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idling speed and cold start

Posted: Thu Jan 06, 2011 2:57 am
by francoisloubser
Now that my gt750 is running nicely I need to know the best idling speed??? I have mine when warm at 1500pm. Second I struggle to start the bike in the morning when cold. Once it has started no problem.

Re: idling speed and cold start

Posted: Thu Jan 06, 2011 12:09 pm
by H2RICK
Francois, anywhere from ~1200 - 1500 is fine for a HOT idle speed.

As to hard starting when cold:
AA) if the bike has sat for a week or more when attempting a cold start, turn the petcock lever to "PRI" for a minute or so to fill the carbs BEFORE attempting to start the bike. EDIT: Do NOT forget to return the petcock lever to "ON" or "RES" before starting the bike.
BB) when you have the choke/enrichener lever in the "ON" position, the throttle grip must be TOTALLY CLOSED. If not, then the enrichener circuit will NOT work and the bike will NOT start, no matter what.

Re: idling speed and cold start

Posted: Thu Jan 06, 2011 2:11 pm
by francoisloubser
Thanks h2rick. Will try that tommorow morning. Problem is it started perfectly the night before. I did turn the throttle with the choke on. The starter then turns the motor and it will kick out some smoke and after about a minute of trying to start it will start slowly running. after 10-20 sec run nicely and no problem after that.

Re: idling speed and cold start

Posted: Thu Jan 06, 2011 8:03 pm
by H2RICK
When you turn the throttle grip with the choke ON during a cold start, you make the choke/enrichener circuit NON-OPERATIONAL. You are/were very fortunate that the bike would eventually start. Your method is VERY hard on the starter motor and the battery.
You need the extra fuel that the choke/enrichener circuit provides to cold-start ANY engine equipped with carbs. These are NOT fuel injected engines with computer control for the fuelling.

Re: idling speed and cold start

Posted: Fri Jan 07, 2011 1:21 am
by francoisloubser
thanks h2rick. I see my peticock has a on position and reserve. No pri. Could this be the incorrect part. It def uses the vacuum to let the fuel out. I see that if I take the fuel line of it will slowly trickle petrol. Could the carbs be empty or flooded???

Re: idling speed and cold start

Posted: Fri Jan 07, 2011 7:06 am
by Coyote
I see my peticock has a on position and reserve. No pri. Could this be the incorrect part.
The lever on the petcock should turn 180 degrees. Prime is at the 3 o'clock position, run at 6 and reserve at 9.

Re: idling speed and cold start

Posted: Fri Jan 07, 2011 2:16 pm
by two-stroke-brit
Coyote wrote:
I see my peticock has a on position and reserve. No pri. Could this be the incorrect part.
The lever on the petcock should turn 180 degrees. Prime is at the 3 o'clock position, run at 6 and reserve at 9.
on my 73 and 72 model the res is at 3 oclock ,pri is at 6 0clock and run is at 12 oclock.

Image

cheers mark

Re: idling speed and cold start

Posted: Fri Jan 07, 2011 2:25 pm
by Coyote
I think the lever design changed in 74 when they went to a single fuel outlet.

The hole on the lever indicates position. The little blip at the top of the lever cover is a stop.

Image

Re: idling speed and cold start

Posted: Fri Jan 07, 2011 9:11 pm
by Coyote
So what does the dimple signify that Suzuki used on these tiny screws?? Love my camera (Fujifilm S-700). Took one shoot at the camera's first macro setting and the results speak for themselves. Ya think??

Re: idling speed and cold start

Posted: Fri Jan 07, 2011 10:33 pm
by tz375
Is that to indicate ISO threads rather than JIS threads perhaps?

Re: idling speed and cold start

Posted: Mon Jan 10, 2011 1:03 pm
by H2RICK
That's exactly what it's for, TZ.
That indicator was dropped from most Japanese bike fasteners by the late 1970's. It was originally introduced ~1968 so the factories figured that after 10 years everyone knew that the changeover had been made.