Help! Trouble shoot my first start after and entire re-build.

My '78 E is ready to go after an entire year of rebuilding! I am a novice and this is my first bike however I have trolled these forums enough to know and be comfortable with most of what im doing. I figured it would be smooth sailing after wasting a night attempting to fill it with fuel for the first time... there was a few leaks and I was not at all prepared. One shop towel handy was not enough...no o-rings handy, no bucket within arms reach

Anyway that got sorted the next day so i threw a new battery in it fully charged. All of the lights work, the horn ect. One small short in a rear signal which I have to repair was noted. Another Quirk which goes against the grain of that which I have read 100 times here, my headlight will turn on when the key is in the on position.... I thought it was not supposed to work until the bike was started? would this be a relay issue?

The real issue is that I cant get it to fire. There is definatley fuel flow, there is spark on both sides, valve clearences checked. I can hear the electric startor motor turning over (i assume this means starter relay is good). I tried all 3 choke positions with no luck, I also tried the kickstart with no desired result, Im not seasoned at kicking it over anyway yet. The closest thing to starting I get is a small backfire on the right side and if im real lucky a bit of smoke from the right side air filter.

Some notable changes are the aftermarket harley fx slip on exhaust and pod air filters, also its been re-jetted (cant remember what size jet but I will have that to post tonight)...needle height not raised ...yet. There is also a point when I put the wiring harness back in noting that I thought the wires from points were reversed from the P.O although Perhaps it was stock configuration...grey wire (right points) to left side ignition coil. Then the orange (left points) to right side ignition coil so I swapped those to make it left points left coil right points right coil. Since I have also read of another person finding the same reversed points to ignition coil wires although im not sure if I should have left the original points wiring setup.

Can anyone help me troubleshoot to get this thing fired up? Whats the deal with the headlight?

I think the headlight is supposed to come on when you turn the ignition on. At least, mine does as well (but then I have a DOHC). Wouldn't worry too much about that.

So you have spark, but you've been messing with the jetting and the exhausts. Some backfiring is good, that means you also have spark under pressure.

Have you tried spraying starter fluid (or brake fluid, or deodorant spray) into the air intakes? And how are your idle mixture screws? Did you adjust the float height as per manual? Did you even clean the carbs? Are your float needles stuck or worn? Did you adjust the timing? Are the plug wires connected to the right sides, you didn't cross over the plug wires?

I have an SOHC. Have not tried spraying starter fluid in the air intakes but duly noted.
I have the idle mixture screws 3 turns out as a safe starting point, I believe at 4 turns out it would be time to raise the needle position one notch, if it has to be raised more than the highest shim position then of course its time to look at the pilot jets.

Alot of people went 2 up on the mains and one up on the pilot for pods and aftermarket exhaust. I ordered a 6sigma jet kit and opted not to do any racing mods only the rejet. I dont plan on riding balls out, and most of these carb mods can be reversed but they will affect low end preformance for the sake of top end. I have brass floats set to 26mm although most documentation states 32mm. The carbs are THOROUGHLY clean. Fully dissassembled seperated parts boiled in for 4 hours, clean rubbers with warm water and soap. Then as an added I was able to have them ultrasonically cleaned through a fireline system (cavitation, basids, and 135 degree temps). The float needles are moving freely with no wear, spring pins on top of them moving freely. I believe that I have stock pilots at 42.5 and my mains were upgraded to 147.5

Lastly the plug wires are connected to the proper sides. The worry is that the points wires that go to the ignition coils then the plugs may have been correct in the first place. I reversed them as I was tracing the wires. Left points is a grey wire sent to the left coil and left plug, orange points wire is to the right ignition coil and right plug. The P.O. has the grey wire to the right side and the orange running to the left side.

I had adjusted the points gap, however the timing may not be correct, I never messed with it as my continuity tester never gave me a proper read on the situation, the light is supposed to go on and off while passing the LF then RF mark, for me the light just stayed on. I also know its vital to only rotate counter clockwise while setting the timing as Ive heard any clockwise rotation during the compression strokes could cause ticking or knack with the cam chain.

