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Blutarsky

YZ 450F as a Baja Bike?

18 posts in this topic

Pastrana and Grider rode the 1000 on an RMZ-450. Everyone knows the Yamaha bikes prioritize stability, and Suzukis lean towards excellent cornering with less stability. Recent reviews on the 06 YZ 450F praise its suspension and stability to no end. It seems to me that with some not so minor mods, the YZ-450F would make an awesome Baja Bike.

Just last week I was riding through some high speed sand washes with a friend. I was on my ZY 250F and he was on a KTM 525XC. For a while we traded bikes. I felt my little YZF was way way more stable in sandy washes that the XC with its light steering.

We are going to do the 500 and later the 1000 (a few years down the line). I know I should go with a mfg that supports the race more (KTM or Honda )...but dammit I like to do things different.....and I like projects like this....

YZ-450 F

*Max Power 523 Big Bore

*Morgan or Gorr Ported Head

*Crower Mid Range Cam

*A good aftermarket exhaust

*Whoop eating off road suspension valving + softer springs (George at ESP etc...)

*Big Tank

*Customized gearbox ratios (Were talkin Baja here...what's a $1500 tranny...)

*Possibly a custom triple clamp or fork bottom mods to enhance stability. Since the fame is AL...it is even possible to weld up and remachine the head to slgihtly flatten the steering tube angle if you want. This sounds like a lot of work...but it's really not if you have acces to the machine tools...

*Plus all the normal desert hardware....

It seems like the YZF would be an ideal starting point for a project like this. With the motor mods noted, I could easily get 63-65 very reliable HP with the RPM 523cc set-up. Combine that with a stable bike that is 25 or more pounds lighter than anything else out there and it would tear up the desert.....

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i agree with you 98%

**web-cam racing cam** would be my only change

and let me know when your going to race it.. i first started going to baja in 1995 and been going ever since.... we raced it in a pro-truck and won in 2004 and second place in 2003 and 2005... i travel to baja at least 10 times a year and know the area and most of the courses from pre-running with my step-dad very well

18 years old and amature-expert rider

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thanks for the offer and encouragement racer dude....

It's a long term project for us. I have a varied group.

One of our likely riders is a young fast off-road and MX racer (our fast guy). Another good friend is a very experienced rider, who has raced everything from karts, to circle track to class 16 to hare scrambles on the bike. He is always fast...and does not crash or tear up equipment. I am the relative neophyte in the group...but I am a racer (4 wheels, alpine DH racer, Mnt Bike...etc) and a very quick study. I have raced a lot, but my motorcycle experience up until this year was minimal. I now ride at least 2x per week because I know I have only two years to get very good....no problem...just go :thumbsup: . I have gone 75 mph on skis on icy jagged race courses....I am learning to ride a motorcycle well very quickly....the body dynamics are VERY similar.

I plan of doing some MX racing...flat track racing...and some hare scrambles over the next few years to build vaious skills.... Barring any injuries we plan to race Baja (likely the 500... to start) in 2007. Everyone says we are doing it just to finish and have fun...but I know better. We are all competitive people...so you know how that goes...

I just keep wondering why no-one has taken a YZ 450F and made a real run at a big desert race. It seems like the 06' would be an awesone bike to do that with since it is a very stable platform to start.......

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Since it IS Baja, and money becomes no object when it comes to performance....I would think taking a YZ frame and putting the new Raptor 700 fuel injected motor into it would be the ticket. Tons of power, spot on jetting all in a chasis that would rip.

What do you think?

:thumbsup:

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Thats crazy talk..... 65Hp is plenty.

Campbells 650s in recent years have had about 68 HP. His 01 and 02 bikes were in the low 60s...minimal motor mods.

They put a lot of effort into lightening up those bikes...and dialing the suspension. A friend of my brother in law supposedly bought Campbells 05 bike recently. Word is they sold the bike pretty much as it raced...except for one minor thing. They totally pulled the suspension and put a more 'normal' shock and fork on. There is a reason they would not sell the fork and shock...because that's where all the speed is.

