Hey all,
I'm a proud new owner of an '83 KX500.
I've wanted a full sized dirtbike for a little while now (I've always had XR/XL Honda 80/100s), and I wanted a bike with a good bit of power on tap, which is why I've been looking at KX/CR 500s. I tried a 99 or so KX500 about a year ago and the price was right but the engine was running strangely (1st gear 2nd gear wouldnt rev, hardly any power, grab third gear and almost flip over backwards), so I didn't buy it. I had looked at an '03 KX500 recently and would have loved to buy it but the guy wanted a good chunk of money for it and, since almost all my disposable income goes into my road-racing campaign, I couldn't afford it. Then just recently I saw an '83 for sale and the price was very right so I took the plunge. Although I would have preferred a liquid cooled bike, I'd rather ride an air cooled KX500 than no KX at all
The bike is in rough shape but the engine has been recently rebuilt and runs well with good compression, starts relatively easily, and for the price I paid for the bike I can afford to put a few dollars into a few parts in order to get the bike dialed.
Things I noticed on the '83/questions :
-Seems to be down on power substantially from the liquid cooled mill, which it should be, but can anyone tell me what the difference in power should be, so I might tell whether I'm just feeling the difference in power from the different engines or if my particular bike might be down on power relative to other air cooled ones. Is it like a 5hp difference or a 20hp diff? Can I expect to gain much with upgrades?
-The front brake hardly works, I pull on the lever what feels like enough to snap it off and I can't seem to lock up the front wheel. Should I expect to be able to lock up the front or are the brakes just that bad on an old MX bike?
-The engine seems very tractor-esque. It has lots of torque right off idle but doesn't seem to rev out like I would think it should. Might this be a fuel/ignition problem or does this engine just not rev that hard?
-The throttle seems very on/off. It feels like there's very little modulation to be had. To balance a wheelie I have to rock the throttle between say 20%-70% throttle all the time, it's very hard to get small increments, it seems like the bike always want's to be either idling or trying to pitch me off the back, with nothing in between. Is this common for these bikes? Is there a solution?
-The engine seems temperamental and very temperature dependant. I have to putter around at low speed for like 10 minutes before I get anything that could be considered decent throttle response or any power to speak of. Is this just another quirk of the '83 engine?
-The front suspension seems soooooooo soft and mushy. I don't know if there's anything wrong with it or if I'm just not used to having the front end of a bike compress so much on the brakes (keep in mind I'm usually riding a very stiffly sprung GSXR 600 which only dives maybe 3 inches on the brakes). What would be appropriate sag measurements for a bike like this?
Thanks a ton for any insight you guys might be able to offer me. You will find I have a TON of questions to ask as my project moves along. I know you will have a lot of answers for me and I've already found a ton of good info reading old threads on the site.
Ciao,
Sean