2012+ WR450F Camshaft Upgrade Info.



187 replies to this topic
  • MidlifeCrisisGuy

Posted August 23, 2014 - 08:25 AM

#1

I spent a ton of time reading WR/YZ cam threads from all over the web last night.  This thread is a compilation of what I learned and hopefully we can update it with new information as we go along.

 

PLEASE do not turn this thread into a debate on whether or not a camshaft should be updated.  This thread is about camshaft information.

 

This thread is SPECIFICALLY about camshafts for 2012+ WR450Fs.   As you will see, they are a different beast from previous WRs.  Please don't discuss putting a cam in a different bike in this thread, unless it has some application to the 2012+ WRs.

 

This thread ignores aftermarket camshafts, for a number of reasons.   i) I couldn't find any concrete lift, duration, etc. information on them.  ii) When I did find lift numbers, it was in excess of the YZ lift, which I, rightly or wrongly, didn't think would work well with the 2012+ head and iii) I could not find anyone that had put an aftermarket cam into a 2012+ bike.

 

Here is what I learned.

 

1) The 2012+ WR450 head is a different beast from previous heads.   Previous heads had a port geometry that was maximized for velocity.  The 2012 WR ports are huge, sort of maximized for volume.  I don't know why this was done, but it was.

 

The change in head geometry is discussed in detail by two guys on the YFZ (ie the Yamaha quad) forum.    The first guy's user name is mixxer.  He apparent is a head porting expert.   The second guy's user name is mbirt.  I'm not sure he owns a quad, but he is a grad student who works on WR450F engines because his college uses them in SAE Forumula cars. 

 

2) Prior to 2007, all (?) of the WR and YZ cams had the same duration and lift.  The only thing that changed between the various years and models was how far apart and where the lobes were placed, ie lobe separation. 

 

Thus in those years people speak of doing the "YZ mod" on WRs, which was to retard the exhaust cam by 1 tooth, thus making the lobe separation on the WR similar to the YZ model. 

 

3) I compiled the following chart of WR and YZ cam part numbers and specifications.

 

Cam table snapshot.jpg

 

This table is obviously incomplete, but its a start.  It also only contains Yamaha OEM cams.  It doesn't contain YFZ cams either, mostly because those cams are tuned to a much different powerband to suit a heavier and much different vehicle, ie a quad.   However, you might be interested to know that some of the newer YFZ engines use the same intake cam as the WR450Fs.

 

Its extremely confusing compiling this information because its leaked out in dribs and drabs all over the place and people propagate information with errors in it as they go.  It took a lot to get this to where it is.  

 

4) There are 2 major changes in the WR450 engine lineage as far as cams and heads go.

 

i) In 2007 WRs stopped using YZ based cams and got their own WR specific cams.   All post 2007 cams have lower lift than the previous WR and YZ cams. 

 

The uptake on this is that even if you swapped a pre 2007 WR cam into a post 2007 WR engine and the cam had the same duration and lobe separation, you would *probably* see a performance gain from the increased lift alone.

 

ii) In 2012 the head on the WR450F went from a velocity maximized design to a volume maximized design.

 

 

5) A 2012+ WR450F owner has *many, many* choices when it comes to making cam changes. 

 

i) retard the stock exhaust cam 1 tooth.   There is evidence that this works on all WR450F engines up to and including the 2011.  Here is a graph that illustrates the improvement (cam plus exhaust) on a 2011.  Remember that the 2011 uses the velocity style head and the low lift WR cams.

 

wrvsyztimingbaseline.jpg

 

The poster, our friend Mixxer.  He says this:

 

The "YZ timing" test features the exhaust cam retarded 22.5 crank degrees (1 cam sprocket tooth), the "grey wire mod", a modified exhaust, and needle clip changes to maintain 13.5:1 afr. After retiming the cam, cranking compression was only 10 psi, down from 50. We took a risk and carefully ground 1mm from the decompression pin. It worked and restored cranking compression to 50 psi--starts at least as well as it did with WR timing. The exhaust used was a Venom TRX450R headpipe (1.625 OD into 1.875 OD) and a Ron Woods TRX450R megaphone/muffler . The tuned length comes out close to 30" and is to thank for the torque peak at 6500rpm.

