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Spada died on the road ... what could've happened?

Discussion in 'Technical and Troubleshooting Torque' started by crembz, Jun 6, 2015.

  1. Took the bike out today in traffic to start getting used to stop start and multi lane riding. So far so good, I've finally hit 500kms in the saddle.

    Last corner before getting home, i turn right at a t-junction, start accelerating hard (suv right up my arse), shift to 2nd accelerate hard, shift to 3rd and BANG! Massive backfire, tacho reads 0 throttle does bugger all buy engine still stumbling very rough. I pull over and the bike dies. Tried starting her back up, and she'd stumble and backfire from what sounded like the front and rear. After the 3rd go she started up fine and I rode home.

    Went back out this evening tried starting her up. Took a long time trying to tick her over, to the point where the battery was going weak. I had to hold the throttle wide open to get her started, she stumbled to life again multiple backfires from front and rear. As soon as I let go of the throttle shed die.

    This went on for a good 20 minutes, revs would rise and fall randomly from 3k to 7k back down again.

    I noticed the wire which plugs into the clutch area was broken and loose. So I sprayed some carb cleaner on the contacts and reattached it. To my amazement the very next start was clean, smooth idle, revs well and back to normal.

    Question is, what could've gone wrong? I fail to believe that my problem had anything to do with the neutral light wire I cleaned and reattached. I did think when she stopped on the road that I may have over revved the motor between gears and blown a gasket or something but something like that doesn't just clear up.

    Anyone got any ideas?

  2. Don't underestimate the problems a wiring short can create.
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  3. I thought the same thing, but I've since pulled that wire out again, and tried starting her up ... all good, except obviously the neutral light doesn't work. So perhaps spraying the carb cleaner affected something else?? Still don't really believe that though, I checked the area I sprayed to see if there's anything else I might have inadvertently sprayed, but there's nothing but the rear brake pedal system, clutch cover and oil check window in that area.

    So I'm still not sure what could've gone wrong.
  4. I have something similar happening to the Suzi GN. I replaced the blinker switch unit and upset the spaghetti monster in the headlight. Similar deal: doesn't start off ignition, but wants to, blinkers work at their own pace, solid, proper then fast as they choose, the idle is fast then slow, it rides rough. My current thinking is a dodgy earth which I upset when I changed the blinker unit and upset the dreaded suzi spaghetti monster. So in short, perhaps your bike has a dodgy earth connection.
  5. The wire to the clutch is an interlock which commonly prevents you starting if the bike is in gear unless the clutch is in. I didn't think it had anything to do with the running engine though.

    Scratch above, I just noticed you said clutch area i.e. Neutral light and neutral start interlock. Same conclusion though.
  6. doesn't cut spark?
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  7. cjvfr, the bike wanted to start, and when it did eventually it was rough as guts, with revs fluctuating on throttle, at idle it would just die. I tried it in neutral and in gear holding the clutch in. Same result.

    Funny thing is that since spraying, it's cleared up completely, starts first go, smooth idle and revs smooth up to red line. I still don't believe that was the problem.

    I'd thought maybe the petcock had gotten stuck and stopped letting fuel through (I know it's faulty since on and red both drain the entire tank), might explain the problems with starting and revving/idling but would that explain the backfire?

    If it happens again I'll stick it on you tube.
  8. What do you mean?
  9. He is saying that the Neutral switch only affects the start cranking circuit not the ignition/spark circuit so it is unlikely to be related. I suspected that was the case, oldcorollasoldcorollas just confirmed it.
  10. Yes true, once I had unplugged the wire I'd need to hold the clutch in for ignition to start. If I'm in gear and hit start ... Nothing happens without holding the clutch. Thus why I can't believe that spraying that are would make any difference at all. It does seem too much of a coincidence though.
  11. #11 oldcorollas, Jun 6, 2015
    Last edited: Jun 6, 2015
    I was asking the question :p
    but looking at http://freespace.virgin.net/simon.r.bromley/downloads/wiring-diagram.jpg
    the starter solenoid earths through the clutch switch, and doesn't seem to affect the ignition

