stock carb and pod filters

[marcelm]

Another question guys, regarding the mixture screw.
Out of my knowledge, the mixture screw should be set, so that the engine to have maximum rpm, when idle. Afterwards, if the idle rpm is too high, idle can be set from the idle screw.

Is this correct ?

Thanks
Marcel

[Gearheadgregg]

Another question guys, regarding the mixture screw.
Out of my knowledge, the mixture screw should be set, so that the engine to have maximum rpm, when idle. Afterwards, if the idle rpm is too high, idle can be set from the idle screw.

Is this correct ?

Thanks
Marcel

Usually if the idle is to high and your having a lean condition and tuning issues points to Carb Rubber isolators mounts or clamps loose, try checking those, propane torch gas next to the rubber next to the clamps while running , if Rpm increases at any joint you will know, i have my CB 750 mixture screw out 3 1/4 turns, stock Airbox, stock 4-1 exhaust, and 1 step larger Slow jet from stock, if you try to tune by rpm make sure all are close to equal turns out from carb to carb, i usually tune by 1/4 turns each and test ride not by rpm increase, but to answer your question Yes Idle adjustment screw would be the correct way to lower rpm, if your Idle adjustment screw will not lower Idle to factory spec, would indicate Vacuum leak

[NobleHops]

Not to be obtuse, but I think it's worth mentioning that Greg means an UNLIT propane torch.

[Gearheadgregg]

Not to be obtuse, but I think it's worth mentioning that Greg means an UNLIT propane torch.

lol prolly should have said that...but it's not a CBX hahaha Just kidding !!

[asacuta]

Another question guys, regarding the mixture screw.
Out of my knowledge, the mixture screw should be set, so that the engine to have maximum rpm, when idle. Afterwards, if the idle rpm is too high, idle can be set from the idle screw.

Is this correct ?

Thanks
Marcel

Good luck twiddling six mixture screws for maximum rpm. The procedure in the SM requires that one screw be seated before adjusting the others — good luck with that one too. I set all of mine to 2 1/8 turns out. I tried everything from 2 to 2 1/2 turns (all carbs set the same). For me, 2 1/8 worked the best. I'm at a fairly high altitude, so a richer setting may be better if you're closer to sea level. Finally, my carbs are stock; air box is stock; air filter is K&N. Obviously, if you're using a different configuration, the screw setting will differ; however, you'll probably find that setting all screws the same works and is much easier than other methods.

[EMS]

you'll probably find that setting all screws the same works and is much easier than other methods.

Thanks for that, Al. Looks like I am not alone.... I am by no means a carb expert or "guru". This is why I probably have never attempted to find the ideal idle rpm by playing with the mixture screws.
I set them 2½ turns out to begin with. Then sync the carbs and adjust the idle with the idle adjuster on the throttle actuator. Bikes run fine. Although the last time I had one on an exhaust gas analyzer ( the 81) the right bank seemed to be a little rich.

[marcelm]

UPDATE :
Story : CBX650e (1986), stock jets (main 115 & pilot 35), pod filters and free flow exhaust => no power, engine running hot, max speed 135 km/h.

After few jet sizes trials, now we are at 147 main (!!) & 40 pilot, mixture screw 2 turns out and stock exhaust... (my friend wanted to put back the stock exhaust due to free flow exhaust was too loud)

Just did a test ride yesterday, (with the above configuration) : about 200 miles, the bike has a lot more power, but I can say still not as it should have, mpg is 50 (!!) (bike was not accelerated too much), max speed around 160 - 170 km/h. The plugs are in the foto attached (don't understand why the no 3 plug is quite black ..), as you see they doesn't have a tan color, they are more like gray.
Before to do any other mod, I'm thinking to synchronise the carbs and to turn mixture screw out at 2,5 turns. Then see how it behavies and decide next step, if needed ..

Thanks for your advices
...

Marcel

[NobleHops]

Your spark plug crush washers look...uncrushed. You should stop fiddling with the carbs and find out what's going on in #3 though.

[daves79x]

I'd be checking the compression on #3, then verify all circuits are open in the #3 carb. I'd think you are surely jetted big enough.

Dave