Carb, vacuum, or something else?

[Waterwalker]

Sorry for the long post, but needed for background. This is my first bike since early 80’s (440 LTD), so I was excited to get this steal of a deal. It had been sitting in a hanger for about 2 years. Changed the fuel, fuel filter, air filter, and added seafoam to 1-1/2 gal fresh fuel, changed battery, tried to check oil in sight glass (joke for a rookie), and wondered if it would start.
Full choke and it started right up. Amazed me!! Sounded good and idled steady about 1100rpm’s. After warm up I carefully gave some throttle. Engine died. Full choke again and she started right up, idled just fine. Dies when choke is reduced any bit. Dies when any throttle is given-with or without choke.
I placed a folded clean shop rag in the air intake (next to igniter) to restrict it and she started with full choke. Idled just fine. Yet this time, with rag stuffed in the intake, I was able to rev the engine up and down as normal as could be. Removed the choke and revved the engine up and down. Engine did fine. But it will always die when I remove the rag (restriction) from the air intake. Is this a vacuum problem, carb issue, or something else?
As before-I am not a carb person much past cleaning the bowl and jets. Hope this is explained OK. Thanks…

[triton28]

I may be wrong but that sounds like blocked jets/passageways. The simple check is drain the float bowls into a container and look for crud/water.
If none is evident, then it sounds like varnish has built up in the jets/passageways.
You may end up removing the carbs, disassembling them and using an ultrasonic cleaner for the bodies only, to open the blocked items. There are some jets which can be removed and cleared but for all the work involved I find it is good insurance to ultrasound the bodies, even while still in a rack configuration.
I believe that by blocking the air intake, you are falsely compensating for a lean fuel mixture caused by the blockages.
Could also be an open hose on the vacuum side, check them.
I hope that may be of some help,
Dave

[Coastvoyager]

Sure does sound like plugged pilot jets if not carb passages as well. Today's fuel is pretty bad when it comes to crapping carbs up. Think of it, shut off the air or run a choke and it runs, give it air and it dies.

[Waterwalker]

So in leaving the carbs racked, removing tops, diaphrams, pilot jets, main jets, slides, bowls, ...to what extent can I go before they have to be synced again? Or will they need to be synced anyway?

[ekap1200]

I agree with Dave, shame you didn't bump the starter with all the carb drains open when you first got battery power hooked up to it and the fresh fuel into it.. That may have flushed some crap out before it got sucked up into the jet passages . You didn't say how you changed out the fuel or if you opened up the bowl drains. Did you drain the tank from the hose going to the filter ? How bad did the old fuel look when you drained it ? Sitting in a hanger with temp changes it may have gotten water that condensed down in the tank and into the carb. Fresh fuel in old carbs will start to eat away a just a bit of the varnish and crud forming on the aluminum. Now if you don't flush the carbs a few times with the fresh gas pumped or gravity fed to them that crap will go straight to the pilot jet and clog it when putting a bike back into service from long down times. I have seen some fuel stabilizers form a snotty / gooey glob in the bowls after a few months of sitting .Not sea-foam but another brand. Check the fuel filter again also if you have a clear one to just view it, and see if any rust that may have made to the filter. If the tank started to get some rust and old gas crap building up, that new filter may show it by now with the time you have been trying to start and run it. Sometimes you just have to flush the tank out. I use fresh kerosene to flush out tanks, its less dangerous to work with in the shop. . . New gas will start to loosen things up and wash what ever parts where dry from sitting. Two years sitting is a long time .... At this point before pulling things apart I would let her sit overnight or so with the fresh fuel in the bowls and flush out the carbs a few times before trying to restart the engine. Its a 50-50 shot and no harm done. If it don't clear up at least you have the tools and covers off to start to remove the carbs . It may be too late for that since the rag trick may have really got the vacuum up and pulled some crap deep into the jets already. IF ; your not a carb comfortable repairer We Got A Guy down in Fla that may have a clean set ready for ya . He will need your carbs as part of this exchange program.

[triton28]

Carbs, "if they are in sync at the start of a bowl/slide/jets/float dis-assembly", can be cleaned/sounded without requiring re-synching provided that NO alteration of the position of the balance screws between #1 and 2 carb, between #3 and 4 carb, and the balance screw between left and right carb banks has taken place. If all this occurs, usually while still racked, they will still be in sync as carburetor synchronization is a mechanical adjustment and not related to the use of cleaners/air blasts.
Usually the first 2 balance screws remain OK but for some reason people like turning the left/right carb banks balance screw.
That having been said, since I have a set of gauges I normally check the sync just to be certain.
http://www.amervoyassoc.org/techtipsXII.php#Engine" onclick="window.open(this.href);return false;
has a great section on carburetors and anything else you may need to look up.
Dave

[Waterwalker]

Thanks for the reply...I did say,'changed the fuel.' What actually should have been stated was that the tank and bowls were bone dry when I first got the bike. I pulled the old filter, added some fuel line long enough to run it to a clear jug and crimped it. Then I mixed the new fuel and seafoam (about 1-1/2 gal). In to the tank overnight it went. In the mean time I split open the old fuel filter. It had some crap in it but not bad for 937 miles since last change + 2 years sitting. I really expected worse. Next day I did the best sloshing around I could and began to drain it out. Sloshed more, drained more. until it was pretty clean. Not much rust, gunk or dirt really came out. From the best I can see the inside of the tank looks decent. Added a new filter and hooked the line up. Was going to just 'bump' it over to fill the bowls and let it set for a couple of days. The bike started pretty dang quick-about as soon as fuel was there. Remember-NEWBIE/ROOKIE!! So I let it set over night. My thinking, "I am NOT a carb guy and the shop can deal with this if it dont work right-no love lost." That was my ticket to start it after I checked the other fluids-mainly oil. So I did and the fun began, thus the post of my issues. But no there was no fuel in the carbs when I got the bike. My worry/thought was that gaskets and such would be dry and cracked. Well so far there are not any leaks, not even gas smell as it sits in the garage.

I do think NOW the residual crap is probably loosened and as stated by a couple folks on here, clogging up some jets. My initial thought was to hear the bike run so when I took it in to have it serviced and inspected I would at least have an idea of what not to get screwed with. I did by 2 fuel filters and will change it again this week to check it.
I did find a couple of clamps on the boots loose so I will also check for vacuum leaks since the idle stays pretty smooth. I really started out saying in other posts that I was not a carb guy-just to much hassle from past experience, yet after watching vids. and reading, these carbs do not look that difficult. (not like those dang quadjets) All else fails... as has been stated-send them to Florida! Just a fun learning time, AND the more I know my bike the better I will feel on the road.

[Waterwalker]

Thanks Dave (triton 38) for the sync info. Wasn't sure. I probably will get some gauges if I decide to bite the bullet and do the carbs myself. It's kind of like, hell might as well learn-it ain't runnin right as it is. What's the worst? Something not be adjusted or cleaned correct? HMMM-we are there now!!

I did have that link bookmarked too! Thanks guys.

[chevyman1]

If you get carb. sync. gauges get the type in the link below.
you can probably find a set on Ebay cheaper.
if you can find a set with mercury in them even better.
http://www.motionpro.com/motorcycle/partno/08-0411/