450r hp

[robjohn74]

does anybody no what the hp is yet

[beak7707]

right around 37 ponies stock.

[robjohn74]

wasent that dyno at 37 with stock tires

[lukester720]

Tc racing said 34.7 hp and curtis sparks said 37 hp. Almost every other place I've talked to said numbers that are right around these 2. More often then any other 37.

[4fiddyR]

What kind of gain should I expect with a full sparks system, and correct jetting for exhaust?
No HRC kit here, gettin a cam later.:devil:

[lukester720]

Originally posted by 4fiddyR
What kind of gain should I expect with a full sparks system, and correct jetting for exhaust?
No HRC kit here, gettin a cam later.:devil:

Sparks racing told me over the phone a full system would bring it from 37 up to 40.5 which is 3.5 hp I thought it would have been more but I haven't seen the powercurve on the dyno yet either.

[beak7707]

In the dirtwheels test they put on a white bros pipe and jetted the 450 and it pulled 40 horse. So i would say it would be close to low 40's.

[robjohn74]

thank you . so do you no what the diff between the yfz and 450r in hp is .

[beak7707]

the yfz stock makes a little under 40, with a pipe and airbox mod they had it up to 45. So its ahead of the honda in hp. I have heard the 450r doesnt respond to mods quite as well as the yfz. Like removing the air box lid and removing the stock exhaust.

[Scottie Mac]

The reason the Yamaha gaons more by adding a pipe is because the YFZ stock exhaust is terrible. It was designed to choke and quiet the 450 motor. The Honda comes stock wiht a much better exhaust, harder for aftermarket manufacturers to imprive on.

Scott

[robjohn74]

cool thanks. going with the 450r

[Maxx_Action]

Originally posted by 4fiddyR

B]What kind of gain should I expect with a full sparks system, and correct jetting for exhaust?
No HRC kit here, gettin a cam later.:devil: [/B]

Dude...

spend the extra hundo and get the cam. It will be well worth it. From what I understand, that is one of the main ways the 450R was detuned. I think it is one of the biggest reasons that the YFZ has 3-4 more hp in similar trim.

Maxx

[norrisboat]

Originally posted by beak7707
I have heard the 450r doesnt respond to mods quite as well as the yfz. Like removing the air box lid and removing the stock exhaust.

Mine didnt have any problem responding to those mods.

[Maxx_Action]

Originally posted by Scottie Mac
The reason the Yamaha gaons more by adding a pipe is because the YFZ stock exhaust is terrible. It was designed to choke and quiet the 450 motor. The Honda comes stock wiht a much better exhaust, harder for aftermarket manufacturers to imprive on.

Scott

http://smilies.sofrayt.com/%5E/d/spy.gif:huh

[r450rr]

honestly.. this is what honda claims.. 42 stock. 47 with HRC kit, 13% increase, they have said this for a long time now.. know idea if thats at the crank, with stockers, or with slicks, but thats what they say and thats what i am going to believe..lol
( somewhere or another is has 42 hp..)

[Honda]

That is probably Crank HP. Most manufactures will state Crank Horspower because it is the higher number compared to Wheel Horsepower.

Wheel horspower numbers are always lower because of Power lost through the drivetrain (gearbox, Chain, Sprockets, Bearing friction, Tire Friction, etc), usually 10-15 percent is lost through friction.

Tire type will not change Horspower readings on a Dyno. Tire Size and Gear selected will play a role in the final HP #'s printed out by the Dyno machine. Also, no two dyno's will read the exact same number, and weather, temperature and many other factors will effect the readings.

[BigThumper33]

Tire type can play a roll in dyno readout. Thats why GT Thunder runs the same tires on all dynos. Its on their site, they even show dynos with the different tires.

[Honda]

Maybe, if the compounds are different. A Softer tire would produce more Drag on the rollers.

Also, I guess tires of the same size, but multiple brands, will not all have the same rolling diameter. some would measure larger or smaller than the size stated on the sidewall.

I stand Corrected!

