Idle Mixture Screwed

[tweeleft]

Hello I had grooves in three of my carbs with #4 having a broken tip. The grooves looked like they were over tightened. I installed each in a drill and with some sandpaper was able to smooth out the groove. Replaced #4 and colortune,sync and she idle great. Good luck

[DGXSER]

While at XSEast this year, my bike decided to spit out an idle mix screw on me. I can speak from experience that if you try to run the bike with no mixture screw in there, it will miss, badly at anything more than idle. It will also sputter and miss and backfire at idle as well, and you will have no ignition in the cylinder most of the time. When you hit the mains, it will take off and run nice. I rode the bike over 100 miles at XSEast missing that screw and then about 200 miles home. Above 3k RPM it ran good. Taking off, had a bad miss under any kind of power.

[conquest87tsi]

Still screwed

So I read somewhere on here that XS650 mixture screws from 76-77 work for the 79 XS1100 Minukis. Well I wish I hadn't listened to that dumbass. They obviously do not. Does anyone know where to get just the mixture screws? I don't need a complete carb kit, and it seems that any place that lists them individually has them listed incorrectly. Mine are just grooved about 1/8-1/4" from the tip. Will sanding them really help? Before when I adjusted the mixture, two of the screws did nothing.

[Tat2demon]

I could only find them with a complete kit from Georgefix on ebay.

[bikerphil]

YamaMama...

http://www.powersportsplus.com/parts...923-00-00.html

[skids]

Sanding-out the groove will likely make them slightly out-of round or will have scratch marks and that would be all that is needed for a slow leak. You might be better of reinstalling them. I have had good luck with Eagle-one polish on a q-tip to remove imperfections around the needle valve seat (even though the tips were grooved)

[WMarshy]

I wonder if they would be less prone to breaking if they were maxe from bronze... any thought on that?

[conquest87tsi]

Idle

Well I got my new mixture screws. Set them at 1.25 turns. Bike seems to be running much better, just waiting until tonight to fine tune it with my digital tach.

I was just remembering that previous to rebuilding the carbs I had a condition where the bike would idel around 1200rpm on start up, but climb to 1900-2100 after it was warm. Does anyone know what this is an indication of?

[DGXSER]

You may need to reset your idle speed down to 1200 when it is warm. This may adjust how much enrichment it requires for start-up.

[conquest87tsi]

Idle Mixture

I got her tuned up last night using the digital tach. The screws ending up being right around 3 to 3.25 turns out. I originally set the idle just under 1100, but upped it to 1200 after riding a bit. I no longer have the high idle condition I experienced prior to the carb rebuild when it warms up.

I did notice that I now have a dead spot with little power around 3500-4500rpm under load, and also over 6000rpm it starts sputtering and loses power.

Am I experiencing a lean condition at these points? Will adjusting the needles richer remedy the midrange power loss? And rejetting the high?

I know others have mentioned that these engines don't make power under 3k and I have noticed that prior to any of this work, put this is something totally different.

I guess I'll give so more info on what Ive done. It had after market exhuast installed when I aquired. I installed pod filters. I recently replaced the float needles, adjusted floats, replaced worn mixture screws, resynced, and adjusted mixture.

[conquest87tsi]

Snap ring pliers

One more quich question.

Does any one know where to purchase a snap ring pliers to remove the snap ring in the diaphram to remove the needles to adjust. It has to have some long forceps.

[motoman]

One more quich question.

Does any one know where to purchase a snap ring pliers to remove the snap ring in the diaphram to remove the needles to adjust. It has to have some long forceps.

??.............none needed......take out the tiny screws that hold that plate down on top of metering rods. Dropping back in, the top portion fits indexed one way, plate back on and screws back in. Haven't read any of the previous as to the bikes set-up, jetting etc. but sounds like your a bit rich in the idle circuit and lean in the main circuit. Your gonna have to do a plug throttle chop(kill it) after running a steady couple miles in the idle circuit(under 4K). Same after a steay pull for a few miles at or above 5K(in alower gear if needed).

[CaptonZap]

You know Brant, you have touched on one of the problems facing those who are trying to do a main jet plug reading, using the ignition chop method.

Just where do you find a hill steep enough to be able to lug it in 5th gear, let alone 4th gear, and long enough to ride it long enough to color the plug?
Makes a guy long for a water brake dynometer.


Or a REAL stiff headwind. CZ

[Rasputin]

You know Brant, you have touched on one of the problems facing those who are trying to do a main jet plug reading, using the ignition chop method.

Just where do you find a hill steep enough to be able to lug it in 5th gear, let alone 4th gear, and long enough to ride it long enough to color the plug?
Makes a guy long for a water brake dynometer.


Or a REAL stiff headwind. CZ

It does not take much of an uphill if one is even needed. An uphill climb just makes sure that the engine is working as hard as it can. The plug color will change faster than you can imagine. Give this a try if you do not believe it, take the bike out and lug it around for a while...way to high a gear for a bit and try to accelerate a few times. Stop with the chop method and check the plug colour. It will be darker than expected. Now take it out to where you can open it up for a short while in any gear of your choice and hold it there for 30 seconds. Stop using the chop method and I almost guarantee the plugs will be lighter in colour.
I have checked plugs on a high speed chop that were a totally different colour than the same bike after idleing for a minute once I arrived home. I am a firm believer in whoever Brant is and his method.

[natemoen]

??.............none needed......take out the tiny screws that hold that plate down on top of metering rods. Dropping back in, the top portion fits indexed one way, plate back on and screws back in. Haven't read any of the previous as to the bikes set-up, jetting etc. but sounds like your a bit rich in the idle circuit and lean in the main circuit. Your gonna have to do a plug throttle chop(kill it) after running a steady couple miles in the idle circuit(under 4K). Same after a steay pull for a few miles at or above 5K(in alower gear if needed).

Oh but the early carbs do not have the screw on pieces in the slides, it is held in by a snap ring. I ground down a snap ring pliers so that it fit.