Hoggs Posted November 11, 2015 Posted November 11, 2015 Hey guys,So over the past week the Ninja has developed a backfire on start (I almost did my own little backfire the first time it happened!). I think this is due to it running a bit rich and the idle speed is creeping up (around 1600rpm).It's merrily starting on half choke in the mornings (albeit with a jolly little bang).So this weekend I am going to adjust the idle and change all the plugs - is there anything else (within my limited skills) I should be looking at or changing? Thanks! Quote
Stu Posted November 11, 2015 Posted November 11, 2015 Is it carbed? You may have a dodgy float on one Carb which is over filling the Carb and leaking in the the cylinder hence the back fire and high idle Any signs of fuel out of the overflow Quote
Hoggs Posted November 11, 2015 Author Posted November 11, 2015 It is, I haven't seen or smelt any fuel - but I will have a proper check later! If it is - is it a replace rather than fix type thing? Quote
Stu Posted November 11, 2015 Posted November 11, 2015 they can be fixed easily but it could just be sticking and need cleaning it could also be a vacuum leak too!! Quote
Fozzie Posted November 11, 2015 Posted November 11, 2015 Carbs are a pain for this, what Stu mentions is what I'd look at first.Is the bike mis-behaving at any other time or is it just start up? Quote
Hoggs Posted November 11, 2015 Author Posted November 11, 2015 Thanks guys, I'll check the float first.No not misbehaving any other time although it did get really hot on the way home yesterday (enough for the fan to kick in after turn off). Because I'm a muppet though I forgot to check the engine temp (I can either have temp or clock on that display). And it was a fairly average run home, mainly 50mph roads with a bit of slow speed (filtering / 30mph) at the end.I'm armed with a Haynes manual and a willingness to learn so quite looking forward to tinkering! Quote
Stu Posted November 11, 2015 Posted November 11, 2015 you dont need to worry about the temp on the bike! if the fans kick in and cool it down its no problem at all Quote
Tango Posted November 11, 2015 Posted November 11, 2015 Check the condition of the carb to head inlet rubbers......any cracks or leaks on them will cause this to happen...... Quote
Stu Posted November 11, 2015 Posted November 11, 2015 Check the condition of the carb to head inlet rubbers......any cracks or leaks on them will cause this to happen...... And easy way to do this is to run the bike and spray the rubbers with wd40 or something If it bogs its a leak in the rubbers Quote
Hoggs Posted November 18, 2015 Author Posted November 18, 2015 Me again! So changing all the spark plugs has stopped the backfire (woot) however the idle tends to fluctuate quite a bit - stopped as some lights this morning (when the engine was fully warmed up) and the needle was merrily bouncing between 1300 and 1800! Then at the next set seemed to decide to idle properly at around 1400. I haven't stripped down the carbs yet but would sticking floats or breaks in the rubbers cause this? I have adjusted the idle speed which worked for approximately a day before it decided it was going to do whatever it wanted! I guess my actual question is... if I don't do anything about this right now is it likely to cause bad things to happen?Lack of lit indoor work space and short wet weekend days are making me slightly reluctant to try anything too adventurous at the moment in case I can't put it back together in time and have to start taking the bus to work again Quote
Stu Posted November 18, 2015 Posted November 18, 2015 sticking floats shouldn't cause that an air/vacuum leak can though Quote
Hoggs Posted November 18, 2015 Author Posted November 18, 2015 Thanks Stu, sounds easier to check that too! Hope you're having a nice week off Quote
Stu Posted November 18, 2015 Posted November 18, 2015 good so far thanks but anything is better than work try spraying wd40 over the carb rubbers to make sure they aren't leaking its not uncommon for a back fire to cause a carb to be unseated Quote
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