Maintenance & Technical > KX500 Original
rattle from motor
Johnniespeed:
I bought my K5 new, so I know what it is supposed to sound like. Whenever I hear a rattle in the "engine" it is always, always,always the exhaust mounting. I just replace the gaskets ( I use two instead of one ) I replace the o-rings, and replace the broken mounts again and again. Also if you do a search for the broken frame exhaust mount, you will find how others fix thier frame mount.
Now maybe you do have an engine noise, but I wouldnt take anything apart until I knew for absolute sure the exhaust is perfectly mounted.
I hope your noise is something simple and easy to fix, keep us posted.
John
RM_Rider14:
--- Quote ---Also make sure you have the exhaust pipe o-rings and a good copper exhaust gasket (I like to use 2 gaskets) . 250/500cc KX's exhaust header pipes often vibrate against the inside bore of the cylinder.
--- End quote ---
Four posts's up, did you read mine? Great minds think alike ;-)
stroke.n.smoke:
I did a compression test and its right at 180psi. Looked into the exhaust port and everything looks great. I don't think I will be pulling anything apart yet. From all the response and the video's I am not going to worry about it. One thing that does worry me somewhat, but after two years of running AV gas I am a little worried about things. I have heard everything from (never run avgas, especially in a two stroke, the motor won't last long) to (don't worry about it, it'll be fine). I realize it has lead, but so does C12... When I looked into the cylinder it was very clean, no piston wash on the top of the piston. I did have the piston top coated by max power and the combustion chamber (actually they did the entire head) It's very clean, the piston is real nice on the exhaust side when you roll it over too. This is a Wiseco piston with a window in it. I run the BR8EG and the timing plate is fully advanced, I also use the thinnest Kawi head gasket available. 40:1 Amsoil Dominator with 100 octane LowLead AVGAS for the last two years. I ride at 1500 ft to 5000ft and weather from 0 degrees C to +30 degrees C. I have never jetted for the elevation and weather, pretty much stock jetting, ya, it doesn't run perfect in all conditions but man, what a great bike. I have a buddy with a new 200cc KTM XCW and he basically jets daily... Just thought I would share that with you guys...
snoopjonnyjon:
Myles, I got my bike back together and ran it for a while this weekend. If anything, the sound is even more pronounced now. I am convinced it is just the the sound of the center kips valve. I think cleaning it really thoroughly made the sound worse.
Sound isn't great with the gopro, but maybe you can make it out.
http://www.youtube.com/v/4qMecD4xvhY
I do recall on our ride though that at least one of your pipe mounts was missing. I replaced the pipe O-rings and all new pipe mounts and springs, but I didn't even realize there was supposed to be a copper gasket in there until I tore it down this winter. Mine was totally pounded out into a paper thin wafer with a few areas totally pounded through. I've got a new one on order, I will let you know what I find when I run it with the new gasket.
I checked out my jetting this weekend. 58 pilot, 168 main. VP110 mixed 50/50 with 91 pump gas, and 40:1 Belray MC1. I've gone a full season without fouling a plug, and it always starts 1st or second kick. Perhaps my seat of the pants isn't calibrated as finely as others, but it seems to always run flawlessly. Do you think Robbie really needs to be rejetting his KTM daily, or is he just doing it because he is looking for something to do?
Polar-Bus:
--- Quote from: stroke.n.smoke on March 01, 2010, 11:07:33 AM --- I have a buddy with a new 200cc KTM XCW and he basically jets daily... Just thought I would share that with you guys...
--- End quote ---
Good for him, he spends painstaking amounts of hours chasing the most perfect tune.... no wonder he's so slow... :-D
I have summer jetting and winter jetting, not perfect jetting but safe. No meltdowns, and no fouled plugs. That's good enough for me.
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