Maintenance & Technical > KX500 Original
top speed
2-Stroke Tom:
I have 15/45 gearing and have ran my bike out on El Mirage Dry Lake with some friends with 650 four strokers (that have speedometers) and I can walk away pretty good from my buddies bike that runs just under 100 mph. This is with mild porting, fmf desert pipe, stock (brand new) reeds, and spot on jetting. I only did this one time when first bought my 500 just to test it out and to see if the wheels/tires were balanced, but I didn't buy this thing to run out where a road bike can!
tcoop474:
yea mine is mostly stock and probably wont see 8500rpm i was just wanting to make sure i was understanding the chart lol...mine has pro circuit exhaust, fresh bottom to top rebuild, bored .30 over, that about all i know for real air filter looks stock and im not sure on the reeds i dont see any writing on the outside like boyesen and v force normally would so im guessing they are prolly stock
Polar-Bus:
--- Quote from: 2-Stroke Tom on July 08, 2011, 04:12:58 AM ---I have 15/45 gearing and have ran my bike out on El Mirage Dry Lake with some friends with 650 four strokers (that have speedometers) and I can walk away pretty good from my buddies bike that runs just under 100 mph. This is with mild porting, fmf desert pipe, stock (brand new) reeds, and spot on jetting. I only did this one time when first bought my 500 just to test it out and to see if the wheels/tires were balanced, but I didn't buy this thing to run out where a road bike can!
--- End quote ---
Odd, I tried 15/45 gearing out on the ice, same basic mods (less porting) and my engine would not pull this gearing on top end. My speeds and rpms flattend out at about the same 85 mph mark.
2-Stroke Tom:
Polar-Bus, doesn't your bike have a moose reed spacer (and a flywheel weight, which only testing could determine how this could affect top speed)? Although some claim reed spacers make more low end to mid range power, don't they hurt power on the top end? Have you tried new stock reeds and removing the spacer (and of course, rejet the bike for these new changes) to see if this improves/hurts top end? Do you have perfect compression?
When the KX500 was being raced by Team Green that last few years (they were still desert raced in 2005), Varner Motorsports built the engines. So, I'm not sure how many internal modifications were made to my motor, but I find it very interesting that Team Green, which had the knowledge and the resources to extensively test the KX500, refrained from installing reed spacers and trick reeds.
Here's an example I like to think about when it comes to aftermarket parts:
Look at the exhaust on Destry Abbott's 2004 KX500. It's interesting that it doesn't have a FMF silencer/spark arrestor on it, yet he was sponsored by FMF and he had a FMF Gnarly desert pipe. He has the stock silencer trimmed by 3 inches and a sparky welded on the end. Team Green claimed no power loss with this set up, and a scientific analysis (maybe a dynomometer) was probably performed to reach this determination. My FMF silencer (Unfortunately, Team Green didn't have this set up on the Brian Brown bike I bought) looks pretty restrictive with bend in it and turbine in the exhaust path, but I have no way of testing the power of one silencer to the next. All I know was on race day, this is what the factory team had on Destry's bike, so I'm inclined to take advantage of their research, and follow their recipe.
Motorrad:
Mine would pull that gearing... in STOCK form, with questionable Reeds. and a gnarly woods...
In a DEEP sand wash, it would top that gearing out without hastle...
Now. that its modified.. and the overdrive 5th (which is taller than that gearing still).. it pulls it around no problem..
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