Yz450 or wr450? Pros and cons.

Good grief ? It sure didn't take long to make those changes to my bike. I did a little bit the night before each ride and a month later it was done. Plus, I've outlined what to do, so there is very little guess work.

 

It may not have taken long, it just seems like A LOT looking at the big picture.  And certain things like removing the tank mount (which you mentioned needed reinforcement) seem like a move in the wrong direction.  Yeah you shaved a bit of weight, but was it really worth the ~1/3 of a pound?  I'm not knocking you for your effort, I think you've done a great job and are on the right track for sure, I just don't know if I'd go about it exactly the same way as you did.

 

Furthermore, its way less work to lighten a WR than it is to get a YZ ready for woods. The YZ suspension is going to need a complete revalve and I'd need a WR transmission for sure.

If you do buy a YZ, be sure to reroute the valve cover breather into the air box so that if you ford a deep stream and stall it, it doesn't suck water into the engine.

 

Admittedly I have spent WAY too much time and money getting my YZ set up for woods.  My old 00 YZ 426F was easy... add handguards, a spark arrestor, and radiator braces, lower the gearing, and twist the throttle.  This 06 has been an exercise in futility, and even after 2 revalves I'm still not happy with the suspension.  It's WAY better than it was though.

FWIW I've never had issues with either of my YZ's sucking water up the crankcase breather.  I think it would take a certain set of circumstances and everything to line up just right for it to happen.  Not that it can't, I just don't think its a huge concern.

 

I'd love to hear what you would do. I'm always looking for ways to improve my WR.

 

If it could be done I'm sure someone would have attempted it by now, but I was thinking it would be interesting to see if you could get the 12+ WR EFI system operational on the 06-09 YZ chassis (or pre EFI WR chassis).  It's probably far more work and $$$ than it's worth, but it would be fun to try.  The big hurdle (I think) would be getting the fuel pump in the tank.

It may not have taken long, it just seems like A LOT looking at the big picture.  And certain things like removing the tank mount (which you mentioned needed reinforcement) seem like a move in the wrong direction.

Its been a learning process. The lack of a mount hasn't given any trouble. One of our local racers keeps losing the seat on his KTM. With a Yamaha, you can leave off half or most of the fasteners and its still built better than a KTM.

 

Yeah you shaved a bit of weight, but was it really worth the ~1/3 of a pound?

Every 1/3 of a pound helps and that was a particularly easy and inexpensive 1/3 of a pound.

 

I'm not knocking you for your effort, I think you've done a great job and are on the right track for sure, I just don't know if I'd go about it exactly the same way as you did.

Fair enough, we all think differently.

 

FWIW I've never had issues with either of my YZ's sucking water up the crankcase breather.  I think it would take a certain set of circumstances and everything to line up just right for it to happen.  Not that it can't, I just don't think its a huge concern.

Depends how much water riding you do and how deep your pockets are. Its things like the valve cover breather set up that a) make a WR more suited for woods B) take time to implement on a YZ and c) make it heavier. I'm not saying that the YZ is a bad place to start, just that there are issues that need to be addressed.

The big thing for me is how to tune the YZ engine to be like the WR, because I think its a darn near perfect woods engine.

 

 

If it could be done I'm sure someone would have attempted it by now, but I was thinking it would be interesting to see if you could get the 12+ WR EFI system operational on the 06-09 YZ chassis (or pre EFI WR chassis).  It's probably far more work and $$$ than it's worth, but it would be fun to try.  The big hurdle (I think) would be getting the fuel pump in the tank.

Why not just stuff the WR450F EFI engine into a 2010+ YZ250F frame ? With the 450F engine mounts, it should pretty much bolt right in. And I'm guessing that the WR tank could be made to fit on the YZ250F frame.

However, the WR450F is essentially the 450F EFI engine bolted into the YZ250F frame. So what is the point ? The YZ250F frame has been beefed up a bit so you might save some weight, but what are you getting other than that ? My friend has a YZ250F with a 310cc bore/stroke kit in it and as I lighten my bike, its getting more and more like his. Except mine kick starts way better and also has a way better engine.

BTW, everything except removing the battery tray from the subframe is reversible in my mods list. I could put my bike back to stock in an afternoon. With a TIG welder, which I have, I could reinstall the battery tray.

Edited by MidlifeCrisisGuy

 

If it could be done I'm sure someone would have attempted it by now, but I was thinking it would be interesting to see if you could get the 12+ WR EFI system operational on the 06-09 YZ chassis (or pre EFI WR chassis).  It's probably far more work and $$$ than it's worth, but it would be fun to try.  The big hurdle (I think) would be getting the fuel pump in the tank.

 

Why? The newer chassis is what makes the 12'+ Wr's smaller and easier to maneuver around on the trails.

Why? The newer chassis is what makes the 12'+ Wr's smaller and easier to maneuver around on the trails.

 

Because I'm hopelessly invested in my 06 already and it would be something different.  IF it could be done affordably (which is unlikely) it would be a good way to breathe new life into a carbed bike.  I would LOVE to have EFI but I don't have $5K plus for a new or newer bike.

Because I'm hopelessly invested in my 06 already and it would be something different.  IF it could be done affordably (which is unlikely) it would be a good way to breathe new life into a carbed bike.  I would LOVE to have EFI but I don't have $5K plus for a new or newer bike.

The EFI is nice but not night and day difference from the carb. Other than tunability there are only a couple situations where I feel the FI is an.improvement. 06 YZ or Wr?

The EFI is nice but not night and day difference from the carb. Other than tunability there are only a couple situations where I feel the FI is an.improvement. 06 YZ or Wr?

