New stainless steel exhaust issues - idling too high

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parsasm
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New stainless steel exhaust issues - idling too high

Post by parsasm »

Hello,
i just bought a new stainless steel manifold, the previous one was covered in rust and packed with holes.
after fitting the new stainless steel downpipes, i attached my slip-on ART race can and the bike is idling between 2,500 - 3,000rpm. when I let the clutch out a little and hold it back in, it stays at 1,500 for 2-3 seconds and then jumps back up to 2,500 - 3,000.
the downpipe was made so that it didnt need tuning for any exhaust with a 51mm inner diameter bore. my Art race can fitted fine but it's still present with the problem.
any idea what i need to do? could it be my art can? if so, i can put the original zxr can on.
or could the engine need tuning to adjust to the new manifold?
thanks
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RedexRobB
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Re: New stainless steel exhaust issues - idling too high

Post by RedexRobB »

Where did the system come from?

Some systems can lean out the mixture which can cause the revs to rise. You could try and richen the mixture by the screw or put a bit of choke on just to see if it helps. but you need to get it on a dyno to get it spot on.

Choke is fully off isnt it?

I am assuming here that the only thing you have changed is the system.
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parsasm
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Re: New stainless steel exhaust issues - idling too high

Post by parsasm »

RedexRobB wrote:Where did the system come from?

Some systems can lean out the mixture which can cause the revs to rise. You could try and richen the mixture by the screw or put a bit of choke on just to see if it helps. but you need to get it on a dyno to get it spot on.

Choke is fully off isnt it?

I am assuming here that the only thing you have changed is the system.
this is what i bought : http://www.ebay.co.uk/itm/141042611663? ... 1423.l2649
choke is fully off yes.
unfortunately my bike knowledge is terrible. how do i richen the mixture?
also, is there any damage by riding the bike with its current mixture?
thanks
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RedexRobB
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Re: New stainless steel exhaust issues - idling too high

Post by RedexRobB »

Sandy bike spares. Quite a few here have used those systems from them and dont think theres ever been an issue.

You can put the choke on a tad to richen the mixture. If the revs settle then you know it could be the mixture running lean.
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parsasm
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Re: New stainless steel exhaust issues - idling too high

Post by parsasm »

RedexRobB wrote:Sandy bike spares. Quite a few here have used those systems from them and dont think theres ever been an issue.

You can put the choke on a tad to richen the mixture. If the revs settle then you know it could be the mixture running lean.
Okay, I'll give the choke a try, is it a bad idea to temporarily drive the bike as it is? It seems to have lost a fair bit of power when I drove it earlier.
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Re: New stainless steel exhaust issues - idling too high

Post by RedexRobB »

It can be, running lean can cause the engne to run hotter, so keep it to a minimum.
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Re: New stainless steel exhaust issues - idling too high

Post by banner001 »

it leaned out my bike when i fitted them, which was fine for me as my pilot system was rich before, so it semi-sorted that out.

you might find that you need larger main jets, or possibly some shims under your needle jets if you are finding that you have a loss in top-end power, as rob said most people report that it leans the system out.

have you tried to drop the idle speed with the idle speed adjuster - its a cable with a knurled end that sits just next to your coolant overflow bottle, turn it anticlockwise to drop your idle rpm and turn it clockwise to raise the rpm...this is only to drop your revs to a more manageable amount, i think you need to look at sorting out your fueling, so bigger mains and turn your pilot air adjusters clockwise (this richens the mix).
UK ZXR400 L3 (1993) - Fully restored and on the roads, my green beast!
JPN ZXR250 A2 (1990) - Revs to 19,200rpm... 'nuff said :smt003
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parsasm
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Re: New stainless steel exhaust issues - idling too high

Post by parsasm »

I removed the art can and installed the original, and that resolved the idling issue.
But after taking it for a test run, the same loss of power remains.
Something else I failed to mention before was a very fast metal rattling sound, this was present with my art end can and also the original, I can't really tell where it's comin from where I'm driving, it sounds more like infront of the tank making the rattling metal sound.
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parsasm
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Re: New stainless steel exhaust issues - idling too high

