Thanks Jens and TT.
I will definitely replace the valve stem seals. I haven't confirmed this yet but like you guys say this XT probably has an iron sleeve, I checked it with a magnet and it sticks, the only reason I mentioned this is cause a guy from another site saw the cylinder pic and thought it had the "yellow" tinge that nikisil has, my bet is on old school steel liner. thanks TT for the rubber ball hone suggestion I'll keep an eye open for one of those, I still have to get some bluing and a suction cup honer for the valves and a 4" micrometer.
Some before and after pics, this really shows just how much grunge collects after 60.000km. the huge globs on the exhaust ports must be from the last days of it's life when it was using lots of oil.






























.

Those valves are definitely going to need lapping in... Probably with two stages..

Good job on the clean up !

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Did some trips.
Rode some bikes.
Fix them for a living.
Can't say anymore.

Awesome pictures really.

Damn that bike will run great when once finished.

My bike have 90k km and doesnt use oil (well, maybe 1dl on 3000km, cant really tell for sure) crazy how different the same bikes can be.

Looking forward to the pics from the rebuild and keeping my fingers crossed the bike starts first time. Just don't do what I did (when I was 15) and put the pistons in the wrong way!

Keep the pics and write up coming.

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TurboCharger + Francois (our BMW R1200gs) '07
www.riding2up.net, blog.riding2up.net

Great close up photos there.

I can't believe how dirty the inside of that cylinder was.

Once you have your bore measurements I reckon you will have your answer.

*Touring Ted*
I do have an old can of Clover compound kicking around, course and fine, I'm looking forward to the lapping process and with any luck getting a really good seal, I did the clean solvent seal test where you fill the intake/exhaust ports and check for leaks, in the dirty condition it failed miserably, I think I'll try it again in the clean condition just to see what happens.

Jens Eskildsen
Yeah it's gonna run awesome ! I'm expecting a bit more of everything, power, torque and a bit quicker throttle response, the Arrow pipe I installed last fall woke it up real nice so after a rebuild it's gonna be sweet :-) I hope you add lots more km to your bike before you have to rebuild.

TurboCharger
You must have a lot of experiance if you were doing top ends at 15 ! this thing tried starting I could hear it firing but with only 55lbs of compression even a Yamaha won't run. I'll be keeping an eye open for the "forward" arrow on the new slug.

gixxer.rob
I agree I can't believe the carbon on that one exhaust port I've never seen anything like it, the buildup on the valves resembles something with 300.000km, I think I may have found my answer today when I measured the ring end gaps :-( I'll post a pic and a few specs.

Glad your all enjoying the pics.

what do you use for the cleaning? looks good

I used a wire wheel on the grinder for the valves carefully avoiding the guide/seat areas, smaller wire wheels that fit into a drill for a few tough spots on the combustion chamber, and the usual asortment of brass/steel wire hand brushes, plastic bottle brushes, tooth brushes etc along with varsol/solvent and elbow grease. it also helps to have 90psi air pressure to blow things clean. the carbon can be tough to remove sometimes you have to carefully use scrapers almost like a wood carver does, holding them with both hands so you don't gouge things up. there's nothing like a shiny clean engine going back together :-)

I measured the ring end gap in the cylinder and was surprised to see the measurment is twice over what the specs are ! I had to use two feeler guages just to get the 1.07mm. I'm wondering if the specs of 0.30mm ~ 0.45mm are correct for my 99 XT600E since they came from a pdi manual for an 03/04 TT600RE. so much for re-using the old piston.

Same specs for rings for a 1990 xt600e, so they should be right.

Thanks Jens.

While looking for a part number I found this hairline crack on the piston skirt, I don't feel so bad now she didn't fire up this spring.

I noticed one of the intake tracts was noticably dirtier than the other.

This could be one of the reasons, the rubber is losing it's bond on the flat part of the aluminum intake manifold, I could also feel movement on the round section which leads into the cylinder.

I think the carbs open at different throttle openings so the port which has the closed carb ('till you open it up) has a vacuum created in it, this could be pulling oil down the valve stem.
What are the valves like for play in the guides, if they're worn you're not going to get a better opportunity to replace, or have guide liners fitted(these are supposed to be the bees knees if you believe the blurb!)

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I wouldn't be too worried about that rubber down there at the cylinder mount bolt. It should only be a problem if it is loose up around the clamp ring. Of course if you have some gasket goo then stick it back down.