 

I'm sick of having a bike that runs great in the morning, and like crap in the afternoon, or on the next ride out with exactly the same conditions.  My 06 has been a NIGHTMARE in every regard.  And it's a YZ.

I'm sick of having a bike that runs great in the morning, and like crap in the afternoon, or on the next ride out with exactly the same conditions.  My 06 has been a NIGHTMARE in every regard.  And it's a YZ.

Not sick enough to fix it, I guess.

To the OP:

 

Go to a dealer and sit on each one, and the differences will be very apparent.

Not sick enough to fix it, I guess.

 

You obviously know me REAL well if you think I've left the thing stock and just whine about it, wise guy.  I've spent countless hours trying to dial it in, and like I said once you get it right you can go out the next day and it's screwy again.  Nobody I ride with, and that includes guys on Honda's, KTM's and Yamaha's both 2 and 4 stroke have to constantly tinker with this or adjust that to keep their bikes running right.

You obviously know me REAL well if you think I've left the thing stock and just whine about it, wise guy.  I've spent countless hours trying to dial it in, and like I said once you get it right you can go out the next day and it's screwy again.  Nobody I ride with, and that includes guys on Honda's, KTM's and Yamaha's both 2 and 4 stroke have to constantly tinker with this or adjust that to keep their bikes running right.

 

There is definitely something not right with your carb if you are needing to adjust it so often.

There is definitely something not right with your carb if you are needing to adjust it so often.

 

I'm convinced this was a Friday at 4:30 bike, it's been a problem child from the start!

I'm convinced this was a Friday at 4:30 bike, it's been a problem child from the start!

 

Now I understand....  For trail or race that bikes platform isn't very far off from the newer Wr. If you can narrow it down to the carb (which would be my guess), send it off to ZipTy and have them go through it. It would be well worth it. Just a suggestion.

You obviously know me REAL well if you think I've left the thing stock and just whine about it, wise guy.  I've spent countless hours trying to dial it in, and like I said once you get it right you can go out the next day and it's screwy again.  Nobody I ride with, and that includes guys on Honda's, KTM's and Yamaha's both 2 and 4 stroke have to constantly tinker with this or adjust that to keep their bikes running right.

I'm not trying to be a smart ass, it's just that every single bike uses essentially the same carb, so it's not a brand or model issue....

I bet I we can solve it right here, if you want.

bought a 2013 yz450f for my brother and i got a 2007 wr450f for myself :) very nice bikes!

Tossing up which one to purchase. I'm not a motor cross rider just enjoy a nice quick trail. What suits me? And which bike has more maintenance?

first thing you need to tell us are you buying new or second hand if second hand what years? i have had wrs and yzs from early 2000s to current efi

You have to test drive a EFI bike. One you do you'll never go back. They are especially good for elevation changes.

The big thing for me is how to tune the YZ engine to be like the WR, because I think its a darn near perfect woods engine.

 

 

Why not just stuff the WR450F EFI engine into a 2010+ YZ250F frame ? With the 450F engine mounts, it should pretty much bolt right in. And I'm guessing that the WR tank could be made to fit on the YZ250F frame.

 

I'm used to the power delivery on my 06 and when I rode my cousin's 12 WR, I wanted the power more like my YZ.  Depends on what you are used to I guess!

I don't know that the 450 engine would fit in the 250 frame without changing the lower cradle, but I can't say for sure.  If there was an affordable way to add EFI to the 06-09 YZ or 07-11 WR's I think it would get a lot of people's attention.  Stuffing a 12+WR EFI engine into a 250F roller would take a pretty substantial investment I would think.

 

 

I'm not trying to be a smart ass, it's just that every single bike uses essentially the same carb, so it's not a brand or model issue....

I bet I we can solve it right here, if you want.

 

Sorry for the misunderstanding.  I'm definitely open to suggestions, but I've lost my notes on what I'm running so I'd have to open it up to see.  I have the JD jetting kit running his recommended needle and clip settings, that's all I can remember at the moment.  No AP mods or other carb mods.

 

 

 

 

Sorry for the misunderstanding.  I'm definitely open to suggestions, but I've lost my notes on what I'm running so I'd have to open it up to see.  I have the JD jetting kit running his recommended needle and clip settings, that's all I can remember at the moment.  No AP mods or other carb mods.

 

I can dial it right in for it if you do ALL the necessary changes.

 

The most common problems are a partial clog above the pilot jet (causing intermittent lean/rich issues) , and improper adjusting of the fuel screw (starting with too high of idle), and air leaks at the hot start and header crush washer.

Well lets see...

I can all but guarantee that there is no clog in the passage above the pilot jet.  Any time I pull the carb to clean it, it comes completely out of the bike, all jets and anything else that unscrews is removed and carb cleaner is run through every passage and opening to ensure they are not blocked

I don't have a tach but I set the idle to what sounds "normal"

Fuel screw I always start at 1.5 turns out and adjust as needed... currently I think I'm about 2 turns out.

Hot start leak is highly unlikely, I have a billet ZipTy hot start nut to avoid that problem

Header crush washer is new as of about 8 hours ago because it was no longer doing its job

Jets... I don't recall.  I want to say 170 main, 42 pilot with the JD jetting red needle in the middle clip position.  Typically ride anywhere from 2500-6500 ft.

Edited by cowboyona426

Did you say 'Carb Cleaner' ?? 

 

Hopefully you meant something else, or MC specific carb cleaner....cause automotive car cleaner will melt the internal parts of an FCR carb....

 

Compressed air won't remove a varnished block above the pilot. You have to send some 40 test fishing line up there....cause it's a right angle and it gets clogged in the corner.

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