Topic: What is the proper uses of the choke mechanism?

[stevenmgrr]

What is the proper way to use the choke when starting the bike?  How long should it be left on?  What are the expected behaviors once the choke is set?

Here is what I am noticing with my 71 CB500. Just for reference, I have done a tuneup, and rebuilt the carbs, sync'ed them, new plugs, points set...etc.  Anyway, when I attempt to start a cold engine without out the choke set I get nothing.  If I set the choke to full, the bike will start, but I need to crack the throttle open a bit once it starts to keep the rpm above 1000-1500.  While doing this, she kind of coughs or misses.  After only about 10-15 seconds I slowly decrease the choke and the engine response by increasing its idle speed and I can subsequently release the throttle.  After about a minute of this routine everything runs fine and by the time I reach the end of my block and stop she is running great.

Is this the 'normal' procedure with these bikes? 

Thanks,
Steve

[kvallelunga]

Sounds about right. Maybe try to not pull it out all of the way initially, that might help with the coughing and sputtering on the start.

[BobbyR]

That is normal, just pull it out full start the bike and if she runs well in that short a time, you have no problems. They are cold blooded by nature.

[TwoTired]

Since you have a 71, you should have a throttle friction adjust under the throttle control.

Just set your main idle screw for the correct RPM when the engine is a t full operating temp.

For cold start, put some friction on the throttle, enough so it will stay in place.  Apply full choke and start. Adjust the twist grip for fast idle.  Back off the choke to about 3/4 applied.

You can now drive off, and incrementally remove choke in bits, till it is off while riding.  When warmed up, you can back off the throttle tension so it will return to idle.

The 500/550 is not even close to cold blooded, particularly when compared to the 750 (assuming no mods from stock).  It has less mass to warm up and hotter spark plugs than the 750.

In fact, I don't allow it to have a stationary warm up.  Suit up ready to ride, apply choke, start, and drive off.  You only apply enough choke so that the engine will take throttle for some acceleration.  Your hand is on the throttle to keep high idle, and after a block or two the choke has gradually been moved to off.

Drive on...

[stevenmgrr]

Thanks TT.  I always wondered what that spring loaded screw was for.  I see, after searching for the proper term 'throttle friction', that you have answered this question a number of times.  Normally, try to search for answers before posting, but I didn't know what to look for. 

I will also try just riding off and see how that goes.

[stevenmgrr]

I will also try just riding off and see how that goes.

Update.  I tried just starting it with some choke and riding off.  Worked fine.  After about a mile or so I took off the choke and it idled fine.  So much for my so called expert friend who said that you 'need to warm these old bikes up before you ride them'. 

[TwoTired]

Thanks, I got a good chuckle out of that, Steven.   Probably cause I've been riding it that way since 1975. 

The only caution I would give is that you keep from heavy acceleration/high RPM while the engine isn't at operating temp.  Moderate accel is ok, flat out - not good until the oil is warmed.  Of course, any operating mode is fair game if you need power to avoid injury/accident.

Cheers,