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Re: Honda CBR 400 NC29 Float Height

Posted: Wed Jun 21, 2017 10:04 am
by slyshot
Hi Everyone

As an update I have checked the following parts as per the Haynes manual and haven't found anything out of spec:

Coils
Ignition Pickups
reg/rec
TPS
Fuel Pump
Replaced all fuses

I have checked the continuity between these parts and the ignition box/CDI and found no problems.

The previous owner bypassed the speed limiter by cutting the wires behind the clocks and soldering a 2.2k resister between 2 of the wires and leaving one blank, as per some diagrams I have seen on this forum it all looks correct but not the best quality work so im going to re-do with another resistor, however I have read that if this was a problem it would be getting issues around 5k but mine are all 9k and above and in every gear or more noticeable the higher the gear.

So I feel like im at the point I need to try swapping some electronic parts out to find some improvement, any ideas on the most likely suspect? or any more ideas on parts to check?

If anyone has some electronic parts for sale let me know.

Thanks


Sam

Re: Honda CBR 400 NC29 Float Height

Posted: Wed Jun 21, 2017 10:32 am
by CB1pod70
Just a thought but have you got an aftermarket 4-1 Delkavic exhaust?

My NC23 has a flat spot between 5K & 8.5K which talking to Graeme France over the weekend, he confirmed is caused by my 4-1 exhaust. The 23 & 29 run best on a 4-2-1 system

Re: Honda CBR 400 NC29 Float Height

Posted: Wed Jun 21, 2017 11:20 am
by dunkenb
Are all the jets standard sizes ? If you've got an after market exhaust or a K&N filter you're going to need bigger main jets. 8-)

Re: Honda CBR 400 NC29 Float Height

Posted: Wed Jun 21, 2017 3:34 pm
by slyshot
Hi

It has an aftermarket stainless system fitted but I don't know the brand, however it has had this on it since I picked her up and was running absolutely fine up until recently, the only previous flat spot was @3k and totally liveable.

It does have a K&N filter and is running on the standard 108 mains but again like this for a while now, I fitted the K&N and had no problems with how it was running until recently.

Thanks for getting back to me, any more ideas?

trying to remain calm as have a trackday booked for the 4th August....

Re: Honda CBR 400 NC29 Float Height

Posted: Wed Jun 21, 2017 3:46 pm
by CB1pod70
The only other thing that comes to mind is the condition of the battery - the CDI's on these things can be a bit temperamental if the battery's on its last legs is there any corrosion on the earth connections to the frame?

Re: Honda CBR 400 NC29 Float Height

Posted: Wed Jun 21, 2017 4:14 pm
by slyshot
Battery seems to charge up just fine and hold voltage without any problems, could be causing issues even though looks in spec?

I did just check the earth that is right by the battery on the main frame, i'll have a poke around at the others as well