[ATC83]

The YFZ450 makes about 47 hp with a "correctly" jetted FCR carb and and a K&N air box and lid removed. If you do the free cam mod you will be looking at between 48 and 49 hp. I've seen several dyno numbers at 50 and 51 hp with the previouse mods and a port job. It will be dificult to get much more than 52 to 54 horse power out the YFZ engine without adding a stroker kit and high compression piston. You have to admit that an engine with out any internal engine work that makes 50 hp is incredible. I wish they would have put the CRF450 engine in the TRX450 because it is capable of 50 hp with only minor mods like the YFZ. I wonder if the engine mounts are the CRF450 engine are the same as on the TRX450. That would make it easy to get rid of the TRX's engine and bolt in the fire breathing CRF450's engine.

[Honda]

I wonder why this is?

I think we need to examine the specs on both motors (TRX vs. CRF) to see what the major diffrences are. Surely thay are not all that different and should respond similarly once modded.

The CRF has a 12.0:1 compression ratio, compared to the TRX's lower 10.5:1.

The CRF also uses a slightly smaller throttle Body at 40mm compared to that of the TRX at 42mm. The TRX's throttle body also incorporates a TPS Switch. More on that in a minute...

The CRF has a Bore of 96.0mm and a stroke of 62.1mm
The TRX has a bore of 94.0mm and a stroke of 64.8mm

I can tell you that after bumping the compression on the TRX to the CRF's high 12.0:1, you will have a totally different machine. More power, and power that works better with the HRC cam, and it will also respond better to mods because of the increased pumping volume. I would put money on it, that with a higher compression piston alone, the YFZ would not be able to pull away from the TRX like we have been hearing.

The Bore and stroke is not a big factor. The CRF will rev easier because of it's shorter stroke and larger bore. The TRX will produce more torque, torque that understandably Honda thought the TRX needed to turn the extra weight and traction produced by two tire's instead of one.

The CRF uses a 40mm Throttle body, that is not influenced in any way by electronic control. The CRF should have better throttle response because of it's smaller bore and the fact that the computer does not really on a TPS to feed fuel into the motor.

I am also wondering whether or not the TRX's power output has been influenced by the additional Emissions systems. That could explain why it does not respond to modification as well.

Overall, I believe the problem lies with the Compression ratio being so low. Honestly, a higher compression piston would really wake the TRX up, and make it more responsive to mods. Why Honda dropped the compression is beyond me. Possibly, they dropped the compression because of reliability concerns, since a higher compression piston would require the motor to be serviced more often, and would make using a high grade fuel necassary. Honda knows we are not going to leave our quads alone, they probably are also skeered as heel of being sued over and over again as they had been in the 80's. I think they designed a great reliable quad for a large majority of people. Honda has produced a foundation which all of us can now build upon. The Legend of the R would not have been such a legend if not for the aftermarket's support.

Now who makes a HCP upgrade?

Class is Dismissed!

[ml450r]

excellent post Honda

[Scottie Mac]

Originally posted by ml450r
excellent post Honda

I agree, Honda, you have outdone yourself.

Scott

[r450rr]

Originally posted by Honda
I wonder why this is?

I think we need to examine the specs on both motors (TRX vs. CRF) to see what the major diffrences are. Surely thay are not all that different and should respond similarly once modded.

The CRF has a 12.0:1 compression ratio, compared to the TRX's lower 10.5:1.

The CRF also uses a slightly smaller throttle Body at 40mm compared to that of the TRX at 42mm. The TRX's throttle body also incorporates a TPS Switch. More on that in a minute...

The CRF has a Bore of 96.0mm and a stroke of 62.1mm
The TRX has a bore of 94.0mm and a stroke of 64.8mm

I can tell you that after bumping the compression on the TRX to the CRF's high 12.0:1, you will have a totally different machine. More power, and power that works better with the HRC cam, and it will also respond better to mods because of the increased pumping volume. I would put money on it, that with a higher compression piston alone, the YFZ would not be able to pull away from the TRX like we have been hearing.