Post by parsasm »

Took it to the garage today, the mechanic suggested that the rattling tin sound is simply the sound of air flowing through the stainless steel pipes. Because the metal is allot thinner? Does this sound correct?
It seems I will still need some tuning done to my engine. On the way to the garage, I had to turn the idle up an down 3-4 times. One moment revs hang at 2,500, so I turn it down to 1,500, then 5 minutes late it's too low at 500rpm, so I have to turn it back up to 1,500, and then repeat (goes to 2,500) again.
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Re: New stainless steel exhaust issues - idling too high

Post by JulianWerner »

I am thinking about buying Sandy Spare pipes.
Have you figured it out? if you have.
Was it the mixture? something else you had to do?
Is rejetting necessery? :excited

I have opened and closed the carbs on my zxr one to many times.. oldman

Thanks in advance :)
* Aprilia RS 125 (2000 modell / 2 Stroke)
* Kawasaki ZXR 400 (1991 / 4 Stroke)
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parsasm
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Re: New stainless steel exhaust issues - idling too high

Post by parsasm »

JulianWerner wrote:I am thinking about buying Sandy Spare pipes.
Have you figured it out? if you have.
Was it the mixture? something else you had to do?
Is rejetting necessery? :excited

I have opened and closed the carbs on my zxr one to many times.. oldman

Thanks in advance :)
depending on your end-can, you may not be able to use an aftermarket one without rejetting. I called up a few garages to see how much it would cost for some engine tuning, and the current quote is £300, so i'm avoiding that.
ive stuck the original end-can on my zxr for the time being, its running fine, the downpipes are making allot of rattling and hooting (literally like an owl). but i think that may be to improper fitting, so im going to refit it myself this friday and hopefully that sorts it out.
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Re: New stainless steel exhaust issues - idling too high

Post by banner001 »

a re-jet, and engine tuning are two COMPLETELY different things.

to get your downpipes and can sorted is gonna cost you £30 max.
UK ZXR400 L3 (1993) - Fully restored and on the roads, my green beast!
JPN ZXR250 A2 (1990) - Revs to 19,200rpm... 'nuff said :smt003
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Re: New stainless steel exhaust issues - idling too high

Post by JulianWerner »

Hi banner,

why the 30 .- ? For a tool or jets ?
The carbs on my bike i bought from ebay (second hand) because the old ones was cracked.
I dont know what size main jets i have, and the small jets is completly stuck ..

So if i buy pipes and can, would i have a problem ? ..
* Aprilia RS 125 (2000 modell / 2 Stroke)
* Kawasaki ZXR 400 (1991 / 4 Stroke)
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banner001
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Re: New stainless steel exhaust issues - idling too high

Post by banner001 »

JulianWerner wrote:Hi banner,

why the 30 .- ? For a tool or jets ?
The carbs on my bike i bought from ebay (second hand) because the old ones was cracked.
I dont know what size main jets i have, and the small jets is completly stuck ..

So if i buy pipes and can, would i have a problem ? ..
any time you touch anything to do with fuel/exhaust, you should expect to have to do 2 things, alter the jetting and balance the carbs.

£30 is what it should cost you to sort out the jetting after you use a new set of downpipes and/or can. and yes, this money is for new main jets and possibly some shims for the needle.
UK ZXR400 L3 (1993) - Fully restored and on the roads, my green beast!
JPN ZXR250 A2 (1990) - Revs to 19,200rpm... 'nuff said :smt003
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Re: New stainless steel exhaust issues - idling too high

Post by ross46 »

£30 is as banner said MAX thats 3 sets of DJ mains and about a million shims :pmsl the small jet your on about should never have to be changed, they are a pain to get out anyway, I had to grind an old screwdriver to make it perfect to get them out, try using the choke to see if you need larger jets, or taping up the airbox
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