Bit of late summer maintenance work today, checking over stuff as you do.

Plugs 1 and 4 look to be running a little rich, 2 and 3 are fine, bikes running good

If my understanding is correct, is this the air adjustment screw?

If it is (and both heads look mullered), is it in or out to weaken?

Thanks

in to weaken. fuel screws between carb and engine, air screws air box and carb.

I'd err on the side of being rich as todays fuel is so bad now

in to weaken. fuel screws between carb and engine, air screws air box and carb.

I'd err on the side of being rich as todays fuel is so bad now

yeh but my TTR is different, its an air screw between carb and engine!

If its running well leave it alone.

Change out the plugs and check after another 500 miles. The plug differences are prob down to different temperatures.

1 and 4 may not burn so completely cos they run cooler than 2 and 3. They may get less air at your normal riding rpm.

When my 600 was tuned they had completely different settings for the middle 2 carbs, even the needles were different. So stock bikes will always show a difference. Sign of running well to be honest.

Think about it. It is nigh impossible for cyl 1 and 4 to be out by the same amount.

Thanks chaps

I did wonder if the difference was related to being the outer two cylinders, the other possibility was an intermittent coil firing from coil 1/4 but I discounted that as the bikes running well

As the screw heads show signs of previous attacks, and there will be no improved performance, I'm gonna leave them alone

Arent the coils 1-3 and 2-4

Yeah my coils run 1-3 2-4.

Arent the coils 1-3 and 2-4

Nope

Yeah my coils run 1-3 2-4.

Mine don't

Ok