Cleaned the carbs, what's next?

Ok , so I tore my carbs apart and cleaned 'em all up nice and clean. I set my floats with the clear tube method. Put the carbs back on and finally got her running. Starts good but I can't get it to idle smooth and can't get it to idle at under 1500rpm. What should my next step be?? I didn't pull the rack apart, just pulled all the jets, the pilot jet and choke components, floats and float pin...do I need to sync these too??..Keep in mind that me and carbs get along like a cat and dog. 8O so keep the solutuions 'duh' simple
I found this thread on tuning by ear, but I need to be able to have it idle at 1050rpm to use that proceedure. Is there something I'm missing here?? I turned the pilots in then backed them out 2 1/2 turns but it doesn't sound like it's hitting all on all 4 at idle.....Thanks for the help guys

 

yes

 

Have you tried to bench sync? Whenever I cleaned my carbs, and bench synced and reinstalled them on my xj it ran very good. Eventually I synced with the YICS tool. Under normal operation temp the bike ran better, but it took a whole lot longer to warm up. If you bench sync these carbs you can just leave them like that. It is not really neccessary to use the YICS tool if it is not readily availible. As far as the high RPM's goes it sounds like your carb to head boots may be sucking in air. I had the same problem after reinstllation. I took off all of my carb boots and resealed them and didnt have the high RPM problem.

 

Thanks guys, i'll bench sync and double check all the intake gaskets...

 

Well I bench sync'd the rack, Ended up using some form-a-gasket on the boot side of my intake gaskets. Still can't get it to idle. It runs nice and smooth at 1500+ rmps , but if I use the idle adjustment knob to lower the rpms, when it gets down around 1200 it starts running rough and will slowly die. I have also notice when I rev it up the rpms don't drop quickly, It slowly 'winds down' These symptoms are starting to sound like my intake boots are leaking...? Have not had a chance to do the propane test. Maybe tomorrow. Do these symptoms sounds like an air leak at the boots??Thanks guys

 

try adjusting the mixture screws now, get it to 1200 with the screws at 3.5 out then do .25 either way and see if you can get all four going, the idle will go up so adjust it down again
if that works your getting close

 

See...this is what I'm talking about when I say me and carbs don't get along. I used to be known as the Happy_Bohemian till one day ,years ago , when I tried to get a one-lung makuni working on my Combat Wombat....for a week...then a guy I Knew came over and had it running in like 10 min....GRRR :evil:
Well....looks like I may need to pull the carbs and clean them again. Must have missed a circuit somewhere. When it's cold the only way I can get it to start is to put my hand over one of the intakes. Once it's running my pilots (at 3.5 out) have no effect on idle until they get to about 4.75-5 turns out. And the throttle response is...shall we say non-existent. I have to nurse it to get it to not die when I give it throttle. I'm still gonna do a propane leak test before I pull the rack....haven't given up..yet....just say a little prayer for me that this doesn't end up with me becoming the PISSED_OFF_Bohemian.. 8O
Oh the joys of bikes...lol

 

where are the airbox boots? nothing's going to work right till the whole fuel systemis back together i'am trying real hard not to think you put pods on it, tell me it ain't so

 

Nope..no pods
I removed the boot off the outside carb to put my hand over the intake..

I will say, however, I couldn't get the airbox boots to line up correctly. I'll try to take a pic to show the alignment issue. If I have the boots in the air box, the collar they should mate to doesn't reach inside the boot and it's about .125" above the carbs. Do I need to loosen the carbs at the intake boots and try to 'split the difference' ?? All the parts are the stock items I took off, and the airbox is as far forward as I can get it with the adjustments on the mounting screws..

 

UPDATE time:
Messed with the boots and airbox and finally got stuff to align enougn to get the boots on both side of the carbs (YAY! MB-1 carbs-0)
Played with the pilot jets a little and finally got her to idle around 1050 without dying ( YAYY!! MB-2 carbs-0) Throttle response is still non-existant as I have to feather it to get it to increase rpms without dying (booo! MB-2 carb-1) and when I DO get it to rev up it comes down slowly to an idle, about 5-10 seconds (boo! MB-2 carbs-2) So right now it's a tie ballgame folks!!
Something else I noticed, when starting it cold w/all boots attached , minus the air filter, if I use the choke it won't start. If I cover the airbox opening without the choke,(the oval shape hole under the seat) it will sput sput putputputter to to life..if I add the choke at all, no start...
Also I should mention this is being done with a fuel source other than the tank...is that something I need to consider as well??
BTW, thanks for the help Polock I appreciate it

Looks like a good time for a '7th inning stretch' to take a breakfrom the carbs and do some body work on the tins...

