Tweet
after more reading I realize I wasnt doing it correctly, the vac sync is for plate adjustment rather than idle mix. have to hook up and revisit. At the same time can anyone suggest a idle mix start point (# of turns)
-
-
Erratic idle speed is frequently caused by air leak(s) around the carb boots or butterfly shafts. It usually gets worse as the engine warms up. The trouble shooting method is to spray lighter fluid around the suspect areas or hold an unlit propane tank torch in those areas. Look for a change in RPM.-Mike
_________
'79 XS1100SF 20k miles
'80 XS1100SG 44k miles
'81 XS1100H Venturer 35k miles
'79 XS750SF 17k miles
'85 Honda V65 Magna ~7k miles
'84 Honda V65 Magna 48k miles (parts bike)
'86 Yamaha VMAX 9k miles
Previous: '68 Motoguzzi 600cc + '79 XS750SF 22k miles +'84 Honda V65Comment
-
Comment
-
Download the service manual from here Ringler.us | My Bike. Go to the section on synchronizing the carbs.
I don't know which gauges you purchased. If they are that erratic, you may need to utilize restrictors in each line to stabilize the fluctuations. I have the Morgan carbtunes that don't have any liquid in them. Some folks don't like them but I have used them now for 20 plus years and they get the job done for me. Morgan Carbtune - carburetor synchronizer for balancing motorcycle carbs. Another tool I have and use is the Gunson Colortune (gunsonshop.com). I use it to dial in the idle mixture screws. I was never good at listening to the engine while I adjusted. This tool is visual and I can get them dialed in. The color I shoot for is just the slightest hint of orange which is towards just to the rich side. My bikes run great at this adjustment. What you don't want is lean which relates to heat and major problems. A good starting point on the idle mixture screws is 1.5 to 2 turns out from lightly seated. On the carbs you have you will have to be very careful when seating the screws. The tips of those idle mixture screws can break off and plug the idle mixture port causing other problems.2 - 80 LGs bought one new
81 LH
02 FXSTB Nighttrain
22 FLTRK Road Glide Limited
JimComment
-
Great stuff, I ordered the Colortune because Im deaf in one ear so this will help.
Last edited by Mjpcarbon; 07-31-2024, 06:47 AM.Comment
-
Info is in the periodic maintenance section of the FSM, pages 2-09 thru 2-11.I cant seem to find the Section on Carb sync
Click on photo to enlarge...
Last edited by bikerphil; 07-31-2024, 08:56 AM.2H7 (79) owned since '89
3H3 owned since '06
"If it ain't broke, modify it"
☮Comment
-
Never tried that method muhself. (´∀｀•)
However....when I had installed the Taiwan Junk jets and garbage needles/seats shown? (O_o)
Bike ran like KrAp so I did my due diligence to Test anything/everything ELSE which might have been responsible. ┐(‘～`)┌
My "Vacuum Leak" test was to hook up the same vac lines/tees I use to ensure my 4 sync gauges all read the same from a single vacuum source. (´◡`)
I connected the vac lines to every one of the 4 ports (Nipples?) on the intake boots and the other (single) end to a DIY smoker device. ｡:ﾟ(｡ﹷ ‸ ﹷ )
Used Duct tape to cover/seal the airbox overflow at the bottom and intake nozzle and poked a pinhole in it to allow the smoke a single exit point. (ˆ⌣ˆ)
My results? No leaks ANYWHERE except foar one spot at the base of the intake snorkel where somehow over the years of R&R'ing the rubber seal had dislodged itself. Easy to move back into position. ( ಠ‿<)
This smoke method tests everything- intake boots seal to engine, boots themselves, boots to carb seal, carb shafts, carb vent lines/seals, slide diaphram seals, carb to airbox tubes seal, airbox tubes, airbox tubes to airbox seal, airbox, lower clamshell to airbox seal. ヽ(•‿•)ノ
In my case there were no leaks but the bike still ran like garbage cuz of the Taiwan carb parts I had installed. (ノ_<、)Comment
-
If you're an "old fart" like me, you still have a tach/dwell meter. You can hook that up to one coil and use it to show you what the RPMs are doing as you adjust the carbs. I usually start on the left and work my way right. As you adjust, you will probably need to turn down the idle a bit. I usually try and keep it about 800RPM for this. The good part, it's ALL visual, so you don't need perfect hearing.Ray Matteis
KE6NHG
XS1100 E '78 (winter project)
XS1100 SF Bob Jones worked on it!Comment
-
An Analog Tach/Dwell meter will only read 1/2 the Rpms but it's still good enuf to do the idle mixture screw adjustment. (^_^)
Latter half of this video.....
Comment
-
Larrym, set correctly, the tach/dwell WILL read the engine RPMS. You have to set the cyl. number at 2, if your machine has that.Ray Matteis
KE6NHG
XS1100 E '78 (winter project)
XS1100 SF Bob Jones worked on it!Comment
-
Only settings were 4, 6, or 8. (｡•́︿•̀｡)
The old school analog tach we used (and I still have...) is the most accurate at "full scale deflection" meaning when the needle is moved farthest away from the normal "at rest/zero" position. At the minor deflection and scale the needle was during the "tuning" it could only barely register the 50 rpm drop at the required point of adjustment fOaR the idle mixture screws. （´-`）. ｡oO
Fairly sure that Scott used his ears to detect that rpm drop and the tach we used was just eye candy fOaR video porposes. (•‿•)Comment
-
Here's another vote for the Colortune. I use it quite a bit. Very accurate tuning.
Comment
-
Where do you fellas get your carb rebuild kits from ?
Dont trust the ebay stuffComment
-
The safest way to proceed is to use all your old brass after the parts soak in a carb dip. I always re-wash the jets in Simple Green to get all the chemical off the parts. The only other parts you would need are gaskets and O-rings. The seat brass can be cleaned in the same way I mentioned but I always use Q-tips to polish out the clean seat with Mother's Mag Polish. I have done this to a lot of bikes with perfect results.
Comment
-
Comment
.
Comment