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Discussion Starter · #1 ·
well thats what we call it in uk. ie to test main jetting richness, ride with on warmed up engine at full throttle for a minute or so (where legally possible of course;)) then kill engine and pull clutch and stop at roadside and check colour of plugs chocky brown being the aim.
so has anyone any tips for my j model zx6r. should i do this with lower right and left fairings removed? does tank need to be loosened to remove plugs?
will the fairings off affect anything?
do i have to check all 4 cylinders? will the middle two be a slightly different colour (or color as you americans spell)
any advice gratefully received. eg should i be going for top speed or as long as throttle is wide open through the gears by the time i get to150mph that would do?
thx
al
 

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I'm sorry mate, but that's the most retared thing I've ever heard. Do a lean idle drop and call it good. If you are still concerned, get the bike back to the house and check the plugs. No need to put yourself at risk by doing a roadside opperation. An EGA is really the best way to tune a bike but if that's not an option, set your pilot screws, sync the carbs, and then check the plugs after a couple days. No point in working on a hot bike either, if it can be avoided.


Cheers
 

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i heard the same thing as aljaxon and it seemed like a little much. im glad you gave me an alternative. i wasnt about to try that. especially with my bad luck with cops haha
 

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sounds like a bad idea to me... roadside plug check.

Just take your bike to a shop that will just put the exhaust gas analizer on it for you. Then make your adjustments and recheck with EGA.
 

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Discussion Starter · #5 ·
I'm sorry mate, but that's the most retared thing I've ever heard. Do a lean idle drop and call it good. If you are still concerned, get the bike back to the house and check the plugs. No need to put yourself at risk by doing a roadside opperation. An EGA is really the best way to tune a bike but if that's not an option, set your pilot screws, sync the carbs, and then check the plugs after a couple days. No point in working on a hot bike either, if it can be avoided.


Cheers
but its my main jet i want to check. i do most of my riding on half to full throttle. no risk there are a couple of deserted roads near me with nice roadside parking.
i dont want to go to a dealer. i want to do something myself. just to get the satisfaction.
whats a lean idle drop? i am in uk and never heard that term before.
as for it being retarded lol. and as for riding it back to the house well im not gonna get a true main jet reading am i. unless you want me to ride full throttle all the way home?
now thats retarded.:buzzsaw:
 

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but its my main jet i want to check. i do most of my riding on half to full throttle. no risk there are a couple of deserted roads near me with nice roadside parking.
i dont want to go to a dealer. i want to do something myself. just to get the satisfaction.
whats a lean idle drop? i am in uk and never heard that term before.
as for it being retarded lol. and as for riding it back to the house well im not gonna get a true main jet reading am i. unless you want me to ride full throttle all the way home?
now thats retarded.:buzzsaw:

A lean idle drop has nothing to do with Brits or Yanks. It is a factory recommended procedure to set low speed mixture screws.

A LID is where you set your idle to the factory recommended engine speed then slowly turn each pilot in until the idle drops 50rpm. Turn the idle up until you get back to recommended idle speed. Move to the next cylinder and repeat the process on all cylinders until the bike idles erratically. When the idle can no longer be raised with the idle speed screw, you turn every pilot screw out 1 full turn. Reset the idle one last time and you are done.

As for running you bike and checking your plugs road-side...DON'T DO IT HOMEBOY. It's pointless. Your plug "reading" is not going to change if you ride it home. Trust me on this.

BTW, could you tell me about what mods (if applicable) you are running. I'm a little curious as to why you are concerned about the main jet circuts.
 

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Discussion Starter · #8 ·
i have fitted a full race system akrapovich exhaust.
so lets say i'm running weak at full throttle but rich on pilot jets. by the time i get home, the last 3 miles in a 30/40mph limit wont this have masked the true reading.
i googled plug chop and it says to get a true reading you have to kill engine and pull clutch. back in the seventies i used to use a colourtune and also do plug chops on my 50cc sports moped. i didnt need to do plug chops on my rd350b cos the baffles used to go chocolate brown. and on later bikes i never bothered as they were standard.
the bike seems to slow down in acceleration as it gets over 150, ok i know its not a musclebike but ive just got a feeling it could do with a bit more richness.
would raising my needle affect full throttle or only at half throttle?

http://www.kawiforums.com/gallery/showphoto.php?photo=643&ppuser=29321
http://www.kawiforums.com/gallery/showphoto.php?photo=724&size=big&cat=
 

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Raising Needles

\the bike seems to slow down in acceleration as it gets over 150, ok i know its not a musclebike but ive just got a feeling it could do with a bit more richness.
would raising my needle affect full throttle or only at half throttle?

http://www.kawiforums.com/gallery/showphoto.php?photo=643&ppuser=29321
http://www.kawiforums.com/gallery/showphoto.php?photo=724&size=big&cat=

Raising the needles doesn't change wide open AF ratio, it just changes the transition points from the low speed circuits to the high speed/main jet circuits, ie mid range values. :)
 

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Raising the needles doesn't change wide open AF ratio, it just changes the transition points from the low speed circuits to the high speed/main jet circuits, ie mid range values. :)

Oh brother. That is very wrong. Raising the needle richens the mixture ACCROSS the entire main circuit range until the main jet needle is fully raised out of the needle jet.


