difference in RFVC xr500 and RFVC xr600 motor parts

i got a few interchangability(is that a word), questions. i got an 83 xr500 engine which is an RFVC motor. it has dual carbs and exhausts.the bike originally did not have the RFVC motor but it had dual exhaust ports. i was told the exhaust pipe will not seal right on an RFVC engine. the pipe fits right into the head and looks like it fits though. i am confused. if the pipe i have won't work, will a pipe from an RFVC equipped xr600 fit it. now how about the engine parts. will the RFVC xr600 head fit on a RFVC xr500. i know the cams will interchange, i am pretty sure they would interchange. thanks.

come on, somebody should know this

My question is why would you transplant an XR500RD/RE engine into an earlier XR500 frame? Anyway I have some answers to those questions. The XR600R header pipe would most likely fit on the 500 head but I'm not 100% as the head is different in that the XR500RD/E actually had LARGER exhaust valves than the XR600's and the combustion chamber will be smaller to accomodate a smaller piston (the XR500RD/RE bore size is 92mm compared to 97mm for the XR6). So the 600 head wont work on the 500, but the 600 headers will probably work because the head is the same shape as the XR600RF-RH (85-87) on the outside, but the valves and actual combustion chamber would be a different shape. The problem with the 600 header pipes is that they might not route around the frame downtube as you may like as they are designed for a different frame, but give it a try! I hope this helps.


the bike is an 81, the original motor blew up and the guy i got it from couldn't find another one so he got this 83 motor. it is an xr500r, not an RE or RX(never heard of those. i am putting this motor into a blaster frame so it does not matter if the exhaust routes the same. this is an RFVC 4 valve engine and the head may be bad. i doubt i can find another for a 500 so a 600 RFVC head would be the best option if it would fit

So an RFVC motor will fit an earlier frame? I thought they were completely different. How about the Xl's?

I am new to this site and am also putting a xr500 in a blaster, judging by the date of the thread yours is probubly done? if so do you have any pics?

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