retarding exhaust cam?

[stevestauff]

has anyone done this?i was told by a buddy this really woke up his bike.if anyone has done this id really like to hear how well i worked.its just my practice bike so cheap power and reliable power is cool.

[quadrider2112]

did it to mine and luv it. yfzcentral.com has i good step by step with pics the whole way through.

[XCRacer236]

supposedly makes the bike run cooler and gives more mid- range through top end.

I've done it and love it. There still isn't an aftermarket cam on the market that gives more power than stock cams with the "cam-mod". If you ever plan on putting a kicker on it, the cam-mod makes it 10 times easier to kick as well.

[Buttermilk]

Absolutely do the cam "mod". It's free horsepower. Worth about two HP accross the board.

There are indeed aftermarket cams that will beat the stockers for power. Problem is, it's really hard to beat the stockers up to ~8000 RPM or so. There are several cams that make more peak hp. The stockers are hard to beat for overall power however.

www.gtthunder.com has some dyno comparisons showing the advantage of the retarded exhaust cam vs. the stock setting on a yfz450.

I've done it to all my yfz's and my son's quad as well. Plus you can even do this "cam mod" to some aftermarket cams such as WEB 963 camshafts (I have these in one of mine... )

[stevestauff]

thanks for the info.hard to believe almost 50 hp with exhaust and mod only.but dyno numbers to prove it looks like ill be doing the mod.

[Ryan'07400ex]

Originally posted by XCRacer236
supposedly makes the bike run cooler and gives more mid- range through top end.

Any disadvantages? Why doesn't yami make it from the factory like that?

[yfzrider690]

all it does is time it like the yzf450 dirtbike. There are no disadavantages to it. The quad is time different so it doesn't have the snap like the dirtbike and the power is more mellow. And there are cams that are better than the stockers over the whole range. Check out mmad's warpspeeds, they are drop in cams and outperform the stockers over the whole range.

[standardryder]

Originally posted by stevestauff
thanks for the info.hard to believe almost 50 hp with exhaust and mod only.but dyno numbers to prove it looks like ill be doing the mod.

It is hard to believe, since I have done the cam mod, and have an exhaust, and also a built motor with a list of other things. I just had it on the dyno and im only putting out 48.1 hp...

[Scro]

Originally posted by Ryan'07400ex
Any disadvantages? Why doesn't yami make it from the factory like that?

They are not as reliable for XC starting. I know countless people that have done the mod, and switched back because it didn't fire as quick. But, it's nothing to worry about if you are not dead engine starting. They did say there was a noticeable difference in power.