Cold weather = lean mixture?

[apolloant]

if I'm bordering on lean, 4-2 headers and a k&n, and I'm running 142.5 with 42.5 pilots, she ran good the other day at about 65 degrees. Today on a ride, 40 and raining, she's cutting out again. If I pull the enricher out 1 notch, and it smooths out, but idles high, of course. The idle mix screws are at 1 1/2 out. Would a little more help? Would a too dry k&n lean it out too much?

[strom]

yep, cold = lean = a bit more overheating of the engine

[TopCatGr58]

Hey ApolloAnt,

The key ingredient here seems more like "RAIN", not necessarily the cold. Rain water is quite impure, pollution gases and such, and can short out electrics easily, so it could have caused problems in many places, from the coils, the plugs, etc.!

Yes, colder air is a bit more dense, but it's also cooler, and so I think what little bit of overheating would be incurred with the slightly leaner ratio would be counterbalanced by the cool air blowing across the fins, keeping the engine actually cooler. Your jets sound about right, wouldn't hurt to try turning out the pilot screws a 1/2 or so turn?
T.C.

[motoman]

Hey there T.C.!............Quite a few threads ago, can't remember where, I stated That my 81 Venturer had 110 mains and I'm guessin' 42.5 pilots(too dang small for me to read) and I had adjusted my floats to a 23mm setting, and riding through out winter putting on some 4500miles. Not doing a carb sync (least not since I've gotten it back, and replacing motor with one with 33,000 miles on it ,same matching year and model) Ive notice the plugs being a little black around threaded base and a bit on electrode. Bored to tears today, so I pulled carbs as I was gonna drop float levels another 2mm as it is sometimes a little 'blubbery' at 3-3500rpm. I obviously incorrectly stated the main jet sizes. The mains are 105's all across and I'm at 4,800ft. elevation. All my riding in any direction from here goes up, so At this point gonna leave mains alone. Have the stock air box with no holes in it, and noticed the Uni-filter is fairly dirty on intake side, kinda looks likegrey color road grime, so am gonna cleanand re-spray it also. I'll spray carb cleaner and blow compressed air in orfices to make sure all's clear. Re-install everything and see if it improves. Don't think things are too far off, as pipes stay a nice shiny chrome all the way up and it idles well(sometimes 1-200rpm different depending on outside temperatures), and is at a fairly constant 34-37mpg. Tell me if there might be something I'm overlooking before I put it all back together. Thanks.

[TopCatGr58]

A natural high!

Hey Brant/Motoman,

I'm flattered that you're asking "ME" about your jetting! But, as I have stated before, I'm NO CARB GURU, just an XS11 enthusiast with a "little" experience playing with my machine! Sounds like you've got it dialed in fairly well, not too rich since according to your previous posts...No Blueing of pipes, so a little carbon around the threaded base is expected. And at your elevation, and even higher, those 105's are probably just what you need.

You state it's a little blubbery at the transition rpm of 3.0-3.5k, but in what gear? I'm still amazed at how many people run their machines at such low rpms, especially in the higher gears, and then expect them to pull like a V-8!? I rarely(never) run BELOW 3.5k when I drive, except when taking off from standstill!

You might try lowering your floats 1 mm, and see how that works for it. As you know we can't adjust our vacuum slide needles (easily) so tweaking the floats sounds like the next easiest technique to try! And, yeah, your filter could have been choking it a little as well!?
T.C.

[motoman]

Well T.C.......must've had one too many Irish Creame's in my coffee when I adjusted floats after installing motor last Oct.......they're at 20-21mm.........Hmmm, you 'spose?.....Well gonna set them at a CORRECTED 24-25mm this time, anyway, just a hair lower than sea level setting of 23mm, since it has 105 mains already. And since I have a media plug cleaner, knock the black off of plugs.......see what happens......and that occassional blubering is at 3-3500rpm in third gear. I used third to see if I could intentionally find a 'flat' or faulting place in fuel circuit. Also figured since your a super moderator.........that made you accountable.........well, maybe just a little anyway.

[xs650mike]

I'm with TC here, while the XS11 will pull pretty good at low rpms it actually runs best above 3500 rpm. On my Special that means 55 mph/3500 rpm cruise in top gear, great roll on for passing but a downshift makes passing really quick. Keep it spinning! At 85 mph cruise the Special is at around 6200 rpm which is the torque peak. A handful of throttle at that speed brings a satisfying roar from the airbox and a satisfying yank on the handlebars for a quick rush to 100 mph+!

[motoman]

Hey there Mike!.........I'm with you on all that. My memory gets fuzzier the older I get(sometimers). Seem to remember when this thing was new it kinda did that at lower rpm's...........At an old age then of 29, it didn't matter then as throttle was twisted more counterclockwise than clockwise knockin' mirrors of of 1100 and 1200 Wings, Any Hardley that rolled, Suzuki GS1000's, and pretty much anything that was on two wheels, cept for a neghbor friend that rode a 81Special.....with fairing on mine would start to get behind halfway thru 4th fighing wind resistance. Anyways, got floats all reset at 30/32nds = 23.8125mm. which is almost a millimeter lower than sea level setting. With the 105mains, didn't want to lower too much and cause it to be lean. Goin to friends for Easter brunch, so will put it back together tomorrow and give her a try around town and check plugs. Then take it on I-70 at 70-75mph for a good twenty plus into Utah, stop, look at plugs and make sure it's not too lean before putting fairing lowers back on. Let you know what results were here. Enjoy the rest of your Easter weekend Mike!