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the only reason 650's rule baja is because they are huge and make decent power and torque stock, therefore they dont do many motor mods which equals reliability... when you start punching out 450's reliability becomes a factor when your doing 100+ mph across el diablo dry lake bed for 5 miles when it is 110 degrees outside in the middle of june for the 500..

now as far as suspension, i can see why they take the forks and shocks off their bikes to sell them... because they have A LOT of money invested in them and with the 650's not changing much, they can reuse them on the next years race bikes

and the big six five o is like a cadillac to ride, doesnt wear you out (depending on the terrain) and you can ride for hours at race speed, now just dont stall it or tip er over..

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the only reason 650's rule baja is because they are huge and make decent power and torque stock, therefore they dont do many motor mods which equals reliability... when you start punching out 450's reliability becomes a factor when your doing 100+ mph across el diablo dry lake bed for 5 miles when it is 110 degrees outside in the middle of june for the 500..

now as far as suspension, i can see why they take the forks and shocks off their bikes to sell them... because they have A LOT of money invested in them and with the 650's not changing much, they can reuse them on the next years race bikes

and the big six five o is like a cadillac to ride, doesnt wear you out (depending on the terrain) and you can ride for hours at race speed, now just dont stall it or tip er over..

i would think just the weight difference would be a major plus,especially making the same HP.if he's using the ice cube cylinder,cooling would probly be better. blutarsky,you might want to throw in some fluidyne rads to your goody list,i run them with excellent resuts. BTW what/who/where is this custom trannie you speak of? thats not really that bad a price :thumbsup: the new 06 suspension seems to lend itself to desert racing OTB,a few mods and it'd be golden. i would really love to try the 500 or even a 250 somewhere. but as usual money just won't grow on my tree(and i fertilize,and fertilize :bonk: )

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ncmountainman...

If you believe Rick Peterson (and I DO) adding 16% to displacement with the Ice Cube will not hurt reliability at all. It may even help because you shift the RPM down, and dont hammer the valves as hard. Getting more HP out of a 450 by going to new cams, pipes and ignitions hurts reliability a lot more than adding displacement. I you wanted to use a high end cam, and jack up the compression...you could get 70 HP out of a 523...but it would be fragile (just like a 60 HP 450 is fragile). But 63-65 HP out of a 523 will be like 54-55 HP out of a 450...and there are a lot of you already doing that with plenty of reliability.

The Ice cube also cools better...and I would also upgrade the raditators to Fluidyne. I might even get a new clutch cover to bump the oil volume the motor could carry. Any extra 1/2 quart would be nice.

The effort that was put into lowering the YZFs CG to me makes it a great starting platform to make a killer desert bike. The suspension would need to be totally reworked and softened (someline ESP could do this)...and you would have the best of all worlds...

As for the tranny...the $1500...that was just a guess on my part.

I am a mechanical engineer, and hobby machinist. I have done some machine design work. I know enough to reverse engineer and draft the necessary drawings. I have a good lathe, access to a CNC mill, etc. I would probably machine the blanks on the lathe...send them to seattle area to a shop that would broach the splines on the IDs where requried (likely an ISO/DIN involute spline). Then I can machine the dogs and dog recesses. Finally send the gear blanks out to a gear mfg to have the teeth hobbed and perhaps nitrided and ground (depending on what material is utilized).

$1500 (maybe less...) plus a lot of work on my part. If Yamaha can mass mfg a gear pair and sell them for $55....Then I'm petty sure I can custom mfg the same for $400 if I do a lot of the work and engineering myself. Its really not rocket science. People have been mfg gears for a hundred years.

With the 06 YZF Box, I would actually leave 1st stock...and change every other gear. I was thinking:

Roll On Peak Tq Peak HP

1st 27 14 17.95067735 28.38711767 37.57118516

2nd 23 16 24.08289632 38.08458023 50.40606207

3rd 24 22 31.73423318 50.18436875 66.42048805

4th 17 20 40.72842761 64.40774598 85.24554616

5th 15 23 53.08271732 83.94476227 111.1033618

The above gearing (which uses a tall countershaft/sprocket combo) would give tall a fairly first gear. 1st to 2nd would be +34%. 2nd to 3rd would be +31% 3rd to 4th wold be +28%. 4th to 5th would be unusual...in that it would be a 30% jump...which is a little large for top gear jumps (WRs are +25% from 4th to 5th). The idea behind this gearing is to have a tall 1st (but still low enough that you could get yourself out of a ditch, etc). 2nd 3rd and 4th are a little tighter than most wide ratio boxes to make sure you always have the sweet spot (the 30-75 mph range is where you spend most of your time). When you need 5th, you are really not so concerned about having a tight gap...because you will likely be spending more time at top speed that you spend getting there.

