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87 RFVC problem

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hi there, so I was given the job of putting a 250 rfvc engine back together that was completely disassembled and in 2 boxes. I did get it all back together but due to the kid who owns it he didn't have much money so I re used the old cam chain (bad idea) so anyways I had the engine all back together and running, shut it down to check it over and when I went to re start it the kicker jambed up on  so I gave it a bit of a roll and it started to spin over (damage done) :banghead:

 

so what happened is the cam chain was stretched and fell off the lower sprocket threw everything out of time and just screwed things rite up on me. so now I am looking for new valves for it. the piston has a couple of marks in it but nothing serious as it wasint running when it happened.

 

I have been looking at bike bandit and on here for valves but it seems that the exhaust valves aren't listed any longer. so I need to know if there is any from other years that will swap over in to this head, aswell as a good source or a new cam chain.

 

any help would be greatly apreciated

Edited by steve_1987

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I assume this is for an XL250, since exhaust valves for that year XR250 are still available.

 

The problem with that head is the exhaust valves are 1mm larger than 86-95 XR250s. I would try calling Kibblewhite and see what they say. Let us know if you have any luck there. I'm sure you can get a machine shop to put new valve seats in the head to fit the smaller exhaust valves used on the later bikes.

 

The cam chain is still available, just pricey.

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well I just measured the valve heads and the intake is measuring at 27.8mm and the exhaust is at 25.5mm

does anybody know off hand what the valves measure for the xr engine?

 

thanks

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Intake valves are the same for 84-95 XR250Rs, 84-87 XL250s and 91-96 XR250Ls

 

According to Kibblewhite the 86-95 XR250 exhaust valves are 23.5mm diameter. I guess I was mistaken on the 1mm part.

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well it has been a little while for no update. I haven't had any luck finding the 25.5mm exhaust valves. does anybody have any ideas?

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I rebuilt an 86 about a year ago that had jumped time and bent both intakes. It took about 18 months of looking at dealers and ebay before finding a pair. Good Luck! If you have to the 96 up head should fit. They were revised but still are the same design and head gasket. Valve sizes are the same as the earlier ones but the stems are apparently longer.The valves have a bad reputation for being soft.

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