The Bore and stroke is not a big factor. The CRF will rev easier because of it's shorter stroke and larger bore. The TRX will produce more torque, torque that understandably Honda thought the TRX needed to turn the extra weight and traction produced by two tire's instead of one.

The CRF uses a 40mm Throttle body, that is not influenced in any way by electronic control. The CRF should have better throttle response because of it's smaller bore and the fact that the computer does not really on a TPS to feed fuel into the motor.

I am also wondering whether or not the TRX's power output has been influenced by the additional Emissions systems. That could explain why it does not respond to modification as well.

Overall, I believe the problem lies with the Compression ratio being so low. Honestly, a higher compression piston would really wake the TRX up, and make it more responsive to mods. Why Honda dropped the compression is beyond me. Possibly, they dropped the compression because of reliability concerns, since a higher compression piston would require the motor to be serviced more often, and would make using a high grade fuel necassary. Honda knows we are not going to leave our quads alone, they probably are also skeered as heel of being sued over and over again as they had been in the 80's. I think they designed a great reliable quad for a large majority of people. Honda has produced a foundation which all of us can now build upon. The Legend of the R would not have been such a legend if not for the aftermarket's support.

Now who makes a HCP upgrade?

Class is Dismissed!

had to quote it cause its so long..lol

yea really good thoughtout post, i totally agree about bumping up the compression and wakeing up a BEAST!!:blah:

[jmpulse]

Originally posted by Honda
I wonder why this is?

I think we need to examine the specs on both motors (TRX vs. CRF) to see what the major diffrences are. Surely thay are not all that different and should respond similarly once modded.

The CRF has a 12.0:1 compression ratio, compared to the TRX's lower 10.5:1.

I can tell you that after bumping the compression on the TRX to the CRF's high 12.0:1, you will have a totally different machine. More power, and power that works better with the HRC cam, and it will also respond better to mods because of the increased pumping volume. I would put money on it, that with a higher compression piston alone, the YFZ would not be able to pull away from the TRX like we have been hearing.

Class is Dismissed!

I got a quick question. With the CRF using a 12:1 compression piston, does it run on pump gas?

Would the TRX be able to run on pump gas with a 12:1 compression ratio?

[ml450r]

A YFZ has 11.9-1 and it runs on pump gas, so it might.

[Maxx_Action]

I...

think that you can run up to about 12.5:1 on 93 octane pump gas. 91 I think you are ok at 12:1 if it TRULY is 91 octane. I have to concur, the compression does make some difference. I think anopther horse and a half to two would be gained by jumping it to 12:1. Add a hot cam, a good pipe, K&N filter, nice intake, and proper jetting it would be meeeeaaannn......

Maxx

[joe1l]

Overall, I believe the problem lies with the Compression ratio being so low. Honestly, a higher compression piston would really wake the TRX up, and make it more responsive to mods. Why Honda dropped the compression is beyond me. Possibly, they dropped the compression because of reliability concerns, since a higher compression piston would require the motor to be serviced more often, and would make using a high grade fuel necassary.

I heard a bunch of guys with CRF's were having problems with their motors eating up pistons. This may be the reason why honda added the 3rd piston ring, and lowered the compression for the atv. They must have figured that with the extra weight and added stress of 2 wheels as opposed to one, that it would be just safer to go with a little lower compression! I think the only way to be sure if the motor will need race fuel is to do a compression check, chances are if it needs super now with stock compression ratio, than it probably will require a little higher octane than super to avoid detonation, but who knows. I'm sure there will be aftermarket pistons out in no time to raise it back up to 12:0:1 ratio.

[2004TRX450R]

Originally posted by Honda
The CRF has a 12.0:1 compression ratio, compared to the TRX's lower 10.5:1.

The CRF also uses a slightly smaller throttle Body at 40mm compared to that of the TRX at 42mm. The TRX's throttle body also incorporates a TPS Switch. More on that in a minute...

