Yes, many will recommend the 15W-40 Diesel oil but you will get more top end clatter using it. I guess it lubes fine, just lets more noise happen. I tried it and went back to the 20W-50 because of that.
What oil grade are you using? These engines are noisy compared to modern engines, so you may just have to get used to it. 20W 50 is the best oil to use, as it reduces the ticking somewhat. I would say its better to ride the bike for a while, before jumping into a re-build.
If you want a super smooth and quiet engine, these are the wrong bike for sure.
I would open up the clutch cover and clean/inspect the oil pump and passageways, and service the sump filter/screen too......
[COUGH] http://www.harborfreight.com/mechanics-stethoscope-69913.html
Oil? Reasonably cheap 20w-50. Changed every 1-2k miles.
Carb issue? Thorough cleaning of pilot circuits/float bowls, and transfer passages in the main body. Plan on it frequently. Will it be necessary? Hopefully not...
I've been aware of the larger clearance benefits for some time. It was explained on this 650Motorcyles.com page a long time ago. It says pretty much exactly what the smedspeed link does .....
http://www.650motorcycles.com/isky.html
But, reading it again now, I may just start tweaking some more. The big benefit here seems to be making the intakes bigger so you can reclaim some of that lost "linger" time. The exhaust is already bigger so I'm thinking it doesn't suffer from the problem as much. I did go back to .004" on the intakes with the elephants feet because they will run that nice and quiet. Maybe I'll bump them up a little, say .006" IN and .007" or .008" EX.
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Thank you for the reply 5twins. That's pretty much what I had deduced from my searching, was that they just about all looked like that. But wanted some second and third opinions to decided what to do.
Got a nice list now of things I need to buy.
Any things to avoid from Mikes XS? or are they generally good quality parts?
It couldn't hurt to post crisp/clear close-ups of:
Cam lobes.
Rocker follower pads.
Valve adjuster tips.
Valve stem ends.