Honda Twins banner

1 - 6 of 6 Posts

·
Registered
Joined
·
21 Posts
Discussion Starter · #1 ·
I need some help or direction in setting the idlefor my bike. How many turns on the idle screw and the fuel mixture screw. Thanks! I’m from Chicago, Illinois! And I got this bike running. Just have the idle running a little rough.
 

·
Registered
Joined
·
7 Posts
Cool looking bike, I almost scored one of these last year.. It had a unique (to me) cable operated front disc brake.
 

·
Registered
Joined
·
35 Posts
I'm pretty sure the "factory" air screw setting on your bike is 1 1/4 turns out (so turn it in all the way and back it out 1 1/4 turns), but obviously you might have to alter that slightly depending on how it runs. As for the idle screws, i think idle speed should be around 1000rpm so set the screws even so it idles nice on both cylinders at that speed. Another thing I would recommend is to make sure the cables are adjusted equally in the top caps of the carbs, when you turn and release the throttle (when the bike isn't running) you will hear the slides "click" in unison as opposed to one slightly after the other if the cables and idle screws are set evenly as they should be.
 

·
Premium Member
Joined
·
10,203 Posts
Idle speed is 1200.

IIRC your idle speed is set by adjusting the slide stop screws on each carburetor. To balance the carbs, with the bike warmed up and at idle, you pull one spark plug wire (if you have or acquire a set of insulated plug wire pliers you can save yourself the thrill of a lifetime:eek:) and note the idle rpm. Re-connect that plug wire and disconnect the opposite plug wire, note the idle rpm. If the single cylinder idle rpm is the same on both sides (all else being properly adjusted) you have them balanced.

The initial setting for the mixture screws is 1 1/4 turns out from lightly seated. With the engine warmed up and idle set as above, adjust each mixture screw to achieve highest idle rpm. Re-adjust the idle rpm by turning each of the slide stop screws the same amount in the same direction. This should maintain balance between the carbs.

Beyond that, you also need to adjust the cables so the slides lift together.

One of the small twins gurus will likely be along to either validate my memory or to correct it.
 

·
Registered
Joined
·
4,770 Posts
1200rpm idle, fully charged battery
Make sure the throttle cable isn't hung up on the tank ( it's a tight fit on the cb200
Make sure you've done a full tune up of the points and valve gap before you start
Check the oil doesn't smell like gas while you're at it ( Thin oil is the fastest way to melt cams)
The screw settings are in the Fsm ( don't use a clymer or Haynes knock off manual they're full of lies) there are free Pdf copies on line.

Pulling either HT lead on a Cb200 should kill the engine since its got a twin fore coil
Here's Steve's (66Sprint) carb setting for smaller twins
Back to setting the carbs
"I start with the slides synchronized (cable adjustment), throttle stops backed out, and the mixture screws turned to the center of their specified range......
Hold the throttle slightly open and start the engine..... Back the throttle down until you get an idle ~1200 RPM, HOLD it there, and gently turn in the throttle stops until it starts to rev.....adjust back to 1200.... Once it is again idling at 1200 with both throttle stops set, you are ready to do the actual adjustments......

Pick a carb....adjust its MIXTURE screw throughout its spec'd range to find the point of highest idle RPM, and leave it there at highest revs...adjust that carb's throttle stop back down to 1200 RPM...
Same procedure, other carb......
Repeat on both carbs to verify/fine tune.......Repeat again IF necessary....
Re-verify slide sync...Adjust IF necessary (usually no more than 1/4 turn on the carb top adjuster, often they are still fine)...
If you did this correctly, vacuum , exhaust pressure, and exhaust heat will be the same on both sides (hard to verify last two on the CL)
Engine response to throttle should be "crisp" and smooth throughout entire range.... Last edited by 66Sprint; 03-05-2015 at 05:29 PM."
 
1 - 6 of 6 Posts
Top