 

First I want to say I went through the same thing as a learning process myself. I had to go through the carbs more than once before I found out that the really critical things to clean are the bronze fuel jets, main and idle. The idle jets collect crud inside that has to be scrubbed out with a few strands from a wire brush, then check them in a strong light with a powerful magnifier. The mains collect a glaze crud on the walls of the openings that can be scrubbed off with a bronze wound guitar string. After that I think you're in the last quarter of Carburetors 101. Keep trying, you've made good progress, and soon you'll be able to get the carbs out and back in the bike complete, in less than an hour.

 

I ran a wire from a wire brush deep into the small brass emulsion tube that sticks down into the float bowl well. If you dislodge crud in there and shoot carb cleaner, you move the grunge further into the enrichment circuit.

You can squirt water on your header pipes to tell which CYL isn't helping at idle.

You need to do a running sync. Buy 20 feet of clear tube for $5 at Home Repo.

You can idle at 2 grand for 5 minutes and check your plugs for "tan-ness", and adjust your Pilots accordingly.

With every minor tweak done correctly, your bike will run better and better. Using a test tank won't hurt unless it's dirty or 8 feet above the bike. You may find that you need to re-tune the bike after a couple months as the last bits of varnish dissolve from internal passages.

 

if they just stop like the key shut it off, your lean, the idle circuit can't let it get to the run circuit, back out the screws a little

this could be from too lean to, kind of like a vacuum leak but different nothings hitting the sync screws or throttle gizmos, right ? i take the throttle cable off so it's out of the picture

you need to have the WHOLE fuel system together, from the air box lid to the intake manifolds, it all has to be there. a dirty air filter is better than no air filter
my aux. gas hangs from the ceiling with no problems
the air box boots have a seam, one of the seams has a little mark that would be under the clamp, that's the top

 

+1 Polock is right. EVERYTHING has to be in place or it won't run right once everything IS.

You're so close I can smell it...

Now that you have established an idle, you'll need to do a running (vacuum) sync.

Now this next statement is going to start a firestorm, but you'll have an easier time of that if you use the YICS block-off tool. 8O

 

Well I know I can get them on and off with my eyes closed...but don't know if I'll ever break the 60minute mark 8O
So yesterday was spent pulling the carb and cleaning them again. I must admit I had ulterior motives for breaking them down again... I wanted to try out my new "mini-soda blaster" Now this isn't my idea and it's not a picture of mine, I found the link from earz_cd on barzu's thread. Here's a link the the page




This little baby worked like a charm. I had one of those air guns that I never use. Got it from (where else) HF years ago(about $1.99). So I got a piece of hose (75¢) Box of Baking Soda ($1.50). Pulled everything off the carbs, all the jets, pilot, choke assem, bowls ...everything. This really worked 8O Usually these el-cheapo ideas leave you with more mess and bugger things up so you have MORE work to do. Not this one! I worked mainly on the outer body of the carbs, but I did blast the 'bridge' where the pilot and choke assem. mounts. In the back of my mind I'm thinking "You probably should have practiced on you spare rack of carbs.. 8O " They cleaned up very nice!! Then I took them in the house, filled a bucket w/hot water and (gasp 8O ) plunged the rack right into it!! pulled it out and dunked it again, swished it around for about 15 seconds, another round of dunking, then pulled them out, took them back to the operating room (aka garage) and blew everything off really good with the compressor. I then went through each carb and thoroughly cleaned everything with carb cleaner. I reassembled the carbs (all the while thinking I just killed them..) double checked and reset the float levels at 17mm, verified the level with the clear tube method. Everything checked. Bench sync'd the butterflies. Put back on the bike, hooked everything up...except I couldn't find my air filter.. Sorry Mr. P ( stop watch has me at just over 2 hrs and 45 min... :wink: )
Put the gas to it and fired her up. Started pretty easy and seemed to run a little better once she warmed up. Was all set to start tweaking the pilots when the wife rang the dinner bell. So that's where she sets. I feeling much more confident this go round....I'll try to post some pics of the cleaned carbs...maybe I'll strip and clean my spare rack..hmmmm :roll:
Thanks for all the help guys...you've been life-savers...or should I say , carb savers

p.s. I found my air filter I'll be putting that in prior to any more work...