No, I cannot quantify how much was gained from the exhaust modifications vs. the cam timing, but I know lots of full exhaust system comparison tests exist. With a 67 deg. BBDC EVO and only 20 degrees of overlap, spending big bucks on an exhaust system for a stock WR seems pointless. The same goes for retiming the cam without fixing the exhaust. The two changes are very much complimentary and should be approached holistically.

 

Source: http://www.trx450r.o...scavenging.html

 

Some of the gain is due to the grey wire mod, but most of that should only come into play above 8500 RPM. 

 

Remember that this gain is from better exhaust breathing alone.  No changes were made to the intake system.  I can't help but think that this engine is going to run cooler too.   The energy that is now being converted to power with the exhaust system change was previously kept in the combustion chamber, mostly as a recycled EGR sort of thing.

 

The really interesting thing to note about this mod is that the retarded exhaust cam engine is making more torque and power at 4,000 RPM than the stock engine was.  So much for the myth that "YZ timing", at least on the exhaust side of things leads to peaky power.

 

I haven't found evidence that its been tested on the 2012+ WRs, but being that it is an exhaust based gain, I have no reason to see why it wouldn't yield a similar sort of gain.  In fact, I suspect it might yield more gain as the 2012+s were subjected to even more stringent emissions.   I suspect that the low lift and restrictive exhaust aspects on the 2007 and especially on the 2012+ WR450Fs is as much about using in cylinder EGR as it is about maximizing the powerband for enduro use.

 

Furthermore, one of the things some WR450F owners would like to see is less engine braking.  Retarding the exhaust cam release more energy from the cylinder and would likely reduce engine braking significantly.

 

ii) Replace the 2012+ cam(s) with pre 2007 WR450F cam(s).

 

As explained above, the pre 2007 WR cams have higher lift than the post 2007 cams.   However, being WR cams, they still have conservative, broad WR timing, at least more conservative than the YZ cams of the same era.  Doing this would be like going half way to YZ cams.

 

One also has the option to mix and match solutions, ie run pre 2007 WR cams and retard the exhaust cam by one tooth.  One doesn't have to do both cams either.  One could do just the intake or just the exhaust.

 

However, the thing about using the higher lift WR cams with the 2012+ WR engine is that, apparently (from mixxer's discussion) the intake port is susceptible to flow reversal.  And, apparently, the higher the valve lift is, the slower the charge velocity and the worst this problem can *hypothetically get*.

 

However, others argue that Yamaha kept the lift low on the WR cams because the exhaust cam closed early (in cylinder EGR ?) and the intake cam needed to as well to keep those products in the cylinder.   (I'm half paraphrasing and half espousing here !)

 

iii) Replace the 2012+ cam(s) with 2003 to 2009 YZ cam(s). 

 

There are many, many factors to consider here. 

 

- one could do just and intake cam or an exhaust cam.

- different cam years have different characteristics.

- how will the YZ cams, which were designed for velocity ported heads, work with the 2012+ volume ported head ?

 

I have not been able to find any evidence of people putting YZ cams in their 2012+ WR450F, save for Jed Haines, so this is essentially new territory. 

 

There is lots of information about people putting YZ cams into pre 2012 engines, but I am not sure how applicable that would be.  Specifically, is intake flow reversal going to be an issue.

 

So there is where we stand as far as information that I could find about putting Yamaha OEM cams into a 2012+ WR450F.  I welcome other people to contribute data and information, subject to the posting request at the top of this post.

 

Caveat: I know just about nothing about camshafts.

 

I found an interesting pattern when I was reading posts last night.   Many times on paper the pundits stated that camshaft xxx wasn't going to work that well.  And yet when the bike owner tried it, he was generally happy.  There were very few reports of people saying that a cam made their bike worse.

 

All of this totally ignores the compression release pin.  That can be added to the discussion as we go forward. 

 

I hope this thread helps someone.


Edited by MidlifeCrisisGuy, August 23, 2014 - 09:31 AM.


  • MidlifeCrisisGuy

Posted August 23, 2014 - 09:13 AM

#2

So... I have the valve cover off my 2012 WR450F.  I need to remove the camshafts to adjust the valve clearances.  I have an 08 YZ camshaft set on my work bench. 

