Go Back   Horizons Unlimited - The HUBB > Technical, Bike forums > KTM Tech

KTM Tech KTM Tech Forum - For Questions specific and of interest to KTM riders only. Questions comparing which bike is best etc go in the "Which Bike" forum.
Contact Overland Solutions for all your custom modifications and setup for overland travel.

Calendar Contest Voting is now CLOSED. Results to be posted shortly.


Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 30 Aug 2010
Registered Users
HUBB regular
 
Join Date: Feb 2009
Location: Sydney, Australia
Posts: 75
KTM 640 Engine Cuts on Braking & Hills

Hi,

My 2006 KTM 640 Adventure engine has a problem. It starts and runs ok, however on heavy braking with high RPM it backfires like a shotgun. When I brake hard with idle RPM the engine cuts. The engine will also cut on idle when going down hills. Rather annoying when riding hard in traffic.

I've tried troubleshooting various things - fuel pump, choke cable, float height. etc. But can't figure it out. One thing I did notice when playing with the needle height is that the membrane slide in the carb seems to have a bit of forwards and backwards play in it causing wear on the needle - It will need replacing when I can afford it.


Does anyone have any suggestions?
__________________
http://ktmthump.blogspot.com
Reply With Quote
  #2  
Old 30 Aug 2010
Registered Users
Veteran HUBBer
 
Join Date: Mar 2008
Location: Rotoiti, New Zealand
Posts: 102
Maybe an electrical problem not a carb one? The weight shift braking & downhill might be nudging something? I'd check the wiring under the tank for any rubbing. Maybe try bypassing the stand switch too.

BST carbs are bad for wearing out, apparently moto-lab.com is the best place to get a rebuild kit. However when I rebuilt mine at about 80K km it was well worn & generally running a bit crappy, but no cutting out like you describe.

Cheers
Clint
Reply With Quote
  #3  
Old 4 Sep 2010
Registered Users
HUBB regular
 
Join Date: Feb 2009
Location: Sydney, Australia
Posts: 75
Thanks for the advice regarding rebuild - once I get some money together I will probably start a rebuild job beginning with the carb.

I've not had a detailed look at the electrical connections but will keep my eye open for anything next time I have the tank off. To me, something screams bottom end mixture problem. I have discovered that the mixture screw is completely jammed solid so have had to lean the needle valve all the way out. The needle also seems to wear pretty quickly too.

My bike doesn't have a sidestand switch so I can cross that one off my list of potential gremlins.

Cheers

Duncan
__________________
http://ktmthump.blogspot.com
Reply With Quote
  #4  
Old 22 Aug 2011
Registered Users
Veteran HUBBer
 
Join Date: Sep 2002
Location: london,england
Posts: 157
i had a lc4 400 that did the same thing, especially when doing stoppies. unfortunately i never found the fault. sorry.
Reply With Quote
  #5  
Old 23 Aug 2011
Registered Users
New on the HUBB
 
Join Date: Dec 2006
Location: York
Posts: 19
1. What was reported in the original post, sounds as if there has been some adjustments from standard. Namely carb settings. I would put these back to standard (all standard carb setting in KTM manual, with specs). Standard setting before trying moving away from those and then only one setting made to try. You will always have a known situation to go back to.

2. Try raising the tickover speed, 1400 to 1500 rpm is about right.

3. Mine used to stall/cut out sometimes for no apparent reason if the air filter is dirty/blocked, clean out airbox properly with blue roll/tissue and maintence spray and fit a new/oiled filter.
4. If you think its electrical - The underseat fuse box towards the back of the bike above the battery. The fuses have a habit of loosening off and being slightly baggy in the holders. You can push up tighter the fuse holder grips for the blades with a very small screwdriver or scriber. This makes them grip the fuses tighter. Could be that cutting out the ignition circuit with vibration, but you did'nt mention electrics cutting out at all in the original post.
Attached Thumbnails
KTM 640 Engine Cuts on Braking & Hills-640-carb-settings.jpg  

