I did the timing Mod on the YFZ 450 last night and I was impressed. It took me about an hour and a half to do it and it was worth it. I still have the stock pipe with the spark arrestor installed. Bottom end may have been a little bit less but everywhere else the power is noticably better. The machine does feel torquier and revs even better. Cant wait to get my sparks pipe this week and see how it will really run. This mod is easy to do. Just take off the valve cover, take a screw driver and insert it into the cam tensioner to release the cam tension, take off both cam caps and when removing caps be careful not the drop the half moon clip that is under them down into the engine, then just turn the exhaust cam 1 tooth clockwise which will move the tooth upward and this will retard it one tooth. When you check your timing the dot will now be about 1/4 inch up instead of level with the head. This mod is well worth it i would recommend it to anyone.

 

OK, the YZ and WR bikes use the same cams.....the WR is de-tuned a tooth on the exhaust and I asume this is for a more mellow power output. Did Yamaha use new cams for the atv application that focus more power lower in the rpm range and too pull the heavier atv around? I would asume they did....and if this is the case, you are gonna potentially hurt power moving the cams around. So you feel since this mod works on the WR, you asume it should work on the YFZ?

 

It does work. and the atv doesn't have different cams. If done right. It gives the bike more torque.
Which is good.

 

iluv2fly.
Thanks mate for the great advice, please keep it coming.
Mine comes next week.

Thanks from down under, Geoff.

 

Check out these extensive dyno runs.... http://www.gtthunder.com/YFZ450.html


Pretty Impressive!


Nocando

 

Looks good...notice the overrev the exhaust gives.

 

I think I believe your name, iluv2fly, you just got the 450 and you are already goin to port it, get a higher compression piston, messin with the cams, and got a pipe. But hey, if I had the funds, I would be right there with ya.[img]i/expressions/face-icon-small-wink.gif[/img]

Street

 

You see the difference the tires made? Showing 7 hp gain? Wow

 

I can't make up my mind on the porting or high compresstion piston. I think I will ride it this season and when winter comes I will get an oversize piston from sparks. As for cams I cannot find a whole lot so those wont be changing. The cam mod did make a difference and the quad has better overall torque not less. I put my name down on the air filter kit that sparks racing is making and it is supposed to help some but it wont be ready for 5 weeks. This is an awesome quad I am even contemplating on leaving it at 440cc. My wife cant believe it either. On my 250r I have had a 295, 310, 330, 350, and to finish it off a 4500 dollar 420cc engine from trinity. I need to learn to be happy with stock. It saves you a lot of money and someone will always beat you. If any of you ever come to Idaho give me a call and we will go to st anthony, the greatest dunes on earth.

 

iluv2fly. We will be making another trip to St. Anthony over Labor Day weekend. Go to dunereview.com and check out the pictures from our latest trip to St. Anthony two weeks ago. We had a blast and can't wait to get back to tear it up. We should hook up for sure.
By the way, I did the cam mod and I was very careful pulling the cam tops off and the ring still came out and got wedged between the cam chain about 6 inches down. Got it out with my magnet and had it ready when I removed the intake side. You gotta be slow and careful that's for sure. I will ride it tomorrow and see how it feels. I had to turn my idle up a hair as well. I will also adjust the air fuel mixture to get it perfect.