 

I ride tight woods with big hills.  I like power.  I don't find my WR to be over powering.  I haven't played around with maps much yet, I'm still running the stock map on our rides.   I'd like a bit less exhaust braking.  I might like a little more snap in the powerband.  I would be OK losing a little off the bottom, but not too much.  Fall rains are going to make our trails somewhat slick.  But it should dry off in October. 

 

What should I do ?

 

1) Leave the stock cams as they are ?

2) Retard the stock exhaust cam 1 tooth ?
3) Install the YZ intake cam ?

4) Install the YZ exhaust cam ?

5) Install both YZ cams ?

 

FWIW, I'll be OK if I have to change it in 10 hours.  I'm going to check my valves then anyway.   


Edited by MidlifeCrisisGuy, August 23, 2014 - 09:14 AM.


  • MidlifeCrisisGuy

Posted August 23, 2014 - 09:28 AM

#3

One more thing.

 

Previous WRs (and YZs for that matter) weren't fuel injected and couldn't easily be tuned by their owners, especially on the timing side.

 

The 2012+ WRs are fuel injected and can be tuned very easily, both on mixture and timing.  The thing about fuel injection is that it isn't as sensitive to intake tract velocity as carburetors are.  Whereas in a carbureted WR the mixture might go wonky when lugging at low RPMs with a sub optimal cam, we may be able to overcome that on our FI bikes with some creative tuning.  

 

Where this thread is going to get interesting is when we mod the FI programs to overcome negatives that come out with various cam setups. 

 

Between the vast number of cam options and the ability to tune the FI programs, the 2012+ WR450 is one of the most versatile dirt bike engines ever built.     



  • Krannie McKranface

Posted August 23, 2014 - 09:49 AM

#4

So... I have the valve cover off my 2012 WR450F.  I need to remove the camshafts to adjust the valve clearances.  I have an 08 YZ camshaft set on my work bench. 

 

I ride tight woods with big hills.  I like power.  I don't find my WR to be over powering.  I haven't played around with maps much yet, I'm still running the stock map on our rides.   I'd like a bit less exhaust braking.  I might like a little more snap in the powerband.  I would be OK losing a little off the bottom, but not too much.  Fall rains are going to make our trails somewhat slick.  But it should dry off in October. 

 

What should I do ?

 

1) Leave the stock cams as they are ?

2) Retard the stock exhaust cam 1 tooth ?
3) Install the YZ intake cam ?

4) Install the YZ exhaust cam ?

5) Install both YZ cams ?

 

FWIW, I'll be OK if I have to change it in 10 hours.  I'm going to check my valves then anyway.   

 

You need to change your mapping first before you do ANYTHING at all.

It makes a huge difference.

Because the new '12 head has better flow, and because the CDI's ignition curves are no longer tied only to throttle position (TPS sensor), mapping makes a very large difference in power delivery.

 

If you change to any year YZ cam, you will loose bottom end.



  • Krannie McKranface

Posted August 23, 2014 - 09:53 AM

#5

One more thing.

 

Previous WRs (and YZs for that matter) weren't fuel injected and couldn't easily be tuned by their owners, especially on the timing side.

 

The 2012+ WRs are fuel injected and can be tuned very easily, both on mixture and timing.  The thing about fuel injection is that it isn't as sensitive to intake tract velocity as carburetors are.  Whereas in a carbureted WR the mixture might go wonky when lugging at low RPMs with a sub optimal cam, we may be able to overcome that on our FI bikes with some creative tuning.  

 

Where this thread is going to get interesting is when we mod the FI programs to overcome negatives that come out with various cam setups. 

 

Between the vast number of cam options and the ability to tune the FI programs, the 2012+ WR450 is one of the most versatile dirt bike engines ever built.     

 

 

I disagree with all of the above.

 

Plus, you already broke your overly complex posting rule structure...

 

You do realize that the FI is just essentially an open-ended electronic carb, right?

...and that every modern dirtbike uses the nearly identicle one on each bike?

 

Once the bike is properly uncorked, and the fuel air mixture is dialed in for 13.5, all you have left is timing changes.

 

There is no 'vast array of options' once it is it tuned, other than timing changes....which you can do on virtually any motorcycle since 2002.....with an upgraded ECU, like the GYTR unit, from Dynatek, or several other companies.

 

I understand you enthusiasm, but let's not get carried away here.


Edited by Kah Ran Nee, August 23, 2014 - 09:55 AM.


  • MidlifeCrisisGuy

Posted August 23, 2014 - 10:10 AM

#6

If you change to any year YZ cam, you will loose bottom end.

 

That is a myth.   It all depends on the cam and which one you change and how its jetted and timed.

 

mbirt, who has done a ton of dyno cam work on these engines says this.

 

You will still see gains across the board switching to the 08-09 yz450f cam. The EFI YFZ's stock intake cam is the same one used to tame the output of the 07+ WR450f (but in conjunction with a similarly low lift and duration exhaust cam on the WR).

 

Source: http://www.yfzcentra...-06-08-a-2.html

 

Another one.

 

"Well since you brought this up directly.... back in 2010 I installed a 08yz450f intake cam into my friends 2009 WR450F and he absolutly LOVES it! Says he can lug his bike around more, and it's a torq monster when he needs it in the woods racing, and has more top end for desert racing too.


Source: http://www.yfzcentra...-06-08-a-2.html  Post #32

 

Not sure how this would play out on the 2012+s, but these installations did not lose bottom end.   Mixxer has some strong opinions on the 2012+ FI FZR engines.  Not sure if they are the same as the WRs though, or if he has an axe to grind because he ports engines and wants work fixing them.  mbirt says gains across the board on the YFZ EFI engine, mixxer says some bottom end loss due to flow reversal.  I suspect the FI FZR engine is fairly close to the 2012+ WR450F engine.  It appears to be cam and head wise.

 

If you look at the  2011 WR450F graph above, it didn't lose bottom end either.   They didn't put a YZ cam in it, but they retimed the the exhaust to YZ specs.   The only difference between doing that on a 2011 and putting an actually YZ cam into that engine is the lift.   The YZ cams have more lift than the 2007 WR cams.  I don't think adding more lift to an exhaust cam is going to hurt low end power.

 

I'll do a post on YZ cam variations in this thread at some point.  There isn't any data on them in the 2012+ WRs, but there is some on them in the EFI YZF quads, which I think would be pretty close.


Edited by MidlifeCrisisGuy, August 23, 2014 - 10:38 AM.


  • MidlifeCrisisGuy

Posted August 23, 2014 - 10:21 AM

#7

Plus, you already broke your overly complex posting rule structure...

 

Trying to add a data point to the 2012+ WR450F database.  It seems applicable to me.  Its relevant to the model year in question and I'm not asking if I need more power, I'm asking which cam setup people think I should chose.  Its an ocassion to test something and learn from it.

 

Your point about leaving the cams stock and playing with maps has merit, though I'm going to play with cams sooner or later.  (Says the would be pot to the kettle running hotcams in his WR !!!)  There is just too much fun to be had here, for very little cost too, I might add.

 

 

You do realize that the FI is just essentially an open-ended electronic carb, right?

...and that every modern dirtbike uses the nearly identicle one on each bike?

 

Carbs need air velocity to atomize fuel.  Fuel injection atomizes it by spraying it at high pressure.

 

Screwed up air streams (turbulent, reversing, etc.) screw up carb metering.  Fuel injection measures air flow better and meters better. 

 

Carbs are difficult to adjust.  I can adjust FI (fuel and ignition) in seconds.


Edited by MidlifeCrisisGuy, August 23, 2014 - 10:26 AM.


  • MidlifeCrisisGuy

Posted August 23, 2014 - 11:53 AM

#8

Re YZ cams result in lost bottom end.

 

On a 2008 WR450F, which has the low lift WR only cams:

 

About a month ago I swapped the exhaust cam out for a hotcam and put the 08 yz intake back in. AWESOME!!!!!! I wanted that smooth power delivery of the 08, the 06 cam has a surge in power that can be a hand full in single track. This is how these bikes are supposed to run. I have torque off the bottom without to much, smooth power delivery, and perfect mid and top end power. I can crack it and wheelie over any obsticle, where before once the rpm's rose it semed to loose torque and the ability to wheelie. I was worried the yz setup would be too much in the singe track but it's the opposite. I can lug 2nd down low and still have torque without too much power, if that makes any sense.