Thanks for your help guys ... even if its not an anwser but a question I forgot to ask myself

So I drained the oil and removed points cover and such to set up timing statically. I stripped 2x points screws so Im in the market for new hardware and Im also going to have to pull out my extract it kit again Timing is definatley off.

I did find out there are 2x ways to set static timing. The first is to wire up a 12v light and each wire should have clips of some sort for ease of connection. One end to the Left points wire other end to Positive battery terminal. Then the light will come on At the LF position... spin the plate set your gaps etc.

The other way is just with any standard continuity tester, which is what I was using. One end can go to any body ground and the other end to each points terminal at a time. The light for this will actually be on most of the time... opposite of the above method the light should turn off after crossing the LF or RF marks respectivley.

I do have an inductive timing light handy.... does anybody actually know how to set full advance timing once I get points sorted out?

Sorry if this sounds elementary, but turn your petock to on, pull the choke a couple times, and open your throttle wide open and kick start the piss out of it.

I just resurrected a 78 XS4002E from a guy that didn't run for a year. I went through the check list and had compression, spark, and fuel but still couldn't get it to start. It wasn't until I opened the throttle wide open that I got it to run. After that, I adjusted some things and now my bike is a one kick start. You might just have to play around with the throttle until you find the sweet spot.

Kinda of related but not directly.My head light isn't working for some reason yet my bike will fire right up.Could be cause its burnt out IDK I haven't dug into it.Since I haven't been riding at night just hasn't been a priority.I know sometimes I can hit the E start and get nothing till I push the horn button.

Aaron it sounds like you might have a bad connection in your main switch (thats the keyhole). That is, if you mean your e-start doesnt operate sometimes, until you press the horn and then it functions again. Sounds like there might be something connecting which shouldn't.

Willem I wonder if that's why its starting to stall on me,I`ll be looking into it today probably.It was flickering a while back when I was riding it then the light just quit all together.

well Im on to set the timing anyway cause I couldnt resist to tinker but at least before I close it up I know I will have the timing set 100%. I will set the static timing and then the advance timing with an inductive light after she fires.

Now i know I will have to kick the snot out of it..... the battery is only good for so long when using the electric starter.

Sounds like shorted ground wire somewhere attached to the handlebars... or possibly a connection within or near the headlight. Its not that much trouble to remove the controlls, clean and test the connections there.

Checked all the wires inside the headlight bucket everything looks good,nothing broken and everything connected.Looked at the filliments inside the bulb they look intact.Im thinking my problem stems from a short in the turn signal.I`ll look into that this afternoon sometime.

So where Im at this point in time is I have checked all of the valve clearances to make sure they are good. I set the static timing but the screws are stripped so Im stuck waiting for new hardware before I tighten the points up for the last time and make final adjustments.

The valves were all pretty far off, and when taking off the valve adjustment cover bolts on the top end I found a few things. The right side exhaust valve cover plate/bolt was not even hand tightened I could remove this by hand. I noticed 3 of the 4 cover caps had standard o-rings, only the left side exhaust valve had proper looking gasket on it. hopefully the o rings will suffice. Maybe you guys could let me in if this will work.

Lastly one of the valve cover caps has a crack past the threaded end, most likley overtightened so it will never seal properly, hopefylly I can find a replacement cap without having to buy a whole new rocker cover.

I feel more confindent and closer to getting it going once these bugs are sorted... I will be scouring for parts for the time being.

The points was set entirely wrong it would only line up on LF with the plate rotated 180 degrees which would never work because the right side points would be in the way of the points cover plate from going back on. I rebuilt the points plate thinking this could work...nope had to put it back the way it was. The actual issue was that the beveled dowel that sets the points gap to open and close as the engine rotates needed to be removed and re set that 180 degrees so left the right opens at their proper LF and RF marks respectivley. I think I am on the right track now ...any thoughts

Those caps should only have an o-ring. I have never seen one with a gasket.

Charging the battery up waiting for some valve adjustment caps for the time being.

Timing is set perfectly, which was not such a quick job starting from scratch. I cleaned and gapped all points and valve adjusters. Rebuilt points... then realized I never had to.
The points open and close around the round center mount dowel (slightly oval shaped). The left points would never initiate where they were supposed to and the only adjustment I was aware of is rotating the plate... which at a half turn is way too far off...for the points plate ... not the center mount dowel itself.

I already have the oil back in it for now rated for the lower temps

sorry to ask a douchey question, but what did you set your valves to??

Intake should be .005, or the thickness of a beer/soda can.
Exhaust can be .008 I believe. Both are in the manual.

I've had the points screws strip out too, so the plate shifted when I started the bike.

you can also have ONE other issue, a very subtle but important one.

There are these screw in connections where the points wires go to the condenser/coils. Those screw in tabs are meant to sit around a screw that you tighten into the end of the points spring. I find that sometimes because of vibration, mine have rotated slightly round the axis of the screw, causing them to ground out. Go over the points plate with a volt meter, or better yet, a test light, and make sure you don't have any continuity before the compression stroke on each side. The points should close, and the testing light will go out completely. if you have a weird grounding issue like I did, the light will change tone, but not go out.

On mine, the wire going into the left side points wore away, and was arcing onto the COVER for the points chamber. Subtle thing, but a good inspection with a light eventually found that.

You're probably grounding out. You'll never start if that's the case.

Check it out and get back to us.

Drewcifer

1978 xs400 is Inlet = 0.08 - 0.12mm (3 - 5 thou) Exhaust = 0.16 - 0.20mm (6 - 8 thou) from what the manual states, points gap is between .3 and .4mm (.0118-.0157 in)

From what I've read these bikes run beter to set the gap on the lower side of the scale. However I have heard to the contrary that if the bike has been re-jetted to run rich then it may be better to lean towards gapping at the wider end of the scale for the points, not so sure this applies to valve clearances.

I set my inlets at .102mm (.004) and the outlets at .178mm (.007). My points are gapped to somewhere between .36 mm and .38 mm (.0141 and .0149 in)

So my points gap is slightly on the wide end and my valve clearances are smack dab center which may be on the tighter end due to the re-jet.

Valuable info none the less. I will have to take the cover plate off again and give those contacts a once over, I wonder if insulating them is possible as I can see why this could cause issues. Thanks for your input i will let you know what i find...

The points are ideally set to .014". The range is .012 to .016 inch, so that puts you in the middle. The point gap has no effect on jetting. Excessive gap helps point mechanical wear and bounce, and also reduces dwell time. Dwell is the recharge time for the coil when the points are closed (conducting). The coil fires the plug when the power is removed from the primary. In this case, when the points open. Too narrow a gap encourages point arcing. If the condensers are old, it could be part of the problem. The condenser is actually a capacitor that momentarily takes the voltage surge when the points open, helping minimize arcing. When they have enough, they either partially conduct continually or allow excessive arcing. That's why they are replaced when you replace the points.

Be sure whatever lube you use on the point's rubbing block doesn't conduct electricity. A good grade of high temp grease (not containing metallic conductors such as moly or similar) Something like synthetic motor oil on the felt wick is a good choice. Assuming the wick is still there.

Waiting on valve adjustment caps to arrive this week to give starting it up another run. In the meantime I picked up another flasher relay thinking mine was dead. Signals still won't work. I went over the wiring again everything seems fine as it was when it actually worked, so I'm thinking it's could be a dead bulb or two. Maybe dead indicator bulb in the control panel as I've heard this bulb will affect the entire circuit if not working. After that I could only guess that the signals need the bike and charging system running to work properly, so I will be checking the voltage regulator. My battery is fully charged and reading over 12.5v...does the flasher relay need more juice than this to work... again it was working and just stopped... nothing was touched when it stopped except the battery died out cause the bike was not started. Also all other lights work just fine,just no signals, so the issue is not interrupting any other power or grounds. I checked the switch and cleaned it again... this being the likely culprit. Is there a chance something is not grounding where it should or things are grounding where they shouldn't? I don't want to start another turn signal thread, after looking through all of them I'm still not sure how to get to the bottom of this. If the bulbs, relay, flasher cancel,battery, switch and v reg are good it can only be a faulty wire (connections are good). With a continuity test all switch wires and grounds seem connected at the switch... is this how it works the switch temporarily lifts ground and power finds next easiest path... relay and signals? What is the best method to scan the wiring for irregularities, is there a meter to check for any break or crossed connections in the circuit while it's all hooked up?

One fix at a time we will get there, it would be amazing if this issue just disappears once I fire my bike. I've been reading up on some oil discussions lately to. Any thoughts or knowledge to share on this? Does our clutch like synthetic? Is 20w30 good for cooler riding conditions?

Looked into the oil conundrum.... I plan on returning the 20w50 Castrol and draining and ditching the Castrol 20w30, and I will be using a higher grade oil. I see that Royal Purple is pricy but their 20w50 is JASF MA rated and is specific for wet clutch applications, no friction modifiers.

Still waiting on valve covers to arrive after a shipping mixup. but I have had time to remove the carbs, clean them up and make sure they are good to go. I went from 135 mains to 142.5 leaving the pilot jets stock, needle raised by one step, and pilot screws turned out 3 1/4 turns. I had to make my own hardware and replace the fragile screws with the pointed ends that hold the choke pin in place. With a keen eye and a light to shine through the carb I sync them the best I could. So once idle is adjusted I can fine tune the sync and re check pilot screws.... which if they are more than 4 turns out I will have to move pilot jets up one size from 42.5 to 45 (most people with pods and aftermarket exhaust seem to be doing this but Im hoping I can be one of the few to showcase it is not a necessity).

While the carbs were off I was playing with my signals, almost bought new bulbs for fear china didn't meet wattage requirements of spec... but glad I didn't. I had them working for a brief period while troubleshooting via the manual. The battery was on trickle charge and I had the spedo cable unhooked for testing purposes. The specs show 1156 lights are rated for 12.8v and 26.9w so technically it is accurate the signals will have a rough time working without a FULL charge on the battery or without the charging system running. I did check my diode which is good, but when checking the v-reg and stator field coil I could not get any accurate resistance reading. I am sure these would play a huge part in my problems... unless anyone can shut up my conscience that my cheapo meter is innacurate, the cold temp is playing a factor somewhere, or that my (poor) choice in oil may be adding some variant here... Anyone else get some out of spec readings on parts that are completely functional?

I will be upgrading my lights and relay in the future... it seems unnecessary to have this much power sag to tell the world Im turning left.

Ok so im back to square one. I have a new set of valve covers, cleaned the carbs again, bench sync carbs, and reconnected it all to make sure there are no kinks in the fuel or vacuum lines. I have spark, Im and there is fuel being delivered, as far as I can tell there is compression. I will have to charge up the battery again, and I also want to look at the headlight relay as Its not supposed to allow operation until the charging system kicks on. It seems to work with the key turned and no start and apparently this can make starting a bit harder.

Other than my signals not working and suspect readings from the field coil and vr it all seems good to go. I will have to check all the ground connections again and make sure they are all solid. I have the pilots out 3 1/4 turns and I rejetted the mains from 132.5 to 142.5 but left the pilots stock. Running pod filters and slip on Harley fx exhaust. Could lean pilot jets be the culprit to not starting?

It will turn over with electric start, with a bit of putter but no real bang or backfire. I cant seem to get the same pressure kind of pressure with the kick start or the same putter (am I not finding tdc or being too easy on it?). Should I set the idle adjust to open the valves a bit more for idle speed as the throttle is set to spring back with just a hair of a turn.

I will have to throw the battery on charge then go over with a volt meter again, I also have a 12v test light. My vr and stator readings were a bit off so these are suspect, but could they cause it to not start? Could the cold weather be throwing the readings out of spec by any degree? Instruments have power, im not blowing fuses. What am I missing here?