84 venture still not running corectly , need some advice.

[ABarnby]

So here are the details, 84 Venture with 31,000 miles. it was not running on all cylinders before i got started and here is what I did. I had spark on all 4 cylinders so I tryed the seafoam soak for 24 hours. That made a noticable improvement but still not perfect. I synced the carbs which were way off and really jut could not get that right. Not knowing what i had I decided to pull the carbs and go for a thorough cleaning and bench sync. I cleaned all four, had to order some gaskets and o rings, so cleaning was certainly no rush. carbs were cleaned 1 to a time and parts lined up for reassemblely. Also Pulled the valve covers and did a valve adjustment to put them all to spec. A Big Thanks to Skydoc for the shim kit, valve tool and new gaskets!! After the valve adjustment and before the Carb install i removed the CDI from under the battery so I could inspect and reistall on top of the air cleaner. (I opened it up and saw no sign of water being in there and the soldier joints all looked fine, no evidence of connections cracking or being repaired.) I gave the contacts and plug ends a cleaning to get ready for the relocation. Also drained the fuel tank, changed the fuel filter and installed new fuel line from the filter to the fuel pump and from the fuel pump to the carbs. Reinstalled the carbs, checked the fuel levels in the bowls, and assembled everything else and relocated the CDI.

Started it up adjusted the idle and it ran great! I was a happy camper. Did a road test and it was great! Went home and pulled out the cleaning supplies and went to town. She looks great. Finished!

 

Then Started her up to put away for the night and it was coughing and popping again........

took temp readings at the exhaust pipes at the head and #2 was 75 degrees. The other 3 were in the 270s . Tonight I checked for spark, and have a good spark at #2 , started it up and now #1 is cold also and also has a good spark.

When i richen it up with the choke, those 2 cyclinders head up. with the choke off, they cool back down.

 

I can't help but think Im in for another carb cleaning but thoughts of a bad CDI are also going through my head????

 

Should I clean the carbs again before I make another move, (I did not flush the fuel pump out and it is after the fuel filter. Fuel Tank, then filter, then fuel pump, then to carbs. (Just like it was originally.)

[videoarizona]

Yep... Sounds like some junk that was hiding came out to play and is caught in carbs... From where... Don't know. Try seafoam again. Run for a few.... Shut down and walk away for a day. Try again.

[bongobobny]

If you are pulling a good spark tested with one of those fancy adjustable gap tools, forgot what the factory spec is but I think it equates to a little over 0.10", then the TCI is most likely good. Maybe the plugs are fouled, new plugs (Use NGK's) are cheap enough, and our bikes EAT plugs very easily. Other than that, as David mentioned then some gunk done plugged up a carb again. With the air box off observe the dance of the pistons on the carb, they should all pretty much move in unison. You may have a sticky one, or a ruptured diaphragm, those pinholes can be hard to spot. Just a note, the bike runs pretty crappy with the airbox off but should run somewhat smoothly on all 4...

[ABarnby]

I agree, just getting frustrated as the weather is getting nice and I want to ride it. Also with the time I have spent on it, which I enjoy, but it is much more enjoyable sitting on the seat and going down the road. Maybe I will try the seafoam soak again before the weekend......and if so signs of improvement pull the carbs over the weekend.

[ABarnby]

bongobob, I will say the spark felt real good when I was testing it. I somehow managed to press the start button myself while holding the plug as I was getting ready to check spark. I did not say in my original post the plugs are new. I do agree that somehow I got some gunk in the carbs. I planed on flushing out the lines before I connected to the carbs and did not....

i did hold the diaphrams up to a light to check for pinhole while I had them out. I will check to be sure the slides are moving nicely. If one is sticky what should I apply to free it up?

[Flyinfool]

A sticky slide can often be freed up with some carb cleaner sprayed on and working it back and fort manually. Once moving freely then get it running with some Seafoam to finish cleaning it out.

[BlueSky]

Will the typical carb cleaner damage the diaphragms?

[garyS-NJ]

I think carb cleaner eats all rubber (except maybe nitrile). I pulled my sliders out and cleaned the bores and slides with pb blast (which seems to rejuvenate rubber). with them installed, depressing each slider should be uniform pressure and spring back (slowing due to vacume release). Yes they should dance the same while running. Try running known good gas directly to carbs. Check plug wire resistance (little bugger resistors in there..) & replace boots if necessary (I had some go bad). When my cdi went bad, I saw in timing hole no advance. You can test the vacume sensor too.

[cowpuc]

Pull the breather cover, slip a screw driver into the carb throats and slide the slides in and out and make sure they move freely (careful not to damage them if they are stuck - the material they are made of scratches and breaks fairly easily). If one is sticky, pull that one and clean the slide with carb cleaner. Also soak a rag with some carb cleaner and reach into the throat where the slide slides and clean it real well - will probably be covered with black gook. Slip it back in and test it, should slide real easily.

If all looks good when you check the slides thru the breather, put some gas in a spray bottle and spray fuel into the carb throat that is not firing and see if it will fire when you spray fuel into it.. If it does hit right off you probably have plugged jetting somewhere. Go to an Ag store and get a 50cc syringe. Fill the syringe with carb cleaner. Pull slide, open drain on carb, attach syringe with carb cleaner to drain hose on carb, inject cleaner until it comes out of main jet orfice (where metering rod attached to slide enters into main jet opening). Pump syringe to agitate carb cleaner in float bowl.

Best way to check for pin holes in diaphrams (IMHO) is to pull diaphram into full extention and pour gas into cup shape of diaphram and carefully roll diaphram and watch for leaks. If there is a pin hole or crack the diaphram will get wet on dry side..

[utadventure]

Like "puc" mentioned, use a screw driver from the inside of the carbs to check or free up any slides. Trying to pull on them from the diaphram side can result in breaking of the slides.

 

Good luck!!

 

Dave

[ABarnby]

Pull the breather cover, slip a screw driver into the carb throats and slide the slides in and out and make sure they move freely (careful not to damage them if they are stuck - the material they are made of scratches and breaks fairly easily). If one is sticky, pull that one and clean the slide with carb cleaner. Also soak a rag with some carb cleaner and reach into the throat where the slide slides and clean it real well - will probably be covered with black gook. Slip it back in and test it, should slide real easily.

If all looks good when you check the slides thru the breather, put some gas in a spray bottle and spray fuel into the carb throat that is not firing and see if it will fire when you spray fuel into it.. If it does hit right off you probably have plugged jetting somewhere. Go to an Ag store and get a 50cc syringe. Fill the syringe with carb cleaner. Pull slide, open drain on carb, attach syringe with carb cleaner to drain hose on carb, inject cleaner until it comes out of main jet orfice (where metering rod attached to slide enters into main jet opening). Pump syringe to agitate carb cleaner in float bowl.

Best way to check for pin holes in diaphrams (IMHO) is to pull diaphram into full extention and pour gas into cup shape of diaphram and carefully roll diaphram and watch for leaks. If there is a pin hole or crack the diaphram will get wet on dry side..

 

When I got home I checked the slides. All good there......then sprayed gas into carb 2 and quickly the exhaust went up to 250 degrees. Stopped spraying gas and the temp slowly dropped. Clearly looks like #2 carb is a bit gunned up again

[cowpuc]

Could be as simple as a hung up float from when you went thru the carbs. Turn the key on and off until the fuel pump stops cycling - means the carbs are full. Open the drain on the #2 and see how much fuel you get out of it. If you get none, leave the drain open - reach in and tap on the side of the carb with a screw driver handle. Turn the key on and off occasionally and see if you can free the float in the carb.

If its filling to proper level, try the syringe method to reclean carb.