 

Prior to this setup, the OP had:

 

08 YZ intake, stock exhaust cam -> "It lost a lot of bottom but gained in the mid and upper."

 

06 YZ intake, stock exhaust cam ->  "got some of my bottom back and still had nice gains everywere else."

 

08 YZ intake, hot cam exhaust cam -> "AWESOME", as above.

 

Notice that his engine came alive when he dealt with the exhaust cam.  It seems to be key in all this.

 

mbirt himself, a member here, replied with the following

 

Yamaha advanced the exhaust cam 22.5 degrees on the WR and YFZ to knock valve overlap down to about 20 deg. to better cope with a restrictive exhaust. The exhaust valves open around 67 BBDC for a more blowdown time into the restrictive system and close around 3 ATDC so the high pressure difference between the intake and exhaust tracts doesn't fill the cylinder with residuals. When you fix the problem that is the stock exhaust, the long blowdown time is no longer necessary and you can take advantage of exhaust scavenging with increased overlap.

 

 

And then he posted this graph, the same one that mixxer posted from before.  The engine in this graph has a stock intake cam.

 

wrvsyztimingbaseline.jpg

 

The OP replied "The wr is really held back with those stock cams."  

 

Source: http://www.thumperta...-hotcam-update/

 

The 2012+ WR450Fs have similar cams to the 2008WR450F.  The big difference is the head design.  Will the YZ cam gains on the 2008 WR450F hold on the 2012 WR450F ?

 

Bets, anyone ?


Edited by MidlifeCrisisGuy, August 23, 2014 - 12:01 PM.


  • Krannie McKranface

Posted August 23, 2014 - 12:55 PM

#9

Way to convoluted to follow

 

Good luck



  • cracker please

Posted August 23, 2014 - 03:46 PM

#10

The '12 intake cam is unchanged since '07.  The '12 got a new exhaust cam with less lift.  I don't know the duration but the owners manual has lobe dimensions specs.  Appears to have about 7.75mm lift.


Edited by cracker please, August 24, 2014 - 03:08 AM.


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  • MidlifeCrisisGuy

Posted August 23, 2014 - 07:38 PM

#11

The '12 intake cam is unchanged since '07.

 

Thanks.  Do you have a source for that ?  I guess a parts manual would tell us ?  

 

 

The '12 got a new exhaust cam with less lift.  I don't know the duration but the owners manual has lobe dimensions specs.  Appears to have about 7.75mm lift.

 

Less lift than a YZ cam or less lift than the lift reduced WR '07 to '11 exhaust cam ?  They were already lift reduced compared to the YZ cams.

 

mbir and mixxer speak poorly of the cams in the EFI YFZ quad engine.  I think the 07 to present WR cams are similar, ie low lift, early exhaust closing to work with restrictive exhaust systems, etc.  As the example of using the 08 YZ cams in the 08 WR demonstrated, there is lots of room for improvement without going to big wild cams that detract from the bottom end.  The big question is if the YZ or high lift (03 to 07) WR cams will work with the big volume WR FI head.

 

I have the cams out of my 2012 WR right now.  I should get a degree wheel and measure them.  Would be easy to do if I had a head to temporarily mount and spin them.   Anyone have a junk head ?



  • cracker please

Posted August 23, 2014 - 07:56 PM

#12

I was just going by the part numbers.  Sorry about that, I think I got confused about there being less lift on the '12.



  • RockerYZWR

Posted August 24, 2014 - 12:30 PM

#13

I'm with Krannie on this one - this thread does seem a bit convoluted with a ton of good info spread too far out with too much narrative to really be easy and useful.  You did a lot of work compiling all of this - maybe make it more ordered and succinct?  And you say it's SPECIFICALLY for 2012+ bikes because they're such different beasts, yet you reference 2011-earlier dyno information and example builds heavily.  I think 'different beasts' is probably a bit of an over-statement when the primary differences are EFI and head port design.  With the exact same bore/stroke/compression ratio, both the 2011 and 2012 bikes post similar low-40s horsepower and high-20s torque numbers all stock.  The newer suspension and frame is obviously superior, but gross weight is the same as well.

 

At first I was a little skeptical of "mixxer" and "mbirt" and pulling too much info from a TRX450 or YFZ forum, but those guys definitely seem to know their stuff...on an engineering level, which is awesome.  Good discussion/instruction on exhaust scavenging.  But I do think referencing stuff like some guy's subjective opinion about how his buddy installed a certain cam and LOVED it, and using that as a source doesn't really add any credibility to the discussion.  

