rginsbtx wrote:
davej wrote:
As far as the screw in the carb put a screwdriver or allen(whichever it is) in the screw and with something supporting the bowl lip hit the screwdriver or allen with a hammer. That should break the screw loose. if you have an impact driver that will also work to get it out.

I used to be a certified Yamaha Electronics tech. Even the electronics side of Yamaha used the same type of soft metal screws.
What I would do to prevent from rounding out a screw head was make sure that I had a Good fitting Phillips screwdriver, I used snap on.
If I still stripped it out, I would use my diagonal wire cutters. Place the cutters over the head of the screw in the middle, squeeze the cutters and turn it sharply ccw. That usually would break the screw loose. It is all about torque. Handheld impacts, I used to use on my dirt bike, but I would not want to use on a carb, since everything is soft/brittle metal.

Rg

Good to hear that even a Yamaha tech struggled with this. You wouldn't believe how many different phillips screw heads I tried in that throttle screw trying to find something that would grab, including the type that I could put in a socket on my ratchet. I finally ended up using a fine chisel to groove one side of the screw and tap it loose with a hammer after putting the housing in a vice. My next choice was to drill it out, which I was avoiding.

My go-to in the past has been a needle nosed set of vice grips to do what you do with the cutters. But in the case of the throttle screw it is inset and protected by a lip so you can't get a grip on the head.

Soft metal screws are fine, as long as you loosen them up every five years or so, but after 16 years they just seem to like living there far too much...

rginsbtx wrote:
davej wrote:
As far as the screw in the carb put a screwdriver or allen(whichever it is) in the screw and with something supporting the bowl lip hit the screwdriver or allen with a hammer. That should break the screw loose. if you have an impact driver that will also work to get it out.

I used to be a certified Yamaha Electronics tech. Even the electronics side of Yamaha used the same type of soft metal screws.
What I would do to prevent from rounding out a screw head was make sure that I had a Good fitting Phillips screwdriver, I used snap on.
If I still stripped it out, I would use my diagonal wire cutters. Place the cutters over the head of the screw in the middle, squeeze the cutters and turn it sharply ccw. That usually would break the screw loose. It is all about torque. Handheld impacts, I used to use on my dirt bike, but I would not want to use on a carb, since everything is soft/brittle metal.

Rg

I"ve broke quite a few carb bowl screws loose with the screwdriver and hammer without an issue. I showed a couple guys in Celina how it is done when I was rebuilding carbs for members there. I guess I just have that magic touch. I've also cut the heads off and used vise grips to remove the threaded part of the screw when the head was too stripped to grip with a screwdriver.

MidnightRide wrote:
SKWEARpeg wrote:


Keep in mind, this is just a mixture adjustment, with a closed throttle, and the idle set correctly. If after all this messing, you think you are seeing some benefit from backing it out further, in hopes of fixing something else, git-r-done. But, you'll have just wasted all the time setting the idle mix, which is what the PMS does. I think you would be better off tweaking either the clip elevation on the needle, or bumping the Pilot size, for off idle hesitation.

It's possible the decel popping may be related to either a vacuum leak, or possibly an exhaust gasket leak. It wouldn't be the first time somebody spent a lot of time chasing a "jetting" issue, only to find out they had extra air getting in from somewhere.

Keep in mind as well, the Roadie is a long stroke air cooled v-twin, with a single carb trying to do it all. They aren't partial to the Maserati style throttle blipping at stop lights or in the driveway. They are just not that kind of a performance machine. They will pull like a freight train though.

Keep in mind that regardless of the PMS settings that I've used, from 2.5 all the way out to 3.3, I'm fine with the results of idle. It runs and sounds fine. I used to run an even lower speed idle because I liked the loping sound, but in reading the RSC posts I've gleaned that the motor may have oiling issues at too low idle so now I run it faster. It used to speed up a bit when it got hot but now with the higher idle speed it doesn't change much.

I'm just trying to figure out how far up the power band the idle mix affects performance and whether leaning out the idle can really affect the higher revs much as it relates to running leaner.

My next experiment may be running it from about 2.0 out to 4.0 to see what results I seem to be getting under the entire throttle range. I think the screw was about 4.0 out when I bought the bike last month and that produced some annoying backfiring. But tweaking the PMS did show that it was causing the backfire because it completely disappeared as I turned the screw in, eliminating any thoughts of gaskets or a cracked manifold. That's all I was really trying to chase down with the PMS adjustment to begin with, and that put that issue to rest.

The idle mix works, until the airflow through the carb, causes enough of an air pressure differential in the throat, versus whats over top of the diaphragm above the slide, to cause the slide to start to lift. That's the transition. At that point, it's all about the elevation of the needle(clip position). To lean on the needle(as in the clip is to high), and the transition causes a hick up or buck and snort. To rich, and there will be a bog until the airflow increase to compensate for the rich condition.
The size of the Pilot, creates a restriction on how much fuel can enter the Pilot circuit at the bowl. No more fuel can come out into the carb throat, then what gets in the Pilot jet.
Bumping the Pilot up, allows more fuel in the Pilot, before you hit the transition. This helps avoid the transition, until the air flow is enough for good atomization as the fuel starts spitting in around the needle. It makes your 1/4 throttle happy for lack of a better definition. The fuel coming in the Pilot, will continue to be part of the full amount the carb is using through out the rest of the throttle range. At WOT, your getting everything from both the Pilot and the Main.

To small of a Pilot, and you need to be richer on the needle to help with the transition. To rich on the needle, and your mileage stinks. If you work the Pilot, the clip position, and the Main correctly, your throttle response will be nice and smooth throughout

In the end if you're happy, that's all that matters. Until you ride another Roadie that may or may not change your perception of how yours is running, your good to go.