New Member..having some issues..need help!

[knoxabilly]

Hey guys, I picked up a 1979 XS1100 last year for $100 bucks. Had 2into1 exhaust. I cleaned carbs and it ran like a champ. Rode it 600 miles first weekend. Over the winter the exhaust rusted out so I bought a new 4into1 exhaust. Since then it has not ran the same, used to pull wheelies. I've played with it, I took the stock airbox off and replaced with air pods. I've played with pulling baffle out and in. Bike runs but takes a long time to get up to speed- really bogging down..I can rev it high when it sitting but when I ride it bogs down. Do I need to rejet? I've also played with using octi and not using it...thoughts? I know this thing could be sweet! I got a nice little taste of it last year when it was running

[knoxabilly]

I should mention bike had same issues with airbox on before I tried pods

[petejw]

did the bike sit over the whole winter?
its possible the carbs have gummed up
from fuel sitting in them?

u could try a fuel additive or pull the carbs down again.

dont go removing the baffles from the muffler/s
itll cause poor performance.

if ur running pods u could bump up the main jets
by 2 sizes, what pods are u running, the cheap
emgo ones have a lip and can block the ports at the
back of the carb bell.


btw, welcome aboard.

[fredintoon]

- - - Over the winter the exhaust rusted out so I bought a new 4into1 exhaust. - - - Since then it has not ran the same, used to pull wheelies. - - - when I ride it bogs down. Do I need to rejet? I've also played with using octi and not using it...thoughts?

Hi Clint and welcome,
scroll down the list of forums and open the "modifications" forum then open "carbs & fuel systems"
There's a post that recommends jets for different exhaust and air filter configurations.
Octo? Mine was long gone when I got my SG.
Seems to me if yours is correctly hooked up and works there's no need to mess with it.
OTOH to hook it up takes a rat's nest of tubes that's far too complex for what it does.

[Aches n Pains]

Yep. Bet you need new jets to deal with the pods and pipes.

Engine cycle is SUCK, SQUEEZE, BANG, BLOW. Right now you're sucking way disproportionate air vs. fuel and blowing faster than the carb can manage. Things need to get balanced out.

[BA80]

Why does eveybody think the jets need to be changed since he left it sit over the winter and now it doesn't run like it did? Here's the first clue "the exhaust rusted out while it was sitting".

Pull those carbs billy and give them a real thorough cleaning. I think you'll find that the corrosion that got your pipes is also causing carb problems. With the 4 into 1 and the pods you may have to jet it up a bit but GET IT RUNNING RIGHT BEFORE YOU GO CHANGING JETS. It will run good with the mods to the exhaust and intake with STOCK JETS. Then decide how much more fuel you need if any.

Geeze, it just makes me shake my head when someone, especially a noob, has a little running problem and every .........body wants to advise changing the damn jets. That in MOST cases will pile one problem on another.

If it was running good and now it's not it DOESN'T need bigger jets. They didn't magically change sizes over the period it sat.


Rant over........

[Aches n Pains]

It's not the same as it was when it ran well. He put on a 4-1 exhaust and pods instead of the original air box. Seems like he may need to think jetting.

Says he has cleaned the carbs so I figured he'd tried doing that after the layoff.

Just sayin, BA80.

[BA80]

It's not the same as it was when it ran well. He put on a 4-1 exhaust and pods instead of the original air box. Seems like he may need to think jetting.

Says he has cleaned the carbs so I figured he'd tried doing that after the layoff.

Just sayin, BA80.

I know people who run the pods and exhaust like that and are using stock jetting and it runs great. If it's not running right there is another problem, not the size of the jets.

That problem needs to be addressed before you try and tune.

Just sayin'

[BA80]

Take the pods off and just run it with the carbs open and give it a test ride. Some of the others have had issues with the cheaper pods covering up the vents at the air intake side of the carbs.

[TopCatGr58]

He had 2-1 exhaust, but didn't say they were OEM or aftermarket, so we also don't know if it had already been jetted differently than OEM to begin with.

He "had" cleaned the carbs before it was stored, but not afterwards, and as we all know/experience, sitting gas gums up fairly quickly especially in the cool climes like where he's at in Iowa. Regrettably, he may not have used Stabil or Sea Foam/Berryman's in the tank/fuel before storage?

Would be nice to know if he noted the jets sizes when he first cleaned them.
The other thing is he should also check to see if he's still hitting on 4 cylinders. That year of 79 XS, as most of the 78-80's are prone to the pickup coil wires going bad....yes, it ran good the season before, but we've seen these things pop up seemingly out of nowhere. No telling how long the bike sat before he got it, so the pickup coil wires may have gotten corroded as well as aged/stiff, and then the NEW activity could have caused a NEW break due to increased flexing with the new use!?

Yes, it's recommended to monitor the plugs after intake/exhaust mods to ensure that it's not running too lean...we've seen several engines with holed pistons because of that...albeit the lean conditions were abnormal events like clogged pilot jet/circuits and such, not just overall lean jetting.

T.C.

[BA80]

That's what I'm trying to get across TC. Every time someone has an issue, I don't care what it is someone jumps in an says "you need bigger jets".

Man, these bikes run GREAT the way the engineers designed them. Changing exhaust and intakes will make slight differences but won't necessarily make them run BAD.

I went though the same thing when I got mine. I wore myself out screwin with carbs and the issue ended up being ignition. Then I had to go back and figure out what I had intercoursed up to get things working properly.

If the carbs are REALLY clean, and by really I mean ACTUALLY emulsion tubes and all, and all float levels are correct and they are PROPERLY synced even if you DO have a lean or rich condition the bike will pretty much run like a bat outta hell.

Just tryin' to save some headaches.

[knoxabilly]

I appreciate all the feedback guys, I think I will start by cleaning the carbs again. The bike takes off hard then bogs down and shakes at 3/4 throttle or full throttle. That's why I thought it needed new jets maybe but I'll start by cleaning them. I can run it "easier" and it will get to speed just takes forever. It ran this way with airbox and pods.

[James England]

[QUOTE=BA80;382373 Man, these bikes run GREAT the way the engineers designed them. Changing exhaust and intakes will make slight differences but won't necessarily make them run BAD.[/QUOTE]
Agreed. Jets changing is tuning, not fault fixing. Bikes run perfectly well on incorrect jets... sure, the tuning is not ideal, but they don't behave like they have a fault. People run bikes with plugs that are light brown, white, black.... yep, not ideal but they do run, often for years.

The last thing I would be doing in response to an unexplained fault is to change jets. There's so much else it could be which needs looking at first...