83 GPZ305 won't rev past 7000RPM??????

I have done a lot of stuff to this bike trying to get it to run good. I've got it running waaay better but it has always not revved past 7000. This is the 2nd set of original carbs I have boiled out and no change in the no rev past 7000. Today I swapped the coils out from my parts bike and no change. I adjusted the valves to spec, checked float level, checked the battery with a volt meter and revved it sky high and it went up to about 13.35. In gear I can hold it wide open and it gets to 10,000 but cuts in and out. If I ride it and go wide open, it falls on its face just past 7000 but will stay running. I have brand new plugs, wires, and NGK boots. Also replaced the intake boots. It has the stock air box on it but someone has made their own filters and put in the stock cages. It looks like upholstery foam. It starts up and idles great. If I was just old man riding it, it would be fine but wanting to get it right. These bikes are extreamly lean stock so I did some carb mods that I read in a Cycle World mag from 1983. I shimmed the needles with a #6 washer and drilled out the pilot jet to a .0135. After I did this the bike starts easier and no more hesitation off idle. I tried one last thing before putting it in the garage, I drilled the main jet from a 135 to a 140. No noticeable change. Does anyone have any ideas? My thinking is its the carb jetting but I would not swear to it. I pulled the plugs and the strap looks white but the ring is lightly black. HELP!

" In gear I can hold it wide open and it gets to 10,000 but cuts in and out."

Is this with the bike sitting still with no load? If so, that is really hard on the engine and can cause serious problems. Also, what's the redline? Ed

Redline starts at 11,000 and goes to 13,000

If that really is furniture foam in the air box, I'd be concerned that it does not flow enough air. Maybe all it needs is a stock filter. Have you checked the ignition advanced to be sure it works properly?

I might add that it is NOT a vacuum petcock. Just a single outlet. No vacuum connections.

i"m with texaskz,suspicious of the mystery foam.

leon

Well, for any engine to run properly, it requires 3 things: fuel, air and spark. You will have to work on each item separately. Since you already know the filter is non-stock, I would replace that first. Second, I would acquire some real main jets, and not use ones that were drilled out. That should get you started down the road to correcting the issue(s).

HAFROD wrote: I might add that it is NOT a vacuum petcock. Just a single outlet. No vacuum connections.

Not an issue, as long as you cap the vacuum nipple on the carb.

Called my local Kawasaki dealer today for the filters. They are discontinued. Now what?

Try z1 enterprises for a new filter

www.denniskirk.com/301500.sku?utm_source...Hgsr0CFRFp7Aod3HMApg

leon

HAFROD wrote: Called my local Kawasaki dealer today for the filters. They are discontinued. Now what?

Easy answer - go to a Kawasaki dealer that wants your business rather than the butthead that told you they are discontinued. According to Kawasaki.com the filter element is still available (see image below). Partzilla.com lists them at $3.25 each (it takes 2) (see link). That's probably why the dealer didn't want to order them - he couldn't make $100 on them. Ed
www.partzilla.com/search/?q=11013-1072&x=6&y=12