No Carbtune reading on #2 carb

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ultra93

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Oct 9, 2008
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Location
Spring Branch, TX
I need some advice, my 93vmax with 23k would not stay running without the choke on. It has been sitting for 3 months due to the S. Texas heat. I decided to do the "shotgun" procedure which I have successfully done many times. When I started the bike and let it warmup, I could not get a reading on my Carbtune on the master carb (#2). The other 3 had a good reading. I thought there might still be some "gunk" in the #2 carb so I repeated the shotgun on the carb 2 more times letting the sea foam sit in the venture's & jets 30 minutes between blowing it out wit air. After starting the bike the Carbtune shows no reading at all. I have to have the enricher on slightly so the bike will idle.

I used WD40 to test the manifold to carb and air cleaner to carb boots for leaks. All clamps on the boots are tight & the boots are in great shape!

I switched out hoses on the carbtune thinking it or the hose or restrictors may be the culprit, but no mater what hose I put on #2 carb there is very little reading.

I am not a novice and the shotgun or the sync procedure as I have learned how to do it from this great forum and have been successful many times.

Anyway I am frustrated and am asking for your help?

The only mods on the bike is the sasy boost control and super trap slip-ons.

Thanks in advance for your help!

Ray Menard
 
Have you checked the hose nipple on the manifold for an obstruction?

+1 also...have you tapped on the carbtune? Ive noticed that sometimes one of the rods would get stuck, and would stay at the bottom, tap on that line....and it would immediately come up and read like it should.
 
Have you swapped the hose to another carb, say carb#1? If the carb tune then reads....you know its a problem with the carb...if not its a problem with the carbtune.
 
Yes I did that and no matter what hose I have hooked up yo #2 there will be no reading. I started the bike and pulled the hose off of #2 and held my finger over the nipple and felt a slight vacuum about the same as #1. The bike still will not idle below 1500 rpm and requires the enricher to be on slightly.
 
Carbs might have sat too long. I use seafoam with all my vehicles. I deployed it started back up and ran pretty good at 4 month. When the deployment was done it wouldn't run unless i had the choke on( this is before I used seafoam). I sent them to Sean and he said they were pretty bad shape from sitting. I haven't had them off or cleaned since, but then again I am a seafoam believer now. I notice a difference in most of the stuff it goes in with the fuel. Lawnmower like and runs better with it also.. I would bet your jet or float is stuck closed with ethanol crap/ varnish. Still never synd them on my bike due to the grear job he did on them.
 
The funny thing is 3 days ago when I did the 1st shotgun I had a reading on #2 carb on the carbtune, but it still would not idle without a little enricher on. So I gave it 2 more treatments thinking there was still some crap in the carbs. I wonder if using compressed air I caused something to blowout say on the enricher or something else on the vacuum side of the carb? Maybe Sean or Dannymax or Kyle or some of the other Guru's will offer some help when they login?
 
Check the exhaust pipe on that cylinder to see if it get hot by spraying some water on it if the engine is already up to temp. If it's cold you can lightly touch it with your finger within seconds after start up. Better if you have an infrared heat gun though. Sounds like the carbs are way out on sync..........
 
Even if your carb is totally clogged and your spakplug is dead, vacuum should be here!
Vacuum come from piston succion and butterlfy restriction.

If vacuum reading is very low :
-Piston rings are totally deads
-Valvetrain is not working correctly
-Carb butterfly is WAY too opened
-Big air leak on the manifold.
 
I bet theres an air leak somewhere... try checking the screw boss for the "H" manifold cover for cracks by where it comes out from the manifold if theres no leaks on the boots. Hell, check the hose claps for all the boots on thak carb... had that one bite me in the ass before, lol.
 
One thing that has happened before....was the level from carb#2 was low....and it rose after I started messing with the settings for the other carbs.

EDIT!! does the vacuum level rise in carb#2 when you blip the throttle after each setting adjustment?
 
Ive got a question? wouldn't the bike basically run like crap with a broken cam? So instead of running on all 4 cylinders....it would only run on 3 and miss either on the intake stroke....or exhaust.

I went back and reread the first post....and he doesn't say that the bike was running bad....just that it wouldn't idle without having the enrichener on.
 
Ive got a question? wouldn't the bike basically run like crap with a broken cam? So instead of running on all 4 cylinders....it would only run on 3 and miss either on the intake stroke....or exhaust.

I went back and reread the first post....and he doesn't say that the bike was running bad....just that it wouldn't idle without having the enrichener on.

a quick exhaust temp check would clear that one up very quickly
 
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