Faltering when cracking the throttle.

[Hired_Goon]

Ok, Where to start.

78E running 4 to 1 and individual pods.
45 pilots 137.5 Mains

Ran perfectly but pinged opening the throttle in top gear. Also lacked the power and pickup of my other older and mored tired 78E


Changed the mains to 145's yesterday and went for a brekky run with the blades and busa's. (read hard ride)

Trouble is now, when I crack open the throttle she stumbles and bogs. Rollit on gentle and it pulls fine until it gets close to redline then starts to falter again.

Pulls better than it did with the new mains but still pings, albeit not as badly.

Timing was set with a light so is spot on and the vacuum advance passes all tests and does what it should when it should.

Pulled the plugs when I got back and according to the plug tech tip pics I would say it came out as high speed glaze. New plugs and change riding habits. Yea, right.


Never had this type of faltering before I changed the mains, but I never pushed it too hard with the standard mains as I knew it was running a bit lean then.

Could this be related to the mechanical advance mechanism behind the timing plate??? Took it off this afternoon and while everything moved ok, there was no sign of any lubrication and it felt a little "jerky" when turned by hand.


Had a few beers while tinkering so another test ride is out of the question and rain forecast for the next few days.

Lubed up the advance so hoping it's fixed. Does this make a huge difference or should I be looking at something else.??

[wingnut]

Have you tried moving the needles up 1 notch? Where are the float levels set? Sounds like a lean condition to me.

[acof911]

Lubed up the advance so hoping it's fixed. Does this make a huge difference

Made a huge difference for me, went from unrideable to fine w/ a bit of spray lube.
best of luck,
Andy

[Hired_Goon]

No, haven't touched the needles yet. I'm a one change at a time guy. I figured if lean was the cause it would have been worse when I had the 137.5 mains in.

Float levels are all to spec.

But going up three jet sizes should reduce the lean condition. Looking at the plugs I reckon I could go one more size up but think I need to workout why it's faltering.


If all else fails, I might start swapping bits off the other bike till I find something different.

[petejw]

mines been pinging a bit lately,
i think its got something to do with the fuel we've been getting lately as ive never noticed mine pinging previously,
try using premium instead of normal unleaded
and being a 78 model u can always retard the timing a
cpl of degrees.
do u think the mains mite b a little to big, maybe dropping
down a size might help.

[Hired_Goon]

Was planning on trying different gas today as the tank is nearly empty.

Don't think the mains are too big as the plugs show no signs of being too rich.

Rode it to work this morning and it seemed a little better but still had a miss when cracking.

Basically only happens when trying to get the top end power which is lacking.


Might swap out the TCI when I get home and see if it makes any difference.

[Hired_Goon]

Ok, pulled the carbs again last night and dropped the needles down two slots to see if it made any difference.

And yep, sure did. Pulls fine and the bad spot has now changed.

Coughs and splutters trying to get away from idle. Pull the choke out a notch and it pulls away fine. Obviously too lean.

So, tonight will see me raising them up a notch above the centre notch to see if that makes a difference.

Question for the guru's, After adjusting the needles, is it worth colourtuning again. Still runs fine at idle and can't really see that changing the needles would have much affect on the pilot circuit at idle.

[TopCatGr58]

Hey Goon,

The slide needles shouldn't affect the Pilot circuit, they are for the transition into the mains. Like you said, lowering them leaned it out even more, so you weren't getting any affect from the mains like you were when they were higher, but stalling/sputtering on take off in low rpms IS the pilot circuit.

Sorry you spent that $$ on the colortune, cause I think you need to put the needles back to where they were, and just start turning out the pilot screws a 1/2 turn at a time, until it comes off the line like it should. You can then turn back the main idle screw if it starts idling too high. Like you said, choke on and it pulls away fine, sure sounds lean to me.
T.C.

[Hired_Goon]

Originally posted by TopCatGr58


Sorry you spent that $$ on the colortune, cause I think you need to put the needles back to where they were, and just start turning out the pilot screws a 1/2 turn at a time, until it comes off the line like it should. You can then turn back the main idle screw if it starts idling too high. Like you said, choke on and it pulls away fine, sure sounds lean to me.
T.C.

The colourtune is worth it TC, as before I touched the needles it was taking of like a greyhound out of the gates. Was trying to get rid of a high end stutter due to main jet change. I think I just went the wrong way with the needles thinking 145's were too rich. She still idles nicely at 950 so I'm guessing the needles too low is starving the pilots circuit up to 1/4 throttle. Remember the 78 has the plug in the pilots and fed thru the shared tube.

Will notch them up tonight when I get home from work and see how she runs tommorow.

Man, I'm glad I have pods.

One query regarding needles. Most of the pics I have seen of our needles are quite thin and tapered.

Mine are quite fat with a less defined taper compared to my other two sets of carbs and very blunt on the end. They came matched with emulsion tubes so the sets match, but would it make a difference on the needle type in our carbs???

[audijunky]

You said that the emulsion tubes and needles came in a set? Are they not the original parts? and if not what brand are they and where did you get them? I have read on here somewhere that some aftermarket parts suck. Are they mikuni? I have a 79 standard and the needles are very tapered and pointed.
Just my 2 cent

[Hired_Goon]

No, Genuine Mikuni.

But, I'm not sure if the carbs I took them out of were for an XS1100. The carbs were exactly the same and the main reason I bought the set (AUD $20) was for the choke lever which is exactly the same.

After opening the carbs, I found a tiptop set of diaphrams and sliders so just swapped them out to replace one of my damaged emulsion tubes.

SOme numbers.

Needle 5059
Emulsion tube 388X-7

As opposed to standard XS11 fare of

Needle 5GZ6
Emulsion 266RX-2

[Hired_Goon]

Lifted the needles up last night (bottom clip) and rode to work this morning. All the power that I expected out of this bike is now where it should be.

Pulls great off the line and opening the throttle in fifth gear at 60 mph now gives the grunt it should have. Pinging also appears to be gone.

But......... (there's always a but, isn't there), Still has a miss at higher revs.

Basically once it gets to about 7k it's like a rev limiter.

Down to 2 options.

1, go up one more jet size since I have the needles as high as it can go.

2, Explore the option it may be electrical. New plugs, swap coils and TCI etc from my other bike.

Think I may start at 2 with new plugs high on the list.

[DiverRay]

Don't forget the pick up coil wires!! They are out to get everyone!!