Took the exhaust manifold off my 99 M2 the other day and ,for the first time, looked closely at the ports. I can see what looks like burnt oil around the upper portion of the rear port and a little bit of clean ally where the guide meets the port -the stem is a little bit gunked. Meanwhile the front port is just carboned up by comparison.
Now - this got me to thinking - some years ago I had to replace the front rocker gaskets for leakage and I noticed at the time that the rear pot already had the later gasket fitted. I imagine this was done under warranty by Carnells (remember them?) in the first 9 months of the bikes life before I bought it. Now - I can't help but be suspicious that they prolly didn't know what they were doing and am concerned that they may have done the job in haste causing a bent valve/split guide.
The bike doesn't smoke or use oil in any detectable volume between changes and the valve seems to seat nicely as far as I can see from the port.
I had planned to take the rocker cover off because I want to remove the Timing case - my question is would I spot a split valve guide without removing the head?
I had planned a more major stripdown next winter and don't want to take the head off at this time without it being essential to prevent a catastrophe.On the other hand I imagine that a leaky stem oil seal is not the end of the world if it's thats the cause?

One of my X1's had a broken valve guide and that had only been Dealer serviced in the past
I was alerted to this when I found the broken piece of guide in the exhaust can I was 'modifying' The fekin Dealer had rebuilt the top end and used obsolete paper rocker gaskets
You can actually get a finger around the exhaust guides for a feel, but I took the heads off to check for any more 'Dealer Damage'

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If your dreams don't scare you, they are not big enough.

you might have the same problem I've got with my S1W. send a PM with email details and I can send some pics of my heads, compare the defect. Mine looks like oil leaking between valve guide and head.

rgds,

john

I had a chiped guide on my x1 front head due to a bent valve, Maz told me the new guides are a nightmare to ream correctly and recomended a new head. So thats what i did.
http://www.lshd1.com new front thunderstorm head (part 16797-98y ), $296 plus shipping, comes with new valves, guides, springs etc.

Black Bear had a Thunderpant head, with no valves, for sale recently...

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08 Specialized Langster

Cheers Nick - but it's a front head and I would need a rear one.

if anyone has old heads that have guide problems and they replace with new i will buy the old heads.

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Do you want it right or right now ?

Thanks for your input fellas - if have understood correctly it would seem that damage to the guide usually results in a piece breaking off at the bottom i.e.
the section that is visible in the port.
Mine seems OK here and I think that a small amount of oil is leaking between guide and head from what I can see.

pm tubbs