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Firestorm backfiring after oil change

Discussion in 'Technical and Troubleshooting Torque' started by Marick, Feb 12, 2013.

  1. Recently I did an oil change on the Firestorm and installed a stock filter and 15w-50 oil. Now the manual says to use 10w-40 however the service dept at Yamaha advised the 15w-50 wouldnt make any difference. Did a bit of reading since then and some riders advocate avoiding the 15w-50 while others say it doesnt matter.

    Since I did the oil change the bike backfires regularly, at times quite violently. It also wont hold a smooth idle and coughs every 1-2 seconds. Open up the throttle and following the backfire the engine dies. Also noticed this morning a knocking sound that periodically comes from under the fuel tank.

    I am running Micron pipes (not sure if that matters) and Im not sure on the oil that was previously in the bike. I do still have the old oil filter.

    Just after some feedback if anyone has experienced this or similar issues. Prior to the change the bike ran perfectly.

    Im inclined to check the old oil filter and see if it matches the new one I bought, as well as draining the oil and replacing with 10w-40. Seeing as I dont know when the spark plugs were last changed I might change these as well.
  2. I wouldn't be too concerned about the heavier grade oil at this time of year, since it's already in.

    But I can't think of how that could account for the sudden onset of issues you're describing if you only did an oil and filter change with the right filter and amount of oil.
  3. too much oil ??
  4. I did remove the sprocket cover to clean the sprocket, however thats it. I even bled the clutch just to be sure I didnt have any air in the lines.

    Its the thump that is the main cause for concern. I havent had time to ride the bike since the change and Im not keen on riding it while that thump is there.
  5. The manual suggested 3.9l if Im correct (am at work atm) and I filled from a 4l drum with enough leftover to be approx 100-200ml. The oil window while on the bikes is on a stand and cool is just below the top level. While running the oil window is virtually empty.
  6. Strange combination of symptoms.
    I had some minor backfiring from one pipe on the TLR last year which was just an exhaust gasket.
  7. The oil change is probably unrelated, but did it look like you drained approx 4L out of the engine? You mentioned the oil level being at the top of window when on the stand, was that side stand or centre stand?
    Could be an air leak. Backfire could have popped one of the carbs halfway out of its manifold. Could be a partially blocked pilot jet. Mixture screws may not be set right to suit your pipes.
  8. I warmed the engine up and drained the oil while on the side stand from the sump. I then removed the filter and allowed that to drain out. For the record the oil was very black and dirty. Replaced the sump plug only when the oil was just dripping out.

    Attached the new filter after oiling the o-ring and set the bike onto a rear bike stand. Filled with oil watching the oil window from a 4L drum. There was only a small amount of oil left in the drum which I transferred to a 1L container of the same type. I filled the 4L drum with the oil from the bike which brought it almost to full.

    Not sure about whether the carbs may have come loose, but I'll see if I can check tomorrow. Its more the knocking sound that concerns me. I'll see if I can video it in the morning.
  9. That is. You should check with your bike upright not on a side stand. So the engine struggling because of excessive pressure and the air filter probably getting flooded by oil and not letting air in.
    • Like Like x 1
  10. in addition if you haven't changed oil filter then there should be much less then 3.9L to fill
  11. Was it running rough prior to the oil change??. Sure you haven't adjusted something or taken something off and forgot to either put a hose on or a clamp on?.

    To my knowledge if you say that you have put the correct oil in then that's not really going to cause a misfire. Have you disconnected something fuel related or air related ?
  12. Well it looks like the Storm is making me into one big fat liar. Grabbed the camera this morning to film it and the bike started up without so much as a hiccup. Well, alright, it backfired once but then sat for about 5 mins on a smooth idle with nothing more than the odd light smokers cough.

    Took the bike out onto the road and for about 10 seconds in first gear it lurched forwards and backwards and then opened up into a very smooth cough free 45min ride through Maleny/Peachester.

    So, ahh, I'll just put this down to atmospheric pressures and environmental factors in conjunction with the lunar cycle and the fact that it was a Tuesday.

    Thanks for all the comments, the support is always greatly appreciated.
  13. Might have been a bit of crap in the fuel that's passed on through now.
  14. May well be. My weekend is on me so I'll take it out for a much longer run tomorrow and see how it performs. Thanks again man.
  15. Maybe a bit of water in your fuel?.. Anyhoo.... Glad your bak on track
  16. Too much oil, I don't know if it causes the symptoms, but I know from my storm that the difference between on the ground and on a rear stand is about half a window. I have to get my wife to hold it, once it goes on the rear stand it drops to about half a window.

    So... It may have had slightly too much oil, which in turn would have pushed up into the airbox through the crank breather. You can check this if you ever feel like it by looking in the airbox, there is a little white reservoir for catching excess oil in there, and an residue in the low spot of the airbox with some dust stuck to it is a dead give away. After it ran for a bit, this would be burned off, resulting in smooth running again.

    The knocking noise from under the airbox is the sound a storm makes when a cylinder misses, it's quite violent sounding, because they have very high compression, which causes the cam chain to lash around against the outer engine casing when a cylinder misses. For the piston that's pushing against the one that misfired, it's like hitting a brick wall from a running start, there's nothing smooth about it. The high compression is also the reason they stall very easily if a piston misfires, it can be too hard to push against at low rpm. This is far less of a problem in i4's when you have 3 other pistons sharing the load.

    Probably too much info, but I hope it helps, these are the small things us storm owners learn along the way.