Jetting for mufflers

[chef1366]

It's 108 here and supposed to go up to 112 tomorrow:-(

[Beemer]

Installed the 105's and intake boot O-Rings. The pilot air screw on the bottom of the bowl's are set to 1.5 turns presently.

The test drive.

Still stutters at low speeds but not quite as bad.
Between 2000 and 4000rpm with heavy throttle it sputters.
At 6000 she takes off like a raped ape all the way to 8500.
I haven't played with any screws yet.

The hoses.
#2 is open and resides on top of the air box.
#3 is attached to the petcock vacuum nipple.
#4 resides on top of the air box.
Need to buy hose for the fuel sensor nipple.

How many turns should the pilot screw be set at.
How many turns should the screws on the side of the carb's be set at approx.
Who do I send a cheque to?

[chef1366]

You need to sync your carbs first. Mark your throttle 1/4, 1/2 and 3/4. First check your mains with a full throttle chop. Pull with full throttle as long as you can and hit the kill switch without letting go of the throttle or pulling in your clutch. When the motor is killed pull in your clutch and coast to the side of the road and pull your spark plugs and read them White is lean, tan is good and black is rich. Adjust the main with full throttle until tan. Then do your needle circuit(you have an adjustible needle) (1/4 to 3/4) Lowering the clip on the notches will raise and richen the needle. Then do the pilot circuit which is the idle adjustment screws and the pilot jet. If you're lean after messing with the adjustment screws from idle to 1/4 throttle then you will have to go up one on the pilot jet. Keith will tell you to do your needle first because you do ride on this circuit most of the time, but it is a matter of preference.

[KEITH KRAUSE]

Installed the 105's and intake boot O-Rings. The pilot air screw on the bottom of the bowl's are set to 1.5 turns presently.
Still stutters at low speeds but not quite as bad.
Between 2000 and 4000rpm with heavy throttle it sputters.
How many turns should the pilot screw be set at.
How many turns should the screws on the side of the carb's be set at approx.
Who do I send a cheque to?

First of all, you haven't done a bench or vacuum synch. It's an important part of the jetting. Basic tuning before jetting. Don't expect good results if you take short cuts.
Then you need to adjust the side air screws using the highest idle method as I said.
Both of these could be causing your "sputter" problems.
Highest idle method: Warm up the bike completely. Turn off and place on centerstand. Initially set each side air screw at 1 1/2 turns out. Adjust throttle cables for correct play. Start the bike and set the idle to 1,000/1,100 rpm's, no more. Starting with any screw, slowly turn it in either direction until you hear the rpm's max out. Fine tune it. Generally, they end up 1 1/2 to 2 turns out. Now reset the idle to base 1,000/1,100 rpm. Repeat to the others one at a time.
Leave the pilot fuel screws where they are for the moment.
Also, don't expect great performance when fully opening the throttle at 2,000 rpm. Allthough a correctly tuned bike shouldn't sputter even under this condition, most people don't ride like this. It's like deliberately trying to make it show a problem.
If a vacuum synch and correct air screw adjustments don't cure the sputter, then I suspect the jet needle needs adjusting. But you have to vacuum synch and set those air screws and take a solid 1/3 plug/performance test first. We need to know how the plugs look at that throttle position after a couple miles. If you find a safe place to test, run it in 4th or 5th gear and chop off. Take a rag and a piece of hose with you that fits snugly over your plugs. The hose will help you remove and install the hot plugs. Careful of cross threading as always.

[KEITH KRAUSE]

Also, after re-reading this thread. The carbs may still need more cleaning and inner o-rings could be bad. Float levels could be wrong.
Valve clearances need to be checked/adjusted and this should be done before any vacuum synch.
What plugs are in it? Do you have a good bluish spark at all four plugs?
Have you checked/cleaned the coil terminals and other connections such as the battery posts and grounds to frame and motor?
What color are the plugs after just general riding around/testing?
Is the filter clean and is the air box lid ON?
Etc, etc.
I just want you to know that it can get difficult when you take short cuts.
You don't want to mix troubleshooting with re-jetting. Taking care of all other tuning first makes the re-jet much easier.

If you're serious about sending a cheque, please send a few bucks to this great site. Future members looking for help will appreciate it.

[Beemer]

Well Keith. Mostly I took the day off today. The heat just got turned on in the Okanagan in a serious way.

I did have a chance to ride and check the plugs. Black and sooty.

I need gages for the vacuum synking of the carb's. I like putting money into tools instead of labour costs.

Slow speeds produce the stuttering ride still. I'll do some more cleaning this week. Never removed the floats so I may have something gumming up the works.
Power band range seems to be good.

You've given me lots to do. I'll be back.

Thanks again.

[KEITH KRAUSE]

OK. Like I said before, you need clean/synched carbs to get accurate plug reads and good performance.
You also have to tell us what throttle positions caused the plug colors/reads. Three separate jetting circuits here.
Black and sooty is obviously rich, or a weak sparking problem. Since it sounds like you need to service the carbs, do that as you've planned. Test, and we'll go from there.