Wierd find when adjusting Air screws

[Guest]

I am so close to there that I can see it from here!!

So I changed out my cols and I installed a new dynatek ignition. Bike explodes to life and rips up to red line but I am/was still having trouble getting it to idle below say 1500rpm so I decided to adjust the air screws on the carbs as has been suggested. I warmed up the bike on a short ride and then put my tank to feed gas remotely. When I cleaned and rebuilt the carbs I set the screws at 2.5 turns as per instructions. This time I just started tightening the screws individually until I heard the engine start to bog then came back up until I get engine weirdness and then found the sweet spot at idle somewhere in the middle. Dont even know how many turns in or out. When it sounded awesome I stopped.

So here is the weird part. My number 3 carb came out quite a bit. I would say it is at about 3-3 1/2 out and it was very easy to pick up the sound. There was a noticeable difference while adjusting the screw even with subtle adjustments. My number 2 also was pretty sensitive to adjustment and #1 I could get to bog when I made it to rich but it wasn't as responsive to subtle changes as was 2 and 3.

But 4 ... Nothing changed. Or it changed so very little I had trouble picking up any noticeable difference. I did find a spot but what concerns me is I was able to completely close the screw and it had no impact. I am going to run some sea foam with 4 gallons of regular gas and see what changes but .. Weird that I could cut off the air and nothing changed??

[60ratrod]

that's telling me that the small pilot passages and possibly the jet are still a little gunked up. the idle air screw plays off of the pilot fuel system. what I do when I do my carbs is I take a piece of small wire, I believe the size is .020, and chase the passages in the throat of the carbs

[Nessism]

It's not unusual for one or two of the pilot screws to have no discernable effect on the idle speed. When that is the case just set the screws at the same general range of adjustment as the others and then move on to the test ride. Be sure to vacuum sync the carbs too.

[JTGS850GL]

Vacuum sync before you do the pilot fuel screw adjustments. If the sync is screwed up the fuel screws may have no effect or too much effect depending on how bad each carb is synced.

[Boriqua]

I will have to ask at the local auto zone or oriellys if they rent tools. A vacuum sync tool is about $100 if my search was right .. Pretty steep for something I plan on using once maybe twice. Hey I am retired and playing mechanic .. $100 tools are kind of tough. Wonder what the local shop charges to do the sync. From what I have looked at it isnt difficult to do.

Maybe I need to pick up another basket case bike so I can justify the expense.

I figured Valve adjustment check was next on my list and I will need new gaskets.

[Nessism]

I'd stop with your carb work and skip forward to the valves. Then circle back and fine tune the carbs.

[JTGS850GL]

I will have to ask at the local auto zone or oriellys if they rent tools. A vacuum sync tool is about $100 if my search was right .. Pretty steep for something I plan on using once maybe twice. Hey I am retired and playing mechanic .. $100 tools are kind of tough. Wonder what the local shop charges to do the sync. From what I have looked at it isnt difficult to do.

Maybe I need to pick up another basket case bike so I can justify the expense.

I figured Valve adjustment check was next on my list and I will need new gaskets.

Keep in mind that you'll need that tool for as long as you own bikes. Doing the carb sync is not a one shot deal. It should be done annually if you ride at all. Purchasing a carb sync tool is pretty standard equipment for a person who works on their own bikes.

I'd stop with your carb work and skip forward to the valves. Then circle back and fine tune the carbs.

Agreed... Always start with the valves first since they will effect carb sync if adjusted. Another reason to own your own carb sync tool.

[Steve]

And you should also realize that the screws you are adjusting are NOT "air screws". They are technically called "pilot screws", but what they control is a MIXTURE of fuel and air, not just air.

That is why turning them out will richen the mixture. If they were AIR screws, turning them out would lean the mixture.

You have received good advice so far. Clean the carbs FIRST. Make sure the pilot fuel jet is open on the end. It's a very tiny hole, I use one strand of electrical wire to poke through it. When the carbs are CLEAN, adjust the valves to make sure each cylinder is getting sealed by properly-closing valves that are opening and closing at the right times. THEN do a vacuum sync to ensure that each cylinder is getting the same amount of air/fuel mix. Finally, do your mixture tweaking, knowing that all the cylinders are breathing, and that they are breathing the same amount.

The Carbtune is the best gauge set to get. The Dollar/Pound exchange is pretty good right now, the tool with the case will cost about $90. As mentioned, you will need to check the sync every once in a while, especially after a valve adjustment or any carb work. Suzuki suggests valve adjustment every 3000 miles, which could easily be more than once a year.

.

[Boriqua]

Well I just got back from out riding with the wife and it ran AWESOME! The hesitation I was feeling at 4000 rpm was no longer there. It reved from bottom to red line with zero flat spots. In addition to adjusting the "pilot" screws I adjusted the throttle cable. It was like a new bike. Well it ought to be .. I have cleaned and lined the tank, changed all the hoses, installed a new petcock and gas cap, cleaned and rebuilt the carbs, installed new coils, installed new plug wires, caps and spark plugs and installed a new ignition. On the Gas,air,spark side I think I covered most of it.

I still have the idle up a bit high but I want to wait until I run through this tank of gas and Sea foam before making more adjustments.

I have been riding and messing with motorcycles since 1976 and have owned probably 10 of them and never owned the sync tool but I did a lot through mechanics back in the day. Plus .. have had so much fun learning on this one that I may indeed look for another "needs help" bike for cheap to mess with.

Alright so the consensus is check valves next. Time to find out what the gaskets are going to cost me and where to get em! I better get back to working on my leather business tomorrow so I can pay for my new needs! Alright ... one nice holster and I have a carb sync tool.

If nothing else the wife is thrilled with this bike, its ride quality and its engine and she has been with me through about 4 other motorcycles and says this is her favorite. I didnt think anything would knock our triumph bonneville out of her favorite spot. They really need to make solid standard style bikes again.

Now crazy tach question .. at rest my tach needle sits about 1/8 inch down from the number 1 on the tach or about 2/3 the way up from the hash mark to the left of the 0. Is that normal and is that messing with my idle reading.

[60ratrod]

Check out ebay seller janquish. He uses a felt base for the majority of his stuff, and i have yet to have one of his fail

Edit: seller's name is jaquishmotorsports, not janquish

[mrbill5491]

I will have to ask at the local auto zone or oriellys if they rent tools. A vacuum sync tool is about $100 if my search was right .. Pretty steep for something I plan on using once maybe twice. Hey I am retired and playing mechanic .. $100 tools are kind of tough. Wonder what the local shop charges to do the sync. From what I have looked at it isnt difficult to do.

Maybe I need to pick up another basket case bike so I can justify the expense.

I figured Valve adjustment check was next on my list and I will need new gaskets.

You'll find most dealers won't touch that old of a bike for anything. Besides what a dealer would charge you, you can buy the Carbtune cheaper.

[Boriqua]

You'll find most dealers won't touch that old of a bike for anything. Besides what a dealer would charge you, you can buy the Carbtune cheaper.

Yea I am going to pick one up. I am now to in to this to let someone else finish it. Just came back from my first jaunt on the highway. It absolutely purrs at 70. Next weekend valve adjustment and the weekend after that if I can get the tool in time the carb sync. Then .. I think I am done with the running side of things.

[JTGS850GL]

You'd be amazed at how much of a difference a carb sync can do. Especially at the lower throttle opening positions. I can always tell when my 850 needs a look at. There's a slight buzziness I feel that completely goes away after a valve adjustment and resync.