Husaberg
Go Back   Husaberg Forum > Lobby > New Users

New Users Post up here and introduce yourself!


Thanks Tree1Thanks
  • 1 Post By thorgan
Reply
 
LinkBack Thread Tools Display Modes
February 12th, 2018, 06:03 AM   #1
Junior Member
 
Joined: Jan 2018
From: Wells, somerset

Posts: 6
Thanks: 1

I Ride:
one eighth throttle issue

Hi folks, I have an 02 fx 650 converted to fs and running with a racing FCR 41 (not the mx, no choke) and standard exhaust. Fuelling looks good on the dyno and getting 55hp at the wheel so happy with that. The issue is what feels like a missfire /luching/surging at 1/8th throttle. The dyno does show a little richness on the needle which raises the question,
is it possible for this condition to be needle taper, size or depth?
Or,
Is there a known ignition /CDI issue?
It has the two stage ignition. Lead, cap and plug all new.
Advice on this would be gratefully received.
Cheers.
Beng is offline  
 
February 12th, 2018, 08:43 AM   #2
Senior Member
 
Joined: Nov 2001
From: Ely, England

Posts: 15,408
Thanks: 396

I Ride: Husaberg FE501e 2003
Hi

I do a jetting kit for these.

if you tell us what you have then i can say what is up but without the numbers it is difficult to help.

generally, most things can be sorted on the pilot screw which is front and centre under the front of the carb. if you don't have an extended one that you can twiddle by hand then get one!

Taffy

Last edited by Taffy; February 12th, 2018 at 10:45 AM.
Taffy is online now  
February 12th, 2018, 09:49 AM   #3
Senior Member
 
thorgan's Avatar
 
Joined: May 2005
From: Sacramento California

Posts: 137
Thanks: 122

I Ride: "2000" FE600, 1996 FC660, 2015 Beta Xtrainer
Beng,
I had a similar problem with a 41mm keihin I put on a 600. It seemed to run pretty well except for a miss/hesitation in the first 1/8th throttle. I spent some time dialing in the pilot jet and the fuel screw adjustment but was never able to completely fix the issue until I started swapping needles to ones with fatter base diameters. I started by noticing that the problem got worse as I went up in elevation which would indicate a rich condition.

You can find a multitude of diagrams online that describe which jet in the Keihin is responsible for which portion of throttle travel. I then researched the various needles available along with their dimensions and eventually settled on the one with the largest base diameter I could find. That needle was an NCYQ which carries Honda code 7531049. However, my engine is somewhat unique in that it has a smaller bore and a larger stroke than your 650 and very low compression so your results may vary from mine. I've often wondered if the larger stroke engines have much stronger vacuum which will tend to pull more fuel through the jets at, or near, idle and maybe this is the reason I had to run this needle.
Thanks from Alan
thorgan is offline  
February 12th, 2018, 10:37 AM   #4
Junior Member
 
Joined: Jan 2018
From: Wells, somerset

Posts: 6
Thanks: 1

I Ride:
Thanks for that. My gut was needle profile or diameter, possibly wear as it seems to be at the transition point. I wanted a starting point because I need a cabinet full of left legs to start it after meddling so I kind of want to hit the mark with the least amount meddling. I'll pull the needle and check the size and hopefully get some positive improvement.
Cheers.
Beng is offline  
February 12th, 2018, 10:48 AM   #5
Junior Member
 
Joined: Jan 2018
From: Wells, somerset

Posts: 6
Thanks: 1

I Ride:
Taffy, if I alter the pilot circuit, make it leaner, what will be the effect on starting. Cold starting is usually okay with a few squirts on the throttle but warm starting can be an issue. A quick refueling stop ended up being half an hour! I do have the screw extension with the adjuster knob.
Beng is offline  
February 12th, 2018, 11:28 AM   #6
Senior Member
 
Joined: Nov 2001
From: Ely, England

Posts: 15,408
Thanks: 396

I Ride: Husaberg FE501e 2003
you're in a tight spot because you have no choke so you need the squirt!

they can have a rich stumble and a lean stumble.

usually it is a rich stumble oddly enough. the plug just can't cope!

I'm trying to be helpful but I REALLY don't know what you have and without it I can't guess whether your rich or lean?

one thing that always works is to raise the needle up.

regards

Taffy

Last edited by Taffy; February 12th, 2018 at 11:18 PM.
Taffy is online now  
February 12th, 2018, 11:07 PM   #7
Junior Member
 
Joined: Jan 2018
From: Wells, somerset

Posts: 6
Thanks: 1

I Ride:
Thanks Taffy, the dyno read a little rich on the needle and went quite sharply to across the line. The tester said pilot and main were spot on so looks like a rich stumble. It's really so good to have experienced input, thank you. I'll get numbers sometime this week and let you know.
Beng is offline  
Reply

  Husaberg Forum > Lobby > New Users

Tags
eighth, ignition, issue, throttle



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
'02 501 Clutch issue. husaferg Mechanical 5 June 11th, 2012 11:09 AM
clock issue snatch Electrical 0 February 6th, 2011 10:04 AM
Robert Loire eighth at Road America, sixth in season points Supermototeam SuperMoto 2 June 6th, 2006 09:48 AM
Starting Issue DOLLARS Electrical 7 May 16th, 2006 12:33 PM
Hot Re Starter Issue Mitchie Mechanical 1 April 27th, 2004 06:48 AM


Facebook Twitter Google+ RSS Feed