Hey guys and gals, I'm new to the forum here and would like to get a bit of information on a good gear ratio to run for track. (I.E. teeth size, brand, o-ring or non o ring chain, 520, 525.?) Also I have a full black widow exhaust from the UK and was wondering if there was a certain brand of jet kit that will really make this bike scream. (I know some kits are better then others.) Any info? Thank you
I used to have the same bike (99 ZX7R) and remember seeing a mechanic work on Muzzy works racebike and he was using a dyno jet kit http://www.dynojet.com/pdf/2170.pdf I ended up getting this same kit because the needle flow is better than most with DJ. I also want to emphasize that the jetting skill and power output your bike gets is based on WHO YOU GET to jet/tune your bike (that is the variable). Some can jet tune better than others. I had my bike jetted 3 times by 3 different ppl and was amazed at how one person can get a totally different HP output number than the last (even with using the same type of dyno) so that's how I know its the person not the jet kit you buy. As for sprockets I used sunstar cuz they last. Also got a DID O-ring 520 chain and I only went down 1 tooth in the front and got the same toothed rear sprocket as stock but in 520. I kept stock rear size on purpose cuz I still wanted to have some top end. I also had a BMC race filter and Muzzy full ti-exhaust system.
After you go thru a bunch of DJ jetting arrangements, I think you'll find that bumping the stock mains a step or two, throwing a shim or two (maybe) under the stock needles, and bumping the pilot a bit will net you the best power delivery with a good pipe. Aftmkt air filters for that bike can be a pain as well. I've been down this road (a long time ago) with many different zx7's. The air jet "correctors" along with drilling and tapping those carbs is the devil. Just a tip. Try and keep it simple. The Muzzy Ti pipes work great on that bike, like KCLARK had.
I did a 92 ZX7 like 8 months back and it was not my favorite thing to do. I used a DJ kit for it and I fought with clip settings forever on it. I ended up getting it pulling nicely when it was fully warm but it ended up with the clip at position 1 and a couple shims. Make sure you get the appropriate kit. One model had khleins and one had mukunis.
All great information. Thank you much. I'll start looking into this DJ kit I need chains and sprockets first however. I know my bike is equipped with the Khlein flat sides though. But has anyone heard of that notorious "float Bowl mod" for the zx7? I tried reading up on it and it seems like everyone is doing some random ass shit to the carbs.
Oh, I forgot to mention. Make sure the float height is right. I just remembered the manual lists 3 different heights. I tried them all. The number that's in my head is 17mm but double check that. This bike and I had it out. You cant even adjust the damn mixture screw without removing the air box every time. And even then if I wanted an accurate count on the mixture screw I would flip the carb and make sure my turns were as exact as I could get them. And that damn fuel pump that only pumps under cranking and when there's load on it. Sheesh. After I did all that, fixed the brakes and made it a normal ride hieght, the bike was a blast. It had a muzzy full system on it and sounded awesome. Customer was super happy. Oh and then every single o-ring leaked after I got it running for longer than a few minutes so I had to disassemble the whole thing again and redo everything.
Do you have proper FCR carbs., or just the stock KH downdrafts that people call "flat-slides"? The stockers are regular diaphragm type carbs. FCR's are a manually operated throttle valve. There's a big difference. Only asking because you said you had "flat slide" carbs.