 

Check out this thread from YFZcentral about the 2011-earlier and 2012-later WR450F head designs.  They're not a fan of the large port/slower velocity design compared to the earlier head.  Unfortunately, they never really finished the thread with the fully modded large port head, which I'm sure has great potential to move a lot of air (make a lot of power) with the right cams and compression:

http://www.yfzcentra...ing-no-hvp.html

 

I don't want to turn this into a volumetric efficiency discussion, but there is so much more to read up on regarding the varying volume and velocity flow set-ups, (stoichiometric) combustion chamber design, the relationship between dynamic compression and cam duration and timing, ignition curves, thermal efficiency, and a lot more to really understand the relationship of the camshaft to everything else and what an optimal profile is based on the rest of the build.  I'm not a super expert at all, but I did a ton of research, talked to a lot of smart people, read a couple of books, and did a ton of trial and error on a Dodge 440 engine I have in an old car that I built a few years ago -- the concepts are the same.

 

Also, here is some concrete info on the Hot Cams (not sure what stage these are - probably Stage 1 or whatever):

 

http://www.hotcamsin...spx?item_id=559

Intake Duration (Degrees at 1mm):

269.00

Intake Lift (mm):

8.86

Intake Lobe Center (Degrees):

110.00

Intake Valve Lash (mm):

.15

 

http://www.hotcamsin...spx?item_id=574

Exhaust Duration (Degrees at 1mm):

265.00

Exhaust Lift (mm):

8.67

Exhaust Lobe Center (Degrees):

103.00

Exhaust Valve Lash (mm):

.20

 

Also interesting to note from the Hot Cams site that their intake cam is for the 03-14 WR450F, 03-09 YZ450F, and 04-09 YFZ450 while the exhaust cam is for just the 03-14 WR450F and 04-09 YFZ450F

 

One more thing:
 

Carbs need air velocity to atomize fuel.  Fuel injection atomizes it by spraying it at high pressure.

 

Screwed up air streams (turbulent, reversing, etc.) screw up carb metering.  Fuel injection measures air flow better and meters better. 

 

Carbs are difficult to adjust.  I can adjust FI (fuel and ignition) in seconds.

 

 

True about carb airflow and fuel atomizing, but it doesn't take much - this is why carburetors have different circuits to meter fuel flow at different throttle, load, and air flow conditions.  EFI may be "cleaner" and more precise at every RPM, but the Keihin FCR39 is a work of art.  Properly set-up, a carburetor can be every bit as responsive and efficient as EFI.  Difficult to set up is subjective - more labor-intensive, for sure.  The real advantage of EFI is, as you mention, the capability to tune fuel and ignition curves quickly and without even getting your hands dirty, and sensors telling the ECU to adjust stuff for you based on environmental conditions.  Huge convenience factor.  I know this isn't a carb vs. EFI discussion.

 

Sorry this post is all over the place, it took me a long time to write.  Not trying to be negative or overly critical with your effort here.  It's interesting reading.



  • cubera

Posted August 24, 2014 - 07:16 PM

#14

So... I have the valve cover off my 2012 WR450F.  I need to remove the camshafts to adjust the valve clearances.  I have an 08 YZ camshaft set on my work bench. 
 
I ride tight woods with big hills.  I like power.  I don't find my WR to be over powering.  I haven't played around with maps much yet, I'm still running the stock map on our rides.   I'd like a bit less exhaust braking.  I might like a little more snap in the powerband.  I would be OK losing a little off the bottom, but not too much.  Fall rains are going to make our trails somewhat slick.  But it should dry off in October. 
 
What should I do ?
 
1) Leave the stock cams as they are ?
2) Retard the stock exhaust cam 1 tooth ?
3) Install the YZ intake cam ?
4) Install the YZ exhaust cam ?
5) Install both YZ cams ?
 
FWIW, I'll be OK if I have to change it in 10 hours.  I'm going to check my valves then anyway.


I love the enthusiasm and all the work you've done to figure out what cams might work on the 2012 and up WR450. Your best bet is run the FMF map or Aussie map and see what other kind of power you might need. Do that and it'll help define what cam changes you might want.

