Backfire at Startup!!!!!! - Page 5

broilmebk · July 9th, 2012, 09:36 AM

http://www.ninjette.org/forums/showthread.php?t=15025

Mine did once with the stock exhaust. I think it's twice now with my danmoto.

PsHYk · July 9th, 2012, 09:43 AM

Quote:

Originally Posted by broilmebk

http://www.ninjette.org/forums/showthread.php?t=15025

Mine did once with the stock exhaust. I think it's twice now with my danmoto.

was just gonna send him to that... XD
theres a video in here somewhere too i just cant find it... =/
seems to be normal though...

Alex · July 9th, 2012, 09:45 AM

/merged

alex.s · July 9th, 2012, 10:31 AM

when you first start cranking it puts gas through the system and it flows out the exhaust until the first fire when it sends hot gas out which ignites the remaining gas vapor that was in the exhaust from before it fired. maybe more backfire on startup means your exhaust pipe has more volume to hold more gas vapors? maybe it means your jetting is rich when its cold. who knows, not me.

lindasninja · September 10th, 2012, 08:12 AM

Was wondering if anyone can tell me if they were totally sure you haven’t touched the throttle grip? First time it happened my son was ‘helping me’ check the oil and said wow this grip doesn’t go round that far! Yep he’s sacked! Left it to sit for a few hours in the ‘hope’ the fuel would drain, but no, sure enough bang! Took me an hour to go check, was so expecting to see aluminum shrapnel, started like a charm!

Has happened perhaps 5 times in 2700ks and only at start up! But I always have to move mine before I start her, anyone 100% sure they haven’t touched a throttle? As I was thinking this was the reason, for the backfire not just a random thing? Like after stoping the bike you give it a small twist while getting off or moving it? As I was almost sure it was extra fuel ??? Poor hubby was right behind the last time, and got the full ‘detonation’ wasn’t at all impressed, and didn’t have his helmet on either!! Woops! Totally 100% sure it’s out the pipe!

dubojr1 · September 10th, 2012, 08:25 AM

I am 100% sure.

lindasninja · September 10th, 2012, 08:29 AM

Thanks, now I know it’s totally random and going to do it somewhere really choice!

bdavison · September 10th, 2012, 08:45 AM

Look guys, I know why this happens.

When you came home the previous night on the bike, you pulled into the driveway, and hit the kill switch.

That is why.

If you pull into the driveway with even with a little bit of throttle and then hit the kill switch, it will load up a bit of unburnt fuel/vapor into the exhaust header.

The next morning when you hit the starter button, and that first burst of hot exhaust gas hits the vapor in the exhaust...it goes BOOM.

You can repeat this scenario....
Hop on your bike, Rev it up a bit, and hit the kill switch, then flip it back and hit the starter....PLUG YOUR EARS...cause its gonna go BOOM big time.

If you dont want it to pop every morning, then dont use the kill switch to stop the engine when you any bit of throttle in it.

Sound Wave · September 10th, 2012, 09:35 AM

i never used to use the kill switch and it would still backfire every now and then. i'd let it idle a bit after the ride before shutting off the engine... didn't matter. totally random and when i least expected it.

lindasninja · September 10th, 2012, 10:29 AM

I always thought you hit the kill switch when you were about to hit something! And the Kill switch is a bit nasty on the bike, maybe used it like 10 times to see if it worked, not crashed!? Also put in neutral when I get home, and idle it have to reverse in between cars, backwards then through a gate, usually get the angle right then, get off and turn of the bike, take helmet off and roll it to its home! I knew nothing at all, when I got my L’s so I did lots of reading, and apparently better for the engine to do the cool down thing? Go nice and gentle just a bit before you get home, and turn it off, after a few seconds of not moving like a cool down lap, but not idling too much as it heats the engine too much? Sorry think that might not help the idle theory!? Totally random again!

g21-30 · September 11th, 2012, 04:06 AM

Quote:

Originally Posted by bdavison

If you dont want it to pop every morning, then dont use the kill switch to stop the engine when you any bit of throttle in it.

Not!

I always use the ignition key to turn off the engine. You WILL get a backfire....sooner or later!

dubojr1 · September 11th, 2012, 04:55 AM

Quote:

Originally Posted by g21-30

Not!

