Top end rebuild "running in problems"

Hi guys let me start of by identifying my bike and my problem
I have a 1981 xj650 maxim non yiccs
Running Pods and a 4-2 custom exhaust

I brought the bike with a slipping start clutch so we all know what that means
Split cases!!
So while in there i did the top end,which lead to further things like stripping the cases to get blasted.
With the top end done and rebuilt carbs

The bike starts very well even in these cold New Zealand winters (choke for 10sec max)
Bike idles great BUT headers 1 & 2 get hot very quickly while 3 & 4 stay cold for quite some time 3-4min
3&4 exhaust spits a flame at around 3k rpm

Work that has been done

Engine split and reassembled with
new top end
New pistons
New rings
New valves
Shimmed vlaves

Carburettors blasted,stripped,cleaned,rebuilt with new
Diaphragms
Shaft seals & O rings
Jets 45 pilots 120 mains
Float level set
Bench synced and then vacuum gauge set

New dyna tek coils and leads (non resistance type)

I will upload a running video in the morning

Your help would be greatly appreciated

 

Photo 1

 

Try a colortune plug. You can order them from Xj4ever

 

What did you set the idle mixture screws to?
More importantly, are they coarse-thread, or fine-thread.

 

No particular method just set to 3turns out and fine thread

 

Those are huge jets for a 650cc engine!

Nice looking engine.

What do the spark plugs look like on #3/4?

You should perform and compression test on all the cylinders.

 

I will do that this afternoon .
45 is what the bike had in it when it was in its factory form and 120 is what SIGMA racing jet kit gave me as well as a 130..

 

Unsure why it’s such poor quality but gives you the idea

 

also one shim added to needle jet

 

Regardless of what it had in it, stock is a 40 pilot, with 110 mains (even in NZ).

3 turns out on a stock bike is a tad on the rich side, and with your jetting you might be rich at idle (even with the pods). Pull the plugs and give us some good pics of the rings and ground straps.

 

^^^+1 know is correct the other item did you wet set your floats? Just a thought uneven filling of the float bowls to find out get a container with markings drain one float bowl at a time see how many ounces drain out as long as close your ok . Cheers

 

Okay these photos wore taken after about 3min of idling
Headers 1&2 wore very hot by then.burn to touch.
3&4 wore cold
Plug 1

 

Cylinder 2

 

Cylinder 3

 

And finally 4

 

Will give this a go to thanks mate

 

Okay another question have you taken it for a high speed ride of say 15 to 25 miles and then checked plug , note if you are only checking at idle this is what plugs can do on occasion.

 

Bike back fires very loudly on low revs (pilot jet)
But pulls well when opened up.
Got upto about 30-40km down my street and killed the engine and checked the plugs and they all pretty much looked like this.. 3rd cylinder was more of a wet black.
It has only started backfiring from been rich since I took it for its first ride down the street last week.
It just concerns me how hot 1&2 headers get from idle when 3&4 stay cold.
Thanks for the reply’s guys
Guess I need to get some smaller jets say 42-116

 

1-4 are all very rich. 3 and 4 are both wet. Did you smell gas on them, or is that oil?

The coldness on 3&4 is the result of the plugs being wet. Those plugs aren't firing well until they get hot, and even then they probably aren't firing well.

 

3 is still wet even when checking this morning without having the bike running.
4 is definitely the cleanest plug.
3 does smell like gass but does look to have oil deposits over it
Or could that be a build up of fuel from not firing? It does leave a black oily stain when I clean it with a rag.
Sorry this is my first engine rebuild so it’s all new to me..
Could I have possibly damaged a oil ring when slidding the cylinder over the pistons?
What would you suggest my next steps are?
Thanks again