CB400 Top End Speed Issue

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
JamieCB400
Settled in member
Reactions:
Posts: 15
Joined: Tue Sep 08, 2015 6:43 pm
Re: CB400 Top End Speed Issue

Post by JamieCB400 » Wed Jun 15, 2016 11:22 am

Well the 180kmh restriction uses a hall-effect sensor in the speedo, but that is based on speed not rpm. My rev counter seems to working fine but does anyone know if there is some sort of gear indicator fed through the rev counter/speedo since the issue seems to isolated to 5th and 6th.

Nunsofanarchy
One Hit Wonder
Reactions:
Posts: 1
Joined: Wed Jun 01, 2016 12:01 am
Re: CB400 Top End Speed Issue

Post by Nunsofanarchy » Sun Jul 24, 2016 10:07 pm

I'm having the same issue hereom my 93 nc31, would love to know a solution

jolly
Settled in member
Reactions:
Posts: 56
Joined: Sat Oct 16, 2010 4:13 pm
Bike owned: super four
Location: kent england
Re: CB400 Top End Speed Issue

Post by jolly » Sat Feb 04, 2017 7:30 pm

what size sprockets are you using.

JamesHambleton
Settled in member
Reactions:
Posts: 31
Joined: Tue Jul 26, 2016 6:26 pm
Bike owned: CBF125,CB400SF,CB500,Bandit400
Location: Bedale, North Yorkshire
Re: CB400 Top End Speed Issue

Post by JamesHambleton » Sat Feb 04, 2017 9:58 pm

my nc31 maxed out at 160km I'm running stock size front sprocket and a 40 rear. Didn't matter what gear I put it in either would not go any faster, got upto that speed really quick though.

amorti
Senior Member
Reactions:
Posts: 1059
Joined: Sun May 18, 2008 4:51 pm
Bike owned: CB-1, MSX125
Location: Gibraltar
Re: CB400 Top End Speed Issue

Post by amorti » Thu May 11, 2017 12:45 am

Any chance there are 33hp restrictor washers in there?

just4kicks
Settled in member
Reactions:
Posts: 16
Joined: Wed Aug 30, 2017 12:37 pm
Re: CB400 Top End Speed Issue

Post by just4kicks » Wed Sep 06, 2017 3:20 pm

Hi Guys,

I have a very similar issue, 1st thru till 4th the bike will happily rev upto 12k rpm, and the speed will climb quickly, but once i hit 120km/h acceleration slows down and I get max 140km/h from 5th and 6th. Also, I can only use half throttle because if I open the accelerator more the bike sort of surges as if it isn't getting enough air or fuel or both.

Any help guys?
TIA


Post Reply