    the neutral switch does connect to the starter solenoid as well, with a diode in there.. (the rectifier in middle of page)
    my brain is a bit tired, but it looks like it should start either with clutch in (if in gear), or when in neutral with clutch out?
    • Informative Informative x 1
  12. Doh!, Missed the question mark, I took it as confirmation. I should pay more attention. :) Yep agree the Neutral switch or the clutch switch don't seem to do anything to the ignition circuitry.
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  13. on my ZZR, the "on" position of petcock just goes to a tube which sticks up a little higher in the tank..
    if the longer tube breaks off, then it will fully drain tank.. and will also not have the fine filtering mesh
    Spada may have single tube.. but basically if tube breaks off or leaks at base, it will suck all fuel from tank, no "reserve"

    try to look in tank and see if it is still there?
  14. Could be the main plug that is common to the oil, neutral and both pulse coils.
    Jiggling the neutral wire has jiggled the contacts for the pulse coils as well. The tacho works of no. 1 coil only. If it dropped that side, it would stop the tacho as well.

    Try checking the pulse coil wires and the plug.
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  15. So went out this morning and she fires right up. grrr ... I just know it's going to happen again when I'm out on a group ride in the middle of nowhere!

    Correct that is how it operates. in gear with no clutch = nothing, no starter, clutch in and everything fires up.

    Good point, fiddling around may have put something back in place. I might remove the tank and have a better poke around tonight.

    Anyways it's a great day albeit a little windy so I'm gonna head out and see if the problem reappears.

    Thanks for the input ... this forum has some really great helpful people on it. I remember looking around the skyline forums when I was thinking of buying one ... OMG, I never bought a skyline in the end because there was no way I was gonna get bashed for posting 'idiot' questions lol.
  16. Thanks mate, I'll have a look. The spada fuel tap seems to be a strange one off design for Honda. Sits at the center of the tank, bolts straight in with 2 bolts and a diamond flange, with a long plastic arm reaching out to the outer side of the tank. I've looked for replacements, but I haven't found any other Honda's with the same fuel tap. It's about $250 from Honda to replace, I'd normally not have a problem with the cost except that I keep seeing MC19 and 22 aftermarket fuel taps for like $30 and I just can't get myself to hand $250 to Honda.
  17. Ok so just got back from a ride. Went from Emerald to Yarra Junction (about 40 minutes) and she backfires and dies just outside of YJ.

    I pull over, try starting ... backfires just like yesterday. Fiddle with the same cable as yesterday, again backfire but she starts. Can hear her missing every few seconds and then she dies. The bike's previous owner was with me and so we pulled the seat for a look.

    I noticed that the front cylinder was hotter to touch than the rear (running lean maybe?) We checked the contact on the battery and coils (battery is a new gel battery fitted 2 months ago) all seem good. Checked the fuel lines briefly and the vac line from the fueltap (which looks as though it's been charred by heat toward the motor). We pulled the plug wires out and had a look, all clean, tested the spark, both seem ok.

    Put everything back together, she fires up fine and we ride from YJ to Gembrook via some dirt roads (good experience trying to keep the bike from sliding) and back to Emerald, another 1hr 30 without an issue. Got back, front cylinder seems same heat as rear.

    I was thinking it may be heat related, but a 10 minute rest wouldn't cool the bike enough to go double the time. Thought maybe a fouled plug, but again, she wouldn't just fire up perfectly again and keep going to 90 minutes.

    At this point I'm thinking there's something loose affecting ignition. But the hot front cylinder could indicate fuel starvation.

    I think it's time I bought some tools and start pulling plugs. Does autobarn/supercheap sell tools for bikes? I definitely need a socket for the plugs and a rod to test spark.
  18. I don't know anything about Spadas but I've had similar symptoms in the past with my XJ900(carbureted) and my car(EFI)

    With the car it was a crook O2 sensor - fixed with new set on sensors

    With the Yamaha it was contaminated fuel - drained carbs for short term fix(globs of stuff just flowed out with the petrol), removed and drained tank for permanent fix.

    Good luck with your troubleshooting.
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  19. Intermittent issues can be a bugger. You can take it to a mechanic and it won't exhibit the problem. No O2 sensor as far as I know sneosneo ,they are a carb bike. Contaminated fuel is a good suggestion, water in the tank perhaps?

    Vacuum line charred is interesting, did these bikes have a vacuum operated fuel valve?
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