Low end stumble

[dbeardslee]

Mikes XS sells them for $6 a pair.

[WMarshy]

Awesome! 'Bout time a real discussion came up regarding that stupid stumble! Seems like a lot of us have it and it varies a little in intensity and range but, for the most part seems to be the same problem across the board. I dont have a color tune so I dont have any visual evidence of the mixture under 3500 RPM is but my plugs look great (probably from all the WOT). I am almost certain my bike is too lean on bottom end though, pulling the enricher usually gets rid of the stumble on a cold engine. Once its warm it's tolerable and just lacks 'passion' lol. Tolerable to the point that IMO isnt worth pulling the carbs to increase pilot jets. Since its my only mode of transportation I would have to get really motivated to tear into those carbs!

[planedick]

Pullin' carbs

I have the carb pulling and adjusting down to a science. In under an hour I can take 'em off, do the adjustments to the floats, change jets, put 'em on, synch, adjust idle mix and go for a test ride. I been thinking about doing a video on the process with all the little tricks I've learned , but no-one to hold the camera, do the zooming etc.

[WMarshy]

That would be great to see! You cant find a neighbor kid that wants to make a quick $10? Just be carefull about going around asking kids to running a camera for ya...somone might get the worng impression.

[3Phase]

I've thought about a spare set test and Larrym has offered to send me a set to test, but it's not something that came on suddenly and probably becuase of the Harley mufflers.

I have a good set of spare carbs but they're '80s style. I have some early style carbs with messed up idle screw mixture holes but no broken float posts so they might be salvageable.

I had spare sets of carbs myself and sold them because I figured I'd never really need them. After I sold them I discovered I did so way cheaper than I should have.

See what happens? I need to break in a new back tire so if you want some help I can ride over with the carbs. They're just sitting in pieces in a box right now so I'll have to clean them up but I'm cleaning a gas tank for a friend today too so I can watch the electrolysis work while I put them back together.

I should probably do that anyway now that I think about it.

[Larrym]

Bad Carb Sync Theater Presents:

I been thinking about doing a video on the process with all the little tricks I've learned , but no-one to hold the camera, do the zooming etc.

Please oh PLEASE make another video!!

I did this one years ago and if it's the best out there...



These aren't the carbs you sold me Planedick. Those were used as parts to make these (the test bank...).

Still...a REAL video of the more than what you see here would be priceless.

[planedick]

Camera man

I thought about getting someone to run the camera for such a video, but someone who didn't know what the process was or understand the process would be a big pain. Just as bad as having SWMBO do it.

3phase, if you wanna break in that new tire maybe best to wait until my new jets arrive which is supposed to be 8-2-10

[3Phase]

You got it. Just send a PM when you get jets and let me know if you want me to tuck the carbs in the saddlebags.

After working on them today both sets look like they have good throttle shaft seals but its hard to tell; could leak like little sieves when they're on a bike.

[DGXSER]

A while ago I found and posted this video of the synching process. Not an XS11, but an inline 4 with individual carbs all the same.

http://www.youtube.com/watch?v=Hr6_Q...eature=related

[81xsproject]

A while ago I found and posted this video of the synching process. Not an XS11, but an inline 4 with individual carbs all the same.

http://www.youtube.com/watch?v=Hr6_Q...eature=related

Some others have a different 'fixed' carb. For the XS it is #3. So, the order you make the adjustments on another bike may differ. My throttle bodies are all set to the number one, IIRC. That threw me.

[planedick]

No change

I received the new #45 idle jets from Mike's XS and installed them. Except for a slightly better color on the plugs after running at low throttle, nothing changes. Still got that low end stumble up to about 3000 RPM then it runs like an XS should. WOT is rather exciting even.

[planedick]

More.....

Well, after much thought about those carbs I'm begining to think maybe the "O" rings on the butterfly shaft are bad. Synch at idle and moving the plates causes major out of synch. Synch at idle is only compensating for the various leaks and when plates are rotated true synch is indicated. Another thing leads me to believe that is because #3 needs the idle adjust out about 6 turns before it gets enough gas to mix with the air to run right and because that carb always goes high upon throttle up while the others go down in relation to each other. This would indicate that that carb probably has the "O" rings both in bad condition or maybe even missing altogether.

Any of you carb gurus wanna pass olong their thoughts on this matter. If test carbs run good I'm gonna be tearing carbs down to the core soon.

[planedick]

Better

After a little more fine tuning and a longer ride I can see a small improvement so I guess even bigger jets are in order. I don't know if I will spend another $20 as I have a double set of 137.5's I might just drill 'em out for test to see what size is best. Then the next step is replace all the "O" rings on the shafts.

[3Phase]

Help on the way this weekend!

[planedick]

"O" rings

Well, after the test by squirting WD 40 on the butterfly shafts it is deffinately the shaft seals. #3 is especially bad, but all leak so I guess I will have to do the big job of taking the butterflys apart and putting in new "O" rings. I think it will have to wait for the winter though.