2008 WR450F WITH YZ SUSPENSION AND CAMS / PART DEUX

How much did the porting run you? Once I have my bike more sorted I might do it. 

It was $499.00.

Paul's work is about 100.00 more than a typical port job, cause it's not a hacky hachet job like most 'porting' guys do.....it's actually hand done by two different technicians, and done to match proven work on other motors. 

There is so much mis-information about porting here on TT it's scary.

It's really the go-to thing to do, if you have your motor apart, way befor HC piston, Big Bore, Ti exhausts, etc, etc.

It does not stress the motor more (accept for the fact you will get on the power a lot more often, cause it's so much fun...) and has no moving parts to break, and doesn't wear out and lasts forever....

 

It's about $1,200 for  the YZ cams, stage 3 port and polish, required jetting changes, gaskets, oils, etc, and all the labor.

It should be pointed out that the 2012+ WR450s have different heads with a much larger port structure.

It should be pointed out that the 2012+ WR450s have different heads with a much larger port structure.

Yes.

The 2012+ head and cams are closer to the 2009 YZ head.

It was $499.00.

Paul's work is about 100.00 more than a typical port job, cause it's not a hacky hachet job like most 'porting' guys do.....it's actually hand done by two different technicians, and done to match proven work on other motors. 

There is so much mis-information about porting here on TT it's scary.

It's really the go-to thing to do, if you have your motor apart, way befor HC piston, Big Bore, Ti exhausts, etc, etc.

It does not stress the motor more (accept for the fact you will get on the power a lot more often, cause it's so much fun...) and has no moving parts to break, and doesn't wear out and lasts forever....

 

It's about $1,200 for  the YZ cams, stage 3 port and polish, required jetting changes, gaskets, oils, etc, and all the labor.

Good info. MOST port jobs are like back surgery, high % failure and not correctable.

Good info. MOST port jobs are like back surgery, high % failure and not correctable.

 

That's especially true of porting 5 valve Yamahas.  The presence of the third intake valve introduces a whole set of complex flow dynamics as air enters the combustion chamber that don't exist in two valve intake tracts, and getting the shape and configuration of the individual ports, the area where the divergence into 3 takes place, and perhaps most of all, the edges of the dividers at that point, is amazingly critical.  A lot of times, the ports need to be partly filled in several areas to make them really work.  It's incredibly easy to drop 2 or 3 horsepower instead of adding any by mucking around with them.

 

But if you get it right, the results can be impressive.  I recall that Big Gun, the pipe people, were doing a port job on YZ250f's that would add 3 full horsepower to an otherwise stock bike running most aftermarket pipes.  

 

I notice that it doesn't look as though the AIS port in the roof of the exhaust port was filled.  That's a high pressure zone within the port, and it seems like it would have been beneficial to fill it in to avoid an obstructive eddy at that point.

Yeah, I had mentioned the same thing, but decided to keep the head stock with the AIS port, in the end. Not sure why I did that......

 

All I know is the new found power is fun as hell and really linear.

Just a random questions but did the 03-06 motor have the same smaller ports like the 07-11 motor? I know the head changed 05-06 a bit. Could I just slap a 2005 YZ had on my bike? I have an 06 steel frame bike. 

The '05 YZ450 head will fit your engine, yes, and it will lack any of the connections to the AIS.  But whether it will by itself improve your performance isn't as clear.  The ports have been changed within the production run of both the Gen1 ('03-'05) YZ450's and the Gen2 ('06-'09) YZ450, and their WR450 brethren, an number of times, and I'm not sure which ones are natively supposed to be better, or which ones are supposed to make the best subjects for serious port work.  Unless your goal is a serious pursuit of the maximum output of this engine, I don't think it really makes too much difference, in most cases.

That's especially true of porting 5 valve Yamahas.  The presence of the third intake valve introduces a whole set of complex flow dynamics as air enters the combustion chamber that don't exist in two valve intake tracts, and getting the shape and configuration of the individual ports, the area where the divergence into 3 takes place, and perhaps most of all, the edges of the dividers at that point, is amazingly critical.  A lot of times, the ports need to be partly filled in several areas to make them really work.  It's incredibly easy to drop 2 or 3 horsepower instead of adding any by mucking around with them.

 

But if you get it right, the results can be impressive.  I recall that Big Gun, the pipe people, were doing a port job on YZ250f's that would add 3 full horsepower to an otherwise stock bike running most aftermarket pipes.  

 

I notice that it doesn't look as though the AIS port in the roof of the exhaust port was filled.  That's a high pressure zone within the port, and it seems like it would have been beneficial to fill it in to avoid an obstructive eddy at that point.

Given all of the variables, how does one verify that what was done was done correctly as the "seat of the pants" test is so subjective?

Given all of the variables, how does one verify that what was done was done correctly as the "seat of the pants" test is so subjective?

You flow test your projects, learning how to create linear acceleration within a port cavity.

Or, you trail and error a real lot.

