Sputtering on takeoff

Hey guys, I own a 1982 xj 550 maxim. I have recently changed the vacuum line, need plugs, a fresh battery, and cleaned the carbs. Bike has been running great but today a threw a girl on the back and road around town for awhile. After about 15 minutes of riding the bike would sputter when i tried to get back on the gas. So i parked it for about an hour and hopped back on it (hoping it would magically fix itself) well it didn't. So now when I am riding and try to take off it sputters, and when I left off the gas and get back on it, it sputters. But it runs great once i get past the sputter

 

When you claned the carbs did you also install an inline fuel filter?
Did you happen to hit reserve and not switch the petcock over?
Is the fuel cap vent clear?

 

. . . how big was the girl?

 

did you use vacuum line?
pop open the gas cap to vent tank when sputter starts it see if problem goes away

Your Gas Cap and You

so you need new plugs ? change them
battery charge it fill it with distilled water only before charging it or just replace battery
both of these could be a problem

what work have you done to the bike?

 

hoping it would magically fix itself .
when things fix them selves you are about to have a big problem

like when your alternator or water pump stop making that noise, then they fail completly

 

It is a brand new battery. New spark plugs. Both of those have been done within the past 50 miles. Girl weighed about 100 pounds. No to the inline fuel filter. When o close the gas cap and turn it upside down gas comes out so I'm reckoning my vent isn't clogged. Yes vacuum line was used. and yes petcock is on on. Just asking, if the alternator was going out, wouldn't it not charge the battery making it hard to start or turn over. Because it starts right up

 

How exciting

 

Hmm maybe the gravitational pull of a larger girl will shift some of the crap from your carbs..

 

My Hypothesis:
There is crud in the tank (there is always crud in the tank). The lack of a fuel fliter allowed said crud to get into the carb (again).

 

your problem can be caused by several things
so if you check out the systems involved you can eliminate potential problems.

ohm out your ignition system. this is a 5 min test which can be done from under the seat
check your charging system this is also a 5 min test
check your fuel system
1. gas cap
2. tank clean
3. fuel flow through pet cock and fuel line to carbs
4. wet set fuel levels
5. carb bowls for crud, needle valve screens for crud, fuel rail for crud

you will find the specs in this link
The Ultimate Relay, Switch, Sensor, and Diodes Guide


so how long have you owned this bike and what work have you done on it?
a little history goes a long way to help you.

 

first thing that came to mind was the spark plug caps..... but follow XJ550's check list..

 

Sadly, girls are more impressed with a running bike than the hour long roadside demonstration of the skills required to keep a bike running. Sigh.

 

Owned the bike for two months, here are the things that have been done to it: Cleaned carbs, new battery, changed oil, changed oil filter, new vacuum line, dumped tank, took apart petcock and cleaned, and fresh plugs.

I have a feeling my plug caps are working because earlier in the week when changing plugs I got the shit shocked out of me. Now that was from only one. And I don't want to test the other three like that...

I have taken the cap off of the tank and rode it, didn't make a different. Next up, I will clean carbs again, dump tank, check plugs. Make sure I got petcock flow and the wet levels are set.

 

Also does running gas with ethanol have a shitty effect on older bikes?

 

My understanding is that it isn't bad unless the gas isn't flowing through it. Ethanol gas has a relatively short 'shelf life', attracts moisture and does bad things if left sitting. So if you are riding regularly and filling up constantly putting 'fresh' ethanol fuel in you should be ok. I use Stabil when going into winter storage and periodically give her a shot of Seafoam since I cleaned the carbs.

My opinion on ethanol is that it is less than desirable, for multiple reasons, the biggest being it's impact on agriculture in the USA. My motorcycle and XJ run ethanol gas, everything else gets the real stuff, but they are items that aren't always used (chainsaw, log splitter, edger, etc.)

 

I don't think a tank of fresh ethanol laden fuel will run much differently than straight gas, other than perhaps lower mileage as it does in my car. As indicated in this post, its shelf life is less, and appears to have more potential to gunk things up if left too long in the carbs.

The long term affect on things like carb seals, etc is, I believe detrimental in older vehicles. In 1983 they may not have used alcohol safe rubber compounds. When I bought the bike brand new, my dealer told me not to run alcohol on a regular basis. 30 plus years later it hasn't had more than a handful of tankfuls of gasohol , and then only on trips when the tank would be emptied in a couple of hours. That may be why it is still running so good!

I can still get straight gas locally.

 

I think I have found my problem. I took out my plugs to check, three were white while one was brown. So out of sync carbs?

 

You don't keep company with the right sort of girls.

 

They did.
There was a big push towards ethanol blends in the late 70's. Ethanol-compatable fuel systems were required at that point.
There was also a big push towards ethanol in the 1930's.
In fact, ethanol blended fuels have been sold in the U.S. for as long as there have been gasoline fueled engines.
Ever hear of Ethyl gasoline?

 

I had the same problem,sputtering on acceleration, It was set too rich for my local altitude. With adjustment the problem went away.
Also if the petcock vacuum tube is loose, the petcock will release insufficiant fuel and the bike might outrun the fuel supply in
the float bowl. With the extra load being a strain.

 

you will want to adjust the mixture screws in the pilot jet circuit, then do a sync.
have you checked the valve clearances?

this is said under the assumption that you do not have any air leaks causing you to run lean.