KDX weird exhaust smell

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KDXrider1989
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KDX weird exhaust smell

Post by KDXrider1989 »

my bike has this weird metal-like exhaust smell, started happening a few weeks ago. I thought it was because I messed with the float valve, so I bought a new one and installed it and no difference. Current jetting is 45 pilot and 155 main, air screw 1.5 turns out and stock needle I believe in the 2nd from the top slot. Jetting has been the same for a while now. When I described this to someone at the dealership, they said that I need to be looking into a bottom-end rebuild soon :cry: on another note, my bike bogs when I give it a good amount of throttle from idle. I've heard mixed stuff, saying that I need to lean my main jet or richen my pilot jet. I've never done a plug-chop test to determine the correct main jet size, so I'm going to assume it's too rich? the bottom end might be bad, but I know the top end is in good shape, so would that also affect jetting?
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rbates9
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KDX weird exhaust smell

Post by rbates9 »

How do you "know" the top end is good? Have you been in there? A bad crank seal (from a worn out bottom end) will cause your jetting to be off.

I'm sorry, but I am not sure what you mean with a "metal like smell". Do you have another way to describe it?

You should probably look at the plug and do a jetting test to see where your at after you check the compression of course.
KDXrider1989
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Re: KDX weird exhaust smell

Post by KDXrider1989 »

Compression checks in @ 175 psi and if I look into the cylinder from the exhaust port and from the spark plug hole, the walls look good and the piston dome and skirt look fine. And as far as the metal-like smell goes, it smells like new exhaust, brand new metal being heated. It definitely does not smell like a 2-stroke. Antifreeze level is fine and transmission oil level hasn't dropped
newbbewb
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Re: KDX weird exhaust smell

Post by newbbewb »

I know *exactly* what that smell your talking about. Anybody here thats has a new exhaust system installed on a car will know. On a 2t though, ive never smelled that. Maybe your muffler packing? You need to give us more info....maintenance, mods.... I'm curious, what oil mix, brand are you running?

Edit.... That smell your talking about is the aluminized coating burning off of the interior piping, for an automobile.
93 kdx200-Highly modified
89 kx125/kdx200E engine
Buelldustin@gmail.com
KDXrider1989
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Re: KDX weird exhaust smell

Post by KDXrider1989 »

uni air filter, boyesen power reeds, ngk spark plug, fmf full exhaust, thats pretty much it. Im running castor 927 at 32:1 at the moment, the bike also smokes quite a bit. I also run the mixture in my CR and it doesnt smell nearly as bad
newbbewb
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Re: KDX weird exhaust smell

Post by newbbewb »

I've no advice to offer except maybe 32:1 is rather rich, maybe it's built up in the muffler?

A number of things can mimic rich jetting...temp change, elevation change, dirty air filter, bad reeds, low compression, bad crank seals, plugged muffler....

Have you by chance looked at the plastic reed cage?
93 kdx200-Highly modified
89 kx125/kdx200E engine
Buelldustin@gmail.com
KDXrider1989
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Re: KDX weird exhaust smell

Post by KDXrider1989 »

I've installed boyesen power reeds last year that are still completely sealed. Engine doesn't make any weird noises, so I don't think it's the crank bearings? Maybe it's the Castor 927 that just smells funny, have you ever tried it in your bike?
newbbewb
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Re: KDX weird exhaust smell

Post by newbbewb »

I have, quite a bit. At 40:1 with 927, there was an alarming amount of buildup in the kips valves so i stopped running it. I don't have much experience with bottom end on a 2t, but i've felt them get real stiff on the kick when they start to seize(can also be the top end) , and it will generally make a god awful racket. Doesn't sound like your issues. However, i think it would be much cheaper to not have it completely fail. If this was my bike, i would be inclined to dig into it before riding.

Does it get harder to kick after it's warm?
93 kdx200-Highly modified
89 kx125/kdx200E engine
Buelldustin@gmail.com
KDXrider1989
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Re: KDX weird exhaust smell

Post by KDXrider1989 »

nope, its just as easy to kick over as the day I got the bike. However, when I went to drain the oil earlier today I found some very small metal shards in the oil, smaller than glitter. I guess that's a tattle-tale sign that my KDX is due for a rebuild :sad: and also I replaced my countershaft seal for the 4th time, along with the collar and the 2 o-rings behind it and it's still leaking, so I guess that's a sign that the bearings are out of service limit
newbbewb
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KDX weird exhaust smell

Post by newbbewb »

Just thinking... unless you had a bad crank seal, which can mimic rich condition(excessive smoke), the transmission fluid should have nothing to do with it. Every time i drain my fluid, there is a bit of glitter in it. If the level in your side sight glass is dropping, i'd say crank seal. If not, well....your trans fluid has nothing to do with the bottom end on a 2t if i'm not mistaken.

Maybe someone else can chime in here. I'm not trying to lead you down the wrong path...
93 kdx200-Highly modified
89 kx125/kdx200E engine
Buelldustin@gmail.com
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