[Arizoni]

The tires on the RE are old school technology which is fitting for the old school motorcycle represented by Royal Enfield.
They have bias plies and stiff sidewalls and what modern riders call "low pressures" were in fact the "normal" tire pressures back in the days.

The 1955-1961 BSA  Rocket Gold Star and Super Rocket 650 twins for instance used 3.25 X 19 and 3.50 X 19 tires on the front and rear.
The factory air pressure for the front tire was 18 psi front, 20 psi rear (solo) or 18 psi front, 28 psi rear (dual).

The 1968-1973 BSA A75 Rocket 3 triple was running a 4.1 X 19 tyre front and rear and the factory tire pressure was 22/28 (front/rear).
That triple was far from a low performance machine so it should be obvious that the old style tires had different pressure requirements than the new super-duper tubeless tires that are used on modern motorcycles.

[Ducati Scotty]

The pressures indicated on a tire only indicates that maximum pressure at which it should be operated. It has nothing whatsoever to do with making the tires handle best for the conditions.
Bare

+1.  The pressure on the tire is the max it will hold and has nothing to do with what pressure us best for the bike it's mounted on.  Arizona, thanks for the history lesson.

Scott

[wildbill]

Hi All
Tyre pressure sorted out .....thanks.  Went for another ride today and did about 12 miles around town. Now about 30 miles total on the bike .
Around  the 10 mile mark when the motor was hot it was a bit jerky in the motor or slightly rough. Didn't stop it or even looked like stopping it.
Pulled the plug out when I got home and here it is. Any thoughts on this NGK colour
Thanks

[barenekd]

They tend to run a bit rough when they are new. Just keep riding it for several hundred miles and it will smooth out and the idling will stabilize. As for the plug, replace it with an NGK BPR6ES for about $3.50 and that will help smooth it out. Replacing the stock muffler with just about anything will help, too, and a K&N filter flows a little more air if you don't over oil it.
But basically, just keep riding it and let it get broken in, that will do more for it than anything else. Except maybe the spark plug.
Do change the oil at about 300 miles, though.
Bare

[wildbill]

bare
thanks for the tips. got the efi muffler and the k&n arrives shortly.