I can tell you that after bumping the compression on the TRX to the CRF's high 12.0:1, you will have a totally different machine. More power, and power that works better with the HRC cam, and it will also respond better to mods because of the increased pumping volume. I would put money on it, that with a higher compression piston alone, the YFZ would not be able to pull away from the TRX like we have been hearing.

The CRF uses a 40mm Throttle body, that is not influenced in any way by electronic control. The CRF should have better throttle response because of it's smaller bore and the fact that the computer does not really on a TPS to feed fuel into the motor.



I agree! However the TPS doesn't do anytying to controll the fuel being delivered to the engine and neither have throttle bodies. You are thinking Fuel Injection. They both have carbs. The TPS just tells the CDI that the throttle is in a certin position so that it can adjust timeing.




Originally posted by joe1l
I heard a bunch of guys with CRF's were having problems with their motors eating up pistons. This may be the reason why honda added the 3rd piston ring, and lowered the compression for the atv. They must have figured that with the extra weight and added stress of 2 wheels as opposed to one, that it would be just safer to go with a little lower compression! I think the only way to be sure if the motor will need race fuel is to do a compression check, chances are if it needs super now with stock compression ratio, than it probably will require a little higher octane than super to avoid detonation, but who knows. I'm sure there will be aftermarket pistons out in no time to raise it back up to 12:0:1 ratio.

I haven't seen many problems with the pistons in the CRFs in the shop I work in. We have had two come in that had valve/piston problems. The valves hit the pistons. I don't know if this was from overreving or from the piston rocking. I would have to guess over reving because there wasn't any piston/cylender dammage. The pistons on the CRFs are very short and only have a short skirt on the very front and back. They only have one ring wich makes them burn a lot of oil. When I went to the Honda update class when the CRF first came out they told us it would use oil from the upper level to the lower level in the sight glass in 4 hours of rideing. I have no doubt that is why they made the TRX piston with two rings. They don't generally make their quads as high strung as the dirt bikes and they know they get less maintainence than the dirt bikes so they want them to be more reliable so we get two rings so it burns less oil and is more reliable. JE is comming out with a couple of pistons for it that should be available in a couple of weeks. One is a 13:1 that I plan on getting. I'm hopeing I don't have to run race gas with it but I'm not sure yet. The CRFs don't require race gas at 12:1 so I'm hopeing one more point won't push it over the edge.

Also the Cams are a bit different. The stock TRX cam has less duration than the CRF and the HRC has more than the CRF. Here are the specs.

------------TRX------------CRF--------HRC
Intake
Opens 10 BTDC 15BTDC 20 BTDC
Intake
Closes 40 ABDC 50ABDC 60 ABDC
Exhaust
Opens 40BBDC 55BBDC 55BBDC
Exhaust
Closes 10ATDC 15ATDC 25ATDC

So the cam is going to make a big difference in power as well. I noticed a big difference in power when I added the HRC kit and I think a higher compression piston along with some head porting will really complement this new cam. As soon as JE get's their pistons out I will be getting one and will be haveing the head work done. After that I will be watching to see what pipes seem to be makeing the most power over the stocker with the HRC end cap. That should really polish off a nice package and hopefully put me right at or just over the 50hp mark. That might be a bit optimistic but hey I can always hope!:D :D :D :D

[Honda]

I agree! However the TPS doesn't do anytying to controll the fuel being delivered to the engine and neither have throttle bodies. You are thinking Fuel Injection. They both have carbs. The TPS just tells the CDI that the throttle is in a certin position so that it can adjust timeing.

Sorry, Carbs. I am used to working with Auto's. You are correct, TPS tells the CDI the throttle Angle, and adjust's timing for riding conditions.


One is a 13:1 that I plan on getting. I'm hopeing I don't have to run race gas with it but I'm not sure yet. The CRFs don't require race gas at 12:1 so I'm hopeing one more point won't push it over the edge.

