Rattle at speed under load (not KIPS?)
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Rattle at speed under load (not KIPS?)
This is my first real post here after reading a lot. I have a fairly new to me 1993 kdx200 that I have been going through. It is clear the maintenance has been neglected, so Ive flushed coolant, changed trans oil, semi-straightened brake rotors, replaced bars/adaptors/grips, muffler packing, countershaft seal, front sprocket, and a couple other small things here and there.
I am fairly competent fixing bikes and I'm mechanically inclined. It starts right up first kick and runs great.
It sounds healthy at idle (rattly at idle as they usually are) but when I get up into 5th and 6th gear under load, theres a knocking sound that it makes. I cant tell if its top end or bottom end (as i was going 40-50mph on the road at night and didn't want to take my eyes off the road).
Im not sure of when the top end was last done, if ever. It doesnt seem to have a TON of hours on it, given I can tell its definitely been ridden by the wear on the frame. The odometer was broken at 59mi, so ill never know.
Could this knocking be carbon deposits on the piston? Or would this knocking be the common kips rattle and I just didn't realize it would sound like this?
I havent pulled the kips cover off. is there any fluid in there or is it dry? im not yet sure how the kips system works.
Thanks for any help, it is greatly appreciated. If i can figure out how, Ill attach some photos so you can see the patient.
I am fairly competent fixing bikes and I'm mechanically inclined. It starts right up first kick and runs great.
It sounds healthy at idle (rattly at idle as they usually are) but when I get up into 5th and 6th gear under load, theres a knocking sound that it makes. I cant tell if its top end or bottom end (as i was going 40-50mph on the road at night and didn't want to take my eyes off the road).
Im not sure of when the top end was last done, if ever. It doesnt seem to have a TON of hours on it, given I can tell its definitely been ridden by the wear on the frame. The odometer was broken at 59mi, so ill never know.
Could this knocking be carbon deposits on the piston? Or would this knocking be the common kips rattle and I just didn't realize it would sound like this?
I havent pulled the kips cover off. is there any fluid in there or is it dry? im not yet sure how the kips system works.
Thanks for any help, it is greatly appreciated. If i can figure out how, Ill attach some photos so you can see the patient.
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Re: Rattle at speed under load (not KIPS?)
The KIPS can be pretty noisy. Are you sure it's got some nice high octane fuel in it? If you're hearing genuine pinging from detonation then you'll want to avoid riding it until you get it figured out so you don't damage anything.
'00 KDX 220R
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Re: Rattle at speed under load (not KIPS?)
I am running MO gas from the airport. Not sure of octane. I can try running avgas (100 low lead) if you think that would be better? Whats the standard octane for these bikes?Slick_Nick wrote: ↑09:24 am May 30 2021 The KIPS can be pretty noisy. Are you sure it's got some nice high octane fuel in it? If you're hearing genuine pinging from detonation then you'll want to avoid riding it until you get it figured out so you don't damage anything.
the sound seems to really come on when i load the bike at a higher speed and the rpm are coming up slower (because of being in a higher gear) which coincides with engine pinging, no?
Last edited by emmett on 09:50 am May 30 2021, edited 1 time in total.
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Re: Rattle at speed under load (not KIPS?)
just looked, the mogas at my airport is 91 octane.
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Re: Rattle at speed under load (not KIPS?)
If you’re sure the rattle is coming from the engine it sounds to me like you have an air leak. Is it hard to start? Does it snap back to idle or hunt it’s way down to idle?
Is the flywheel key sheared?
Otherwise, are you sure your chain isn’t completely shot and making noise?
Is the flywheel key sheared?
Otherwise, are you sure your chain isn’t completely shot and making noise?
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Re: Rattle at speed under load (not KIPS?)
I would say since it’s new to you and other maintenance was neglected I would pull the top end and at very least take apart, clean and check the KIPS. It’s never a bad thing to put a fresh piston and rings. That way you know what you’re dealing with. I thought mine had a rattling KIPS sound and it turned out to be the piston slapping around in there. A quick top end job and there is no rattle.
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Re: Rattle at speed under load (not KIPS?)
Runs awesome, and does not have any issue returning to idle. What makes you think air leak?Goofaroo wrote: ↑10:41 am May 30 2021 If you’re sure the rattle is coming from the engine it sounds to me like you have an air leak. Is it hard to start? Does it snap back to idle or hunt it’s way down to idle?
Is the flywheel key sheared?
Otherwise, are you sure your chain isn’t completely shot and making noise?
Not sure if it could be a flywheel key, but im replacing the stator soon so ill check.