Reply With Quote
  #6  
Old 14 Sep 2011
Registered Users
New on the HUBB
 
Join Date: Mar 2008
Location: Arkansas
Posts: 14
Sounds like you need to check the float level in the carb.
There is a similar issue thread on advrider about LC4 bogging after jumps.
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 Registered Users and/or Members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
HELP- XT600 cuts out at 65MPH rdelta Yamaha Tech 31 9 Apr 2012 18:03
Anyone been to Tsodilo Hills, Aha Hills and Gcwihaba Caves? Roboyobo sub-Saharan Africa 3 4 Aug 2010 17:21
Engine braking & gear ratios TommyT Kawasaki 2 12 Dec 2009 16:10
Engine cuts out over 50 mph pt5eng2 Yamaha Tech 15 21 Jan 2009 20:26
braking up lost1 KTM Tech 0 18 Jul 2003 04:22

 
 



HU DVD Spring Special!

Buy the Achievable Dream Collectors Set and get Road Heroes Part 1 FREE!

Achievable Dream - The Whole Enchilada!

Cooped up indoors in crap weather? Binge watch over 20 hours of inspiring, informative and entertaining stories and tips from 150 travellers! Check it out at the HU Store! Remember to order them both and use Coupon Code 'BoxSet+' on your order when you checkout.


What others say about HU...

"I just wanted to say thanks for doing this and sharing so much with the rest of us." Dave, USA

"Your website is a mecca of valuable information and the DVD series is informative, entertaining, and inspiring! The new look of the website is very impressive, updated and catchy. Thank you so very much!" Jennifer, Canada

"...Great site. Keep up the good work." Murray and Carmen, Australia

"We just finished a 7 month 22,000+ mile scouting trip from Alaska to the bottom of Chile and I can't tell you how many times we referred to your site for help. From how to adjust your valves, to where to stay in the back country of Peru. Horizons Unlimited was a key player in our success. Motorcycle enthusiasts from around the world are in debt to your services." Alaska Riders


contest pic

10th Annual HU Travellers Photo Contest is on now! This is an opportunity for YOU to show us your best photos and win prizes!

NEW! HU 2014 Adventure Travel T-shirts! are now available in several colors! Be the first kid on your block to have them! New lower prices on synths!

HU 2014 T-shirts now in!

Check out the new Gildan Performance cotton-feel t-shirt - 100% poly, feels like soft cotton!


What turns you on to motorcycle travel?


Global Rescue, WORLDwide evacuation services for EVERYONE

Global Rescue is the premier provider of medical, security and evacuation services worldwide and is the only company that will come to you, wherever you are, and evacuate you to your home hospital of choice. Additionally, Global Rescue places no restrictions on country of citizenship - all nationalities are eligible to sign-up!




New to Horizons Unlimited?

New to motorcycle travelling? New to the HU site? Confused? Too many options? It's really very simple - just 4 easy steps!

Horizons Unlimited was founded in 1997 by Grant and Susan Johnson following their journey around the world on a BMW R80 G/S motorcycle.

Susan and Grant Johnson Read more about Grant & Susan's story

Membership - help keep us going!

Horizons Unlimited is not a big multi-national company, just two people who love motorcycle travel and have grown what started as a hobby in 1997 into a full time job (usually 8-10 hours per day and 7 days a week) and a labour of love. To keep it going and a roof over our heads, we run events (22 this year!); we sell inspirational and informative DVDs; we have a few selected advertisers; and we make a small amount from memberships.

You don't have to be a Member to come to an HU meeting, access the website, the HUBB or to receive the e-zine. What you get for your membership contribution is our sincere gratitude, good karma and knowing that you're helping to keep the motorcycle travel dream alive. Contributing Members and Gold Members do get additional features on the HUBB. Here's a list of all the Member benefits on the HUBB.



Books & DVDs

amazon

All the best travel books and videos listed and often reviewed on HU's famous Books page. Check it out and get great travel books from all over the world.


Motorcycle Express for shipping and insurance!

Motorcycle Express

MC Air Shipping, (uncrated) USA / Canada / Europe and other areas. Be sure to say "Horizons Unlimited" to get your $25 discount on Shipping!
Insurance - see: For foreigners traveling in US and Canada and for Americans and Canadians traveling in other countries, then mail it to MC Express and get your HU $15 discount!






All times are GMT +1. The time now is 09:53.