Choke and idle speed

[Melnic]

So, bike running great. Couple things.
I use the choke/Fuel enrichment on the side of the Mikuni carbs to start it but after a few seconds, if I leave the choke on , it will die.
NOW, if I push down on the choke handle which lifts the fuel enrichment plunger more, it will keep running and idle 500-800RPM more.
Strange, like wondering if there is a way to adjust how much the plunger goes up, I have not looked at it hard, but maybe a way to bend the spring?

So,until I have the bike fully warmed up which seems like after I've ridden it a couple miles, I turn the idle screw on the left carb up so it idles nicely at the beginning at 1000rpm, but after the warm up of a few miles or more, it will be at 1500rpm so I have to drop it back down with the screw. Is this typical?

 

[5twins]

Yes, the spring steel clip that holds the choke on can be bent to try and adjust how much the lever lifts the choke plunger, but before you do that, try this .... there is some play in the mount so loosen the screw and rotate the bracket to the left (CCW), then re-tighten the screw. That may be enough to do what you want.

Yes, it is typical for the idle speed to be low when cold, then increase as the bike warms up. If you eventually get the bike in a good enough state of tune, you should be able to find an idle speed setting that will work for both a cold and hot motor, and not have to adjust it up then down all the time. But even so, this bike has a 1200 RPM idle speed spec for good reason. It will up and stall sometimes if the idle speed is set much below that. When I first got mine, I thought that 1200 setting sounded kind of "busy" so I set it lower, at like 1000. But then I encountered the issue of it randomly stalling at idle. So, it really does need that faster idle speed. I've grown accustomed to it now and it doesn't bother me any more.

Even though I have gotten mine to idle OK both cold and warm at one setting, I still need to "tweak" the setting a couple times a season it seems. I need to turn it up a little in the cooler weather (early spring and late fall) then turn it down a little during the summer once it's hot out.

 

[Raymond]

I like to set mine so it idles at 1200 rpm once thoroughly warmed up - after a few miles of riding. But this means I have to hold a small amount of throttle for the first few junctions or it stalls.

 

[Melnic]

thx guys
5twins, since I pulled that spring all the way off when I cleaned the carbs, I bet its not set as far as it can go in the amount of play. I'll start there when I have the chance. I'm hopeful this will help with starting it with the kicker too. If I forget to bump up the idle speed screw, its much harder to start on the kicker right now. If I remember to bump that up a half turn or so and use the choke, after 2 prime kicks, it usually starts on the first or 2nd kick.

 

[5twins]

To make those "on the fly" idle speed adjustments easier, I've started pressing knurled "caps" onto the screw heads .....

The top remains open so you can still use a screwdriver on it .....

I use Presta valve stem adapters sourced from eBay (less than a dollar each) .....

I drill them out slightly smaller than the top of the screw and press them on .....

However, this can be difficult sometimes because if you look closely, you'll notice the screw head is tapered slightly .....

So, as one of the first little projects with my "new" mini-lathe, I want to try and get rid of that taper, make the screw head straight down it's sides. That should make pressing the knurled cap on much easier.

 

[Jan_P]

Very fine idea Mr 5t creative thinking outside the box

 

[Melnic]

Thx, we are thinking along the same lines, I have a 3D printer and can do basic mechanical drawings.
I'm considering making a knurled knob to go on the top that will be as big as it reasonably can so I can get to it w/ my gloved hand a tad easier.
Even the existing screw is not too bad with my gloves and I can adjust it at a stop light already. But not with 1 finger yet.

 

[Raymond]

You can adjust the idle screw when stopped at traffic lights, left glove off, thumbnail in the screw.