2008 WR450F WITH YZ SUSPENSION AND CAMS / PART DEUX

Oh no you don't get out of this that easy. You could always drill the hole or have it drilled through. :rolleyes:

My Dad has a bitchin' set of tools. I can fix it.

My Dad has a bitchin' set of tools. I can fix it.

If he's got drool bits your in. Jump on it Kawi man.

Edited by stevethe

Very nice!

Any updates?

Any updates?

 

Yes.

Hot Cams YZ cams work best with a HC piston and some porting, which I don't have.

The motor is PERFECT for supermoto, but the power comes on too late and too strong for casual trail riding.

It's fine if you keep it above 6 k rpm for acceleration, or below 5k for grunting around. It's just that theres no acceleration to speak of down there. 

The stock header works MUCH better than the YZ header, with low end power delivery, and no change on top. 

 

My vavle train has suddenly become very noisy, so I have to back inside....

The head comes off this week for porting.

The overall concensus by the dozen or so tuners I talked to is "the Yamaha heads are all different, and all restrictive. Port it or be un-happy"

 

So, since I want to be happy, I shall port.

 

And polish.

The head comes off this week for porting.

The overall concensus by the dozen or so tuners I talked to is "the Yamaha heads are all different, and all restrictive. Port it or be un-happy"

 

So, since I want to be happy, I shall port.

 

And polish.

Do it man, just do it! :-). Let me know what, if any, jetting changes they recommend after the porting. I know you know mine but if AS isn't doing it, don't tell whoever is. It would be interesting to see what there recommendation would be.

Porting should have no effect on jetting, but to possibly allow you to run a larger main without side effects.

Porting should have no effect on jetting, but to possibly allow you to run a larger main without side effects.

I was just saying that if whoever does the porting suggests a jetting change to post up what they suggested if anything.  I wasn't saying to make a change.

I was just saying that if whoever does the porting suggests a jetting change to post up what they suggested if anything.  I wasn't saying to make a change.

Oh, of course, I will dial it in and report back.

I expect big things, as the 450X has similar issues with I added a cam to it (though not as severe): very stage-y power.

Head will be off shortly.....

PORTING_zps769b2f75.jpg

Head is off.

It's running way to rich, just like I thought, but leaner needles did not help.

 

head2_zps701de4a8.jpg

nice needle jet tuning. Honda CR250 carbs from 01-03 also were tuned similarly no a needle jet DO make a difference. 

nice needle jet tuning. Honda CR250 carbs from 01-03 also were tuned similarly no a needle jet DO make a difference. 

..don't understand what you are saying...this is not a two stroke CR....?!

..don't understand what you are saying...this is not a two stroke CR....?!

 

Yes, I'm aware of this. Just pointing out the similarity. Most two strokes don't have needle jets to tune either. Glad you found a way to improve it. 

Yes, I'm aware of this. Just pointing out the similarity. Most two strokes don't have needle jets to tune either. Glad you found a way to improve it. 

 

Oooohhh, needle jet.

 

Yeah,  will porting will solve EVERYTHING, or else....

Head is off.

It's running way to rich, just like I thought, but leaner needles did not help.

 

head2_zps701de4a8.jpg

Plug certainly doesn't look rich...

OK, getting a bit closer.

The  center intake port is notoriously very small and oddly shaped. You can't even get your finger down inside it like you can the other ports.

Well, now you can....the shape has been corrected for laminar flow, and the diameter changed to be linear. Can't give too much of the 'secrets' away here....

IMG_2834_zpsa9d3caac.jpg

 

 

Again, without giving too much away, the front of the intake has been changed so the intake volume is more closely matched to the exhaust port volume, and has been changed from square to oval shape... sorry, can't find the 'before' pics anymore....

 

IMG_2835_zps4050bf37.jpg

HEAD IS FINISHED!

 

1236716_10200681478659586_640779056_n_zp

 

BEAD BLASTED AND PORTED INTAKE

 

999761_10200681488859841_1656129212_n_zp

 

POLISHED AND PORTED EXHAUST

 

551144_10200681474459481_1787908149_n_zp

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now