I've read a topic hereabouts regarding a "cold start procedure" for Superhawks / Scramblers -- I can't find the question now -- so I thought I'd throw in my own experiences & routine for good measure! All the ensuing scribe is assuming that the valves / carbs / timing are all correct, as laid out in various posts, that the plugs are indicating that you have the mixture absolutely spot-on and that you are satisfied with the idle speed once the motor is up to temp.
- 1. adjust the camchain tensioner, as per the handbook/manual
2. adjust the valve clearances, as per the handbook/manual
3. check that there's no valve train backlash as described in the attached pic
- 4. http://www.honda305.com/forum/index.htm and click on FAQ in the left pane; follow Ed's recipe
When the motor is cold (after an overnight rest) turn on the petcock, close the choke (lever up) fully,
- turn each idle screw exactly 1½-turns c/w
start the motor using your preferred method -- no throttle
immediately open the choke lever to about a 90%-closed position
turn each idle screw exactly ½-turn a/c/w
after about 30 secs, open the choke (lever down) fully
By the time I reach my first light junction -- about ½-mile -- I can back the screws a/c/w to ¼-turn; and at the next light -- another mile -- the screws can be returned to 'hot idle' and about 800-1000 rpm.
NB: Once my carbs were set as Ed suggests, I then warmed the motor to op-temp and 'fine-tuned' the balance (opening sync and idle sync) using a length of smallbore tubing as a stethoscope as follows:
- Remove the air filters & ducts.
One end of a metre-length of 4mm-bore screenwasher tubing held adjacent to one ear canal (not in the canal!) with a biiiiig elastic band, the other end held 90º to the throat of each carb in turn in exactly the same position at the 6-o'clock point
Feather the throttle gently to about ¼-open -- the induction rush should sound identical
Allow the motor to idle and repeat the blue text -- adjust to a satisfactory idle, once again the induction rush should sound identical