13:1 Compression and Pump fuel? That is a very hazardous combination. You are probably not going to get away with 13:1 compression on pump fuel, unless you have some really high octane pump fuel available. Even at 12:1 it is getting dangerous. You have to keep in mind that under some conditions, higher compression might not be a factor, but on a very hot day with a hot motor, your high compression engine running low octane pump fuel is going to want to detonate. Detonation is what kills pistons, rods, valves. Detonation can burn holes in pistons and melt spark plugs.

The only way you could run 13:1 compression is if you retarded the timing, Retarded timing will take power away from the motor, and that is Retarded.

I would say 12:5.1 compression would be the max you could safely run on 93-94 octane Premium fuel, and that may not even be safe under all conditions.

13.1 ? Maybe, with Race gas!

[joe1l]

I haven't seen many problems with the pistons in the CRFs in the shop I work in. We have had two come in that had valve/piston problems. The valves hit the pistons.

That is a relief, it may have been just a fluke, that the pistons were going on their bikes, but it would not shock me that these guys were eating their pistons up. They go out for all day rides in Wyoming, and chances are they were not aware of the CRF burning up as much oil as it does with the 1 piston ring, and chances are were running them low on oil, causing them to burn out. Does anyone know why they are not using the Titanium valves in this motor??
Joe

[Quadaholic]

The Titanium was used for strength and light weight. On a quad duability is more of an issue. Therefore they had to lower the compression, upgrade gears and use different valves(among other things). A lot of the Crf's, especially '02's, are having problems with the Ti valves being too soft. The fix is Stainless Steel intake valves with a different spring kit. None of our customers have noticed any difference in the rev-ability of their motor.

[BigThumper33]

Ti is much harder than stainless, are you sure they aren't having issues with the Ti being to brittle?

[Honda]

Yes Ti is much more brittle than Stainless. Engine builders don't like to use Ti in turbo motors either, it doesn't stand up to heat as well.

[Quadaholic]

Perhaps it was the grade or manufacturer of the valves, I don't know. The Ti valves were mushrooming. The s/s valves are holding up just fine. Maybe just a bad batch.

[Chevy454]

The only way you could run 13:1 compression is if you retarded the timing, Retarded timing will take power away from the motor, and that is Retarded.

That's not always the case. Honestly, I don't a flippin' thing about compression ratios on a quad engine, but I do know about the big block Chevy's that I drag race, and how the cr effected the timing on them.

With a change in compression ratio, comes a change in mixture density, which brings with it a change in flame travel. Example: our last 427 got a bump in compression (2 points) before last season, and thusly required pulling in the neighborhood of 6 degrees of timing out of it to make it run where it should. I started at 40 degrees and 110mph, and ended up at 34 degrees and 113+ mph ("Pure Stock" Camaro). I tried this on 2 seperate outings, as well as on the dyno, and got the same results each time. What happened was that the better mixture, caused by the higher compression ratio, had a better, and thus "quicker", flame travel, which caused the ignition timing to happen too early. Retarding the timing delayed it to where it needed to be, and picked up both mph and hp. We've found our low compression (10:1) 427s like MORE timing whereas our high compression (12:1) 427s like LESS timing...and that's with IDENTICAL parts (required by class), except compression ratio.

Not picking on anyone, just stopping by to share what little I know...

[2004TRX450R]

To be honest I haven't even looked to see what the valves in our engines are made of. I know the CRFs had Titanium intakes and I think Stainless exhausts. I know the exhaust valves aren't Titanium. The reason for it is because Titainium retains heat to well and won't let it go so in the exhaust side they are more likey to have heat related problems. That may be what they had problems with the Titanium valves getting to hot and softening up and dishing. I don't know this for sure just an idea why they were failing.

On compression ratios and detonation you can't just say X cr is going to cause detonation. Where a certin point may cause detonation in one engine it won't in another. It has a lot to do with combustion chamber design. The CRFs run 12:1 compression and they run fine on pump gas. If JE offers a piston in teh 12:1-12.5:1 range I'll probably go that route but I didn't catch the other ratio they are working on in the message and it got deleted already. I figured that 13:1 is going to be to high for straight pump gas but worst case I guess I can mix 50/50 premium/race gas.

