Re degree your can to yz spec

Engine Power Up Kits Hot Cams Stage 1 Inlet & Stage 2 Exhaust

31 replies to this topic
  • Bass Mechanic

Posted December 07, 2015 - 01:16 PM

#21

Hum 10-13 hp is really not doable for a pipe and a cam change.

Carbed bikes don't give up hp and a 08 YZ450 on a Dyno jet made 49+ hp.

Maybe a funny Dyno.

well believe what you wish, he stated that we were within a couple hp of the pre reverse flow YZ engines. the current yz engines he gets about 61-62 hp out of with a tune. so one of the main reasons im upgrading to the new YZ is because of that engine and the wide ratio trans.



  • stevethe

Posted December 07, 2015 - 02:19 PM

#22

well believe what you wish, he stated that we were within a couple hp of the pre reverse flow YZ engines. the current yz engines he gets about 61-62 hp out of with a tune. so one of the main reasons im upgrading to the new YZ is because of that engine and the wide ratio trans.


I'll stay with what I know and have seen on the Dyno. But a before and after of the tweaks your taking about I sure would like to see on paper or in person.
I personally know of a mid 60 hp carbed YZ on a un funny Dyno. However there is about one guy in the Country that gets those numbers and it does not come from cheap nor with minor tweaks.

  • jams33

Posted December 08, 2015 - 04:27 AM

#23

No it is not.
You don't have that option anymore.


Hi, could you explain why not? Out of interest. I was looking for a way to reduce engine braking and thought I had bagged it with this mod. It catches me so unawares sometimes I end up over the handle bars!

Thanks

  • Krannie McKranface

Posted December 08, 2015 - 05:44 AM

#24

Hi, could you explain why not? Out of interest. I was looking for a way to reduce engine braking and thought I had bagged it with this mod. It catches me so unawares sometimes I end up over the handle bars!

Thanks

 Run in a higher gear and do more clutch modulating, or get a Rekluse



  • stevethe

Posted December 08, 2015 - 06:53 AM

#25

Hi, could you explain why not? Out of interest. I was looking for a way to reduce engine braking and thought I had bagged it with this mod. It catches me so unawares sometimes I end up over the handle bars!
Thanks


Other answers a one tooth difference on the cam and it won't run and you could hit and bend your valves.

The compression breaking is perfect on a WR450 get use to it and use it to your advantage.

  • jams33

Posted December 09, 2015 - 01:00 AM

#26

Run in a higher gear and do more clutch modulating, or get a Rekluse


Thanks for the advice, could you explain why though? I'm just interested. Most topics on this subject suggest that you can retard the exhaust cam. However I'm aware that there is a lot of sh1t on forums so if I hear something as definitive as your comment it suggests you know what you are talking about.

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  • chu

Posted December 09, 2015 - 05:21 AM

#27

The exhaust cam changed in 2012. The specs might be on the YFZcentral quad forum somewhere. They probably changed the lobe center or something.

  • Krannie McKranface

Posted December 09, 2015 - 06:48 AM

#28

Thanks for the advice, could you explain why though? I'm just interested. Most topics on this subject suggest that you can retard the exhaust cam. However I'm aware that there is a lot of sh1t on forums so if I hear something as definitive as your comment it suggests you know what you are talking about.

You will lose the estart

You will not change the decompression braking

 

If you are experiencing decompression braking enough to cause substantial weight redistribution, you are in too low of a gear when you shut off the the throttle.

If you want, you can run a gear higher and use more brakes to slow down.

You will need to learn how to cover the clutch and modulate it's grab in most situations.

 

If your goal is more control and traction, the higher the gear the better (assuming you can pull it).

The suspenion reacts negatively to sharp/fast input, like decompression braking, so it will 'lock up' causing the rear wheel to bounce more.

 

Going down hill, it is less work to use the engine for braking, but it is less effective too. Very hard to keep traction using engine braking.

 

You should practice pulling in the clutch completely and using only the brakes for corners and downhills (for practice).

You should also practice NOT downshifting one gear into a corner, but using your clutch to 'modulate' the motors rpm and allow you to accelerate with no loss of traction whatsoever.

 

...or you can use a Rekluse auto clutch. It allows the clutch to have controlled slip/modulation over a narrow rpm change, vastly improving traction and control.

 

Eventually you will find the best combination of the engine/clutch/brakes for all situations.

 

If you watch videos of superior riders of Offroad (not modern MX or SX, that is a one gear sport..) , you will notice that they don't usually 'scream' the motor, they ride in the sweet spot for the need: low rpm for traction, mid rpm for acceleration, high rpm to carry the next gear or for overrev (the need to rev high rather than shut off to shift, which may loose you control or position).


Edited by KRANNIE, December 09, 2015 - 06:49 AM.


  • jams33

Posted December 10, 2015 - 04:49 AM

#29

Thanks KRANNIE. I have an issue when zapping a vertical face or stopping atop a narrow obstacle, where I have to chop the throttle as part of the technique. Quite right about clutch modulation. I latched onto the exhaust cam as a means of bringing the WR nearer to the KTM 300 I used to ride in regards to the above. Will have to investigate yz cams. Not that I intend to start a thread on that!

  • Bass Mechanic

Posted December 11, 2015 - 10:24 PM

#30

Hi, could you explain why not? Out of interest. I was looking for a way to reduce engine braking and thought I had bagged it with this mod. It catches me so unawares sometimes I end up over the handle bars!

Thanks

EASY! adjust your idle setting you can literally dial in how much you want.



  • chu

Posted December 12, 2015 - 04:36 AM

#31

An intake cam that closes the valves later would lower the dynamic compression.  The exhaust valves would be closed on the compression stroke no matter what cam you're using.



  • Krannie McKranface

Posted December 12, 2015 - 05:21 AM

#32

EASY! adjust your idle setting you can literally dial in how much you want.

 

......and then you will have 'idle push' in the corners when you shut off the throttle, and have to pull in the clutch....or understeer.

 

I prefer lowest possible idle for no push.







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