Porting has been around a lot longer than Flow machines have.

In short order, you learn what works and what doesn't work.

Basic Physics regarding the mechanics of fluids is what Paul uses. 

Most stock heads are very good, until you start modifying the rest of the motor......

The stock center port on the '08' heads have a 90 degree turn with quickly decreasing volume. I'm not sure what it is supposed to do stock.

It's now more like three 30 degree turns with about 30% more volume. 

Gaaa-runt.

You flow test your projects, learning how to create linear acceleration within a port cavity.

Or, you trail and error a real lot.

Porting has been around a lot longer than Flow machines have.

In short order, you learn what works and what doesn't work.

Basic Physics regarding the mechanics of fluids is what Paul uses. 

Most stock heads are very good, until you start modifying the rest of the motor......

The stock center port on the '08' heads have a 90 degree turn with quickly decreasing volume. I'm not sure what it is supposed to do stock.

It's now more like three 30 degree turns with about 30% more volume. 

Gaaa-runt.

Yeah, Paul went to Cal Poly San Louis Obispo, an Engineering school. They built the Teeter Toter that the Penguins Motorcycle club uses in their annual Dual Sport Ride. The one you use to cross the 5' deep, 25' across pond. Yeah, it broke this year before we got to it :banghead::D

GOD DANG I LOVE THIS MOTOR!

28 miles of single track and fire road today.

More tomorrow.

Just to confirm, you think the bike runs better with the stock header is you have not done the porting correct ? I'm going to see if my stock header fits by PC pipe just to try it out.

Just to confirm, you think the bike runs better with the stock header is you have not done the porting correct ? I'm going to see if my stock header fits by PC pipe just to try it out.

After the HotCams cam YZ cam install, the power was very peaky. Fine on flat easy trails, but not so good on very steep sketchy trails.

The motor had two powerbands: a 3000-6000 mellow power, then 6500-9000 massive slam of power.

You were forced to shift down and keep the bike in higher rpms, cause you could not able carry a higher gear up hills.

Changing back to the stock exhaust header and the more restrictive Lexx exhaust took some of the 'peak' out of the power, and gave it more low end, and made it slightly better for short shifting.

 

Other than that, it was not 'better'. 

 

After the porting I put the full Dubach Racing '07 YZ exhaust back on, and now I can ride in any gear I want (almost literally) on any surface.

Just to confirm, you think the bike runs better with the stock header is you have not done the porting correct ? I'm going to see if my stock header fits by PC pipe just to try it out.

My bike is a bit different than Krannies.  Hotcams for the WR (YZ timing), just a clean-up port, stock header pipe, Yoshi slip-on exhaust, a slight bump up in the piston (12:3 to a 12:5), 172 main, 48 pilot, don't recall the others.

 

From day 1 that I picked my bike up from ASRacing it has run like a champ.  I haven't experienced any hiccups or other issues throughout the rpm ranges.  I ride in all types of terrain and elevations from 2,500' to 9,600' without making any adjustments, even to the adj fuel screw.  Been very happy with it. :thumbsup:

Cool, I'm going to try the stock header. 

 

I did a 500 mile 3 day ride in the dez and see what you are talking about. The bike screams in the upper top end but you have to rev it good to shift. This got worse on day 3 in the desert when my air filter was super dirty. on top of that i'm running 15/48 gearing so the the gap between gears is pretty good now. (the ratios are closer for the 03-06 than the 07+ bikes. 

 

Bike has yz cams and a full Ti PC pipe that was on a 03 yz450. I'm not sure if the older pc pipe will slip on to the stock header though. It has no clamp at the joint. I also have a smaller end camp I could use. 

 

I think the port job is in my future but I need to pay for a wedding and house projects first. 

Cool, I'm going to try the stock header. 

 

I did a 500 mile 3 day ride in the dez and see what you are talking about. The bike screams in the upper top end but you have to rev it good to shift. This got worse on day 3 in the desert when my air filter was super dirty. on top of that i'm running 15/48 gearing so the the gap between gears is pretty good now. (the ratios are closer for the 03-06 than the 07+ bikes. 

 

Bike has yz cams and a full Ti PC pipe that was on a 03 yz450. I'm not sure if the older pc pipe will slip on to the stock header though. It has no clamp at the joint. I also have a smaller end camp I could use. 

 

I think the port job is in my future but I need to pay for a wedding and house projects first. 

My "clean up port job" was $100.  I used to have an FMF slip-on and it did not have a clamp at the joint.  It just sliped on over the supplied reducer.  The yoshi came with a clamp.  I am also test running a 12/49 combo right now.  So far I like it.  Gives me a bit more confidence in the 1st/2nd gear slower techincal stuff as I feather the clutch.  IMO, clutch work is a skill that is underutilized, especially the ability to feather it consistantly to help keep a steady momentum without stalling or spinning the wheels.  Very helpful in loose, rocky uphills :thumbsup:

Edited by kenshaw720

Yep, almost as good as a Rekluse.

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