Planet Minis

tubbs10 · 09-14-2009, 11:56 AM

Does anyone know if a xr 200 cylinder will fit a xr100 engine?

I have installed two xr 100 pistons and cylinders (stock) they keep burning the piston really bad and scarring the cylinder wall something awful they will have to be replaced AGAIN. That gets expensinve I have found a xr 200 cylinder and piston and was wondering if they would fit on 100 engine.

nola_fiddy · 09-14-2009, 12:38 PM

The parts will not interchange. You need to find out why the pistons are getting burned up. Could you have an oil pump failure, clogged oil pathways, rod or crankshaft problem? Something somewere is malfunctioning and you need to figure this out before you replace again.

I would split the case and start inspecting, cleaning and/or replacing bearings and the filter etc.

good luck

tubbs10 · 09-14-2009, 02:42 PM

i have completely split cases changed left case, transmission, clutch and all someone said it may be the way we are doing break in that is doing it, is that possible.

nola_fiddy · 09-14-2009, 03:23 PM

It is possible but not likely that the break-in is causing the damage. These xr100 engines are very forgiving. My guess is that you are overheating for some reason. Did you check your oil pump? It has to be disassembled to be cleaned out. I have done this on an xr80 engine and I think they are the same. You need a special spanner type nut remover to disassemble. Once you have it all apart, use an air compressor to blow air through the pathways where the oil flows.

One other thing, are you installing the piston with the arrow toward the exhaust port? (there is some marking either an arrow or some other to indicate the exhaust side of the piston) If not, this could cause the piston to seize in the cylinder.

let us know

nola_fiddy · 09-14-2009, 03:29 PM

One other thing, buy an oversize xr100 piston and send it to someone to bore your existing jug to this size. This will be alot cheaper. You can find shops on ebay or here on PlanetMinis that will bore your cyliner. avg cost $50 or $60 plus the cost for a new piston and rings $100.

If you jug is really scored, you may want to go 2 or 3 sizes over standard bore.

BlackBeard · 09-14-2009, 04:26 PM

Or your jetting is far off, What does your plug look like? I doubt its oil related as the cam bearings would fail before anything else if oil starvation was an issue. Its either jetting or even rings installed upside-down?

09-14-2009, 11:56 AM	#1 (permalink)
tubbs10 PM Newbie Join Date: Aug 2009 Posts: 2	xr 100 problems Does anyone know if a xr 200 cylinder will fit a xr100 engine? I have installed two xr 100 pistons and cylinders (stock) they keep burning the piston really bad and scarring the cylinder wall something awful they will have to be replaced AGAIN. That gets expensinve I have found a xr 200 cylinder and piston and was wondering if they would fit on 100 engine.

09-14-2009, 12:38 PM	#2 (permalink)
nola_fiddy PM Newbie Join Date: Dec 2007 Location: New Orleans Posts: 77	Re: xr 100 problems The parts will not interchange. You need to find out why the pistons are getting burned up. Could you have an oil pump failure, clogged oil pathways, rod or crankshaft problem? Something somewere is malfunctioning and you need to figure this out before you replace again. I would split the case and start inspecting, cleaning and/or replacing bearings and the filter etc. good luck

09-14-2009, 02:42 PM	#3 (permalink)
tubbs10 PM Newbie Join Date: Aug 2009 Posts: 2	Re: xr 100 problems i have completely split cases changed left case, transmission, clutch and all someone said it may be the way we are doing break in that is doing it, is that possible.

09-14-2009, 03:23 PM	#4 (permalink)
nola_fiddy PM Newbie Join Date: Dec 2007 Location: New Orleans Posts: 77	Re: xr 100 problems It is possible but not likely that the break-in is causing the damage. These xr100 engines are very forgiving. My guess is that you are overheating for some reason. Did you check your oil pump? It has to be disassembled to be cleaned out. I have done this on an xr80 engine and I think they are the same. You need a special spanner type nut remover to disassemble. Once you have it all apart, use an air compressor to blow air through the pathways where the oil flows. One other thing, are you installing the piston with the arrow toward the exhaust port? (there is some marking either an arrow or some other to indicate the exhaust side of the piston) If not, this could cause the piston to seize in the cylinder. let us know

09-14-2009, 03:29 PM	#5 (permalink)
nola_fiddy PM Newbie Join Date: Dec 2007 Location: New Orleans Posts: 77	Re: xr 100 problems One other thing, buy an oversize xr100 piston and send it to someone to bore your existing jug to this size. This will be alot cheaper. You can find shops on ebay or here on PlanetMinis that will bore your cyliner. avg cost $50 or $60 plus the cost for a new piston and rings $100. If you jug is really scored, you may want to go 2 or 3 sizes over standard bore.

09-14-2009, 04:26 PM	#6 (permalink)
BlackBeard "ZBBT" Join Date: Oct 2007 Location: 50 riders Posts: 1,836 My Mood:	Re: xr 100 problems Or your jetting is far off, What does your plug look like? I doubt its oil related as the cam bearings would fail before anything else if oil starvation was an issue. Its either jetting or even rings installed upside-down?

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