Engine knock or growl

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Griffbones
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Engine knock or growl

Post by Griffbones »

I just picked up a 2006 KDX200, I notice at idle this thing really growls, or maybe it is better described as a knock. If I gradually bring up the rpm's with the throttle, then when I hit a certain RPM it quits making noise just like someone flipped a switch. I tried this several times, and every time it quits at a certain rpm.

I have pulled the pipe, the piston looks great and so does what I can see of the cylinder. Compression test showed 180 psi. It was a one owner bike, owned and ridden by a 40 + year old dad following his kids around, never raced and supposedly not ridden hard.

I have not been able to ride the bike yet due to my work schedule and it has been raining everyday. I can say that the bike starts up first kick, and other than this noise seems fine.

Could this be the famous KIPS rattle that I have been reading about on this site? It just seems weird because it sounds more like a growly kinda knock rather than a metallic rattle. My son's KX 85 (103cc stroker) has the KIPS system and it doesn't sound anything like this bike.

I hope this is nothing to worry about, but I will admit that I am a worrier!
'83 CR60R Fully restored
'97 DR350 (407cc)
2005 KX85 (103.5cc)
2006 KDX 200 (Bone stock other than Jetting, Gnarley woods, Turbine Core II)
2007 250 XC-W (SX head)
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Indawoods
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Post by Indawoods »

That's the KIPS! All very normal..... If it doesn't rattle and sound like a jar of marbles... then you got something to worry about! :lol:
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TWMOODY
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Post by TWMOODY »

How did you do your compression test ?
180 seems unreasonably high ?
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Post by OLHILLBILLY »

>|<>QBB<
TWMOODY wrote:How did you do your compression test ?
180 seems unreasonably high ?
+1
Manual says 95 to 151psi on a 200. Mine blew 150psi, motor warm. Probably not an issue, but does sound kinda high.

Now, while it's raining and you can't ride it. Is the bike stock, with stock jetting? If so, it's horribly rich, so getting the bike jetted properly needs to be your first order of business.
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Post by kdxmaniac »

on my 96 it has 165psi cold.... this is in s.c.... i dont know why its that high? my ktm 300 has 165, and my ktm 380 has 185.
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Post by Griffbones »

Compression test was performed on a cold engine, clean air filter, throttle wide open, holding the kill switch down and giving it 20 good solid kicks.

My '07 250XC-W KTM with an SX head installed blew 195 on a fresh top end and that seemed to be right in line with what other KTM owners were claiming after installing the SX head, so I don't think my tester is off that far. Also, my sons 103cc stroker blew 190 on this gauge a couple of years ago, (160 psi on a stock engine) and at that time I tested the gauge against a known good Snap-on brand gauge. The two gauges matched exactly. Looking through the spark plug hole, the piston doesn't look carbon-ed up on top, so I don't know why it would read higher than normal. Not saying my gauge couldn't have just gone flaky, but I don't thing so.

Inspection of the piston through the exhaust port revealed no marks what so ever on the piston skirt, and the intake side of the cylinder walls appear to still have lots of cross hatching.

I went through my jet box and of course had everything bigger and smaller than what I needed, so I have ordered some jets. I can tell it has been running very rich. I am planning on starting out by dropping the stock pilot down one size to a 45 and the main down two sizes to a 155 and lean the needle one clip. I will have to see how it runs and fine tune from there.

The bike does have a Gnarly Woods pipe and a Turbine Core 2 silencer, but the air box lid is intact and no other mods have been made. The previous owner gave me a brand new set of Boysen two stage reeds still in the pack. I am not sure if I will bother putting them in, as I have used these same reeds in the past and never really noticed any big gain out of them.

I have been riding and wrenching on bikes for well over 30 years, but still find new things to learn! I'm a 46 year old dad/woods rider just setting-up this KDX to be my 14 year old son's next trail bike. When I get the bike done I will try to post up a picture.

Basically I just had to ask some questions about the noise this engine makes, seems kind of noisey compared to our other bikes, but seems like it must be normal for a KDX 200. :grin:

Thanks for the input fellas :razz:
Last edited by Griffbones on 11:11 pm Jun 13 2010, edited 1 time in total.
'83 CR60R Fully restored
'97 DR350 (407cc)
2005 KX85 (103.5cc)
2006 KDX 200 (Bone stock other than Jetting, Gnarley woods, Turbine Core II)
2007 250 XC-W (SX head)
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Post by Indawoods »

You will probably end up at 42 and 152.... just sayin'.....
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"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
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Post by Griffbones »

>|<>QBB<
Indawoods wrote:You will probably end up at 42 and 152.... just sayin'.....
Cool, thanks for the heads up.

I guess I always tend to go a little at a time, I'm always scared of getting too lean. By the way the bike sounded and by how the pipe and silencer looked when I cleaned them up it was just a guess at a 45/155.
'83 CR60R Fully restored
'97 DR350 (407cc)
2005 KX85 (103.5cc)
2006 KDX 200 (Bone stock other than Jetting, Gnarley woods, Turbine Core II)
2007 250 XC-W (SX head)
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Indawoods
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Post by Indawoods »

That's where I tell everyone to start on a 200... 45/155 is a great starting point. I think a 40 pilot is pushing it.... I have gone down as low as a 148 main but it's not good when your WFO! :mrgreen:
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****'95 KDX 200/****

"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
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Griffbones
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Post by Griffbones »

>|<>QBB<
Indawoods wrote:You will probably end up at 42 and 152.... just sayin'.....
Indawoods,
With the 42/152 combo do you run the needle in the 2nd or 3rd clip? Just wondering if 2nd clip with a 42 pilot will be a little bit boggy?

If my parts ever get here from Motosport, I will stick in the 45/155 and put the needle in the 2nd clip and give it a try. I do have a 42 pilot on hand but not a 152 main.

Thanks, Duane
'83 CR60R Fully restored
'97 DR350 (407cc)
2005 KX85 (103.5cc)
2006 KDX 200 (Bone stock other than Jetting, Gnarley woods, Turbine Core II)
2007 250 XC-W (SX head)
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Post by fuzzy »

Also, run a full quart of oil in the trans....Helps with typical clutch noise as well....the other thing that makes noise besided the KIPS.
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Post by Julien D »

Wish there was one for an E bike!

I have what I think is an H series basket out in the garage. When I got my bike it was installed. Took some investigation to figure out that the grinding noise when slowly pushing the kickstart down was that basket rubbing on the edge of the main gear. I think if one could fashion a spacer between the basket and the ring gear it would work. My E series basket has an angle at the bottom edge of the basket that clears the main gear, the other basket I have does not have such an angle, so it interferes with with the main gear on the end of the crank.

Again, I THINK it's an H series basket, but could be kx125 or something....
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Post by OLHILLBILLY »

>|<>QBB<
Indawoods wrote:That's where I tell everyone to start on a 200... 45/155 is a great starting point. I think a 40 pilot is pushing it.... I have gone down as low as a 148 main but it's not good when your WFO! :mrgreen:
FWIW.. I've used a 40/152, needle second notch from the top, A/S out 1.5-2 turns, for a year or more now, and it runs great. 40:1, 91 octane pump gas at 90-1200 ft altitude, FMF Gnarly Woods and PC2 silencer, still seems a little bit rich. Slight amount of spooge, turns the plug black, though it's never fouled one (yet.. knock on wood).
2004 KDX 200.. Coupla mods
2009 KX250F.. Track Star
2007 Hayabusa.. Street Madness
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