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You're welcome SK They probably have better stuff than the High density foam but my rear is very happy with it and we gotta think of the budget.Hopefully you can get it there for a good price. Think the bit i got was about $30 metre but i needed bugger all.
I have had the same K & N air filter (white cotton) for near 20 years and it has worked perfectly for the ZR. They should work better than standard.
Exactly the same symptoms as original carbs ?
Do your carbs have return cable ? And throttle grip opens and returns smoothly.

No eBay APP ID and/or Cert ID defined in Kunena configurationHmm yea i know the K&N's are meant to be pretty much stock replacement just with a bit more flow, this filter seems to be a UNI 2 stage one though it looks identical to this:



Im hoping its just a really high flowing air filter that PO put on without realising as a replacement or perhaps because he had carb issues and didnt fix them and hoped a higher flowing filter would balance it out or something? if a £8 stock air filter fixes it then i'd be happy with that, fingers crossed never know.

I got round to checking the timing today, seems pretty spot on, the 'f' mark was maybe 1mm in front of the static mark though, would that make any difference? It advanced as normal to the double line mark at 3500 rpm though which all seems correct.

ZR: theres no throttle return cable, throttle is working all smoothly and the problem is pretty much exactly the same as it was before just a bit better, the bike is a bit more rideable now but still no go over 6k or so.

Edit: I just had a thought, could it be that the air filter is to blame?! I just did an eBay search for a filter and the one I have in my bike looks like it could be an aftermarket high flow one, could be on to something here!

Hmm yea i know the K&N's are meant to be pretty much stock replacement just with a bit more flow, this filter seems to be a UNI 2 stage one though it looks identical to this:



Im hoping its just a really high flowing air filter that PO put on without realising as a replacement or perhaps because he had carb issues and didnt fix them and hoped a higher flowing filter would balance it out or something? if a £8 stock air filter fixes it then i'd be happy with that, fingers crossed never know.

Could well be the problem. Uni recommend re jetting. Unis should be oiled. If yours is dry then it will flow even more air
Higher air flow - you feel it is lean - causing hanging idle and running out of gas at 6k rpm. That would make sense.

I remember a few years ago there was a new member here with lots of carb problems until he looked in the air box and found the previous owner had replaced the air filter with an old shirt. Swapping the shirt for a stock filter pretty much resolved all problems.

Please let us know how the new stock type air filter goes. If you have backed out the mixture screws to 4 turns out you may have to put them back a tad.

Good luck

SK the UNI filter looks very different to the K & N .K&N are about $60 also.The cotton is much better than my old stock black foam one.See how you go with your standard filter.

JR had crossed my mind but wasnt sure
shirts arent real good filters

As to the lack of performance beyond 6000 rpm, would also assure that the ignition is producing fat blue sparks on the plugs, by visually examining the spark on removed plugs while spinning over the engine.

Assure that the correct factory-recommended spark plugs are installed, such as NGKB8ES and NOT "R" resistor style plugs such as NGKBR8ES. Brand new plugs are preferable. And that solid core plug wires -- NOT "resistor style plug wires -- are fitted. And that the spark plug caps have not developed abnormally high resistance. It's okay to fit caps having zero resistance, such as the caps built in on Dyna solid core spark plug wires.

Old plug wires can leak voltage from being cracked and worn, thereby weakening the spark.

If not already done, would perform the spray water-mist test onto exhaust header pipes shortly after starting the stone-cold engine to assure that combustion is occurring in every cylinder.
The spray should instantly vaporize as it sizzles off the hot exhaust header pipe, which evidences combustion within the cylinder.
If the water spray just runs down the pipe without instant sizzle, there's lack of combustion in the cylinder.

(Apologies for what may have already been covered.)

Good Fortune!

Haha there's newbieness and then there's just plain idiocy, Wtf was the guy thinking using a shirt instead of a proper filter?! I know times are hard but its got to be one of the cheapest simplest bits to replace lol.

And yea your right JR I forgot that aftermarket filters have to be oiled, this one is bone dry! So like you say gonna be letting loads of air through most likely I'm really looking forward to getting the stock filter through and seeing how the bike runs over 6k now, I'll be gutted if it doesn't work though!

Thanks for the extra electrical info Patton I'll have a look into all that gumpf if the filter doesn't work, let's hope I don't have to though

ZR I had a k&n on my CBR, it was definately higher flowing than the stock on that and the Honda didn't much like it, made it run a bit lean, shame cos would of saved me loads in filters! My mates got one on his Ninja though and it runs fine so guess it just depends on the bike?!
Pretty cool that you've had yours for twenty years that's value for money!

What do the KZ's run like with K&N's then? I might look into getting one next time I need a filter change if they are ok.

SK You cant be far off solving that problem,
K&N say the filters are supposed to be good for 500,000 miles and are a lot better made than original.
Filter cant be far away mate .

Sure hope so mate!
I put some lower trail style bars on it today, handles a lot better now

500, 000 miles, that will do a few bike lifetimes i imagine, I'll probably invest in one once this stock one has worn out.
Should get the filter tomorrow so will post up if it sorts it or not.

Any sign of your new filter SK ?

I have my 2nd K&N on my Z1. The last one I left out in the weather. I cleaned it up but bought a new one after a few hundred miles. No problems.
Steve

They are an excellent upgrade to the standard - my original frame is plastic and the crappy black foam just fell to pieces.Roughly twice the price but well worth it.Are they about $50 there Steve ?