerful, other more durable and technical and this is all just my opinion. And good job the the guy who made them numbers, very sweet engine.

[Buttermilk]

Some of what is posted above is a bit inaccurate at best. The top fuel drag cars run on nitromethane, not alky, which is the reason they get so much more hp out of the engine.

Alcohol is only worth ~8%-12% more power, depending on how well you can tune an engine on both fuels (compared to race gas).

I've witnessed gas vs. methanol alcohol being dyno'd on a 4 stroke and I know what the % difference normally runs. I've also got a buddy who's ran it in his 4 stroke.

What you have to consider when you compare the 2 stroke to the 4 stroke is the HP per CC to see where you really are.

It is entirely possible (I've owned one...) to get a two stroke up to 3.5 hp/ci and even higher on a twin based two stroke (mine was up to 3.7 hp/ci on my twin and 3.5 hp/ci on my single on gas). Alcohol can bump this up to over 4 hp/ci on the right setup.

Now on a 4 stroke, the best I've seen on a single is 2.2 hp/ci on a 450cc Honda. Some of the Yamaha 450's are running about 2.1 hp/ci or so. My own Yamaha is about there, and my son's Honda is about there.

The best Raptor based motors I've seen are ~1.5-1.7 hp/ci, with some I've "heard" of getting a bit more than that.

Bottom line is this: Ain't know four stroke gonna match the two stroke on a CC per CC basis on a naturally aspirated engine. Even turbo'd applications still give the two stroke an edge.

And on the example you give below on the +37.5% increase in displacement, the two stroke still gets more power than the four stroke.

As far as durability, I'd put the built two stroke up against the built four stroke any day of the week. I've owned both and the modern high performance four stroke is not as reliable as the two stroke in most cases. My wallet can attest to that also.

And this is all my opinion based on observation of some facts surrounding my own motors as well as personal friends motors.

:)

Rog




Originally posted by twincat800
Yeah they wont ever be made like that anymore just like cars with all the hp they used to have. Now companys focus on reliability and have to meet certain regulations. I personally never saw a 4-stroke quad ran on alky but there out there. Did you guys know that top fuel drag cars only make 1000hp on regular gas? When ran on alky they make over 8000hp which is what makes them so fast and then they have to rebuild them all the time. Took me forever to figure this out and not 100% percent if its right but this is what i came up with... A 250cc bumped up to a 400cc is a gain of 37.5% of cc. If you bumped a 450cc engine size up 37.5% that would make it a 720cc which is hugee! And a 720cc high compression engine with the biggest bores everywhere ran on alky like your 400cc, im guessing would make more power than your quad. But realisticly its not possible to make a 450 that big, but if you want to compare it to an actual 4-stroke quad that can be around 720cc, and do everything possible to it to make more power and then run it on alky, imo would make numbers way up there like yours. Just something for everyone to think about when they talk about a fully modded to hell 250 2stroke compared to a 450 4stroke, we all know 4strokes dont make a much power as 2strokes congrats and get over it, they are there own classes which is why there named different, one more powerful, other more durable and technical and this is all just my opinion. And good job the the guy who made them numbers, very sweet engine. :) :) :) :) :) :) :)

[LT250_JOE]

Originally posted by Buttermilk
Some of what is posted above is a bit inaccurate at best. The top fuel drag cars run on nitromethane, not alky, which is the reason they get so much more hp out of the engine.

Alcohol is only worth ~8%-12% more power, depending on how well you can tune an engine on both fuels (compared to race gas).

I've witnessed gas vs. methanol alcohol being dyno'd on a 4 stroke and I know what the % difference normally runs. I've also got a buddy who's ran it in his 4 stroke.

What you have to consider when you compare the 2 stroke to the 4 stroke is the HP per CC to see where you really are.

It is entirely possible (I've owned one...) to get a two stroke up to 3.5 hp/cc and even higher on a twin based two stroke (mine was up to 3.7 hp/cc on my twin and 3.5 hp/cc on my single on gas). Alcohol can bump this up to over 4 hp/cc on the right setup.

Now on a 4 stroke, the best I've seen on a single is 2.2 hp/cc on a 450cc Honda. Some of the Yamaha 450's are running about 2.1 hp/cc or so. My own Yamaha is about there, and my son's Honda is about there.

The best Raptor based motors I've seen are ~1.5-1.7 hp/cc, with some I've "heard" of getting a bit more than that.

Bottom line is this: Ain't know four stroke gonna match the two stroke on a CC per CC basis on a naturally aspirated engine. Even turbo'd applications still give the two stroke an edge.

And on the example you give below on the +37.5% increase in displacement, the two stroke still gets more power than the four stroke.

As far as durability, I'd put the built two stroke up against the built four stroke any day of the week. I've owned both and the modern high performance four stroke is not as reliable as the two stroke in most cases. My wallet can attest to that also.

And this is all my opinion based on observation of some facts surrounding my own motors as well as personal friends motors.

:)

Rog



:) :) :) :) :) :) :)






WOW so lets take the Raptor: 686cc's X 1.5 hp/cc = 1029 Horsepower !!!!! even @ .15 hp/cc (assuming you misplaced the decimal point).... 102.9 hp.

Now the Honda : 450 cc's x 2.2hp/cc = 990 horsepower !!!

Now the two stroke.
249cc x 3.5 hp/cc = 871.5 hp !!

I don't know bro....... I think your post is WAY less accurate !!!!

[Buttermilk]

My Bad! I meant cubic inches not cubic centimeters... :D

My post is still more accurate...:) :D

[twincat800]

Yeah i see what your saying and we got 2 different point of views, neither of which are wrong, just different :) And a 450's cc increased by 37.5% would be a 720 like i said and modded raptors on pump gas with stock bores can make what this 400 did and probably more (tq too)whereas this 400 cant be built anymore. But I do see your point and it is amazing what this guy with 400cc of 2stroke and someones always faster anyways.

[Buttermilk]

Actually, the guy who built this 399cc motor is now getting them up to 92-94 hp so they can be "built" more... :)

Also, you will not get a Raptor up to that HP level running pump gas. Ain't gonna happen! And not on stock bore either! (naturally aspirated, no power adders...)

By the way, taking a 250cc to 400cc is a 60% increase in displacement as is a 450cc to 720cc... not 37.5% increase.... :D

Regards,

Roger Carlton

[slamdak8782]

the new cp industries big bores are godlike. I cannot beleive how awesome these things are. This post should have music from 300 or something to signify how awesome this thing is. I mean it really is unnatural for a 250r two be this powerful. I just cant beleive the numbers it astounds me to no end simply amazing.