I have not done the gear math in a while though...and I'm not sure if I can make the (ISO/DIN) tooth profiles available and pitch diameters match up to the center distances. But my gut feel is that it is easily doable. I will know soon enough.

One more comment...if heavy is good...why do the Factory Honda 650s have every piece of hardware possible converted to Ti? (saves 6#) Why are the fork bodies made from carbon fiber (saves 3#)? Don't fool yourself...lighter IS better. You just have to adjust the suspension accordingly.

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cool,

its great that you have the access and know how to gitter'done :bonk:

a rekluse might come in handy because not only does it tame the tall 1st gear if the going gets tight but after a certain rpm's (i'm guessing around 4-5K) it actually has more clamping pressure than a stock clutch,i'd say that would be a good thing tapped out in 5th @ 110-120 mph i've been running the same clutch(different plates)in 2 different bikes going on the 3rd season with no problems :thumbsup:

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It's just another crazy idea.

I am planning of making a custom 5ths for my Yz 250F. I will know within a few months how hard it is to get custom gear pairs made....I already have about 4 custom gear mfgs/machine shops that have said they can do it....

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ncmountainman...

I am a mechanical engineer, and hobby machinist. I have done some machine design work. I know enough to reverse engineer and draft the necessary drawings. I have a good lathe, access to a CNC mill, etc. I would probably machine the blanks on the lathe...send them to seattle area to a shop that would broach the splines on the IDs where requried (likely an ISO/DIN involute spline). Then I can machine the dogs and dog recesses. Finally send the gear blanks out to a gear mfg to have the teeth hobbed and perhaps nitrided and ground (depending on what material is utilized).

$1500 (maybe less...) plus a lot of work on my part. If Yamaha can mass mfg a gear pair and sell them for $55....Then I'm petty sure I can custom mfg the same for $400 if I do a lot of the work and engineering myself. Its really not rocket science. People have been mfg gears for a hundred years.

Hey, I've been doing machine work for 26 years. You're right, it's not rocket science. If you are an ME, you know materials, you know machining, all it takes is money. Oh, yeah, don't forget the heat treating. And if you are making a set for yourself, it won't be too much more to make 10 sets for your buddies, maybe even 20, and make a buck.

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Hey, I've been doing machine work for 26 years. You're right, it's not rocket science. If you are an ME, you know materials, you know machining, all it takes is money. Oh, yeah, don't forget the heat treating. And if you are making a set for yourself, it won't be too much more to make 10 sets for your buddies, maybe even 20, and make a buck.

First thing I plan on doing is taking a stock gear pair...and sending them to a guy in TX to get then PMI'd (postitive material ID). From that I can figure out the material. After determining the hardness of the gear teeth and dogs I can likely also figure out the heat treat (through HT or whether they are nitrided or carburized)

The next issue is reverse engineering:

First thing is to measuere the center distances...which requires motor tear down and inspection. I can machine some gauge plugs to do that pretty easy. Next is determine the fits on IDs to shaft and ID splines to spline. The thing I am most worried about is the spline on the ID. It is likely a DIN 5480 involute...but its hard to measure splines. I will have to send it out for identification as DIN spline measurement tooling is rare in the US. At the same time...I will get the gear teeth profiled so I can determine what module, pressure angle, and tolerance level the gear teeth are. From this I will need to put together the whole package...and review the accumulation of tolerances so that I don't get into a tooth interference or gapping issue. This is prehaps the most important step. You will have variance in the center distance...and variance in the gear to shaft bore and spline fits. You also have variance in the gear teeth machining. All this results in an accumulated variance in the gear meshing. You have to review these worst case tolerance accumulations in both directions...and then make sure the gear is made to center its best operating range evenly around those tolerances.

My guess is that when I review the design of the gears, I will find that the mechanical design is very conservative, thus allowing for lesser materials that are easier/cheaper to mfg. I do not expect to find the gears are highly stressed, and mfg from exotic alloy steels with elaborate heat treats and nitiriding that required high precision tooth grinding, etc.

