Wierd carb issues.

[BOOST]

Left side carbs seem to run fine. Had issue of all four cabs not running as a "group". Started with a low rpm stumble, from a stop. During the "Shotgun" process, I found a bad and broken idle mixture screw in carb #3. Replaced it, syncd the carbs and it seemed fixed. Nice buttery smooth take off, and ran sweet through the gears. Now it suddenly turned on me! Before a nice 20 mile run, I could hear that both pipes were in unison or somewhat "stereo" as I call it. Then I noticed at about 25 miles on the freeway, that the right tail pipe "note" was coming on at accelleration and would go in and out as I rode further...this was the problem I had previously to finding that bad idle screw. When I got off the freeway, the bike ran like crap. The idle was now hickuping and rough. I had to blip the throttle just to keep it up. Well it died, and would not restart. The battery drained and I had to pop the clutch on a hill to get me to my destination. The bike now ran like it was totally starved for fuel. At the stop lights I had to rev the throttle just to get moving. I did a quick fix just to get me back home... a shot of seafoam, reset my idle mixture screws and tweeked the sync screws till it idled better. My question is why did my tuned carbs just completly crapped out on me? The bike ran like crap when at a normal warm temp. I did get it home, the exhaust note was not even unless under accelleration. Could the main jets be the culprit? I have not checked them. Could they be dirty and restricting fuel? The fuel filter is clean. 9K service complete. My PAJ1 and 2 were clean. HELP! I am at my wits END! I only want my Vmax to run consistently good so I can go on long rides without fear. Give me your thoughts. I am not afraid to do the work. But, I am close to giving up on my low mile beauty due to frustration. It has 8700 miles on a 1997. Please help guys! ullhair:

 

[grimmie]

I would clean the pilot jet and circuit. That's normally the issue.

I've had plug wires go bad do the same thing too. Try cleaning the pilot jet and circuit and see if that takes care of it.

 

[BOOST]

Did that just previous to the short ride.

 

[FootNote]

I am tempted to say bring it to my buddys place, he might be able to figure it out.

 

[grimmie]

Did that just previous to the short ride.

Are you using any fuel stabilizer? Last year I had a lot of issues with startron. Took me a while to figure out that startron was clogging my pilot circuit. I would clean the carbs and they would run great until I put the startron in there again. I ended up running no stabilizer for a while and it ran really good. When I finally did run the startron again it clogged the pilot circuit within 3 miles of adding it to a full tank of gas. The entire time that I was having the issues I checked my fuel filter and only got gas at 1 of 2 gas stations. I still get gas at those same two stations without any issues. I have not had the first issue with my pilot circuit since then.

On a side note, my folks have a pontoon boat with a carbureted 40 horsepower Mercury engine. The motor has never had any issues. My dad started running startron in the boat and the first time out it run fine for a few minutes and then got to where it would not idle. Had to clean the carbs on it as well and he doesn't run startron in that anymore.

So to make a long story short, I don't run startron in anything that has carbs. I have run startron in my Fuel injected vehicles and bass boat without any issues.

 

[MaxMidnight]

From what you describe it does sound like something is causing a blockage.
Have you had a look in the fuel tank to see if there is any sign of corrosion?
If not already done change the fuel filter.
Drain the float chambers into a container and see if any crud comes out.

 

[naughtyG]

+1 to MaxMidnight's comments. It sounds like some **** made its way from the tank to the carbs and caused havoc. If you see any rust in the tank (take a good look with a bright flashlight) then that's most prolly your issue.

 

[BOOST]

Thanks..will drain the float bowls into a clear glass and examine it closely. Then shotgun the carbs again, blow air to remove the carb cleaner and re-assemble. You guys do not think it may be a clogged main jet? Dan

 

[Rollie]

Have you pulled the plugs ? A cracked plug can act like a starved / dirty fuel line.

 

[naughtyG]

Thanks..will drain the float bowls into a clear glass and examine it closely. Then shotgun the carbs again, blow air to remove the carb cleaner and re-assemble. You guys do not think it may be a clogged main jet? Dan

If there's rust dust or such coming through, it could be a clogged anything in your carbs.. I've been there, it only gets worse. Make sure your tank is clean/not rusty first.

Shotgun is good for a quick clear-up, but if things are really gummed up in there it's no replacement for a proper carbs tear-up and clean. I had to do that on my '86!

 

[PATMAX]

Not that this is gonna help you in any way but I wish everybody had a spare rack of carbs they could throw on when they experience drivability issues. It was not until recently that I myself tackled a full breakdown, cleaning and refurbishment of a rack of carbs. I cannot tell you how valuable it has to become intimately familiar with carb function and resultant hiccups that manifest themselves on the ride. My experience has led me to declare our persistant problems on clogs from the normal ingredients in gasoline which over years and many gallons leave traces, build ups and break down of rubber parts that cause our woes. In a perfect world, we would have pure gas with no impurities, enough cleaners and never let our bikes sit. I'm guilty but now take responsibility for my carb issues. Shotgunning and Peashooting may cure a problem, it may loosen and dislodge more crap. Kyle was telling me about some non Max carbs that he sonically cleaned many times to the point he thought they were beyond salvage but finally came clean and working fine.
In summary, find you those reasonable priced used carbs, go through them completely and mothball them safely. Do all the easy crap to fix the carbs you currently run and when you have exhausted your options and patience, yank them suckers off, throw on your back ups and toss on new fuel filters for peace of mind. Sync, A/F adjust, and enjoy your "new" bike.
Get cracking on those old carbs and you too will never fret a poor driving Max!

