Rev Limiters

All,

Anybody have any experiences with the after market rev limiter? The limiter will allow the bike to go from 8200 RPM to 9500. Will the higher RPMs hurt the bike? Is it worth $134?

Don't do it cause your engine will explode into a billion pieces :)

Seriously, I would not even consider it unless you've built your engine specifically to make its peak power at a higher RPM and wanted to use the bike mainly for motarding, etc. Acceleration is based on torqe and your bike will accelerate fastest at its peak torque delivered to the rear tire. The power on the XR650R drops off well below the current redline, so the only things you'll accomplish by removing the rev limiter is being able to stay in a particular gear a bit longer while the power continues to drop off and at some point above redline your valves will begin to float and you'll cause more wear and tear to engine.

If the aftermraket rev limter device also modifies the ignition curve in addition to removing the rev limiter, then maybe there's some merit to it, but I would want to put my bike on a dyno and instrument everything to see just what's going on.

If you're looking for more power, have your engine balanced, check into a 680 kit, a new cam, etc. A new cam by itself only costs $100 to $150 and installation should be about the same. I would bet you'll get way more performance per dollar from a good cam than you would from a rev limiter, but that's just my guess.

I just don't see anything to gain by only removing the rev limiter other than staying in a particular gear a bit longer while the power continues to drop off, but maybe someone else can shed some new light on this.

Thanks Qadsan. Once again, you are the king of mechanics. :)

Qadsan, This is interesting because I didn't even know the 650R had a rev limiter! I've been riding mine for almost two years now, and had no idea! I guess because it's got so much midrange torque that I've never revved it all that high. I have run the bike to top speed a few times but never noticed a rev limiter making it cut out, I guess it won't pull to redline in high gear or something with stock gearing? Well anyway, it's good to know that it does have a rev limiter.

L.L.

I have tried a few very long steep sandy hills that almost border on being a cliff at the top. I have never made it on my 650. I just needed a few more rpm but the rev limiter kicked in. there no shifting from third to fourth on this hill. So I intalled a Hotcam. Wow the cam really gave me more grunt in every gear. But the rev limiter still kicks in and I couldn't make the hill. I get pretty close and I suspect if I could just get a few more rpm I would make it. Long live the pig. :)

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