ZX7 motor won't go from midrange to high end
#1
ZX7 motor won't go from midrange to high end
Hi*everyone I'm new to the forum and am new to the motorcycle engine world. The reason I am here today is I took on a part of a crew guy in the exciting world of racing. But not the kind of racing you may think of. My friend races in the "Lucas-Oil Can-Am Midget Series". They are 3/4 scale usac sprint car. They ran either Suzuki or Kawasaki which my friend is running. He has a ZX7 "superstock" motor (cam, springs, port, polish) we r having a hard time getting it to even pull from 5500rpm-10000rpm. Its like it hits a wall in power and sputters. He said if he kinda pedaled it it would maybe hit 11000rpm. Or if he would let off 100% pedal and then 100% on it would kinda act like he was peddling it and reach a little higher in the rpm. His wideband is saying he is rich under full throttle but he noticed spikes of a lean condition under caution or lower rpm. We r curious if anyone here may have a good baseline for a carb setup? Jets, needles, floats, a/f ratio screws. Some other side notes is he's running 112 octane, dyna2000 ignition. We also noticed when changing needle clips that one of the slide things the needles go into had 1 holes where the other 3 had 3 holes. Obviously we think that's one problem it should be either all 4 the same or 2 different like the stock jetting. I believe he is running 130 and 132 dynojets. And needle clips are all the way at the top. Would that be 1 or 5 on clips? All these symptoms only happen under load. Revs hard and strong in neutral. He also think his battery might be going. But would that have anything to do with it? Only thing that points maybe that way is cause it progressively got worst over the night but not a huge difference it pulled like garbage all night. We went from clip 3 to the top and he said it felt better and in my eyes as a spectator it did byt it still sputtered and ran no where even close to its potential. Sorry for the novel I hope you guys can help us :-)
Last edited by chipskey; 05-12-2013 at 08:04 PM.
#2
What year of the zx7 engine? Superstock can run ported and modified heads?
I have not played with the mini's or whatever they are called. Legends I think around here. My first thought was also of the charging system and battery with the cut out.
Welcome to KF. May we get some pics of the ride???? lol
I have not played with the mini's or whatever they are called. Legends I think around here. My first thought was also of the charging system and battery with the cut out.
Welcome to KF. May we get some pics of the ride???? lol
#6
I was at the dirt track last year and they were running the gokart rides and the rides like that. I was not sure on what name they went with. The legends are the older car mini's that I was thinking of. Like a '37 ford look but made to fit. lol
Thanks for the pic, that looks like a helluva time.
Thanks for the pic, that looks like a helluva time.
#8
I know what a shifter kart is. I ran the centrifugal clutch stuff classes on paved track. Emmick, Rotax and Parilla. I just never evolved beyond that due to the price tags to keep me sane from my other addiction of tracking my rides. (I could afford the kart tires and not motorcycle tires and gate fees)