Topic: Mixture screws on CB350, help...

[zanzara]

So I bought my wife a 1971 cb350 twin. Tonight after cleaning and putting back together the carbs with K&L kits the idle is sitting in the 4000 range. As there isn't much to adjust here all I can think is that these wacky mixture screws that come with these kits are totally different that they have a different setting than 3/4 turn out. Does anyone know a setting? Or maybe something else here? Cables are out to drop the gates all the way. Any help would be awesome. Also anyone with knowlege of these kits, what is the silver barrel thing for?

[Raul CB750K1]

Green550F just posted this link. You can check the idle screw setting for the CB350; it's either 3/4 of turns out or 1 full turn out.

http://oldmanhonda.com/MC/DataTable.html


Regarding the high idle, on the opposite side of the carb to where the throttle cable attach, there is a throttle stop screw. They are used to synchronize the carbs, but obviously, if set too high the idle would be high too. Once both carbs are synchronized with the cable fully loose, they you use the throttle cable sleeve locknuts to "synchronize" the siamese cable in such a way they both pull the same amount when twisting the grip.

I don't kinow if I have explained myself; in case I don't just ask and I'll try to be more clear.


Raul

[Cowboy]

Rauls right, Zanzara. If your bike is idling at 4000 RPMs, the mixture screw is not the cause. The mixture screw just controls mixture, and no matter how weak or rich the mixture, you will not be able to get the RPMs that high by turning the mixture screw.  In order to reach RPMs that high, you have to open the throttle plate. One of the throttle shaft adjustments is causing your high idle.

Like Raul said, there are two adjustments that could hold the throttle plate open. One is the adjustment screw on the outside of each carb. The other is the cable adjustment on the inside of each carb. First, slack off the cables so that they are loose. next, Screw the adjustment screws out so that the tips of the screws are not touching the carb body, then screw them back so that they just touch again.  Now, check how loose your cables are. Adjust the cable attachment to each carb so that there is the same amount of slack in each cable. Basically, you want them to be just snug, yet not pulling on the throttle shaft at all. When the hand grip is not turned, those adjustment screw tips should still be touching the carb body. If one of them has a gap, that throttle cable is too tight. When you turn the grip a minute amount, you should see both cables begin to pull on their respective throttle shafts at exactly the same time. When you let the springs pull the throttle back closed, those screw tips should touch the carb bodies again, on  both sides. If they do not, you could have one of tow problems: either the cable is adjusted too tight where it attaches to that carb, or your throttle shaft or plate is sticking open slightly.

Once you reach the point where twisting the grip slightly begins to open both carbs at the same time, and the springs pull the throttle plates completely closed (with the adjuster screw tips JUST touching their plates) you are ready to start the bike. It will probably idle nicely just like it is, at that point. If not, you can turn the adjuster screws in to increase the idle a bit, but be sure to turn each one exactly the same amount.

[zanzara]

Thanks guys! now to work...after I messed with it, it didn't make too much sense. Give it a whirl. It did calm down a little. The p.o. had a clogged carb and was running around on solo for a while so maybe that is part of it. Will go through the steps at least.