  • GP1K

Posted August 25, 2014 - 08:28 AM

#15

I still simply cannot fathom why you seem to flatly refuse to tune your FI mapping FIRST, which is absolutely positively what you should be doing. THEN If you still aren't happy, maybe look at cams. You can make it soft and fluffy, almost like a 250. You can make it snap and hit like MX bike, and everything in between. You can experiment with different maps WHILE YOU RIDE as it literally takes a minute to change maps. It really is a no-brainer, and just baffles me as to why you won't do it, when you have tinkered with damn near every other part of you bike BUT the mapping. I don't get it.

 

Also, all your data and examples are from pre 2012 WRs. Well guess what? They're a different animal, and don't respond to the same mods the same way. Just look at that Dirt Rider (or Dirt Bike?) article where they did just that, and it made the 2012 WR *worse*, not better. So just be careful what you ask for....



  • MidlifeCrisisGuy

Posted August 25, 2014 - 09:08 AM

#16

I was just going by the part numbers.  Sorry about that, I think I got confused about there being less lift on the '12.

 

Its all good.

 

I did some investigation.

Part numbers:

2011 intake cam: 5TJ-12170-00

2014 intake cam: same

 

2011 exhaust cam: 5TJ-12180-30

2014 exhaust cam: 5TJ-12180-40

 

So it looks like there has been a revision in the exhaust cam.  I suspect its in the decompression pin, but I have no data to prove that.

 

FWIW, the 2012 Press Info document (http://mxpmag.com/wp...F-May-15.12.pdf) says it has "Enduro focused camshafts" on page 10 and doesn't list the camshafts as a change from the 2011 engine on page 11.  If they significantly changed the cam(s) I suspect they would have boasted about it.

 

What I take from this is, as mbirt says, the 2007+ WR450Fs have lift reduced camshafts to deal with blow back of exhaust gases due to restrictive exhaust systems.


Edited by MidlifeCrisisGuy, August 25, 2014 - 09:42 AM.


  • MidlifeCrisisGuy

Posted August 25, 2014 - 09:12 AM

#17

I still simply cannot fathom why you seem to flatly refuse to tune your FI mapping FIRST, which is absolutely positively what you should be doing. THEN If you still aren't happy, maybe look at cams. You can make it soft and fluffy, almost like a 250. You can make it snap and hit like MX bike, and everything in between. You can experiment with different maps WHILE YOU RIDE as it literally takes a minute to change maps. It really is a no-brainer, and just baffles me as to why you won't do it, when you have tinkered with damn near every other part of you bike BUT the mapping. I don't get it.

 

I think differently than you do !

 

PLEASE do not turn this thread into a debate on whether or not a camshaft should be updated.  This thread is about camshaft information.

Edited by MidlifeCrisisGuy, August 25, 2014 - 09:14 AM.


  • MidlifeCrisisGuy

Posted August 25, 2014 - 09:55 AM

#18

Updated camshaft info table.

 

Note the lift on the 2012 exhaust camshaft: 7.75mm, compared to that of the 2009 EFI YZF engine 8.48mm.   This is the crappy WR exhaust cam (compared to the 2009 EFI YFZ exhaust cam)  that mbirt speaks of.

 

Note the duration, lift and lobe centers on the Hotcams.  They are beyond even what the hottest YZ cams are.  Hotcams are an upgrade to YZ cams, let alone WR cams.

 

In order of profile/timing aggressiveness, the cams in the table go like this: Hotcams, early YZ cams, later YZ cams, Early WR cams, later WR cams.  How they work in the 2012+ engines might be an entirely different story.

 

 

 

Cam table snapshot2.jpg


Edited by MidlifeCrisisGuy, August 25, 2014 - 10:16 AM.


  • cracker please

Posted August 25, 2014 - 11:31 AM

#19

Those YZ duration numbers of 244 degrees were measured at .050" lift

I think at .040" they are 256 in 258 ex.

I think all the other duration numbers on your chart are measured at .040"



  • MidlifeCrisisGuy

Posted August 25, 2014 - 11:55 AM

#20

Those YZ duration numbers of 244 degrees were measured at .050" lift

I think at .040" they are 256 in 258 ex.

I think all the other duration numbers on your chart are measured at .040"

 

Thanks.

 

What is your source on this ?






 
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