Go Back   Horizons Unlimited - The HUBB > Technical, Bike forums > Yamaha Tech
Second carb opening Second carb opening
Register FAQ Calendar Today's Posts
Yamaha Tech Originally the Yamaha XT600 Tech Forum, due to demand it now includes all Yamaha's technical / mechanical / repair / preparation questions.
Photo by Hendi Kaf, in Cambodia

I haven't been everywhere...
but it's on my list!


Photo by Hendi Kaf,
in Cambodia



Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 28 Dec 2006
Contributing Member
Veteran HUBBer
  
Join Date: Mar 2003
Location: London,England
Posts: 358
Second carb opening
My XT600 3AJ would missfire and hicup at 3000 rpm or higher when engine got hot. After alot of trial and error I think I have fixed this problem by changing the stator plate but still using oringal pick up,
Now the bike feels low on power when I acelarate it feels like you are riding with the choke on.I have disconected the choke cable but no different.
Today I took carbs off again and to measure when the second carb starts to open it was at about 9mm I have adjusted it to open at 5mm but ran out of time to put every thing back together.
What affect would you get if the second carb was opening not opening till 9mm?
Is there any thing else I can check before carbs get put back.
I cleaned carbs about 5 weeks ago but found what I think is very fine rust at the bottom of float bowl,my bike used to have inline fuel filters on petrol pipes but these were removed by a mechanic as he said they were very close to the exhaust and as I had fuel filters in the tank they were not needed has any one had problems fitting inline filters?
Thanks
Reply With Quote
  #2  
Old 28 Dec 2006
Brian Williams's Avatar
Contributing Member
Veteran HUBBer
  
Join Date: Oct 2006
Location: england
Posts: 137
Possibly secondary carb might have a jet blockage or wrong float hight. Run the engine till warm, then slowly twist throttle till you can see second carb opening up. The sound of the engine should change a little (not just getting louder but a slightly more deeper note) as more fuel/air is burnt. If the engine just increases in volume its time for another clean and check up. Use aerosol carb cleaner. As for 5mm or 9mm before 2nd carb opens,( I think standard is 5.5mm so 5mm will be fine) a to early opening would mean air speed through two carbs (rather than one) would be too slow so fuel/air mix wouldn't be so good and so less power at low revs (below 3000rpm) but above that will be ok. While a late opening wouldn't flow enough fuel/air at higher revs so would be low on power above 3000rpm. Fit inline filters and cable-tie them away from exhaust
__________________
rust & dust
Last edited by Brian Williams; 28 Dec 2006 at 20:19.
Reply With Quote
  #3  
Old 28 Dec 2006
Gold Member
Veteran HUBBer
  
Join Date: Sep 2006
Location: N.Yorkshire
Posts: 336
timing?
not sure about how the yammie ignition is set up, but a charectaristic of retarded static ignition timing is loss of torque, especially at lower RPM. retading by 10 degrees or so may give the effect you are mentioning.
Is it feasible that the pickup is in a different place?
only a guess tho, apologies if I am wide of the mark.
__________________
Harley Davidsons,
The most effective way of turning petrol into noise without the side-effect of horsepower
Reply With Quote
  #4  
Old 28 Dec 2006
Brian Williams's Avatar
Contributing Member
Veteran HUBBer
  
Join Date: Oct 2006
Location: england
Posts: 137
Im not sure if you can move the pick up on XT,s, seems fixed in place by two bolts. If the carb service don't work try contact cleaner and a bit of a polish with wet and dry on the cdi and ignition electrical connections, they might be corroded or dirty.
__________________
rust & dust
Reply With Quote
  #5  
Old 28 Dec 2006
Gold Member
Veteran HUBBer
  
Join Date: Sep 2006
Location: N.Yorkshire
Posts: 336
The only reason I thought it may be possible is due to the stator plate being swapped out. not sure if a different model or type may have been accidentally used.
__________________
Harley Davidsons,
The most effective way of turning petrol into noise without the side-effect of horsepower
Reply With Quote
  #6  
Old 28 Dec 2006
Brian Williams's Avatar
Contributing Member
Veteran HUBBer
  
Join Date: Oct 2006
Location: england
Posts: 137
Could be that different models have the bolt holes in different places, might be worth checking yamaha part numbers or comparing original part with replacement if its from a different model of XT.
__________________
rust & dust
Reply With Quote
  #7  
Old 29 Dec 2006
Contributing Member
Veteran HUBBer
  
Join Date: Mar 2003
Location: London,England
Posts: 358
Thanks for quick replys
I will put carbs back on bike tommrow and sort some inline filters.
When I replaced the stator I used a pattern one from Eletrex £95 as the Yamaha one is about £400.I had to use my old pick up as no one makes a pattern pick up and you can only get one from Yamaha if you buy there stator. The stator and pick up are not adjustable.
I have also tried a different CDI and coil and also cleaned all connections.
Are there any tests I can do to work out if its a carb or ignition problem?
Reply With Quote
  #8  
Old 29 Dec 2006
Registered Users
HUBB regular
  
