1991 KDX 250 knocking noise
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1991 KDX 250 knocking noise
i recently brought a 1991 KDX 250 and the engine made a slight knocking noise, it didnt sound like big end or crank bearings and when listening to the engine with a stethoscope the noise could only be heard on the cylinder and head area.
i suspected little end bearing or piston slap...
compression at this point with the engine warm was 180 psi and it ran and started very well.
now its apart the big end has no play and neither does the little end...
neither the piston or bore look particularly worn but i dont have a spec about wear limits or piston and bore clearence.
the guy also gave me a spare cylinder and a new and used piston but these pistons are different by being about 5mm taller and the wrist pin being 18mm rather than 19mm..... the cylinder is also different as there is a removable blanking plate just above the exhaust and the exhaust mounting is a different shape and size.
could any one offer an opinion to the knocking noise or help with any specs.... both much appreciated
sorry for the long post
thanks all
matt
i suspected little end bearing or piston slap...
compression at this point with the engine warm was 180 psi and it ran and started very well.
now its apart the big end has no play and neither does the little end...
neither the piston or bore look particularly worn but i dont have a spec about wear limits or piston and bore clearence.
the guy also gave me a spare cylinder and a new and used piston but these pistons are different by being about 5mm taller and the wrist pin being 18mm rather than 19mm..... the cylinder is also different as there is a removable blanking plate just above the exhaust and the exhaust mounting is a different shape and size.
could any one offer an opinion to the knocking noise or help with any specs.... both much appreciated
sorry for the long post
thanks all
matt
- Indawoods
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KIPS... KDX's make noise.
*** Administrator //***
****'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!!! "
****'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!!! "
- Julien D
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The knocking is probably just Kips noise. Very common, nothing to worry about. If it makes the noise at idle, but goes away when you rev it, it's the KIPS vavles doing what they should. If the noise increases as you rev it, then it's most likely piston slap.
Now that you have it apart you need to replace the rings at the very least. I would go ahead and put a new piston in it. Have no idea on the pistons he gave you, except that they obviously are not the correct pistons.
*edit*
Dang, Inda beat me to it.....
Now that you have it apart you need to replace the rings at the very least. I would go ahead and put a new piston in it. Have no idea on the pistons he gave you, except that they obviously are not the correct pistons.
*edit*
Dang, Inda beat me to it.....
- scheckaet
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pics?
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wow thanks for the quick replys... dont think it is the kips valves as they dont have enough play to rattle around and it doesn't go away when revved... stayed almost a constant volume but was at engine speed.
i also have a kmx 125 with a similar kips engine which is almost silent so pretty sure its not that.
i am after the piston and bore sizes as there is no point replacing the piston if its the bore that is worn.
any one know of a manual download for the kdx?
cant wait to get it on the road but cant legally as i have 2 months left of my 33hp restriction so have some time to sort it out.
i also have a kmx 125 with a similar kips engine which is almost silent so pretty sure its not that.
i am after the piston and bore sizes as there is no point replacing the piston if its the bore that is worn.
any one know of a manual download for the kdx?
cant wait to get it on the road but cant legally as i have 2 months left of my 33hp restriction so have some time to sort it out.
- scheckaet
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manual: TOP LEFT and RIGHT of this site.
what's that 33 hp restriction??? You in Europe or something?
what's that 33 hp restriction??? You in Europe or something?
02 KX 200 hybrid: RB head and carb
Sold ☹ DRZ 400 SM
bike build: http://www.kdxrider.net/forums/viewtopi ... ike+stable
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newb info: http://www.kdxrider.net/forums/viewtopi ... 57#p117919
jetting guide: http://www.kdxrider.net/forums/viewtopi ... 105&t=1156
Sold ☹ DRZ 400 SM
bike build: http://www.kdxrider.net/forums/viewtopi ... ike+stable
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newb info: http://www.kdxrider.net/forums/viewtopi ... 57#p117919
jetting guide: http://www.kdxrider.net/forums/viewtopi ... 105&t=1156
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yes from the UK... if you do you test under the age of 21 you are limited to 33hp for 2 years.
tried the manual but they took my money and it wont me download.
i measured the piston and bore today with clearences from a kmx 200 as the bore diameter is the same... it is not any where the wear limits although the rings were so i replaced them but it is still knocking.... just going to use it as is i think.
thanks for all the help.
tried the manual but they took my money and it wont me download.
i measured the piston and bore today with clearences from a kmx 200 as the bore diameter is the same... it is not any where the wear limits although the rings were so i replaced them but it is still knocking.... just going to use it as is i think.
thanks for all the help.
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