626 Concentric idle circuit ?

[bsa-bill]

I think most  here would agree with your plan Rob.
Congrats Colin getting it sorted, yep black oil is good I'd be worried if it stayed clean

[Triton Thrasher]

Yes, it is normal for the oil to get dirty quickly after a build. Others on here may have different ideas but this is what I recommend.
1/. Ride 25 miles away from home, head back and drop the oil on arrival home. Don't go over 40mph and don't open the throttle more than 1/4, but allow the engine to rev out. ie light load/maximum oil pressure.
2/. Change oil after 500 miles, no faster than 50mph. From this point start increasing throttle opening gradually.
3/. Change oil at 1,000 miles. I take my oil tank off at this point and run a full jet wash cycle through it and re-fit. (I actually have two tanks, one dry and ready to go on and the other in the wash, so to speak.)
4/.Change oil 1,000 miles.
5/. Change oil and clean the tank again after another1,000 miles.
                                        Rob.

I must say I do things very differently.

Do you retorque the head?

[Triton Thrasher]

commended mod for concentrics on Vincent twins also calls for cutting away part of the  brass bush that surrounds the throttle needle in the venturi !!!!

John

Another trick is blocking the needle jet bleed holes. Can work wonders on hesitant bikes of other marques, too.

[metalflake11]

Triton Thrasher, as I said, others may have different opinions. I am interested to hear your method, it will also give the origional poster another option. As for head re-torqueing yes, I do. Why do you ask?

[Triton Thrasher]

Triton Thrasher, as I said, others may have differnt opinions. I am interested to hear your method, it will also give the origional poster another option. As for head re-torqueing yes, I do. Why do you ask?

I just thought retorqueing was worth a mention.

I've had good success with the fashionable "dry bore and open throttle" method of running in.

[BSA_54A10]

As no one has pointed you there I would highly recommend you go tohttp://www.jba.bc.ca/Bushmans%20Carb%20Tuning.html this site.
Every thing you need to know about concentrics is there.
Note in particular the chart which shows the tuning overlaps between jets.
I use the dry assembly & ride like you stole it similar to Mr Thrasher & have found it better than the flood with oil method I used previously.
What really is important is that for the first few hundred miles you avoid leaving the engine idleing with no load as much as possible.
This was the biggest proble I had with all my rerings as I would start the bike then frig around for 1/2 hour or more adjusting the carb  playing with the timing.
Now days , if the engine fires up I jump on and go for a ride, up & down through the gears always keeping some light load on the engine.
After I have knocked up a couple of hundred miles, then I do the fine tune.

As previously noted, you need to change the oil as oft as you can and run the dirty oil through some thing like a coffe drip filter so you can see any nasties in the oil.