help with power delay

hi all,i got my z500b v reg with 22.000 miles on the clock a few weeks ago.i am chuffed to bits with the condition of it and it runs like a dream.its all standard apart from the 4 into 1 motad pipe.tonite i went out for a spin with a next door neighbour(hes got a kawa er5),we swapped bikes for a while and upon swapping back he told me he loved the bike,but found that with a fast sharp turn of the throttle the power gave a little dive then picked up angain and was fine.i tried it a right anuff it does it.this only happens if ur hard on the throttle.in idle the bike revs up fine.now im not sure when the last time the plugs,oil,oil filter and air filter were changed.i really hope this isnt something serious and that its something i can sort out myself.i would appreciate so much some advice and help on fixing this wat i hope is a little problem.normal driving and the bike rides fine its only when ur driving along and ur sharp on the throttle,its a half second the power dips then bites back up again and is fine.is there anything i can try to see if it fixes this.many thanks.

kevin
aberdeen scotland

have you tuned it up lately?

nope i not long bought it,i havent tunned anything up.im also a bit of a novice with bike engines,i have done some little jobs,ie cleaning all cables and lubing,copper greassing screws and bolts,fill brake fluid levels,thats all ive done.

kevin

Not sure what a "motad" exhaust is, but if it allows better scavaging than does the stock pipes, it is possible your air:fuel mix is slightly lean. Since you are a novice, try adjusting the air or pilot mixture screws to richen the idle mixture slightly. It would probably be better to raise the jet needles, a notch by reclipping, if you are up to it. What type carbs are on this model... not familiar with it.

hi mate,thanks for the reply.its just the standard cards on the bike,ill take a look at the name today and let u know the exact make.yea the motad pipe is an after market 4 into 1 pipe thats very popular over here on these bikes,they do sound nice.it was on the bike when i bought it from the garage,so i thought it might have all been setup.i checked the air filter the other day and its in a shocking state.its past cleaning,its black.by looking at the plugs its easy to see that they been in there a good long while as i supose has the oil filter and oil.tommorow i am going to the garage to get new plugs,oil,oil filter and air filter insert.do you think this might help or the air filter being totaly filthy.i just wonder if all this would help.if not ill try ur method of adjusting the screw to make it a bit richer.ill let u know that carb makes ok bud,thanks again,much appreciated.

kevin
aberdeen scotland

yeah if filter is that nasty i would guess it is probably running rich and fouling plugs.an airfilter and tuneup will definately help;)

If that's a 79 to early 1980's Z500, it should have the Teikei (TK) 22mm carbs. Those are not CV carbs so if you wrench it wide open, there will be a stumble. Those type of carbs need the throttle rolled smoothly, otherwise the intake velocity drops too low. Proper jetting can really reduce the problem, but nothing will make it so you can instantly crack it wide at low RPMs.

It's the same on all of the 81 gpz and KZ 550's I've ridden using the TK22's. I would imagine it would be worse on the Z500 with the smaller motor.

Post edited by: loudhvx, at: 2007/05/24 03:33

I used ot have that same step-up power jump but now I know what it is. My clutch now slips above 5000 on the 650 and I cant go over hills as fast as I would like. So I would also check the clutch on your ride. I have a question to ask you guys in engine forum!