YFZ450
Stock Dyno Graph
This is a dyno graph for a stock YFZ450.
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Below are some dyno graphs of tests performed on the YFZ450. They do not represent the order in which modification should be done on this bike but simply give some info on how different things affect this engine. I take great pride in consistent readings and as such,  all runs are done with the same tires, external air flow over the bike, and all readings are corrected horespower so that day to day differences are kept as minimal as possible.
This shows the effect of removing the pea shooter (spark arrestor) from the stock silencer.
Dyno Graph
This is the same as above but also has a run added with the air box lid removed. No jet changes were made for this run. Notice the dip in the power at low rpm from the lean condition that this created.
Dyno Graph
This has a stock run, a run with the SA removed and the lid off, and a run with the air box lid back on and a torque slip-on silencer installed instead of the stock one. Notice the dip in power at the top that is caused by the restriction from the airbox lid and from the long tuned length of the exhaust.
Dyno Graph
This shows the effect of removing the airbox lid while running the torque slip on.
Dyno Graph
By now many of you have heard of the "cam mod". This graph has a stock run, a run with the torque slip-on and the lid off, and a run with the same specs but with the cam mod done. Again notice the dip at low RPM from the bike being to lean.
Dyno Graph
"Cam Mod"
This again has the stock , and the cam mod runs. It also has a run added after the bike is rejetted. 170 Main, #5 clip position, 3 turns out on the idle mixture screw.
Dyno Graph
And for the guys who wish to see some torque numbers of a stock bike verses one with a slip-on, cam mod, rejetted, and the airbox lid removed.
Dyno Graph
In this graph I have the cam mod done as well as no airbox lid, 170 main jet, #5 clip position on the needle and the stock pilot jet. The one run is with the stock silencer and the other run is with the new HMF full system exhaust. Yes I had to beg and many other things to get to test this and no I did not get to keep it but it sure looks good to me.
Dyno Graph
I have heard a lot of talk regarding different dyno readings from different companies. There is a lot to be said about who is doing the dyno testing as well as the honesty of the dyno operator. This is a comparison of the best YFZ450 run that I have to date with what I call my dyno tires. I use them on all quad dyno runs. The other run is with the stock knobbys. So when you look at dyno runs be sure to look at what they are comparing it to and not the actual numbers unless they will give you accurate info on their runs.
Dyno Graph
Jetting
Rear Shock
Fuel Ratio
Rezy Kit