My son has a 1993 sportster 1200 (Stock) We recently rebuilt the top end. After about 200 miles engine started smoking (Blue=oil) ? During rebuild valve job was done seals replaced, rings, stock cams etc. Pretty straight forward. What am I missing any ideas? thanks in advance.

 

Crimped metal valve seal came off the guide? (if those were used)
Scott

 

Let me clarify some things,
I did the top end because I was in a rush and used a set of of used complete heads I had. After 150-200 miles the smoke started out of both pipes so I had the valve job done, replaced the heads still smoking at Idle and when you let off the throttle. I'm getting small amount of oil out of the vent as well. I'm heading out to check the plugs for fouling, but otherwise bike is running strong. Could the vent system being plug cause this? I have rebuilt car engines in the past, but Harley is new to me. I have a tech manual and all that but not finding much pertaining to this issue. Thanks

 

No one else?

 

Smoke under acceleration is usually rings/bore related, and smoke under deccel would be guide fitment or seal related.
Scott

 

Thanks man,

I'm going to pull the heads again. My machinist still says guides were ok, But I,m going to have them replace anyway. Which incidentally I asked him to do in the first place but went with his judgement that they were good.I feel like I am chasing shadows here.