Nice, i literally just finished my carb right now haha. this Forum was an amazing help
Carb Technical advice needed pls.
- Thread starter Mitch 570
- Start date
Congrats on sorting out the carbs and reinstalling them.
John, I am trying to understand this. What is the difference between adjusting four carbs to read the same vacuum on a 4-channel gage, and individually adjusting each vs. the #4? I have an excellent 2-channel vacuum gage called a Harmonizer (no longer available) that would be ideal for the procedure you describe. I was thinking of selling it and using my 4-channel Morgan CarbTune for the ST. Looks like I may need to keep the Harmonizer.
I think what John may have been saying is there's an error in the Haynes manual that calls out an incorrect procedure. Since I don't have that manual, that's just a guess. However, the #4 carb is the 'baseline' carb that has no adjusting screw, so you adjust the other 3 to it. Whether you do that in pairs with a 2-channel tool, or all together with a 4-channel tool doesn't make much difference as long as you double-check it after all adjustments are done, because tweaking one carb sometimes has an effect on one of the others. With 4-channels you see that effect immediately, with a 2-channel tool you wouldn't notice it until you went back to re-check later. So, using a 4-channel tool is a lot easier and faster.
That's how I understand it as well. I used my Morgan CarbTune on my ST11 and it worked great.
John OoSTerhuis
Life Is Good!
From the Haynes, page 1-10:
The base carb on ST1100s is the #4. Sync the others to it, individually, in any order. Adjust the idle to spec (1,200 +/- 100) as necessary during.
FWIW
John
More than a few STriders have hopelessly screwed up their carbs over the years with this erroneous procedure. I seem to recall a Brit once opined that this seemed to be some common “boilerplate” text from other earlier bikes’ manuals.
The base carb on ST1100s is the #4. Sync the others to it, individually, in any order. Adjust the idle to spec (1,200 +/- 100) as necessary during.
FWIW
John
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This is a good example why a person needs to have a good understanding of "what's, what" and not blindly follow a procedure and think it must be "gospel" because it's in print.
I have on my You Tube channel of Max1Chase1 where I show how to take the covers off all the way down to the water hoses under the carbs and other issues with a 98 ST1100. If you see something which I could have done easier let me know for all of us to use, Thanks in advance.
Since I have 2 You Tube Channels, The ST1100 videos are on the channel with 82 videos, Again Thanks in Advance.
John OoSTerhuis
Life Is Good!
Here ya go:
John OoSTerhuis
Life Is Good!
I didn’t watch the whole video but will just mention that the carbs can be lifted up and swung over to sit on the frame with the throttle cables still attached, if you’re just wanting access to the coolant plumbing for R&R. BTDT.
John
Thanks John for posting my video on the site, I hope how I did this helps those in the same situation, and your advice is greatly appreciated.
Hello all,
I have a '95 ST1100 that I was thrilled to purchase from the original owner. It only has 22K miles on the clock and is in great condition. It was in need of a carb sync, which I performed using a mercury manometer. (FYI, I have sync'd two other ST's I've owned in the past, so I'm not new to the process) My issue was between #2 and #4. In order to get those two synchronized I had to turn the adjusting screw down to the point of completely compressing the spring that is under the screw head. The two cylinders were pretty close at that point and I was able to sync 1 and 3 to 4. The bike runs great but I'm not satisfied with that screw being bottomed out between 2 and 4. Something else must be out of adjustment.
Note: I did remove the carbs, cleaned them, and installed new intake boots prior to the sync procedure.
Any suggestions as to what is the cause/fix? Thank you in advance.
I have a '95 ST1100 that I was thrilled to purchase from the original owner. It only has 22K miles on the clock and is in great condition. It was in need of a carb sync, which I performed using a mercury manometer. (FYI, I have sync'd two other ST's I've owned in the past, so I'm not new to the process) My issue was between #2 and #4. In order to get those two synchronized I had to turn the adjusting screw down to the point of completely compressing the spring that is under the screw head. The two cylinders were pretty close at that point and I was able to sync 1 and 3 to 4. The bike runs great but I'm not satisfied with that screw being bottomed out between 2 and 4. Something else must be out of adjustment.
Note: I did remove the carbs, cleaned them, and installed new intake boots prior to the sync procedure.
Any suggestions as to what is the cause/fix? Thank you in advance.
John OoSTerhuis
Life Is Good!
#1,2, and 3 carbs are synced to the #4 carb. Individually, in any order. Adjust the rpm as necessary during. The Haynes manual has an egregious error trying to balance cylinder banks.
Edit: if that’s not the issue: air leak in the sync hose or isolator?
Edit: if that’s not the issue: air leak in the sync hose or isolator?
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John,
Thanks for the comment. I have read your good advice on this site for quite some time and appreciate your expertise.
#1 and #3 sync to #4 with slight tweeks of the adjustment screws. It's #2 that has to be screwed down completely and that doesn't seem right.
Thanks for the comment. I have read your good advice on this site for quite some time and appreciate your expertise.
#1 and #3 sync to #4 with slight tweeks of the adjustment screws. It's #2 that has to be screwed down completely and that doesn't seem right.
John OoSTerhuis
Life Is Good!
I left this page up for a while, then edited my post above without refreshing the page to see new posts. Note my edit. Yes, that’s not right, IMO. Good luck…
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ST1100Y
Site Supporter
IMO them choke plungers get bend while trying to pry the carb-bank out (old/hardened) isolators/boots...
Synched my 1991 after a complete cleaning and rebuild, and found similar with one of the carbs. I thought to check the vacuum fittings and found two were loose, #1 was apparently leaking a lot. In the photo the order is carbs 1-2-3-4. Bike is warmed up, idled at 1000 rpm.
John and Oldbikefixr,
Thanks for the suggestions of a possible leak. I'll give the connections a good inspection for looseness/leakage. Didn't think about a possible leak in my manometer hose either, so I'll give that a good inspection as well. Sometimes a longer hose can slip down by the exhaust manifold and melt - has happened to me before.
Thanks for the suggestions of a possible leak. I'll give the connections a good inspection for looseness/leakage. Didn't think about a possible leak in my manometer hose either, so I'll give that a good inspection as well. Sometimes a longer hose can slip down by the exhaust manifold and melt - has happened to me before.