And once again, about the throttle chop crap. NO your idle circuit is not going to change the color on the plugs by any detectable amount. You say you are doing a plug check to determine AFR. Checking the plugs is the LEAST accurate way to determine a bike's AFR. It IS however a good, quick method to check if a bike is GROSSLY rich or lean, or if it's in the neighborhood of stoich.


Damn, when are you noobs gonna listen. I have been a technician in the industry for 8 years. I have factory training on Japanese, Italian, British, and German motorcycles/watercraft/ATV's. I have tuned bikes in my garage (ghetto-style) and I have tuned bikes on Dynomometers with four gas analyzers and digital throttle body vacuum gauges.

Now you can disregard my advice and fuck your bike up and put yourself at risk, or listen to me, and do things the right way and maybe save yourself some time and money. The choice is yours, but contradicting me because of some BS you googled is only going to neutralize my willingness to help you in the future.

As for the setup, if ALL you have is an Akrapovich pipe, and no fuel management, there in lies you problem. A race system reduces back-pressure wich, in turn affects the torque curve drastically. It will also increase the VE of the engine and lean it out considerably. You will NEED a jet kit installed with that system.
 

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Well, Keihins is wrong also

Oh brother. That is very wrong. Raising the needle richens the mixture ACCROSS the entire main circuit range until the main jet needle is fully raised out of the needle jet.


And once again, about the throttle chop crap. NO your idle circuit is not going to change the color on the plugs by any detectable amount. You say you are doing a plug check to determine AFR. Checking the plugs is the LEAST accurate way to determine a bike's AFR. It IS however a good, quick method to check if a bike is GROSSLY rich or lean, or if it's in the neighborhood of stoich.


Damn, when are you noobs gonna listen. I have been a technician in the industry for 8 years. I have factory training on Japanese, Italian, British, and German motorcycles/watercraft/ATV's. I have tuned bikes in my garage (ghetto-style) and I have tuned bikes on Dynomometers with four gas analyzers and digital throttle body vacuum gauges.

Now you can disregard my advice and fuck your bike up and put yourself at risk, or listen to me, and do things the right way and maybe save yourself some time and money. The choice is yours, but contradicting me because of some BS you googled is only going to neutralize my willingness to help you in the future.

As for the setup, if ALL you have is an Akrapovich pipe, and no fuel management, there in lies you problem. A race system reduces back-pressure wich, in turn affects the torque curve drastically. It will also increase the VE of the engine and lean it out considerably. You will NEED a jet kit installed with that system.

http://www.keihin-us.com/tune1.htm :) If you have mains that are too small, they will still be too small at wide open. The above link is to Keihins tuning guide which tune the same as SU's, Zeniths, and Mikuni's
 

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http://www.keihin-us.com/tune1.htm :) If you have mains that are too small, they will still be too small at wide open. The above link is to Keihins tuning guide which tune the same as SU's, Zeniths, and Mikuni's
What point are you trying to make and how does it relate to the topic of this thread? The topic is killing the bike at high RPM to get a plug read. Yes if the mains are too small the bike will run lean and the inverse is true. We know that.

"Raising the needles doesn't change wide open AF ratio, it just changes the transition points from the low speed circuits to the high speed/main jet circuits, ie mid range values. "

Raising the needles DOES change WOT AFR's it just doen't change the AFR's when the main needle and slide are fully open. You can be at WOT at 5K RPM and if your needles are at say position 1 as opposed to position 4 on the clips, the AFR is certainlty going to be different between the two setting at the given engine speed/load.

My point is, interupting ignition at high RPM will stop spark but not fuel (in a carburetted bike). This unburned fuel can cause "cylinder wash" damaging pistons and rings leading to blow-by, blow-back, and carbon deposits in the combustion chamber.

If you are tuning a J-model/ZZR/ZX-6R in your garage, the best thing to do is set your base setting as described in your jet kit, then calculate air temp and altitude and adjust the mains as necessary.

To get any more finite than that, you are going to need a GAS ANALIZER and a DYNO. Plug readings are not going to get you even close or EVERY shop on the planet would do that and save the $30k for dynos and supporting emssions equipment.
 

