Nc29 won't run properly

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
dunkenb
Regular Member
Reactions:
Posts: 695
Joined: Wed Jun 03, 2009 9:39 pm
Bike owned: Cbr400rr nc29 type8 NSR250
Location: West Midlands
Nc29 won't run properly

Post by dunkenb » Mon Aug 21, 2017 9:07 pm

So... She starts ok, but tick over seems like it's on three cylinders unless I use a bit of choke. After a while running it gets rough. Bogging down and low on power. Outer two plugs seem good but inner ones look like theyre not running but they are as they get hot?
I've replace plug caps,leads,plugs....had the carbs ultrasonically cleaned and new mixture screw o-rings...checked coils for resistance and both within spec.checked the pick up coil and that's all good. Checked the battery and charging system.

What the hell is going on? I've had the carbs off about 30 times. The only thing I found wrong was the two plug caps for 2 and 3 were duff.

Any thoughts? Would a dodgy ECU give any symptoms? Or perhaps a speed limiter fault?

CB1pod70
NWAA Supporter
NWAA Supporter
Reactions:
Posts: 465
Joined: Thu Apr 09, 2015 1:55 pm
Location: Gravesend
Re: Nc29 won't run properly

Post by CB1pod70 » Tue Aug 22, 2017 12:57 pm

The ECU would be about the only thing you haven't checked. I think you've covered everything else....

dunkenb
Regular Member
Reactions:
Posts: 695
Joined: Wed Jun 03, 2009 9:39 pm
Bike owned: Cbr400rr nc29 type8 NSR250
Location: West Midlands
Re: Nc29 won't run properly

Post by dunkenb » Tue Aug 22, 2017 1:11 pm

Yeah, think I'm gonna have to go down that root next! It's driving me insane!!!

dunkenb
Regular Member
Reactions:
Posts: 695
Joined: Wed Jun 03, 2009 9:39 pm
Bike owned: Cbr400rr nc29 type8 NSR250
Location: West Midlands
Re: Nc29 won't run properly

Post by dunkenb » Wed Sep 06, 2017 8:09 pm

Still struggling to get it to run cleanly.
Of the air jets by the trumpet on the front of the carb,
Anyone know which ones the pilot air jet (PAJ) and which ones the main air jet (MAJ) ??
I've got a blockage somewhere!!

User avatar
Davez29
Site Supporter
Site Supporter
Reactions:
Posts: 1931
Joined: Sun Aug 03, 2008 8:38 pm
Bike owned: NC29 forever
Re: Nc29 won't run properly

Post by Davez29 » Wed Sep 06, 2017 8:31 pm

I recently had a dodgy ECU and the symptoms were that the bike started fine and ran ok but after six miles virtually at the same spot on the road it would cough and splutter and would not run properly until cold again. I tried everything expecting it to be carb, ignition or HT related without getting anywhere and having a spare ECU I eventually got around to changing it and to my surprise it worked.

Bowches
Familiar Member
Reactions:
Posts: 393
Joined: Thu Mar 10, 2016 5:47 pm
Bike owned: cbr 400 zxr 400 gsx 1300r
Re: Nc29 won't run properly

Post by Bowches » Thu Sep 07, 2017 8:57 am

Davez29 wrote:I recently had a dodgy ECU and the symptoms were that the bike started fine and ran ok but after six miles virtually at the same spot on the road it would cough and splutter and would not run properly until cold again. I tried everything expecting it to be carb, ignition or HT related without getting anywhere and having a spare ECU I eventually got around to changing it and to my surprise it worked.
hi Davez29,

How many miles have you done on your CBR 400? Have you had to do any engine rebuild?

I am currently at 26100 Km/Miles

Thanks

User avatar
Davez29
Site Supporter
Site Supporter
Reactions:
Posts: 1931
Joined: Sun Aug 03, 2008 8:38 pm
Bike owned: NC29 forever
Re: Nc29 won't run properly

Post by Davez29 » Fri Sep 08, 2017 12:44 am

hi Davez29,

How many miles have you done on your CBR 400? Have you had to do any engine rebuild?

I am currently at 26100 Km/Miles

Thanks
I think it's over 75000k which is a good run for a small old sportsbike I guess. I know the first 25k were KM after that I'm not certain of 10k wether its miles or km as the bike had the converter fitted when I bought it. I guess it's a tad noisier than when I bought it, so maybe I will give it a top end overall one day, possibly.

Btw a tip, if you ever buy anything electrical off eBay secondhand as backup, fit it asap, even if your original electrical part is fine. That way you will know it's ok or not and you can keep your original as back up for a rainy day. That's how I had a spare ECU to quickly fit.

Bowches
Familiar Member
Reactions:
Posts: 393
Joined: Thu Mar 10, 2016 5:47 pm
Bike owned: cbr 400 zxr 400 gsx 1300r
Re: Nc29 won't run properly

Post by Bowches » Fri Sep 08, 2017 10:17 am

Davez29 wrote:
hi Davez29,

How many miles have you done on your CBR 400? Have you had to do any engine rebuild?

I am currently at 26100 Km/Miles

Thanks
I think it's over 75000k which is a good run for a small old sportsbike I guess. I know the first 25k were KM after that I'm not certain of 10k wether its miles or km as the bike had the converter fitted when I bought it. I guess it's a tad noisier than when I bought it, so maybe I will give it a top end overall one day, possibly.

Btw a tip, if you ever buy anything electrical off eBay secondhand as backup, fit it asap, even if your original electrical part is fine. That way you will know it's ok or not and you can keep your original as back up for a rainy day. That's how I had a spare ECU to quickly fit.
75000k is very good....hopefully you will reach 100k miles/km on the clock without having to do any engine rebuild....

How often did you adjust the valves? IT says in the haynes manual to do it every 8000 miles?

Bowches
Familiar Member
Reactions:
Posts: 393
Joined: Thu Mar 10, 2016 5:47 pm
Bike owned: cbr 400 zxr 400 gsx 1300r
Re: Nc29 won't run properly

Post by Bowches » Fri Sep 08, 2017 11:07 am

What other bikes have you ever had Davez?

Is the NC29 the only bike you have ever had?

User avatar
Davez29
Site Supporter
Site Supporter
Reactions:
Posts: 1931
Joined: Sun Aug 03, 2008 8:38 pm
Bike owned: NC29 forever
Re: Nc29 won't run properly

Post by Davez29 » Fri Sep 08, 2017 8:40 pm

Bowches wrote:75000k is very good....hopefully you will reach 100k miles/km on the clock without having to do any engine rebuild....

How often did you adjust the valves? IT says in the haynes manual to do it every 8000 miles?
Well there are a few out there over 100k but 75k is still a good running. To be honest I have checked the valves only three times since I got the bike in 2008. Only the second time did I actually have to change two shims as they were just on the edge of the spec. To answer your other question, I have had a few bikes most being of the 125 variety, although I once had a Suzuki, 250, 400 and 500 for a short period. Nothing anywhere as good as the nc29.


Post Reply