Topic: Cb750 lean cylinder help.

[PeWe]

I think that the leaner carbs (1,2) are OK,  the richer (3,4) make plugs to look better despite too lean jets.
I'll see if it turns better when all 4 have same level and larger mains.

It was strange that I had to correct carb 1, 2 when carbs were brand new. If all were equal at delivery, I reduced 1,2 and made them leaner than 3,4.

There is a risk that the float bowls migh be filled different when doing one by one draining all fuel. Level is one thing, they must have same level so the jettings will be the same.

The angle of how the carbs are mounted will have an effect of float levels too. I did not have carbs strapped into frame when the fuel levels were checked as I did later on. Only clamped to new OEM carb boots.

Wrong float/fuel level can become very expensive.

[flybox1]

Good work on the clear tube test, Pewe.  Diligence pays off.

How is the throttle response?

[PeWe]

Response is very good.Too good on 1:st gear when I have to twist the grip very gentle.
I'm in Spain on vacation for the moment. Looking forward to check my postbox when back home for the 3 clear tube tools doing all 4 at the same time to get an accurate result. I think bowls can be filled different time to time. With tubes on all 4, it will be visible how carbs affect each other via the fuel hoses connecting them. All must be OK at same level when mounted. The photos here were done last year. I strapped the entire set up against the frame later on, a little bit more up. The carbs cannot hang in the boots only. I' ll add new photos here when I have checked all 4 simultaneously. Fuel levels seems to be very important as the TS verified. I'm convinced that I have same reason for extra lean on cyl 2.