First of all, an 88 jet has about 20% less surface area than a 98, meaning it will flow about 20% less fuel. Use the formula pi times radius squared to find the area. The 98 jets are less than 1% smaller than the 100s. You might want to check the existing 100 jets with the shank of a 1mm drill bit to see if they have been drilled larger than the marked size. Was the stock air filter element new?
I don't know where that 1.2% figure came from, but that hasn't been my experience. I've ridden my Honda over Monarch Pass (11,312 feet) and Independence Pass (12,095 feet) in Colorado with no changes from the Sea level jetting, and the guys I was riding with, two Honda CBXs and a Kawasaki 750 twin, never had to re-jet either.
Check reply 27 here:
http://forums.sohc4.net/index.php/topic,195383.25.html
Gotcha. I got the 1.2% per 1000 feet elevation from Hondaman.
"For altitude: for bikes with per-cylinder CCs of under 200cc you can use 1.2% per thousand feet altitude and get real close. The 750 has always been on the borderline where 1.0% applies, due to the larger cylinders. When the cylinders get bigger the precision drops off due to volumetric inefficiency. Smaller ones are often affected more-per-thousand-feet when jetting is "off"."
I figured it would apply to the jet size, not the jet's surface area. But that would still put me around 92 or 93 (without actually doing the math) -- and there is no jet close to that either.
The air filter element is new. I can check the hole in the jet to verify (and there is also the fact that the orings aren't sealing so potentially letting in more gas). What I don't want to do is get 98 jets and have it run the same. Unless anyone has anything different, though, it's either 98 or 80 if I want Keihin jets.
I'm open to experimenting a little -- pulling out the air filter, etc., and riding around a little. But that's not a long-term solution -- unless I can come up with some kind of higher flowing filter set up.
I rode the bike the day before with the pods set up, ran just fine. And with the airbox the plugs were fouled when I pulled them. That being said, and reading the post you sent, I was riding in traffic and sitting at lights, etc. So if at idle it was super rich maybe that was enough to foul the plugs and make it not respond at higher revs. I can lean out the idle mixture and try again.
I'm still baffled, though, that if a 98 is a stock jet that Keihin wouldn't have anything close-but-smaller.
I'm also going to Columbus, OH, next week and figured I could buy stuff and get it shipped to my hotel. I'm getting a few other things for the bike while I am there as well, and wanted to try rejetting. I could leave the airbox on and just not ride it for a few days as opposed to taking off the airbox, putting the pods back on, then putting the airbox on right away again to try new jets.
And, of course, in the back of my mind is the fact that it ran and pulled fine before...
