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View Full Version : XL250r head, question.


unstuck
14th May 2012, 15:05
The old XL has finally sucked a kumara, the center cam bearing? holder? has melted itself, as these old beasties are prone to do. I have heard that the head and cam can be ground out to accept a ballbearing. Anyone done this? If so was it sussesfull, sucsessful, did it work? I have a spare head but it is cracked between the valve seats and spark plug hole:mad:
tigertim20
14th May 2012, 17:24
The old XL has finally sucked a kumara, the center cam bearing? holder? has melted itself, as these old beasties are prone to do. I have heard that the head and cam can be ground out to accept a ballbearing. Anyone done this? If so was it sussesfull, sucsessful, did it work? I have a spare head but it is cracked between the valve seats and spark plug hole:mad:

Im not an expert on these, but it sounds like you have no choice but to pull the trigger, try it, and let us know if it works!
unstuck
14th May 2012, 17:31
Personally I can not see how the bearing would go over the cams.:confused:
Ocean1
14th May 2012, 18:32
The old XL has finally sucked a kumara, the center cam bearing? holder? has melted itself, as these old beasties are prone to do. I have heard that the head and cam can be ground out to accept a ballbearing. Anyone done this? If so was it sussesfull, sucsessful, did it work? I have a spare head but it is cracked between the valve seats and spark plug hole:mad:

Ball bearing? No.

I've seen needle rollers in there, but it's a tricky job and prob not worth the trouble. Best fix I found was to grind the cam to the next nominal dia, line-bore the head and make sinterted bronze shells to fit. Drill the bottom shell to match the oil feed and drill and pin the top shell.
unstuck
14th May 2012, 18:38
Ball bearing? No.

I've seen needle rollers in there, but it's a tricky job and prob not worth the trouble. Best fix I found was to grind the cam to the next nominal dia, line-bore the head and make sinterted bronze shells to fit. Drill the bottom shell to match the oil feed and drill and pin the top shell.

Cheers for that, something to think about. It,s hard to get good head these days.:Punk: