Tweet
Does anyone have any ideas on this issue: I've had a popping back in the carbs at idle since I bought the bike over 10 years ago. Also noted ticking from the valvetrain at idle.I've changed coils,spark plugs,cleaned the carbs extensively and installed new diaphragms,inspected the vacuum advance and wires as noted on the forum,changed plug wires/boots with the proper resistance boots. I also replaced the carb boots after I bought it with Yamaha oem. Nothing seems to change it and it seems lean coming off idle, though at idle the left pipe exhaust appears rich.I have MAC 4 into 2 exhaust on this 1980 midight 1100. I appreciate any ideas-I guess it's gonna be a winter project for me here in Wisconsin. possibly valve clearance issue or sticking valve?
-
1980 MIDNIGHT1100 RIDER.
TRACY -
These engines have a very noisy valve train. They get quieter as the valves wear.
For the popping, just try opening up your idle mixture screws 1/2 a turn and see if the popping goes away. You can always then it back if nothing changes.Nathan
KD9ARL
μολὼν λαβέ
1978 XS1100E
K&N Filter
#45 pilot Jet, #137.5 Main Jet
OEM Exhaust
ATK Fork Brace
LED Dash lights
Ammeter, Oil Pressure, Oil Temp, and Volt Meters
Green Monster Coils
SS Brake Lines
Vision 550 Auto Tensioner
In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.
Theodore Roosevelt -
When's the last time you check your valve clearance?
Sounds like you could benefit from a sync and idle tune.'79 XS11 F
Stock except K&N
'79 XS11 SF
Stock, no title.
'84 Chevy K-10 "Big Blue"
GM 350, Muncie SM465, NP208, GM 10 Bolt with 3.42gears turnin 31x10.5 Baja Claws
"What they do have is an implacable, unrelenting presence and movement that bespeaks massive power lurking behind paint and chrome. They don't wail like a screeching ninja, the don't rumble like a harley. They just growl like a spactic, stressed out badger waiting to rip your face off and eat your soul." Trainzz~RIP~Comment
-
valve train
I never have adjusted the valve train and set the sync with carbs off-not by flow-it responded better than ever,but still needs work. My thought is that I didn't want to flow sync the carbs until I stopped the popping back. I have backed off the idle mixture to no avail. I guess I posted this under the wrong header-sorry-not too computer saavy..1980 MIDNIGHT1100 RIDER.
TRACYComment
-
Popping back through the carbs is a sign of a lean fuel mixture and/or valves that are out of adjustment and tight. Since you have never checked the valves I would do that first. It is necessary for a smooth engine. After the valves are in spec try richening the idle mixture by turning the mixture screws out 1/4 turn at a time.Slow down and enjoy life. If you are in that much of a hurry, you should have left eariler.
Current rides:
80 XS1100SG
82 JX1100
83 Venture Royale
86 V-MaxComment
-
After you synch the vacuums of the carbs, try coloring clean plugs around idle rpms:
Use a box fan and just do it in the garage. Warm up the engine first, change to the clean plugs, run the engine at say 1500 rpms for about 5 minutes and shut it off. Check the plugs for color. Too rich? screw in the idle mixture screw a bit...too lean? screw it out just a little. It also might help to check the temperatures of the head pipes. This has worked for me.
I have a throttle lock that helps the process. I also use a propane torche to clean the standby plugs for a retest.Skids (Sid Hansen)
Down to one 1978 E. Stock air box with K&N filter, 81H pipes and carbs, 8500 feet elevation.Comment
-
valvetrain
Thanks for the input guys. I'll check the valve clearance next and see where it leads...1980 MIDNIGHT1100 RIDER.
TRACYComment
-
One other consideration, check you idle screw tips arnt broken off on the carb bodies...'79 XS11 F
Stock except K&N
'79 XS11 SF
Stock, no title.
