Top Speed, Surprising

[adam728]

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]

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

 

[kdx220freak]

dang son, thats fast, i think my kdx220 only goes about 70 mph

 

[kdx220freak]

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

 

[kdxrider220]

are you sure I have a 05 kdx 220 with powercore 2 silencer modified airbox and a twin air filter and my friends swear that it only
hits 60

 

[cicone]

are you sure I have a 05 kdx 220 with powercore 2 silencer modified airbox and a twin air filter and my friends swear that it only
hits 60

As they say in these parts--"somethin' aint right with his bike"

 

[razrbakcrzy]

I will second the speeds he has stated. I have a trail tech computer on our 92' 200 and with me on it, it will cruise at 75. I verified this with a friend of mine that is a cop. I asked him to use his radar gun on it We went out on the old highway in the bottoms and it would top out at about 88 with my son riding it. Understand this bike has been street legaled with DOT approved tires, head light and turn signals. 13 tooth front and 48 tooth rear sprockets. It also has a gold series fatty and turbine core 2.

 

[adam728]

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

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. :)

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

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.

 

[G. Gearloose]

You get used to it...I ran 15/48 for years, great on the road.

 

[JasonRan]

I have never tested top speed, but I know that I can hit 60 in 4th gear with no problem. I have a few mods, but nothing extreme. This is from a Trail Tech computer. Don't forget too that if the computer isn't calibrated exactly right, the speeds will be off quite a bit. I could make mine say that I am doing 110mph, but what's the point? :laugh: