weird starting probs

[ScottsXS]

ok started fine 2 weeks ago went out to start it monday no start had it in neutral crank no start, went through all the gears crank no start. left for work came home tried again neut lite lit cank no start in neut & all gears disconnect plug wire no spark, getting mad walk away. tues went work came home tried again turned key in neut no neut lite fires rite up no has no neut lite and is still working any suggestions would greatly be appreciated

[TopCatGr58]

Hey Scott,

First, for now and in future, would be helpful to either edit your profile to mention what YEAR and MODEL your XS is, or state it in your post, or your signature. Our comments and recommendations CAN be model specific!?

The Neutral light is NOT a control for starting, you can start the bike IN OR OUT OF GEAR while holding in the clutch! The Clutch lever safety switch IS a control that prevents starting in gear IF it's not pulled!

The wire for the neutral light is a light blue colored one that runs with the PICKUP coil wires, according to the 79SF wiring diagram. The neutral switch is just a way to connect the wire from the light to a ground when in neutral.

IIRC, the clutch switch would allow the bike to turn over, but would not send any juice to the TCI, so it wouldn't start, so I'd look there first. Other more knowledgable Electrical GURU's will hopefully chime in with more info, or "Corrections" if I've mispoken, wouldn't be the first time!
T.C.

[LoserShoes]

Sounds like one of them fuse broken but looks good problems. Sometimes the fuse element can crack and make intermittent contact, so just the right vibration can get it working again. Fuses are easy to replace, and you can clean the clips at the same time. Probably needs to be done anyway, so if that doesn't fix it, it's not a waste of time.

Steve

[bandet01]

like i said in another post i was have some issues with the electrical stuff on my bike not wanting to work and i checked all the fuses but they all looked good but 2 were bad so i replaced all the fuses and it cost less the 5.00 so i would start at your fuses and replace all them first

[mro]

TopCatGr58

The Neutral light is NOT a control for starting, you can start the bike IN OR OUT OF GEAR while holding in the clutch! The Clutch lever safety switch IS a control that prevents starting in gear IF it's not pulled!

My 80G will start any time, on side stand, in/outa gear. Very embarrassing to be standing next to bike, hit start button and have bike take off with out you.


mro

[charles]

will start but wont stay running

i recently bought a 1980 xs100 special full dress it has only 24000 actual miles on it and has not been started since 1994 i have rebuilt the carbs and new gas lines and spark plugs .......i can get it to start and it will idle for 5 sec with the chokes closed and the throttle not touched then it dies the minute you open chokes or throttle its cranking a dead engine it has well over 100 pounds of compression all four carbs has gas and all 4 cylinders are firing ......why or what am i missing to make it run .....it also has electronic igtion and ive check all 4 vacuum diaphrams and all are good if any one could help it would be a great help

[randy]

Charles;

Your carburetors are dirty. From sitting 12 years. Clean 'em and sync 'em and that problem should go away.

[charles]

i did clean them i sprayed carb cleaner threw every passage i could fine and even the passage in the bowls i spray either across the carbs from 3 foot from the bike and it runs and revs up just fine take the either away and it dies 5 sec later

[randy]

Did you remove the main and pilot jets and clean them out? Each jet has small holes in the side that get clogged with gum. You can clean them with a sewing needle or a piece of #22 guage copper wire.

THEN, while the jets are out, spray through every passage you can find.

[TopCatGr58]

Hey Charles,

Randy is right, just spraying into the orifices won't do it! IF you'll check out the tech tips, you'll find diagrams and pictures that show the pilot jets, the main jets, the vacuum slide nozzle that the main jets screws into which needs to be removed thru the TOP of the carb where the vacuum slides fit, and inspect and clean out the fine holes in the nozzle, the pilot jets, and also remove the pilot screws on the top front of the carbs, and THEN spray thru the orifices, reassemble, and it should perform!

However, also verify that the carbs are getting enough fuel, that the petcocks are flowing properly, and that the float needle valves are working, not getting stuck, etc.! When you first roll on the throttle, you are getting into the pilot circuits, and with it dying, shows it's starving for fuel, cause it WILL RUN on the ether spray.

Okay, this will be #2 cleaning, you might get lucky and not have to do it a third time....do search for TRIPLE CLean if you don't believe me!
T.C.

[charles]

thanks guys i did take it apart again and did what you suggested and now it will idle like crazy as long as chokes are closed and with it that way it will rev up if i pump the accelator a little at a time and everyso often it back fires as soon as i open the chokes though it still dies..the only thing i havent done is sycronize them cause i dont have the tool for that yet a buddy is bring his over tomarrow so thanks for your help at least it idles now rough but does idle

[prometheus578]

"Don't sweat it, Man.... no pressure."

Charles.... what does...

it has well over 100 pounds of compression

mean? 105? 110? Standard value is for around 142lbs pressure. Is the value of all four cylinders within 14 lbs of each other?, Or are two cylinders 142 and the other two 110?
How do you know that it is hitting on all cylinders? If it runs long enough to heat the pipes, spray some water on the headers.(I use a spray bottle of 409 cleaner 'cause it's handy) Do they all sizzle the same? Seems to me(and others) that you're not getting fuel. These things will run on three cylinders, and I've also seen one run just hitting on one! Is the coil on the left connected to plugs 1 and 4, and the coil on the right to 2 and 3? You're either not getting enough fuel, have lousey compression, or have the firing order honked.

[jakeman]

Charles, I had a similiar problem to yours while working on a Kawasaki. It sounds like you are running the bike with the airbox not connected to the back of the carbs because you said it would run fine as long as you sprayed either across the back of the carbs. Running like this messes up the air/fuel ratio, too much air and not enough fuel and not enough concentrated air flow through the back of the carbs to lift the slides and open the main jets.

I took my carbs apart 4 or 5 times before someone on this board, maybe GNEPIG, told me to put the airbox back on. This may not be your problem but it sure sounds like it's starving for fuel to me.

Good luck,

[charles]

one more guestion you all i checked the plug wires they are right according to what you told me i checked to see if iim getting all four cylinders firing or not and cylinders 2 and 4 are not firing i take them plugs out and they are wet with gas and tested to see if they sparked and they do ......now all of a sudden i have a carb leaking out the back again grrrrr lol .....is there a place that i can get a look at a pic of the carbs for all passages and parts i checked out that one site and it didnt show a very good pic of the carbs

[DiverRay]

Charles, Your bike has the "press in" needle and seat. The "O" ring on the seat may be bad. I would just get a set of four needle/seats/"O" rings and replace them all. Then recheck the float height. That should cure the problems with the gas flowing out of the carbs.
The wet spark plugs are probably not working because of the exess fuel. The coils fire # 1 & 4 together, and 2 & 3 together. Do a search on carb repair, or carb and seat, to find the thread with the pictures of your needle and seat. You may also want to "shake" the floats, if they are the metal type. They can develope a pin hole, and fill with fuel. This can cause a LOT of problems.
Ray