'84 Chevy K-10 "Big Blue"
GM 350, Muncie SM465, NP208, GM 10 Bolt with 3.42gears turnin 31x10.5 Baja Claws
"What they do have is an implacable, unrelenting presence and movement that bespeaks massive power lurking behind paint and chrome. They don't wail like a screeching ninja, the don't rumble like a harley. They just growl like a spactic, stressed out badger waiting to rip your face off and eat your soul." Trainzz~RIP~Comment
-
Yeah, if those are broken off, then there'd be nothing from the idle circuit and it sure would be a bit leaner.Originally posted by WMarshy View PostHi, my name is George & I'm a twisty addict!
80G (Green paint(PO idea))
The Green Monster
K&N A/F, TC's fuse block, '81 oil cooler, TC's homemade 4-2 w/Mac Mufflers, Raptor 660 ACCT
Got him in '04.
bald tire & borrowing parts
80SG (Black w/red emblems & calipers)
Scarlet
K&N A/F, TC's fuse block, WJ5, Shoei bags, Raptor 660 ACCT.
Got her in '11
Ready for the twisties!
81H (previously CPMaynard's)
Hugo
Full Venturer, Indigo Blue with B/W painted tank.
Cold weather rideComment
-
Assuming he still has the stock '80 carbs, those have the the newer blunt tipped idle mix screws that are very hard to break off in comparison the the early model carbs mix screws.Nathan
KD9ARL
μολὼν λαβέ
1978 XS1100E
K&N Filter
#45 pilot Jet, #137.5 Main Jet
OEM Exhaust
ATK Fork Brace
LED Dash lights
Ammeter, Oil Pressure, Oil Temp, and Volt Meters
Green Monster Coils
SS Brake Lines
Vision 550 Auto Tensioner
In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.
Theodore RooseveltComment
-
I don't know if you have mentioned what kind of jetting you have in your carbs....Nick
1979 XS11 F,Yamaha fairings w/hard bags, TC's fuse box, K&N air filter
1982 Virago 750 (it's alive!)
1979 XS 11 F, Windjammer IV, Samsonite luggage cases(another rescue)Comment
-
Jets
I had switched to 1 size larger mains before when MAC exhaust and K&n air filter were installed,but it turned out to be too rich. I switched back to the original size (I can't remember off-hand the #) when the carbs were off last year.1980 MIDNIGHT1100 RIDER.
TRACYComment
-
Popping
Popping at or off idle is usually attributed to the pilot circuit. I know you stated that you have cleaned the carbs extensively. Just want to be sure that you cleaned and verify function of the entire pilot circuit. This would be the pilot jet, pilot air jet, and the passage at the butterfly for obstruction. And making sure that the plug for the pilot jet well is reinstalled.
MP1981 XS1100H Venturer
K&N Air Filter
ACCT
Custom Paint by Deitz
Geezer Rectifier/Regulator
Chacal Stainless Steel Braided Brake Lines
Chrome Front Rotor & Caliper Covers
Stebel Nautilus Horn
EBC Front Rotors
Limie Accent Moves On In 2015
MikeComment
-
Any time mine starts popping, I will look and find one of the rubber plugs on the carb nipples missing/torn/cracked.Try your hardest to be the kind of person your dog thinks you are.
You can live to be 100, as long as you give up everything that would make you want to live to be 100!
Current bikes:
'06 Suzuki DR650
*'82 XJ1100 with the 1179 kit. "Mad Maxim"
'82 XJ1100 Completely stock fixer-upper
'82 XJ1100 Bagger fixer-upper
'82 XJ1100 Motor/frame and lots of boxes of parts
'82 XJ1100 Parts bike
'81 XS1100 Special
'81 YZ250
'80 XS850 Special
'80 XR100
*Crashed/Totalled, still ownComment
-
So Do I. This also makes the assumption that the carbs etc were right in the first place though. Much more likely on your bike Tod, than a possibly less experienced member. Good advice for sure though.Originally posted by trbig View Post2-79 XS1100 SF
2-78 XS1100 E Best bike Ever
80 XS 1100 SG Big bore kit but not fully running yet.
Couple of more parts bikes of which 2 more will live!Comment
Comment