Subject: RE: Help! Carb adjustments
Author: Ian Adkins
Date: Jan 17, 2005, 3:43 AM
Post ID: 1718222151
Gerard,
I hope that I am not repeating what others have said....here is a basic
recount from Guzziology:
The idea is that since each cylinder has their own carb you have to get each
cylinder running like one. To do that you need to balance the idle rpm (big
screw) and then get each running as perfectly (perfect mixture = best burn
rate) as you can (by adjusting the mixture screw).
The big screws merely set the idle speed. That is where your carb balancer
comes in. Some people look into the intake and measure the height of each
slide. Best way is to synch with a meter. Once you have each cylinder
balanced with the other you can set the mixture.
Keep in mind that the mixture screws (the little ones) are really a fine
tune adjustment. To really change the mixture you will need to change the
jets, however, if the carb slides are not worn, you have not made major
alterations to the engine and everything is ok then you shouldn't need to
change anything....I have never had to, at least. Screws are 45 for main jet
and 145 idle jet...I think. Becareful...you can mix the two up. the 45
screws into the pump assembly.
Assuming the carbs are now balanced for idle speed then you can fine tune
the mixture. To do this you rotate the little mixture screw a 1/4 turn at a
time and listen to the engine. Turning in will lean the mixture and out will
richen. I always turn in first because a lean mixture is more pronounced. Be
sure to wait about 5 seconds between turns to listen to the engine. Once you
find your "lean point" rotate out till you hear the engine start to run
better. As the mixture gets better the rpms will increase slightly as well.
Rotate past the "sweet spot" till it starts to run rich. This will help you
find the extremes. Once you have that you can find the best place to set
your mixtures.
Once you have done all of this you may need to readjust the idle speed.
As others have said...be sure that your timing is correct. Let us know how
you make out...Ian
| -----Original Message----- From: Mike Walker [mailto:moto7-@yahoo.com] Sent: Sunday, January 16, 2005 11:12 AM To: Loopfram-@topica.com Subject: RE: Help! Carb adjustments Thank you Paul and thank you Pat for your resopnses- The throttle cables are new and lubed and slippery and do not seem to be binding. There is just enough free play at the throttle grip to prevent the throttle cable sheath from slipping out of the little 'port' at the end of the little chain device that translates the rotational motion of the throttle grip into the back and forth motion of the cable. There is about 4mm of play there. A vintage BMW friend has a digital carb ballancer, and he installed threated ports on the inlets while I rebuilt/cleaned the carbs. I got the bike running strong enough to ride out to a club breakfast and then to the Easyriders show here in Sac, but the bike was still inconsistent enough at idle to die twice at stoplights along the way. Fortunately it restarted quickly enough. Fortunately, because I was surrounded by rich Harley bikers with fabulous paint jobs! I'm not quite sure how I should adjust the carbs once the digital balancer is hooked up. I suppose I should set the pilot screws to the factory setting and adjust the idle screw and the throttle slide adjustments to get the vaccuum even between the two carbs? Thanks in advance- Gerard in Sacramento |