Valve Clearance Gen 2

[g2gboom]

Thus the 2hp gain he told me about.

A forum member reached out to me to inform me that Tim Nash discovered differences in cam profiles over a few years.

Apparently the 09/10 models shipped with cams that had a centerline of 101/109 whereas all the late models shipped with 105/105. This resulted in a 10hp difference between those models on a dyno. He also stated that changing the profile of the 101/109 cams resulted in negligible results hence your buddy only getting 2hp im thinking.

Tims the man, im gonna pick his brain and see if he can help me identify which ones I have.

 

[g2gboom]

Oh I should mention, when ordering from yamaha directly Tim had mixed results on Cam centerline profiles.

 

[g2gboom]

Post Weekend Update:

Spoke with the man the myth and the legend this weekend, Tim Nash.

Tim confirmed that there were in fact two cam profiles that came from Yamaha and unless you dismantle down to the flywheel its incredibly difficult to determine which one you might have. For those that have the 101/109 centerline you can expect on average 10hp less than a 105/105 centerline camshaft model. These were predominantly found in the 09/10 model years and they likely phased out after a few years.
However, you do take the risk of getting the wrong camshaft profile when you order the parts from Yamaha. There was never a superseded model number.

Tim mentioned that changing the cam profile (adding duration, valve lift, etc) netted hardly any difference for the 101/109 camshaft models. This resulted in wasted fuel and negligible horsepower gains.

The 105/105 models however received a hefty boost in power when given additional lift/duration. Tim was one of the first to swap cams in his Gen 2, and he said he netted roughly +7rwhp with grind profile 941 from Webcamshafts.



So that likely explains why we are seeing mixed results on cam upgrades.
"So where does that leave me? What would you advise I do? I'd hate to let a crisis go to waste."

Now im paraphrasing here but Tim said, "Throw a hog-ass cam in it."
Ladies and gentlemen, I received his blessing.

More to follow,

Brandon

 

[MileHayabusa]

I'm curious as to why changing a cam profile, adding lift or duration, netted such minor gains on one bike (the 101/109) vs. the other (105/105). All other things being equal within the engine which I assume they are, a change in cam duration or timing should have relatively the same effect on either motor and end-up producing roughly the same horsepower.

For example, going from a 101/109 to a 105/105 should, in theory, net you that same +7 horsepower but we're saying that's not the case?

 

[g2gboom]

I'm curious as to why changing a cam profile, adding lift or duration, netted such minor gains on one bike (the 101/109) vs. the other (105/105). All other things being equal within the engine which I assume they are, a change in cam duration or timing should have relatively the same effect on either motor and end-up producing roughly the same horsepower.

For example, going from a 101/109 to a 105/105 should, in theory, net you that same +7 horsepower but we're saying that's not the case?

I think there is more to this. Now im no expert but, 4 Degrees of timing difference on intake and exhaust completely changes the power band and valve overlap. I fully suspect that hardwelding and adding additional duration or valve lift to the 101/109 cams could result in negligible results. You can add additional duration and lift without changing the centerline and I think thats the issue here. The only person who knows for certain here is Tim. He's likely the only one here who has dyno'd a bike before and after with both sets of cams.

Edit:

If there were two bone stock gen 2's, #1 has 101/109 camshaft bike and #2 has a 105/105 id be willing to bet that by swapping cams bike #1 would net an increase in power and would baseline the same HP wise as the bone stock #2.

 

[MileHayabusa]

Now that makes sense...no changes in centerline resulting in minimal gains with the 101/109. Sounds like 105/105 is the way to go if you're swapping cams.

One thing that didn't hit me until I looked at Web Cam's site...their re-grinds are advertised as 109/101 (intake/exhaust), which yields an overall advertised lobe center of 105-degrees.

Hoping Tim chimes in here with some feedback on cams and what his experience has been.

 

[g2gboom]

Now that makes sense...no changes in centerline resulting in minimal gains with the 101/109. Sounds like 105/105 is the way to go if you're swapping cams.

One thing that didn't hit me until I looked at Web Cam's site...their re-grinds are advertised as 109/101 (intake/exhaust), which yields an overall advertised lobe center of 105-degrees.

Hoping Tim chimes in here with some feedback on cams and what his experience has been.

Oh shit I missed that timing card!

Good catch!

I punched the info into cam cruncher and this is what it looks like.

-Brandon

 

[g2gboom]

Called webcamshafts and confirmed that 09/10 has 109/101 cam centerlines. 10'-20' has 105/105. Sounds like they offer military discount on their services so im going this route.
Attached is the stock cam cards for both.

-Brandon V

 

[g2gboom]

Shipped my camshafts out to Webcamshafts!