Maxing out my 450

[PRYOUNG]

Formula Juan, if memory serves me correctly, I was running a 99mm piston and cylinder kit from Athena for the CRF450. Although I had no problems with this cylinder kit, I knw two people running them for supermoto that had piston failures more than once. Take that for what it is worth.

Also note that the HP and torque figures I quoted where for a motor with no head work, stock exhaust, stock ignition, cam was a Webcam, so the motor was flow restricted. It is my opinion that if the head was ported, the exhaust altered, carb modified and the ignition tuned to suite, the motor would of made way more HP than quoted. My use was for motocross and what the motor produced was plenty enough, in fact too much, not from a wheel spin point of view, but from a response point of view. Just touching the throttle and the bike took of at a rate of knots. Good fun!

[Formula Juan]

Formula Juan, if memory serves me correctly, I was running a 99mm piston and cylinder kit from Athena for the CRF450. Although I had no problems with this cylinder kit, I knw two people running them for supermoto that had piston failures more than once. Take that for what it is worth.

Also note that the HP and torque figures I quoted where for a motor with no head work, stock exhaust, stock ignition, cam was a Webcam, so the motor was flow restricted. It is my opinion that if the head was ported, the exhaust altered, carb modified and the ignition tuned to suite, the motor would of made way more HP than quoted. My use was for motocross and what the motor produced was plenty enough, in fact too much, not from a wheel spin point of view, but from a response point of view. Just touching the throttle and the bike took of at a rate of knots. Good fun!

Thank you for your input. Seeing as how i'm using slicks and an LSD for traction, a lot of the problems you experienced won't be seen on my end. The problems of longevity will be seen though. Reliability will be an issue especially with a stroked/bored motor. If honda was currently making a 600cc single cyl motor i would be more than happy to use it.

In fact, what exhaust modification would you have considered to be adequate for this displacement? Is the stock exhuast port large enough? Would the stock exhaust need a larger resonator? Exactly what mod's to the exhaust would you have considered? I'm not familiar at all with single cilynder applications, so exhaust solutions can be extreemely different.

I just want to make the most out of my bottom end, then make a top end to match.

[Katoom Gumbee]

Thank you for your input. Seeing as how i'm using slicks and an LSD for traction, a lot of the problems you experienced won't be seen on my end. The problems of longevity will be seen though. Reliability will be an issue especially with a stroked/bored motor. If honda was currently making a 600cc single cyl motor i would be more than happy to use it.

In fact, what exhaust modification would you have considered to be adequate for this displacement? Is the stock exhuast port large enough? Would the stock exhaust need a larger resonator? Exactly what mod's to the exhaust would you have considered? I'm not familiar at all with single cilynder applications, so exhaust solutions can be extreemely different.

I just want to make the most out of my bottom end, then make a top end to match.

Juan, what you do with the following comments is your choice…

One minute you’re educating theoretically one of most experienced and respected engine builders on TT with the problems of stroking a 450r with the following comment “The ability to make power at Higher RPM's is solely a factor of the head flow and camshaft characteristics” then you ask if the exhaust system is adequate!!! Maybe not quite as simplistic as you think for getting optimum results? And there are other performance considerations as well…

FWIW, the very best mechanical engineers I know always show respect for experienced trade people as they will often have a practical solution for a particular problem or information to pass on, which often gets lost with the attitude “how good am I”. I’ll only employ engineers with the right attitude as they always quickly gain respect of fellow employees.

BTW, I often get told where to go...

KG.

[PSD_Sun]

You could have picked a better source motor. Like a KTM LC4 motor single that fully restricted and 100% reliable puts out 62 rwhp. Of an Ape V-twin. Or a Husaberg 650 single.

PS. I've spent some time on a good rotax TAG and that stuff is so much fun! The G's while turning are insane and fun!

[GENE426]

I FEEL SICK TO MY STOMACH!!!!!!!!!!!!

Rip apart a BAD AZZ MX bike to make a go cart????????????????

:busted: ?

Wish I had that kind of money!!!

[AngryYeti]

Formula Juan sounds exactly like an engineering student building an FSAE car. FWIW, that's what this is all about.

Juan,

What school? '09 car?

[crowerpowerhp]

formmula uuuhhh

while your at it send it over to me and we will stuff a titanium rod in there and some airsprings so you can twist it on up to 13000. we can reduce the rotational mass like the nascar products we do.

[crowerpowerhp]

almost forgot tration control while your at i can set that up too..

[Shawn_Mc]

Thank you for your input. Seeing as how i'm using slicks and an LSD for traction, a lot of the problems you experienced won't be seen on my end. The problems of longevity will be seen though. Reliability will be an issue especially with a stroked/bored motor. If honda was currently making a 600cc single cyl motor i would be more than happy to use it.

In fact, what exhaust modification would you have considered to be adequate for this displacement? Is the stock exhuast port large enough? Would the stock exhaust need a larger resonator? Exactly what mod's to the exhaust would you have considered? I'm not familiar at all with single cilynder applications, so exhaust solutions can be extreemely different.

