I recently bought a as much as can fit the word, a 12+y.o. mint-condition stock 99 WR400, after selling that much ridden and last owned bike, a 2000 WR400 tuned spot on six years ago. FCR39H carb on this one - turns out to be way different (and crappy) when compared to the carb on the 2000.
Knowing I played the jet game to get there on the 2000, I just bought the JDJetting kit to simplify things. I live at 8000 feet in Colorado. My altitude riding is typically 5500 to 10000, occassionlly higher. I used the red needle in the 5th clip position and 165 main jet as suggested for 6k-9k in in the JDY001 (98-06) for the bike. Only change from stock is a White Bros. E-Series and mid-pipe, also found in "mint" condition on ebay (same outstanding pipe I had on my 2000 several years ago). The bike ran pretty good stock with the throttlestop fixed, stock pipe uncorked.
Now, with this kit, I'm about to just go back to uncorked stock - but I would like the gains I've felt glimpses of while trying to jet and tune it. The bike runs pretty good with the choke fully on. Now, the bike with choke off has a low-end bog, back-fire and it seems to even out in the mid-range and then seems to miss in the top end, maybe lean again. Seems to be running very lean, but the kit seem to be generally set to lean it out from prior stock jets/needle. Seems to me I need to go up in both my main back to at least stock 168, maybe higher to a 170 and a higher pilot jet from the stock pilot jet of a 45, not down to a 42 as is put in the kit, which would lean me out further in the low end, right?
Is there anyone out there specifically familiar with the bike that started it all? I know it will run strong all the way from low to high-end, as my 2000 WR did, but so far the kit seems to be off. I need someone that knows more about jetting than me. Thanks!
Edited by ColoradoXR, March 25, 2012 - 05:09 PM.