[lukester720]

Titainium valves or not this thing revs quick!

[dork]

i've heard the problem on the 02 crf's were the springs were too weak causing valve bounce at high rpm which cupped the valves. also the 02's had airbox seal problems which let dirt in and wore the coating off the valves.

i don't think you can lap titanium valves either

[2004TRX450R]

Originally posted by dork
also the 02's had airbox seal problems which let dirt in and wore the coating off the valves.

This isn't really true. The air boxes and filters sealed fine. They just didn't seal the the conventional filters did. Rather than the flat part of the seal sitting flat on the air box there was a lip on the inner portion of the seal on the filter that it sealed against. Many people would complain you could stick your fingers under the seal and it wasn't sealing but that isn't where they seal at. There was a company that sold an aluminum ging to go in there claiming it would make it seal correctly but it actually made it worse. This was one thing I remember going over in the Honda update class when the CRFs first came out. It wasn't a bike error but an opperator or servicer error.

[Guy400]

Great discussion guys!

2004TRX450R, you quoted some cam specs from a service manual I'm assuming. Can you happen to look up valve lift specs on the different cams?

Chevy454, I have had the same experience with timing except in small block Chevys. My 355 with about 10:1 compression on pump gas ran at about 36 degrees of total timing. My 331 with 12.5:1 on race gas needed to have about 4 degrees of timing pulled out of it.

The biggest factors in detonation are compression ratio, combustion chamber design and cylinder head cooling. The LT1 350 was one of the first domestic engines to use reverse cooling. In typical engines the coolant from the radiator was pumped in the water jacket in the block where it was warmed and then went to the heads. Chevy found that if you pumped the coolant into the heads first and then allowed it to the block many benefits could be had. First, cooler cylinder head temps lent itself to higher compression ratios (12:1 on pump gas), reduced emissions, more spark advance and higher horsepower. Also, the coolant is heated in the cylinder head before making its way to the block. Now the coolant's temperature is more even in the block. This translates to more even cylinder temps and less friction from the piston rings. All this has me wondering about the TRX's cooling system. Does anyone know for sure which direction the coolant gets pumped? Does the pump pull coolant from the bottom of the radiator into the cylinder's water jacket which then goes to the head and then out to the top of the radiator? Or, does the pump push coolant out from the bottom of the engine and then into radiator?

[2004TRX450R]

I don't have any lift specs. They show lobe heigth but that doesn't really tell you anything unless you know what the base circle is.

It has a thermostat on it wich is cast into the head so I'm assumeing that it it flows into the heat at the thermostat first.

[Chevy454]

Guy400:

Interesting about the SBC comparo...I kinda assumed this was an across the board deal, as I know several NHRA superstock guys that have found this on the dyno and through testing. Flame travel is science in itself...that's why flat tops rule, IF you can get the CR up. No dome to impede the travel, and flame propogation is even.

And the reverse cooling thing is something else of interest. While the LT-1s used reverse cooling (and are a BOOGER to change the water pump and stuff on), GM went back to the regular flow direction on the Gen. IIIs, such as my LS-1. Just curious why they switched back?

[C41Xracer]

Originally posted by Honda
Yes Ti is much more brittle than Stainless. Engine builders don't like to use Ti in turbo motors either, it doesn't stand up to heat as well.

Dude you are way wrong about TI.Its whats used in F-16 engines and has a higher flash point than stainless(the point at which it melts)I should know this I machine both types of material

[2004TRX450R]

Originally posted by C41Xracer
Dude you are way wrong about TI.Its whats used in F-16 engines and has a higher flash point than stainless(the point at which it melts)I should know this I machine both types of material

I don't know a whole lot about the metal flash points or how brittle they are but I know that stainless will get more and more brittle if it gets super hot then cools. It acts like heat treating. Also just because a flash point is higher than one doesn't mean it is more or less brittle than the other.