I think chain would be most likely out of these options now that you mention it....
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Re: Rattle at speed under load (not KIPS?)
Leaving for college this fall, and would like to be able to ride in the little free time I have, not spend all of it working on it! I don't think thats a bad idea, but working on a budget, alongside very limited time.John_S wrote: ↑10:43 am May 30 2021 I would say since it’s new to you and other maintenance was neglected I would pull the top end and at very least take apart, clean and check the KIPS. It’s never a bad thing to put a fresh piston and rings. That way you know what you’re dealing with. I thought mine had a rattling KIPS sound and it turned out to be the piston slapping around in there. A quick top end job and there is no rattle.
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Re: Rattle at speed under load (not KIPS?)
run it till it pops then :-)
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Re: Rattle at speed under load (not KIPS?)
First thing I would recommend is you get a proper SERVICE MANUAL. This will answer many of your questions and is your best investment if you own a KDX. From the looks of your bike, I think you have an E series, not the later and final H series.
That noise you hear could be detonation or pinging. If it is, you could end up with a hole in your piston crown. Been there & done that. Check your ignition timing and don't go too far advanced. Your SERVICE MANUAL will tell you how to set the timing.
Also useful is an OWNER'S MANUAL. I understand these are available as a free download.
Good luck with your KDX.
That noise you hear could be detonation or pinging. If it is, you could end up with a hole in your piston crown. Been there & done that. Check your ignition timing and don't go too far advanced. Your SERVICE MANUAL will tell you how to set the timing.
Also useful is an OWNER'S MANUAL. I understand these are available as a free download.
Good luck with your KDX.
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Re: Rattle at speed under load (not KIPS?)
yup its an e series. Ive got an owners manual already, and ive been looking around for a service manual. I have not adjusted ignition timing before, but i will look into that. Thankspumpguy wrote: ↑11:44 am May 30 2021 First thing I would recommend is you get a proper SERVICE MANUAL. This will answer many of your questions and is your best investment if you own a KDX. From the looks of your bike, I think you have an E series, not the later and final H series.
That noise you hear could be detonation or pinging. If it is, you could end up with a hole in your piston crown. Been there & done that. Check your ignition timing and don't go too far advanced. Your SERVICE MANUAL will tell you how to set the timing.
Also useful is an OWNER'S MANUAL. I understand these are available as a free download.
Good luck with your KDX.
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Re: Rattle at speed under load (not KIPS?)
yep, could damage the cylinder, head, crankcases and/or crankshaft
If you don't want to work on a dirt bike, then don't. Ride it until it tears up, then sell it for what you can and go get another one. It is not the cheapest way to go, but if your focus is riding, then skip learning and maintaining, just ride it.
You're not spending my money, and it won't be me getting a scratch if it causes you to wreck.
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Re: Rattle at speed under load (not KIPS?)
I do enjoy working on and taking care of my machines, that is why I came here for advice. The previous owner seems to be someone who rode it until he sold it, whereas I would like to bring it back to life. It seems to have some issues that may point to just doing a rebuild, but trying to gauge where to draw a line.KDXGarage wrote: ↑12:23 pm May 30 2021yep, could damage the cylinder, head, crankcases and/or crankshaft
If you don't want to work on a dirt bike, then don't. Ride it until it tears up, then sell it for what you can and go get another one. It is not the cheapest way to go, but if your focus is riding, then skip learning and maintaining, just ride it.
You're not spending my money, and it won't be me getting a scratch if it causes you to wreck.
two main ones are:
I have noticed the airbox drips oil after riding (trans oil?). Not sure what would cause that.
Theres the tick/knock, which is why I created this thread.
Ive got lots of projects going on and Im not sure Id have the time to do a bottom-up rebuild. I feel that would probably be the best bet rather than do a top end and then realize it then needs a full rebuild.
Whats the rough price to have the motor completely rebuilt at a shop? $750? $1500? $2000?
Or maybe I should just run it...
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Re: Rattle at speed under load (not KIPS?)
An air leak will make it run hot and can definitely make it ping. A sheared flywheel key can advance the timing and make it ping. If the flywheel is loose that could certainly explain the knock you’re experiencing.emmett wrote: ↑10:45 am May 30 2021Runs awesome, and does not have any issue returning to idle. What makes you think air leak?Goofaroo wrote: ↑10:41 am May 30 2021 If you’re sure the rattle is coming from the engine it sounds to me like you have an air leak. Is it hard to start? Does it snap back to idle or hunt it’s way down to idle?
Is the flywheel key sheared?