I always use the ignition key to turn off the engine. You WILL get a backfire....sooner or later!

He speaketh the truth. There is NO known cause.

250rr · November 14th, 2012, 03:03 PM

Happened to me for the first time this morning. High 40's degrees. No throttle, full choke. As one of the previous replies pointed out, it sounds like a gun shot! Thank goodness for my ear plugs.

thomason2wheels · November 18th, 2012, 08:16 PM

Quote:

Originally Posted by g21-30

Two weeks to the day! My bike had a healthy backfire at startup this afternoon. Lady a few houses down was working in her flower garden. It gave her a pretty good startle, So much for the thought that the CDI retrofit fixed it! I knew I shouldn't have mentioned it.

I know this is off topic, but did you notice a fuel economy improvement after backdating your cdi? Respond by pm if u like...thx.
Tom

thomason2wheels · November 18th, 2012, 08:25 PM

When you stop the engine the odds are good at some point you will do so in a way that leaves one cylinder with fuel vapor in it and unignited. Then when you hit the starterif the exhaust valvehappens to beopen when the plug fires, boom, you get a bigbang. Makes sense to me anyway.

a

Corona · January 17th, 2013, 12:16 PM

I bought my bike used, the first backfire happened months after and it happened about 6 times within a month, after that I haven't had another, it's been about 3 months without it happening

July 9th, 2012, 09:45 AM	#163
Alex ninjette.org dude Name: 1 guess :-) Location: SF Bay Area Join Date: Jun 2008 Motorcycle(s): '13 Ninja 300 (white, the fastest color!), '13 R1200RT, '14 CRF250L, '12 TT-R125LE Posts: Too much. Blog Entries: 7	/merged __________________________________________________ Montgomery Street Motorcycle Club / cal24.com / crf250l.org / ninjette.org ninjette.org Terms of Service Shopping for motorcycle parts or equipment? Come here first. The friendliest Ninja 250R/300/400 forum on the internet! (especially Unregistered)

July 9th, 2012, 10:31 AM	#164
alex.s wat Name: wat Location: tustin/long beach Join Date: Sep 2009 Motorcycle(s): wat Posts: Too much. Blog Entries: 5 MOTM - Oct '12, Feb '14	when you first start cranking it puts gas through the system and it flows out the exhaust until the first fire when it sends hot gas out which ignites the remaining gas vapor that was in the exhaust from before it fired. maybe more backfire on startup means your exhaust pipe has more volume to hold more gas vapors? maybe it means your jetting is rich when its cold. who knows, not me. __________________________________________________

September 10th, 2012, 08:25 AM	#166
dubojr1 ninjette.org certified postwhore Name: Jason Location: Jacksonville, Florida Join Date: May 2010 Motorcycle(s): 09 Ninja 250R SE, 07 Honda CRF230F, 06 Honda CRF150F Posts: A lot.	I am 100% sure. __________________________________________________ 09 250R SE: Paying it forward one post at a time! Don't forget to add yourself to our Member Map

November 14th, 2012, 03:03 PM	#173
250rr ninjette.org certified postwhore Name: Mark Location: Portland Join Date: Sep 2010 Motorcycle(s): Cheap Italian Suit. Otherwise known as Dew Kitty Posts: A lot.	Happened to me for the first time this morning. High 40's degrees. No throttle, full choke. As one of the previous replies pointed out, it sounds like a gun shot! Thank goodness for my ear plugs. Last futzed with by 250rr; November 14th, 2012 at 03:03 PM. Reason: Forgot something.

November 18th, 2012, 08:25 PM	#175
thomason2wheels ninjette.org member Name: tom Location: Roanoke va Join Date: Sep 2012 Motorcycle(s): dl650 Posts: 139 Blog Entries: 2	When you stop the engine the odds are good at some point you will do so in a way that leaves one cylinder with fuel vapor in it and unignited. Then when you hit the starterif the exhaust valvehappens to beopen when the plug fires, boom, you get a bigbang. Makes sense to me anyway. a __________________________________________________ I was with Alex.S and Jiggles last night and they had sex....the video is on utube. :-)

July 9th, 2012, 09:36 AM	#161
broilmebk ninjette.org sage Name: Brian Location: Orange County, CA Join Date: Apr 2012 Motorcycle(s): '12 ninja 250r Posts: 762	http://www.ninjette.org/forums/showthread.php?t=15025 Mine did once with the stock exhaust. I think it's twice now with my danmoto.