I just want to make the most out of my bottom end, then make a top end to match.

There is another aspect to your application you may not have considered and that's the trans. We had one guy on here using a 450 in a cart and he went through trans after trans after trans. Turns out that the lateral G forces created by the kart are enough to starve the trans because the engine remains upright in the corner and the oil goes where its not supposed to. He finally gave up and went back to the case reed CR250 engines he'd been using.

He was using the first gen motor though. Nobody has done what youre doing with the 09 motor that I know of.

[MRD RACING]

There is another aspect to your application you may not have considered and that's the trans. We had one guy on here using a 450 in a cart and he went through trans after trans after trans. Turns out that the lateral G forces created by the kart are enough to starve the trans because the engine remains upright in the corner and the oil goes where its not supposed to. He finally gave up and went back to the case reed CR250 engines he'd been using.

He was using the first gen motor though. Nobody has done what youre doing with the 09 motor that I know of.

he was going to machine his own piston , so he could fab up a nice trans oil pump system with a couple nozzels to spray the trans

[MRD RACING]

formmula uuuhhh

while your at it send it over to me and we will stuff a titanium rod in there and some airsprings so you can twist it on up to 13000. we can reduce the rotational mass like the nascar products we do.

the sky's the limit ..... I mean the wallet's the limit

[Formula Juan]

What is normally required for a 450 to make 66 hp? Mr. Ron Hamp says its possible, but the only dyno's i've seen are weekend wariors who can barley push 50hp. Also, is that 66 at the wheel? Anyone have any links to such bikes? I'm kinda new to the MX world, so i'm sorry if i've offended anyone

[beaner568]

So i just got an '09 crf 450 and i was looking to max out the displacement. I really don't want to touch the stroke because the short skirt piston design is going to ruin my reliability and increase my maintenance intervals. So far, the largest big bore kit i could find for a 450 is a 100mm piston, but that only brings me up to 487cc's. I wanna go bigger (550 or higher if possible)!! I was thinking about machining my own piston sleve, but i don't know if i can design a piston as well as some of the other manufacturers. Also, i'm not sure if the piston sleves are coated with a specific material, or use some sort of exotic material.

Do you guys know of any racing companies that can make some specialized parts?

I'm kind of at a loss for how you got your hands on two 09 crf450x crate engines.

[Ron Hamp]

What is normally required for a 450 to make 66 hp? Mr. Ron Hamp says its possible, but the only dyno's i've seen are weekend wariors who can barley push 50hp. Also, is that 66 at the wheel? Anyone have any links to such bikes? I'm kinda new to the MX world, so i'm sorry if i've offended anyone

truthfully the most i have seen from a 450 was actual hp on my dyno and it was just above 64 hp i have seen other dyno graphs with my components showing nearly 67 hp from a 450 .this is rear wheel hp if you add in about 14% to simulate crank shaft hp and do your math you will see by the BMEP that it is very possible .the heads can flow over 300 cfm @ 28" which will also suport that kind of power port cross section needs to be altered also to control velocities @ the higher rpms instead of peaking @ 9000 rpm and carring flat to 11000-12000 rpm your peak has to raise i beleive the engine producing 66 hp peaked @ 10500 rpm .the power curve like this would probally work better with 4 wheels it was dangerous on a half mile dirt track .

[mxaddict]

He was using the first gen motor though. Nobody has done what youre doing with the 09 motor that I know of.

The 2009 450x motor is the old motor, not the new 450r motor.

[Formula Juan]

truthfully the most i have seen from a 450 was actual hp on my dyno and it was just above 64 hp i have seen other dyno graphs with my components showing nearly 67 hp from a 450 .this is rear wheel hp if you add in about 14% to simulate crank shaft hp and do your math you will see by the BMEP that it is very possible .the heads can flow over 300 cfm @ 28" which will also suport that kind of power port cross section needs to be altered also to control velocities @ the higher rpms instead of peaking @ 9000 rpm and carring flat to 11000-12000 rpm your peak has to raise i beleive the engine producing 66 hp peaked @ 10500 rpm .the power curve like this would probally work better with 4 wheels it was dangerous on a half mile dirt track .

Wow so i would need to modify the port cross section to move the power band up? It seems like you had great success with that though.

Because of the restriction that the engines are required to run in the intake, The head modifications will more than likely be minimal. Depending on the displacement, i may see max particle velocity at 7k rpm's. I gotta run some calcs and do some serious dyno testing to find out what the engine is capable of in stock displacement.

What were the camshaft profiles that you were using with that?

[AngryYeti]

Juan,

Again.. What school? '09 car?

[555 KingR]

This whole thread was just rediculous. I think K.G. hits the nail on the head with his reply. Everything in this discussion is just silly.

Surprised someone hasnt suggested a John Deere piston yet for this knuckle head......lol

[fastmq]

troll

[Formula Juan]

Juan,

Again.. What school? '09 car?

University of Texas in San Antonio. And ya, its for the '09 car. What team are you on?

When i told everyone on the team that a stroke/bore kit is going to cost 2300 they flipped lol. Personally, I wanted to stay with a 4 cyl.