Otherwise, are you sure your chain isn’t completely shot and making noise?
Not sure if it could be a flywheel key, but im replacing the stator soon so ill check.
I think chain would be most likely out of these options now that you mention it....
A compression test might reveal some clues. Aviation fuel is designed to burn cooler and run at steady throttle. If your compression test shows unusually high compression it could very well be severe carbon deposits from burning aviation fuel. Pull the plug and look at the top of the piston or pull the pipe away from the exhaust port and see how it looks. What does the plug look like?
You said the chain seems most likely of my suggestions. Is it shot? Can you only hear this noise when riding or is it there with the engine running in neutral? Chains can make all kinds of noise if they’re worn, damaged, and neglected. What about your chain rollers and sliders?
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Re: Rattle at speed under load (not KIPS?)
if running hot is one way it will ping, i should mention that one of my radiators is bent. It does not leak, but maybe that is causing the bike to get warmer than usual? I only took it for a ride around the block (maybe 10 minutes of riding, if that). ill attach a photo below to show the left rad.Goofaroo wrote: ↑01:25 pm May 30 2021An air leak will make it run hot and can definitely make it ping. A sheared flywheel key can advance the timing and make it ping. If the flywheel is loose that could certainly explain the knock you’re experiencing.emmett wrote: ↑10:45 am May 30 2021Runs awesome, and does not have any issue returning to idle. What makes you think air leak?Goofaroo wrote: ↑10:41 am May 30 2021 If you’re sure the rattle is coming from the engine it sounds to me like you have an air leak. Is it hard to start? Does it snap back to idle or hunt it’s way down to idle?
Is the flywheel key sheared?
Otherwise, are you sure your chain isn’t completely shot and making noise?
Not sure if it could be a flywheel key, but im replacing the stator soon so ill check.
I think chain would be most likely out of these options now that you mention it....
A compression test might reveal some clues. Aviation fuel is designed to burn cooler and run at steady throttle. If your compression test shows unusually high compression it could very well be severe carbon deposits from burning aviation fuel. Pull the plug and look at the top of the piston or pull the pipe away from the exhaust port and see how it looks. What does the plug look like?
You said the chain seems most likely of my suggestions. Is it shot? Can you only hear this noise when riding or is it there with the engine running in neutral? Chains can make all kinds of noise if they’re worn, damaged, and neglected. What about your chain rollers and sliders?
I have not run avgas, only mo gas. and im fairly confident the previous owner just ran pump gas.
I havent seen the plug yet, because no wrench that i have will fit in there... ordered a low profile tusk plug wrench but it hasnt come in yet. I will run a compression test as soon as i can, and i will check the plug to see if its white.
Im not sure if the chain is shot. I did clean it up as much as i could, but couldnt get the master link pin out to remove and fully soak/scrub. Ive only noticed the noise under load, at speed. No unusual sounds when in neutral revving or riding around the yard. Just seems to be up in 6th, 5th, and maybe as low as 4th gear as i accelerate.
Ill try and get an audio clip of it whenever this rain stops. Just tricky riding it down the road I live on, as its busy and this bike is not street legal yet. I'm in the process of setting it up to be plated (small battery, reg/recitifer, stator, horn, hi/lo beam, brake light sw, speedo, etc).
It would be wonderful if this is only a chain issue
Radiator:
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Re: Rattle at speed under load (not KIPS?)
You definitely need a radiator. Are you sure you aren’t just hearing the radiator banging against the frame while you’re riding? Stick a piece of rubber between the radiator and the frame and see if the noise stops. Is the radiator mounting tab broken off the frame?
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Re: Rattle at speed under load (not KIPS?)
A bigger problem is the crack in your triple clamp. This bike took a very awkward hit.
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Re: Rattle at speed under load (not KIPS?)
rad is solid and does not move or rattle. I do plan on replacing it, but i am 100% sure that is not the noise. mounting tab is not broken either. and theres at least 1/4" between rad and frame and i cant make it touch the frame or even wiggle by pushing on it.Goofaroo wrote: ↑02:00 pm May 30 2021 You definitely need a radiator. Are you sure you aren’t just hearing the radiator banging against the frame while you’re riding? Stick a piece of rubber between the radiator and the frame and see if the noise stops. Is the radiator mounting tab broken off the frame?
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Re: Rattle at speed under load (not KIPS?)
haha you had me worried for a second because that photo makes it look like a crack. but nope, thats just the clamp. My theory is the bike fell over onto a rock/sharp edge at a stop, and the rider weight added to the impact.
heres the clamp so you can see it.