September 10th, 2012, 08:12 AM	#165
lindasninja ninjette.org newbie Name: Linda Location: Victoria Australia Join Date: Nov 2011 Motorcycle(s): Ninja 250J Posts: 9	Was wondering if anyone can tell me if they were totally sure you haven’t touched the throttle grip? First time it happened my son was ‘helping me’ check the oil and said wow this grip doesn’t go round that far! Yep he’s sacked! Left it to sit for a few hours in the ‘hope’ the fuel would drain, but no, sure enough bang! Took me an hour to go check, was so expecting to see aluminum shrapnel, started like a charm! Has happened perhaps 5 times in 2700ks and only at start up! But I always have to move mine before I start her, anyone 100% sure they haven’t touched a throttle? As I was thinking this was the reason, for the backfire not just a random thing? Like after stoping the bike you give it a small twist while getting off or moving it? As I was almost sure it was extra fuel ??? Poor hubby was right behind the last time, and got the full ‘detonation’ wasn’t at all impressed, and didn’t have his helmet on either!! Woops! Totally 100% sure it’s out the pipe!

September 10th, 2012, 08:29 AM	#167
lindasninja ninjette.org newbie Name: Linda Location: Victoria Australia Join Date: Nov 2011 Motorcycle(s): Ninja 250J Posts: 9	Thanks, now I know it’s totally random and going to do it somewhere really choice!

September 10th, 2012, 08:45 AM	#168
bdavison Wartown, USA Name: Bryan Location: Warner Robins, GA Join Date: Nov 2009 Motorcycle(s): 2009 Ninja 250R SE, 2007 Ninja 650R, and assorted other bikes Posts: A lot.	Look guys, I know why this happens. When you came home the previous night on the bike, you pulled into the driveway, and hit the kill switch. That is why. If you pull into the driveway with even with a little bit of throttle and then hit the kill switch, it will load up a bit of unburnt fuel/vapor into the exhaust header. The next morning when you hit the starter button, and that first burst of hot exhaust gas hits the vapor in the exhaust...it goes BOOM. You can repeat this scenario.... Hop on your bike, Rev it up a bit, and hit the kill switch, then flip it back and hit the starter....PLUG YOUR EARS...cause its gonna go BOOM big time. If you dont want it to pop every morning, then dont use the kill switch to stop the engine when you any bit of throttle in it.

September 10th, 2012, 09:35 AM	#169
Sound Wave Ramen Rider Name: Gary Location: Honolulu, Hawaii Join Date: Jan 2009 Motorcycle(s): 2015 BMW R1200R, 08 Honda VFR800A (sold), 09 Ninja 250R (sold) Posts: A lot.	i never used to use the kill switch and it would still backfire every now and then. i'd let it idle a bit after the ride before shutting off the engine... didn't matter. totally random and when i least expected it.

September 10th, 2012, 10:29 AM	#170
lindasninja ninjette.org newbie Name: Linda Location: Victoria Australia Join Date: Nov 2011 Motorcycle(s): Ninja 250J Posts: 9	I always thought you hit the kill switch when you were about to hit something! And the Kill switch is a bit nasty on the bike, maybe used it like 10 times to see if it worked, not crashed!? Also put in neutral when I get home, and idle it have to reverse in between cars, backwards then through a gate, usually get the angle right then, get off and turn of the bike, take helmet off and roll it to its home! I knew nothing at all, when I got my L’s so I did lots of reading, and apparently better for the engine to do the cool down thing? Go nice and gentle just a bit before you get home, and turn it off, after a few seconds of not moving like a cool down lap, but not idling too much as it heats the engine too much? Sorry think that might not help the idle theory!? Totally random again!

January 17th, 2013, 12:16 PM	#176
Corona ninjette.org member Name: Carlos Location: Mo Val Join Date: Apr 2012 Motorcycle(s): 09 Ninja 250R (Crashed/Unexistent) / 11 Ninja ZX6R Posts: 83	I bought my bike used, the first backfire happened months after and it happened about 6 times within a month, after that I haven't had another, it's been about 3 months without it happening

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