Sputtering problem I am having with my 81 maxim

I bought an 81 yamaha xj maxim about 2 months ago. It's got 11k miles on it, and the guy I got it from said he had the carbs cleaned and synced. Also he said the sputtering started after having new spark plugs put in.

Ok, I removed the carbs and cleaned them, and bought some spark plug wires, with the attachment piece off ebay and replaced those. I also checked out the spark plugs and they were black, not oily, but very black. I replaced the plugs and they are black again after 200 miles. I have been riding the bike back and forth too work.

It rides fine, but it does have the sputtering going on, which doesn't seem to slow it down. I was told on another site to try to adjust the fuel mixture, I have been told that twice. I was also told the carbs are out of synch by someone else.

Anyhow, what do you guys think? The only adjusting I have done is to turn the idle up a bit so that it would not cut off on me when sitting still. Now the rpms are around 1400-1500 when warmed up. Before I turned the idle up the bike would have to be run with the choke on for 2-3 miles and would sometimes cut off and be a told pain to get back running. Adjusting the idle by maybe 1 half turn fixed this.

Anyhow I could use some advice on where to start, I see something called sea foam being mentioned in some of the other posts, what does this do? Also I see something about color tuning? Don't know what that is either.

1 more thing, this is my first bike, I bought it to learn to ride on, so far I have put 300 miles on it. I am not a mechanic, but I bought the haynes manual and was able to break the carbs don and clean them along with replacing the spark plug wires and checking the ai filter. I did not break the carb linkage down because I think then I would have to have them resynced, instead I cleaned out all the bowls, and jets. There was some black stuff in one of the intakes.

And finally the exhaust pipes have turned kind of blue, someone mentioned this meaning something. I can take pics if needed and I can even record the sound the bike is making if it will help. Thanks for any help folks.

 

If you cleaned the carbs right ... :

Have the Carbs synchronized and the Idle Mixtues set correctly!
Have these functions performed with a YICS Tool inserted in the YICS Passage for the most accurate synchronization and mixture setting.

Having both a YICS Tool and a ColorTune Plug used to do the tuning will most likely rectify for sputtering problem.

Unless it's related to ignition break-down resulting from the Spark Plug wires.

Surely you must suspect that the bike is running Rich from the condition of the "Black, not oily, but very black" Plugs ... and, "Some black stuff in one of the intakes" of the Carbs you just recently cleaned.

Why don't you experiment and set your Pilot Mixture Screws to between 2-3/4 - and - 3 Turns OUT from bottom ... splitting the difference a little closer to 3 Turns.

Use new plugs to see how the situation improves ... or not!

 

tommorrow I will see about adjusting the screws. They are still sealed up so I will need to drill them out.

 

You might need to re clean the carbs. See Rick's guide in the suggested faq section. They need to be really really "white room" clean. You will need to sync the carbs, see my $5 sync tool guide in the same section.

Sync or mixture off will cause idle problems and can make the bike "bog" when you hit the gas. A clean air filter is also a good idea.

Did you set the float level? Are the floats sealing correctly?

If the bike stalls and won't start try starting it with the throttle held wide open, if it starts then the bike is flooded.

Could you please explain what you mean by spluttering? When? Throttle position? Idle? Any hesitation? Any backfire? Try to be as clear as possible and even use words like vroom if that helps

Sea foam is a additive similar to the Winns or STP you get at the service station.

 

Note well where they are set. Carefully turn the screws in untill they bottom out and count (take note of) exactly how far each needs to be turned. This might help if you have problems getting the bike going again.

If you are taking the carbs off, bench sync them before re installing.

Sync then mixtures then check both again (they affect each other).

 

If I said that I didn't get all the black stuff out of the butterfly area, would you say that could be my problem?

 

I doubt it... Unless i's heavily caked on crud and even then it probably wouldn' make much difference.

What have you already done and did it make any difference?

 

I haven't done anything today except go buy a screw driver that will fit the pilot screws. Probally work on it tommorow, first I am going to try adjusting the pilot screws and see if it helps because I know something if off with the mixture.

As far as the sputtering, when I first start the bike up it doesn't happen, after it heats up though the engine will be making the normal engine sound at idle, rpms around 1400, then there will be a popping sound, I can't tell there is any power loss. The pop sound will continue as I acelerate until I get going 45mph or so and then I think it may stop, or atleast I don't notice it.

It does seem to happen mainly as the bike heats up. The guy I got it from claims it started after he had the plugs changed, and that it was the wires for the plugs, I have ruled that out though.

 

The Pilot Mixture Screws are just a little bit RICH. Your description of the problem could not be better for what is happening.

Here's what's going on.
The Pilot Mixture -- alone -- is sufficiently RICH to:
Make the bike run
Keep the bike running
Provide enough fuel for the bike to sustain a good Idle.

When you go into TRANSITION:
At the point where you open the Throttles and Come Off Idle the Fuel Supply becomes -- momentarily TOO RICH and the bike begins to act-up and misfire -- because while you are IN TRANSITION the Mixture is a little TOO RICH.

For a moment -- too much Fuel is being drawn into the Combustion Chamber causing the misfire and popping sound ...

Until ... the bike is OUT of TRANSITION and being supplied BOTH enough AIR and FUEL to create a good burn and make power.

That little bit of extra Fuel is coming from the Pilot Mixture. The adjustment is just above the CORRECT amount of Fuel needed to provide a smooth Transition -- Coming OFF IDLE going over to MAIN JETS with just the right amount of Fuel for the changing volume of AIR.

