Help & FAQs    Search BCF    Members    Groups    Events Calendar
Resend my activation email : Register : Log in 
BCF: Bike Chat Forums


Carbs

 Reply to topic
Bike Chat Forums Index -> The Workshop
View previous topic : View next topic  
Author Message

Baffler186
World Chat Champion



Joined: 31 May 2013
Karma :
PostPosted: 22:43 - 27 Jan 2017    Post subject: Carbs Reply with quote
Cb400a _ starts fine and idles fine, it accelerates normally if you open it up gradually, but if you whack it open it bogs and stays where it is.it also won't rev up to the redline. It does the same in neutral and in gear. Could it be the mixture needs adjusting? I considered having the carb cleaned and rebuilt but i did that with a previous bike and it made the problem worse.

It has new intake rubbers. I've put in new oil, oil filter and air filter, new plugs. I want to try adjusting the mixture before i pull it all apart but don't know how really. Is it just a case of fiddling with mixture screw whilst running, like you would the idle screw?
____________________
Current: 2009 SV650 S, 1990 Kawasaki GT550
Previous: 2009 CBF125, 1998 GSF600, 2004 FZ6 Fazer, 1978 CB400a Hondamatic
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

redeem ouzzer
World Chat Champion



Joined: 06 Oct 2015
Karma :
PostPosted: 23:10 - 27 Jan 2017    Post subject: Reply with quote
Mixture screw only affects idle > quarter throttle.

Sounds like mucky carbs.
____________________
Be a REAL MAN!
 Back to top
View user's profile Send private message You must be logged in to rate posts

Commuter_Tim
World Chat Champion



Joined: 08 May 2013
Karma :
PostPosted: 00:04 - 28 Jan 2017    Post subject: Re: Carbs Reply with quote
Baffler186 wrote:
Could it be the mixture needs adjusting? I considered having the carb cleaned and rebuilt but i did that with a previous bike and it made the problem worse.

Cleaning Carbs is only going to make a problem "worse" if the person fucked up the cleaning or that wasn't the problem in the first place.
____________________
The above post is most likely nonsensical.

I ride a Bandit 600... badly.
 Back to top
View user's profile Send private message You must be logged in to rate posts

jaffa90
World Chat Champion



Joined: 06 Apr 2016
Karma :
PostPosted: 00:06 - 28 Jan 2017    Post subject: Reply with quote
What year what carb is fitted?
It sounds short of fuel (lean) so is the air filter standard?
 Back to top
View user's profile Send private message You must be logged in to rate posts

Baffler186
World Chat Champion



Joined: 31 May 2013
Karma :
PostPosted: 06:48 - 28 Jan 2017    Post subject: Reply with quote
jaffa90 wrote:
What year what carb is fitted?
It sounds short of fuel (lean) so is the air filter standard?
it's a 1980 model, carb is a vb24 i think. I doubt it has been cleaned before. Air filter is standard, I've just fitted a new oem one.
____________________
Current: 2009 SV650 S, 1990 Kawasaki GT550
Previous: 2009 CBF125, 1998 GSF600, 2004 FZ6 Fazer, 1978 CB400a Hondamatic
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

Baffler186
World Chat Champion



Joined: 31 May 2013
Karma :
PostPosted: 06:50 - 28 Jan 2017    Post subject: Reply with quote
Ok thanks, i will get the carbs cleaned. There is a guy nearby who will ultrasonic clean and rebuild them for £50 plus cost of parts.
____________________
Current: 2009 SV650 S, 1990 Kawasaki GT550
Previous: 2009 CBF125, 1998 GSF600, 2004 FZ6 Fazer, 1978 CB400a Hondamatic
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

Petemate
Trackday Trickster



Joined: 13 Nov 2015
Karma :
PostPosted: 08:50 - 28 Jan 2017    Post subject: Reply with quote
Baffler186 wrote:
Ok thanks, i will get the carbs cleaned. There is a guy nearby who will ultrasonic clean and rebuild them for £50 plus cost of parts.


Ultrasonic deffo the way to go with the VB carbs. I have one on my LA. It was a beggar to sort out but now OK. The slow running passages are a nightmare. Have a look on the Honda Twins forum - lots of info there and cutaway pics of the passages. Most interesting.
HTH
____________________
82 not out....1983 Honda LA250 Custom
2008 Saab 9-3 1.9 Tid 150 Vector Sport estate
2005 Stirling Eccles Topaz 2-berth
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts
Old Thread Alert!

The last post was made 9 years, 24 days ago. Instead of replying here, would creating a new thread be more useful?
  Display posts from previous:   
This page may contain affiliate links, which means we may earn a small commission if a visitor clicks through and makes a purchase. By clicking on an affiliate link, you accept that third-party cookies will be set.

Post new topic   Reply to topic    Bike Chat Forums Index -> The Workshop All times are GMT
Page 1 of 1

 
 You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum

Read the Terms of Use! - Powered by phpBB © phpBB Group
 
Debug Mode: ON - Server: birks (www) - Page Generation Time: 0.06 Sec - Server Load: 0.64 - MySQL Queries: 14 - Page Size: 51.82 Kb