 

[jfeagins]

Did that just previous to the short ride.

I'd do the shotgun again anyway. Stuff happens. It don't necessarily have to get in via the fuel filter.

Check that the air cleaner gasket is in good condition and not dissentigrating into the airway. (had that happen on my Venture one time). Might be some bits coming from your diaphrams, or even your coasting enrichener diaphrams.

One time, I sprayed so much carb cleaner, down so many orifices, in despiration to solve similar problems as you now describe, that I actually caused the coasting enrichener diaphrams damage with the cleaner. That was a complete tear down to fix @ $45.00 per carb.

 

[95spfldmax]

From what you describe it does sound like something is causing a blockage.
Have you had a look in the fuel tank to see if there is any sign of corrosion?
If not already done change the fuel filter.
Drain the float chambers into a container and see if any crud comes out.

...check for water too.........

 

[BOOST]

Started the work. Replaced fuel filter with a clear bulb, will replace all PAJ1 and PAJ2 with new 90 and 170. Replace with new sparkplugs...found #3 clearly fouled and wet with gas. Plan is to shotgun the carbs, spend extra time blowing everything out, replace PAJ1 and 2 with new, new fuel filter, set my idle speed needles at 3 turns out, Sync. Man, I hope this works. What do you think could foul that plug like that?

 

[PATMAX]

If the plug was fine in the past, there is plenty to rule out. Needles are fine, no need to shim, A/F screws fine, slides fine. Logically what makes for a rich condition? Ignition issue? Does a bad coasting enricher lean out or richen mixture constantly? Float bad or out of adjustment or float needle not seating fully?
Carbs are aggravating I agree but they are not overly complex that a guy who can replace a car waterpump or similar task should be able to undertake. Captain Kyle has a late model rack of carbs for sale CHEAP CHEAP CHEAP! Good time to score a set and remember, everything rubber is fairly new when you consider guys are running mid to late eighties carbs successfully still. Rubber has a finite lifespan.

 

[95spfldmax]

If the plug was fine in the past, there is plenty to rule out. Needles are fine, no need to shim, A/F screws fine, slides fine. Logically what makes for a rich condition? Ignition issue? Does a bad coasting enricher lean out or richen mixture constantly? Float bad or out of adjustment or float needle not seating fully?
Carbs are aggravating I agree but they are not overly complex that a guy who can replace a car waterpump or similar task should be able to undertake. Captain Kyle has a late model rack of carbs for sale CHEAP CHEAP CHEAP! Good time to score a set and remember, everything rubber is fairly new when you consider guys are running mid to late eighties carbs successfully still. Rubber has a finite lifespan.

I'd put money on it being one of those.........

 

[BOOST]

Got the job done, new plugs, shotguned, new PAJ1 and 2 jets. While syncing, the #3 cylinder was a bit lazy. Got them all very close. I took the bike out and I had that familiar butter smooth take off. I got a nice dual stereo exhaust note which is also a good sign. But...I have an ocassional muffled pop, pop out of the #3 cylinder side exhaust pipe. The other side purrs. Is my idle mixture screw out a bit? I went 3 turns out on all. By the way, the fuel filter was stained orange and I took it apart and noticed the filter paper a dark brown to orange. Probably from all the gas stabilzer that the previous owner used. Guys, this bike is freaking emaculate...the carbs look brand new. 8400 miles on a '97. If I can get that pop out, I'd be happy. Don't think it is a miss. Dan

 

[jfeagins]

I'm guessing that orange stain is a bit of rust coming out of the gas tank.

If the bike is still coughing, try shotgunning one more time. If it's still doing it after all that, I'm guessing you will need to pull the carbs and go through the jet block to manually remove some blockage(s).

 

[BOOST]

Took it for a 20 mile ride after filling with a fresh tank of Premium gas ( had all that trouble start after I tried a tank of Regular). Our gas in Washington state has 10% ethanol in it. The occasional pop and thup, thup was still there...BUT, the bike ran pretty good. When I got home, I decided to ever so slightly turn the idle mixture screw left to the rich on the #3 cylinder. I got it to completely smooth out to a nice idle. I'm telling you, very delicate 1/32 " turns. Will run it out again after I re-check the gas in the float bowls. Did find some dust size particles prior to all the work. I think I might be finally getting the bugs out. Heck the prior owner hardly rode it, and I have only ran maybe 5 tanks through it.

 

[BOOST]

The bike now runs beautiful! Thanks to all of you that kept me trying. I cannot believe how sensitive the carb system was. With the new filter replacement, repeated fuel bowl draining with the shotgun process, I finally got all of the debri irritatating the circuits clear. The bike never idled and ran out so nicely as now. Thank you VMF.