October 24th, 2016, 12:05 PM | #1 |
ninjette.org newbie
Name: Cole
Location: Monroe, La
Join Date: Oct 2016 Motorcycle(s): 2007 Ninja 250r Posts: 2
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Backfiring wont start 2007 Ninja 250r
Put fresh carbs on bike and rode it for a couple of days.
Went to start and starter just whizzed. Looked in portal and bolt holding flywheel had backed off. I tightened bolt and tried to start the bike but all it does is backfire. What did I do that would cause this and how can it be fixed? Thanks |
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October 24th, 2016, 01:25 PM | #2 | |
Rev Limiter
Name: Jay
Location: WI
Join Date: Jul 2013 Motorcycle(s): '06 SV650n, '00 Derbi GPR, '64 CA77 Dream 305, '70 CL450 Scrambler, numerous dirt bikes Posts: A lot.
MOTM - Jun '18, Oct '16
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Quote:
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1 out of 1 members found this post helpful. |
October 24th, 2016, 03:13 PM | #3 |
One ugly son of a gun.
Name: Andrew
Location: Raleigh, NC
Join Date: Sep 2016 Motorcycle(s): 2012 250 Posts: 167
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October 24th, 2016, 04:35 PM | #4 |
in your machine
Name: Scott
Location: Summer Shade, Ky.
Join Date: Oct 2014 Motorcycle(s): 98 Ninja 250/F12 aka ZX-2R "SERENITY", 91 Ninja 500/A5 aka ZX-5R "Phoenix", 84 Honda GL1200A "SIREN" Posts: A lot.
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That's what I was thinking.
More importantly is why did that bolt loosen up? Not a common problem with the ninjette. I had a similar problem with my EX500 many years ago, the cause was I failed to properly torque the flywheel bolt. It's an easy enough problem to fit, and cheap as well. No worries about valves, the flywheel has nothing to do with valve timing, just the triggers on the flywheel, which sends signals to the CDI.
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violente et ignorantia ZX-2R BLOG Twitter and Instagram = Ghostt_Scott I'm not here to change your mind, just to inform. |
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October 24th, 2016, 05:02 PM | #5 |
Guy Who Enjoys Riding
Name: Jim
Location: North Carolina
Join Date: Jul 2016 Motorcycle(s): Ninja 250 Posts: A lot.
MOTM - Oct '18, Aug '17, Aug '16
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Correct me if I'm wrong please, since I'm in the ignition system manufacturing business, but I thought our Ninjas used non-CDI electronic ignition system. Transistor switched, that is. The wiring diagram shows 12v to the coils, which seems to agree with my understanding.
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October 24th, 2016, 05:05 PM | #6 | |
in your machine
Name: Scott
Location: Summer Shade, Ky.
Join Date: Oct 2014 Motorcycle(s): 98 Ninja 250/F12 aka ZX-2R "SERENITY", 91 Ninja 500/A5 aka ZX-5R "Phoenix", 84 Honda GL1200A "SIREN" Posts: A lot.
Blog Entries: 25
MOTM - Jun '17, May '16, Mar '15
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Quote:
I'm used to calling the module that, old habits you know.
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violente et ignorantia ZX-2R BLOG Twitter and Instagram = Ghostt_Scott I'm not here to change your mind, just to inform. |
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October 24th, 2016, 05:08 PM | #7 | |
One ugly son of a gun.
Name: Andrew
Location: Raleigh, NC
Join Date: Sep 2016 Motorcycle(s): 2012 250 Posts: 167
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Quote:
Yeah, it's connected to the crank, but not associated with timing outside of the pickup mounted on it. Derp. |
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October 24th, 2016, 05:14 PM | #8 |
Guy Who Enjoys Riding
Name: Jim
Location: North Carolina
Join Date: Jul 2016 Motorcycle(s): Ninja 250 Posts: A lot.
MOTM - Oct '18, Aug '17, Aug '16
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October 24th, 2016, 05:31 PM | #9 |
in your machine
Name: Scott
Location: Summer Shade, Ky.
Join Date: Oct 2014 Motorcycle(s): 98 Ninja 250/F12 aka ZX-2R "SERENITY", 91 Ninja 500/A5 aka ZX-5R "Phoenix", 84 Honda GL1200A "SIREN" Posts: A lot.
Blog Entries: 25
MOTM - Jun '17, May '16, Mar '15
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The EX-250's igniter uses a very simple advance curve: 2-dimensions, X and Y, with no compensation for load. It's pre-historic, rudimentary.
At about 4,000 or 4,200 rpm, depending on the year-model of the EX-250, the igniter has the ignition timing at full advance (38 degrees BTDC for the older engines or 42 degrees BTDC for the newer engines). When you roll-on full throttle at about 4,000 rpm you suddenly make the air/fuel ratio much richer. In a modern car or motorcycle engine the ECU knows when this happens and it retards the ignition a bit because richer air/fuel ratios burn faster than leaner mixtures. Because the EX-250 igniter has no way to compensate for the sudden rich (faster burning) mixture the ignition advance stays way up there at 38 or 42 degrees and you end up with too much of the burn occurring before the cylinder reaches TDC. Instead of instantly making a lot more power (as you're anticipating when you open the throttle wide) you make only a little bit more. And the engine slowly lifts itself out of the situation.
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violente et ignorantia ZX-2R BLOG Twitter and Instagram = Ghostt_Scott I'm not here to change your mind, just to inform. |
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