Just a counter point I ran Amsoil 20w-50 for several years with no leaks.
No I have leaks at both base gaskets and push rod tubes and I have Valvoline 50 weight in her.

Weird huh???????

 

dirt has eaten them away from outside.

 

I have seen a lot of dirt but I have yet to see dirt with teeth.

 

I would drain the gas ,get fresh gas & some lucas fuel treatment small bottle about 5-6 bucks A zone or Orileys start it up & let it ideal about 5 min gets the carb some fresh gas in it then easy ride around the block , & the new plugs as well

 

Put Seafoam in the tank.

 

You just didn't look close enough mate.

 

Remove the float bowl and give it a shot of carburetor cleaner. You may have some debris in the needle and seat.

 

i hate it when i get a can of 20/50 backfire oil too, boy o boy that china oil $ucks dont it - jz

 

And people wonder why everyone doesn't do their own service. Would be so much easier to take it back to the dealer and say, "you screwed up". But I'll keep doing mine anyway. I do hope you tell us what it was when you find it.

 

Found the probem... but first a little of my frustration. When I got the bike on 1 January we broke the jiffy stand spring. Not a real problem except when you have an off-size spring. So far I have bought 4 springs. The first one was the right size but the old penny trick sprung my spring so it was too loose to work correctly. Then I ordered based on year and model. So I ordered two springs. They finaly came in. Too big. Then I went to a bike shop and got another spring. Too big again. So between having to work for a living, futzing around with the jiffy stand not working, winter weather with a few nice afternoons for a ride and the frustration of not being able to ride safely I was a little elated when I finally got the jiffy spring to work by cutting one down.
Added two gallons of pure gas (non-ethanol) and went for a 40 mile ride and enjoyed every minute of it.
So then I decided to change the oil. New K&N filter too. Drove 1 mile up road and then it started missing and backfiring.
Got it home and did some searching. Saw that a loose battery connection could cause this. My point about the oil change was more directed to wondering if I had jostled some battery cables loose when I took the right side oil cover off and put it back on.
So this morning I took it all apart and checked the connections. All was tight.
Then I drained the gas tank and refilled with fresh 90 octane. Went up the road a bit and it started missing badly. I nursed it over to New Life Builders - custom motorcycle shop and Rich took a look and yanked the plugs The number two plug was coated in black. Number 1 was fine. He replaced the Champions with Denso's and the bike was purring like a kitten.
So now life is good and there is some good weather for this weekend.

Thanks for all your help and advice and suggestions.

My next tasks are to change the primary and crankcase oil and get a new air filter on the bike.

Hopefully these will be with out drama!