 

SUCCESS!!

Well I finally got some time to work on the bike today. Been working a cash job for the last few days and not getting home til 7pm...

First thing is I adjusted my pilots til I had a nice smooth idle at 1000-1050 rpm. 1,2,and 4 are around 4-5ish turns out, but #3 is at 9 1/2 turns out 8O . More on that later...

I had made the YICS tool to plug the ports and put together a four carb vac sync tool as well. The four carb system was based on the two carb system I found on the forum here. I mounted it on some spare shelving parts I had lying around...





Got everything hooked up and started the bike. 3 had the strongest pull, the 4 then 1 and lastly 2....Within 5min I was so confused with trying to adjust the butterflies...1/2 turn here , one there..no, wrong way,,it's worse now...that didn't help!! 8O By now I had NO idea where I started from :twisted: Time to pull the carbs and bench sync...again! :roll:
This time once I got them close, I took 4 paper clips, mic'ed the last section to make sure they were the same dia ( they were within .0002-.0003) and I clipped off the end section with some wire cutters. Now I had 4 pins I knew were the same size. Then I did the 'pin-drop method'. I'd adjust the butterfly screws so they felt like they had the same pressure applied from the butterfly valve on the paperclip 'pin' that was laid in the bottom center of each barrel. Then I tipped the carbs up so the 'barrel' of the carb was vertical. Then I very slowly applied pressure till the first pin dropped out of the carb. A little more pressure til the next one dropped and so on till they all fell. Then I would tweak the screws accordingly, and test again, until I got all 4 pins to drop at the same time.
Put the carbs back on, hooked everything up and started the bike. Everything was much closer. This time I made adjustments in 1/8 turn increments and kept track of where I was relative to my start point. THIS time , within 5 min I had all 4 carbs synced . Nice smooth idle , good response when I give the throttle a twist and she drops right back down to an idle quickly!!
I did a quick plug chop test, held her at 4k for about 15 seconds and kill the power (yeah I have a fan blowin' to keep her cool..) 1 and 4 are really dark (too rich) and 2 and 3 are a nice tan. 3 is lighter than 2, which would mean 3 is still a little lean.... but I'm 9plus turns out on 3. And I noticed when I hold the throttle at 4k (no load) I am getting an occasional 'pop' coming from the left side exhaust (#1or #2). Would that indicate a lean condition as well? Next step will be to throw the stock pegs back on, get the front brakes on and take her for a short spin. It SEEMS like I'm finally headed in the right direction.... :?

 

I was wondering if a 4 bottle rig would work or not. Good job !
Adjust the pilots a little rich for now, you can always go leaner later.
Something is up with your #3 at 9 turns out, any further and you could lose the screw while riding !!

 

that is one impressive piece of plumbing but 2 bottles are so much easier to work with

 

Thanks P! You're probably right about the two bottle system. I was running the bike in 30 sec 'spurts', tweak, run the bike, tweak. Once I was close I kept it running...I think the next time I'm gonna tweak and sync I'll start with the 2bottle system, then do a 4 carb sync to sooper fine tune it

 

Paper Clip diameter is introducing too much Air to set the Idles.
3X5 Card 1/4" Wide Strips would be better.
You want the Throttles Closed.
You want the Pilot Mixture Screw regulating the Mixture ... alone.

The Pilot Screws are fully opened well before 9 Turns Out.
9 Turns Out is too loose. You could lose the Screw.

 

The paper clip is used ( as I understand it) to simply set or 'sync' all the butterflies so they all close at the same time. The way I understand it, you could use a 1/4" dowel to sync the height of the butterflies or a .020 shim. The idea is to have a 'benchmark' consistent to all 4 carbs to adjust the opening of your butterflies. The thickness of your benchmark doesn't matter as long as it is identical for all 4. That way when your 'master' carb (#3) closes, all the others should close at the exact same time....unless I'm completely missing the principle of syncing the carbs....
I would agree about #3 and 9 turns out, I need to look into that further...

 

Precisely.

Cut 4 Strips of 3X5 Card 1/4" Wide.
The strips conform to the circumference.
The Throttles are practically closed.

(Set the Pilot Mixture Screws > 4.40 mm deep fm the Top of the Mixture Screw Hole.)

That should get you running.