CBR 400 nc29 - lot of backfire on turnover and won’t start
Forum rules
Please can you post items for sale or wanted in the correct For Sale section. Items / bikes for sale here will be removed without warning. Reasons for this are in the FAQ. Thanks
Please can you post items for sale or wanted in the correct For Sale section. Items / bikes for sale here will be removed without warning. Reasons for this are in the FAQ. Thanks
-
Fahd
- Settled in member
- Posts: 4
- Joined: Mon Aug 25, 2008 3:50 pm
CBR 400 nc29 - lot of backfire on turnover and won’t start
Hi all,
Having some issues with my CBR 400 nc29.
It’s been sitting unloved for a long while (bought an r6 2co - now miss the small nimble size of 400 which has sat in garage).
It turns over fine and has good spark but will not spark (and backfires pretty aggressively when I try).
Thus far, in my quest to bring this 400 back to life, I have changed quite few parts recently (it had inconsistent spark previously which has since now been resolved):
New coil packs and coil pack wires,
New Stator,
New Pulse generator (tested and reading 425 ohms)
New Plugs,
New fuel,
Cleaned carbs,
I have now removed the engine casing and am looking for the woodruff key to see if is worn. Can anyone point me in right direction to how to correctly remove and view?
Does anyone have any other suggestions I am missing? I’m convinced the timing just seems off given the way it’s backfiring and just doesn’t want to start at all.
Hoping by the end of this thread to share a video of it alive and well again.
Thanks,
Fahd
Having some issues with my CBR 400 nc29.
It’s been sitting unloved for a long while (bought an r6 2co - now miss the small nimble size of 400 which has sat in garage).
It turns over fine and has good spark but will not spark (and backfires pretty aggressively when I try).
Thus far, in my quest to bring this 400 back to life, I have changed quite few parts recently (it had inconsistent spark previously which has since now been resolved):
New coil packs and coil pack wires,
New Stator,
New Pulse generator (tested and reading 425 ohms)
New Plugs,
New fuel,
Cleaned carbs,
I have now removed the engine casing and am looking for the woodruff key to see if is worn. Can anyone point me in right direction to how to correctly remove and view?
Does anyone have any other suggestions I am missing? I’m convinced the timing just seems off given the way it’s backfiring and just doesn’t want to start at all.
Hoping by the end of this thread to share a video of it alive and well again.
Thanks,
Fahd
-
magg
- Senior Member
- Posts: 1920
- Joined: Mon Sep 20, 2010 11:55 pm
- Bike owned: VFR400
- Location: Blue Mountain NSW Australia
Re: CBR 400 nc29 - lot of backfire on turnover and won’t start
Timing is derived from a rotor and 2 signal pickups on the right hand end of the crank. Stator is not part of the timing equation. How did you resolve the inconsistent spark.
-
Fahd
- Settled in member
- Posts: 4
- Joined: Mon Aug 25, 2008 3:50 pm
Re: CBR 400 nc29 - lot of backfire on turnover and won’t start
Thanks for taking the time to respond Magg. I believe the inconsistent spark was resolved when putting in new coil packs/ coil pack wires.magg wrote: Thu Jan 08, 2026 11:13 pm Timing is derived from a rotor and 2 signal pickups on the right hand end of the crank. Stator is not part of the timing equation. How did you resolve the inconsistent spark.
Can you tell me more about this rotor and 2 signal pickup on the right hand side of the crank? Anything I can do to test/ review?