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Discussion Starter · #13 · (Edited)
ok so i am at full throttle and have been for thirty seconds or so and then shut the throttle and pull the clutch at the same time and then 2 seconds later kill the ignition. negligible amounts of unburnt fuel. same as killing at idle.

i want to see the colour of my plugs and refer them to a chart just like at the back of haynes manuals.
i didnt want a lecture on the 'correct' way to tune a bike. i just wanted some advice on the best way to do this plug chop. ie would riding with the fairing off somehow alter results etc.
i didnt want to know the best way 'not' to do this.
thanks for your input anyway especially tough guy. who i am sure is nice and cuddly really.:eek:

my bike is a 2000 euro and my main jets are numbered different to some of the jet kits so wouldnt have a clue how many sizes i'd have gone up.
it would be nice to buy a bagfull of main jets and mess around.
and do roadside plug chops.:D
(to be honest its the flat out riding bit before the engine kill that i am really looking forward too)

at w.o.t how far is the needle away from the main jet hole? surely it will be all the way out so a 2 mm raisng wount affect this that much if its already out of the way.? i am only familiar with old mikuni throttle cable direct to throttle slide set up. this is my first bike with fancy carbs on.

now to google/ebay hand held gas analyzers
 

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Discussion Starter · #15 ·
thx for that loffen
time for me to read up on exactly a vacuum carb works or whatever the correct term is. to be honest the short amount of time i ride my bike once ive reached the deserted roads im not very often as low as 5k. ok maybe i am on the urban journey to get there, but im not really bothered about how it runs as i'm only doing 30-40mph. once on my fave roads im usually half to full throttle and above 7k (apart from some corners where i bottle it and almost have a closed throttle:eek:)
i dont even know what make carbs my zx6r j 2000 euro has fitted.:cool:
 

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ok so i am at full throttle and have been for thirty seconds or so and then shut the throttle and pull the clutch at the same time and then 2 seconds later kill the ignition. negligible amounts of unburnt fuel. same as killing at idle.

i want to see the colour of my plugs and refer them to a chart just like at the back of haynes manuals.
i didnt want a lecture on the 'correct' way to tune a bike. i just wanted some advice on the best way to do this plug chop. ie would riding with the fairing off somehow alter results etc.
i didnt want to know the best way 'not' to do this.
thanks for your input anyway especially tough guy. who i am sure is nice and cuddly really.:eek:

my bike is a 2000 euro and my main jets are numbered different to some of the jet kits so wouldnt have a clue how many sizes i'd have gone up.
it would be nice to buy a bagfull of main jets and mess around.
and do roadside plug chops.:D
(to be honest its the flat out riding bit before the engine kill that i am really looking forward too)

at w.o.t how far is the needle away from the main jet hole? surely it will be all the way out so a 2 mm raisng wount affect this that much if its already out of the way.? i am only familiar with old mikuni throttle cable direct to throttle slide set up. this is my first bike with fancy carbs on.

time for me to read up on exactly a vacuum carb works or whatever the correct term is.

now to google/ebay hand held gas analyzers
The carbs are called CV (constant Velocity) carbs, there is no such thing as a "hand-held gas analizer, and this thread is called the lamest noob post I've seen to-date.

You REALLY should not be working on your bike without a basic knowledge of how it operates, but that's not gonna stop you, is it? So good luck with that. I'm unsubscribing to this epic fail thread.
 

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Discussion Starter · #17 ·
the gospel according to tough guy.
and why shouldnt i work on my bike? how the hell am i supposed to learn?
i didnt have a clue how my old rd350b air cooled worked but eventually managed a roadside crankshaft swap in the middle of bodmin moor (hound of the baskervilles country)
i havent a clue how my carbs work but 5 mins studying diagrams will sort that out. im going to find out how they work when i strip them. only then do you get a good idea what its all about. surely you know that.
i wasnt really sure how the forks worked especially the damping but i dismantled them 2 months ago and now its no longer a mystery.

the three main jet kit manufacturers are all american. their products are designed for american bikes. mine is euro and different spec. for all i know the jets in the kits may be smaller than mine standard.
i do apologise for not knowing everything and wanting to have a tinker with my pride and joy.
maybe now the tough guy has disappeared i might get some friendly help and advice.
isnt this board all about seeking and finding help and for some offering help and advice.?
maybe tough guy is right but he is wrong the way he goes around being nasty.
he reminds me of my wife when she is premenstrual. actually thinking about it tough guy might be a woman. so sorry for any offence caused.
thx for the snippets of tech info inbetween the testosterone.
 

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man i bet tough guy has a huge penis. but anyways you should just get a jet kit and experiment with diff settings and jets. there really isnt a better way to really learn than by doing. and i bet you can find a cross-reference on the jets somewhere. good luck
 
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