Join Date: Aug 2006
Location: UK
Posts: 45
The second carb is a CV with a diaphragm, have you checked to see if the diaphragm on the CV is OK?
Reply With Quote
  #9  
Old 29 Dec 2006
Brian Williams's Avatar
Contributing Member
Veteran HUBBer
  
Join Date: Oct 2006
Location: england
Posts: 137
The only way to check the ignition electrics would be to test the resistance of the various components, you will need a workshop book (do you have the Yamaha sevice manual) and a good mutimeter. As for carbs, just try whats been mentioned and make sure slides, jets, and diaphrams are good. Is the choke part of the carb moving freely? And the colour of the spark plug will tell you a lot.
__________________
rust & dust
Reply With Quote
Reply

« Previous Thread | Next Thread »

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

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
Newby 1988 XT600 carb prob. TANTHONY Yamaha Tech 2 4 Mar 2007 18:50
Carb Overflowing patta KTM Tech 21 27 Dec 2006 01:40
Xt225 Serrow Carb Prob Oz Yamaha Tech 3 14 Dec 2006 04:33
LC4 Carb ash_d KTM Tech 13 6 Oct 2005 13:00
carb adjustment ShaunC Yamaha Tech 3 29 Apr 2004 18:11

 
 

Announcements

Thinking about traveling? Not sure about the whole thing? Watch the HU Achievable Dream Video Trailers and then get ALL the information you need to get inspired and learn how to travel anywhere in the world!

Have YOU ever wondered who has ridden around the world? We did too - and now here's the list of Circumnavigators!
Check it out now, and add your information if we didn't find you.

Next HU Eventscalendar

25 years of HU Events
Be sure to join us for this huge milestone!

ALL Dates subject to change.

2025 Confirmed Events:

Virginia: April 24-27 2025
Queensland is back! May 2-4 2025
Germany Summer: May 29-June 1 2025
CanWest: July 10-13 2025
Switzerland: Date TBC
Ecuador: Date TBC
Romania: Date TBC
Austria: Sept. 11-14
California: September 18-21
France: September 19-21 2025
Germany Autumn: Oct 30-Nov 2 2025

Add yourself to the Updates List for each event!

Questions about an event? Ask here

See all event details

 
World's most listened to Adventure Motorbike Show!
Check the RAW segments; Grant, your HU host is on every month!
Episodes below to listen to while you, err, pretend to do something or other...

Adventurous Bikers – We've got all your Hygiene & Protection needs SORTED! Powdered Hair & Body Wash, Moisturising Cream Insect Repellent, and Moisturising Cream Sunscreen SPF50. ESSENTIAL | CONVENIENT | FUNCTIONAL.

2020 Edition of Chris Scott's Adventure Motorcycling Handbook.

2020 Edition of Chris Scott's Adventure Motorcycling Handbook.

"Ultimate global guide for red-blooded bikers planning overseas exploration. Covers choice & preparation of best bike, shipping overseas, baggage design, riding techniques, travel health, visas, documentation, safety and useful addresses." Recommended. (Grant)



Ripcord Rescue Travel Insurance.

Ripcord Rescue Travel Insurance™ combines into a single integrated program the best evacuation and rescue with the premier travel insurance coverages designed for adventurers.

Led by special operations veterans, Stanford Medicine affiliated physicians, paramedics and other travel experts, Ripcord is perfect for adventure seekers, climbers, skiers, sports enthusiasts, hunters, international travelers, humanitarian efforts, expeditions and more.

Ripcord travel protection is now available for ALL nationalities, and travel is covered on motorcycles of all sizes!


 

What others say about HU...

"This site is the BIBLE for international bike travelers." Greg, Australia

"Thank you! The web site, The travels, The insight, The inspiration, Everything, just thanks." Colin, UK

"My friend and I are planning a trip from Singapore to England... We found (the HU) site invaluable as an aid to planning and have based a lot of our purchases (bikes, riding gear, etc.) on what we have learned from this site." Phil, Australia

"I for one always had an adventurous spirit, but you and Susan lit the fire for my trip and I'll be forever grateful for what you two do to inspire others to just do it." Brent, USA

"Your website is a mecca of valuable information and the (video) series is informative, entertaining, and inspiring!" Jennifer, Canada

"Your worldwide organisation and events are the Go To places to for all serious touring and aspiring touring bikers." Trevor, South Africa

"This is the answer to all my questions." Haydn, Australia

"Keep going the excellent work you are doing for Horizons Unlimited - I love it!" Thomas, Germany

Lots more comments here!



Five books by Graham Field!

Diaries of a compulsive traveller
by Graham Field
Book, eBook, Audiobook

"A compelling, honest, inspiring and entertaining writing style with a built-in feel-good factor" Get them NOW from the authors' website and Amazon.com, Amazon.ca, Amazon.co.uk.



Back Road Map Books and Backroad GPS Maps for all of Canada - a must have!

Your ad could be here, on EVERY page of the HUBB, or the whole website, or as many as you like!

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 R80G/S.

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 all over the world with the help of volunteers; 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, or ask questions on the HUBB. 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.



All times are GMT +1. The time now is 19:25.

Contact Us - Horizons Unlimited Motorcycle Travellers Website - Archive - Privacy Statement - Top