I would anticipate buying the raw material stock myself...and machining the blanks to the starting dimensions myself....then sending the rough machined blanks out to be finished. I may change the material if the shop/mfg I choose has an equivalent material that will fit in with their normal heat treating work. That way I can piggy back on their normal heat treatment orders and it will be cheap...

Can you think of anyhthing I am overlooking corndog?

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I think the biggest issue in using a YZ 523F for a big desert race will be the fuel tank. The largest aftermarket tank that will be developed is probably about 3.1-3.5 Gallons. That is likely not enough. A baja bike should probably have enough capacity (I would think) to skip a pit. With 60 mile pits...that is 120 miles.... :thumbsup:

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I think the biggest issue in using a YZ 523F for a big desert race will be the fuel tank. The largest aftermarket tank that will be developed is probably about 3.1-3.5 Gallons. That is likely not enough. A baja bike should probably have enough capacity (I would think) to skip a pit. With 60 mile pits...that is 120 miles.... :thumbsup:

there is a australian tank that was posted here some while ago that was 5 gallons i think. and there is a new side # panel tank that ties into a T that hold 1.5 gal. just saw it in dirt rider,installed on a wr450.(but these are all for the old style steel framed yz) there is also a front # panel tanks but that might interfere with the headlights? :thumbsup: and if all else fails have one fabricated from aluminum. i would think one might be ready for a break after 60 miles anyhow,unless you were trying to win it really wouldn't matter. i would be happy just to finish something like that :bonk:

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Sounds like a helluva project you got going....

IMO you should keep it much closer to stock.

- Keep it reliable.

- Stock tranny. Gear it super tall.

- Stock motor cc with a clean port job. Make it easy to ride, not a hard hitter, no hi comp.

- Bigger HP does not mean you will place better. You will likely get beaten by bikes with far less HP.

- None of those auto-clutch things, a Hinson. There is absolutely no use for an auto clutch in a Baja race.

- A common large tank is plenty. A super large tank (like the Aussie tank) will not benifit you at all. It will be harder to ride, effect the suspension, and will rob HP.

- No need for a custom triple clamp to make it more stable. A dampner will do the job. Triple clamps are totally a subjective item - each persons style and taste determine clamp like/dislikes. You would actually be better off making the YZF excell at turns and in the tighter sections because you'll be loosing some ground in the fast. Exploit the bikes strengths.

- Stock wheels, nothing fancy.

- The best figured out suspension you can do.

- Likely your best resource for a bullet proof YZF desert racer would be Ty Davis' company.

It's a great bike. Don't mess it up and it will do fine.

Tim

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Baja is more about endurance (you and the bike). Yamaha is a good platform. You just need to give the bike some legs with proper gearing. My 426 is a whinny machine that needs some sprocket changes before it can begin doing the proper speeds. Baja is something I'd like to do in a couple of years. Finishing would be my only goal

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The MX gearing will really not work well. You gear for decent top speed and 1st will be way way too tall. Way too much overlap...for going 20 mph to 100 mph.

You are probably right about the HP...but I will decide what I'm going to do after riding my RPM YZ 315F for a while. Rick insists that its actually just as reliable because you lower the torque band, increase torque...and thus dont have to hammer the valves to make HP.

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Sounds like a helluva project you got going....

IMO you should keep it much closer to stock.

- Keep it reliable.

- Stock tranny. Gear it super tall.

- Stock motor cc with a clean port job. Make it easy to ride, not a hard hitter, no hi comp.

- Bigger HP does not mean you will place better. You will likely get beaten by bikes with far less HP.

- None of those auto-clutch things, a Hinson. There is absolutely no use for an auto clutch in a Baja race.

- A common large tank is plenty. A super large tank (like the Aussie tank) will not benifit you at all. It will be harder to ride, effect the suspension, and will rob HP.

- No need for a custom triple clamp to make it more stable. A dampner will do the job. Triple clamps are totally a subjective item - each persons style and taste determine clamp like/dislikes. You would actually be better off making the YZF excell at turns and in the tighter sections because you'll be loosing some ground in the fast. Exploit the bikes strengths.

- Stock wheels, nothing fancy.

- The best figured out suspension you can do.

- Likely your best resource for a bullet proof YZF desert racer would be Ty Davis' company.

It's a great bike. Don't mess it up and it will do fine.

Tim

AMEN!

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