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Discussion Starter #1 (Edited)
Here's a little side by side comparison of the "09" motor next to the "07" motor. Both from the UK MT series of course.

yamaha motors.jpg

At least I'm pretty sure that's what this is. I got it off a French web site and I don't read French.
 

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I believe you are correct. I saw that picture some were else with that explanation.
 

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Discussion Starter #3
I guess the only point I was trying to make with the picture is the FZ-07 (should one ever materialize) will be really narrow.
 

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I believe you are right. I think the 07 looks nice and if the price is right, it should kill the mid range standard market.
 
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I noticed the FZ-07 has an exhaust cam centrifugal adjuster - which will either advance or retard the timing as RPM increases - kind of interesting

FZ-07.JPG
 

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Basically variable valve timing, but instead of using a servo motor to advance the cam, it uses weights. When the cam spins up, the centrifugal force causes the weights to follow a path. Those weights are connected to the cam (or a planetary gear or something like that) which in turn rotates the cam relative to the cam chain/ignition/crankshaft.

Basically this, but not using an electric servo motor.

 

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if the 07 had variable valve timing, yamaha would have bragged about it in the specs. it's more likely to be an automatic compression release.

also, single cam variable valve timing is usually implemented on the intake, not exhaust.
 

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I agree, they usually do put the variable cam timing on the intake, so seeing it on the exhaust is odd - but if they are only interested in changing intake - exhaust overlap, it could work with either cam.

I don't think it's a decompressor as you would want that active at zero speed - so the centrifugal bit would be useless - unless it kicks in at 500rpm - there are easier ways to do decompression. Most modern start systems don't need decompression - Royal Enfield is an exception
 

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They use two counterweights to keep the assembly balanced, but the decompression works on both cylinders. The system keeps one exhaust valve per cylinder cracked open during starting via a little sliding protrusion on the cam.
 
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