For a moment ... you've got slightly more FUEL going-in than the limited supply of Air going-in ... for the Fuel to ignite ... until the on-rush of Air from the Open Throttles provide the needed Air for Combustion.

You are VERY close to being really nicely dialed-in!

I'm "Swearing you in ... to the World of Fine-Tuning Tweakers!"

Your not off by much.
If you adjust those Pilot Mixtures back IN ... ever-so-slightly ... you are going to arrive at THE SPOT where the amount of Fuel regulated by the Pilot Screws is going to be just the right amount to maintain a Powerful Fuel to Air Ratio ...

That's where you'll be wishing that your Motorcycle License was a "Pilots License"

Be patient and Tweak that Motor-scooter -- "Right on the edge!"

"FEEL the force ... sb!"

 

another question...do all four screws have to be the same amount of turns? or can they all be screwed out differently until we hit this "sweet spot?" cuz I seem to be running rich on sparkplugs 1 & 2...but lean on 3 & 4....

 

And THAT ... My good Man, is precisely why the ColorTune Plug was invented.

All the factors of Engine Condition, compression and valve adjustments come into play.

All four could be different.
But, within a few degrees ... probably not quarter-turns.

 

Thanks for the info bud, I am guesing I need to turn the screws clockwise to make the mixture more lean?

 

Yes ... but, let's not say TURN ... instead, TWEAK.

Right now, you're not only "In the ballpark"

But, you're someplace between 3rd base and HOME!

Close enough to start your slide ...

Touch the plate and score!

 

k..now where can we get a colortune tool for cheap?

 

http://www.ekmpowershop.com/ekmps/shops ... oductid=11

I don't know about cheap, but that is the home site. I just ordered one myself.

 

My pilot screws are only 1/2- 3/4 of the way out atm, is that to little, we are talking full turns as the screw needs to go in a 360 degree circle to equal 1 turn, correct?

 

Yes 360 degree full turns.

Ball park figure is between 2 and a half and 3 full turns out from fully (gently) closed. That should get you started.

 

Seems like you've picked-up the scent.

Could you take time and fill-out the Signature section with the info on your bike and put-in your location under your Avatar.

You could be living close enough to someone with the "Gift of Tweak" and have them wave a Magic YICS Tool over your bike.

And, you could be out beeping the horn at chicks!

 

Will do bud, I went ahead and opened them up to the almost 3 mark and the sputtering stopped, seems to have a little more power maybe also. Only problem I had is the 2nd screw will not open all the way, only got it open about 2 full turns, where as the others will keep turning, it stops. I sprayed it with some lube but it didn't seem to help much

 

Leave it alone, then.
Deal with it after the rear wheel has a few million more revolutions on it.

Pull that plug and look at it after a couple rides.
If the plug is too clean. You'll be forced to deal with it.

Right now you need to get-out riding and get a sunburn.

 

Mmmm...keep the lube (WD40 or similar) at it then. It really needs to come out to match the others. Be very careful and keep "worrying" it. See if you can get a nylon brush in there to clean the dirt etc out of the threads and a blast with a air compressor. The "ears" of that mixture screw can shear off 8O . Make sure that the screw driver is a perfect fit even if you have to modify a screw driver to fit. It's one of those situations where "how much force is too much?" and if it is too much then the problem gets (alot) worse.

You could also use the cunning plan of asking at a good bike repair shop if they could get it out WithOut breaking it and ask them what it would cost if they do break it and make sure they have (or can get) the replacement part.

It is not good to have the bike running lean on the one cylinder.

 

Try this ancient "Old School" trick.

First ... turn that stubborn Pilot Screw all the way IN until it bottoms-out.
Leave it there.

Add one single drop of Olive Oil to the hole.
Let it drip off the end of a real sharp pencil and try not to get any on the threads inside the hole. Just on top of the head of the Pilot Screw itself.

Using the Pencil Point Flame of a Butane lighter ... (The kind they sell in "Specialty Shops" where Crack and Meth smokers shop) ... burn-out the Oxidation on the inside diameter of that hole that's preventing that Pilot Screw to be turned OUT.

If you pull this off right ... the oxidation turns to dust and the Olive Oil will lube the threads of the Pilot Screw as the heat causes the housing to expand and capillary action causes the Olive Oil to seek the space surrounding the threaded screw.

When everything cools ... soak the ends of two or three Q-Tips and "Screw" the Q-Tips into the hole.
Then, reverse direction and screw them OUT of there.

Now, shoot some WD-40 into your coffee cup. Dip the ends of a few Q-Tips in the stuff and squeeze it out into the freshly cleaned-out hole.

Screw the Pilot Screw OUT with a driver that fits that slot with ZERO freeplay.

Come-on up and out.
If things start getting tight ... go back in and then come back OUT until you make a little gain on it and keep doing it like that until you can get it ...

Either 3-1/2 Turns OUT ... or,
Right the F-out if you think it wants to go!

 

i'm a little confused now, i turned the screws that are on top of the carbs, they are inset screws, 1 over each intake, I didn't have to pull any plugs for anything.

 

Rick was referring to the spark plug on the affected carberator's cylinder, eg,. ride for a while and have a look at the number 2 spark plug tip to see what colour it is.

Have a look here to see what a spark plug will look like under different conditions:

http://www.gnttype.org/techarea/engine/plugs.html

and here:

http://www.dansmc.com/spark_plugs/spark ... talog.html

You want all four plugs to look like number 14 on the second link

 

Gotcha, thanks for the info on the plugs, I am going to put new ones in today or tommorow because the ones I have in now are prety rough looking, gonna see if the tweaking helped, but it does run a whole lot better. Is it possible to clean the plugs?