Top Speed, Surprising

I know every now and then a post pops up about top speed, so I though I would share. Speeds are from my handlebar mounted GPS.

Last year my 2003 KDX220 ran 71.9mph dead stock.

This year I had FRP porting, head mod, and bored carb, plus an FMF rev pipe, Turbine Core II silencer, Boyseen reeds, and a Wiseco piston. Changed my gearing out to 13-49. I know my bike revs a lot higher now, but I figured with the gear change my top end would be about the same.

Tested that out last night, ran 81.3 mph!

I didn't think it'd even get over 75, let alone 80. I was running along just under 60 mph, then tucked and gave on it. I counted to 3-one-thousand and it ran out of revs. Gave it another 3-4 seconds and then let off. I'm guessing with a tooth or 2 less in the rear 85 mph would be doable, although I'm not going to give up off-road performance just so I can go fast once a year.

Just thought someone might be interested to know.

Green Hornet said:

Did you have any problems with the FRP Porting? IE: Running too rich and not being able to correct w/jetting.

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I can't say I've had any problems. I did sacrifice the tractor-like low end. It's still got plenty for me, but riding the bike back-to-back with a friends stock 220 I notice I lost some down low. But the trade off it that mine pulls seemingly twice as hard, and revs much, much higher. Fredette sent my carb back with a 160 main and 45 pilot, I'm now at a 42 and 155. I'm still rich on the main, my jetting is about spot on for 45ºF or so, which it often is in the morning when I ride to work. I'm sure with a bag of jets and needles and an entire day of tuning I could get some more out of it, but I am content with just riding. :)

kdx220freak said:

how much did it cost to have your carb bored out and how much did it help?

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I believe it was $70 to have the carb bored and new jets. Like I said above, it came back set up WAY rich. I'm guessing I could ride in zero degree weather with the jets that he gave me. Lots of people here say to go with the RB Designs carb bore ($160 I believe), because they do a lot to clean up passages and also install a divider plate to help lowend. I went the cheap way, plus I was already getting the porting, head mod, pipe, and silencer from FRP, so I figured why not have him do my carb too? I can't say how much it helped, I did all the mods at once.