Horizons Unlimited, the website for motorcycle travellers.    
in cooperation with
Quality Touring equipment worldwide.
 
Be a Member!
Is HU useful & helpful?
Become a Member! And get more goodies!
Navigation
Art
Amazon

Buy your books and goodies from Amazon - but start at the HU Books Search page
Buy your books and goodies from Amazon.
and we get a small percentage of your purchases - and it costs you nothing! Thanks!

 
Go Back   The HUBB > Technical, Bike forums > Yamaha Tech
Contact Overland Solutions for all your custom modifications and setup for overland travel.  Follow the DAKAR 2010 with South America Motorbike Tours  
Search 

Search tips

Yamaha Tech Originally the Yamaha XT600 Tech Forum, due to demand it now includes all Yamaha's technical / mechanical / repair / preparation questions.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1  
Old 6th October 2006
chipompom's Avatar
chipompom chipompom is offline
Registered Users
New on the HUBB
 
Join Date: Sep 2006
Location: uk
Posts: 17
Carb Help Needed

Guys,

On the secondry carb is an upward facing tube connection that works the slide, where does this connect to and is it positive pressure or vacuum????

The airbox has been removed and 2 pancake filters installed. When i turn the throttle full the slide doesn't move!!!!

Cheers

Paul
Reply With Quote
  #2  
Old 6th October 2006
chipompom's Avatar
chipompom chipompom is offline
Registered Users
New on the HUBB
 
Join Date: Sep 2006
Location: uk
Posts: 17
Ignore the last post I was having a senior moment

The problem I'm having is the bike wont pull strongly from about 4500 rpm, taking the airfilters off and looking at the slides the secondry slide doesn't lift smoothly (although it isn't sticking) it sort of bobs up and down just short of half open. The diapragm is ok

I am at a loss

Any help would be appreciated

Thanks

P
Reply With Quote
  #3  
Old 6th October 2006
aukeboss aukeboss is offline
Registered Users
Veteran HUBBer
 
Join Date: Jan 2001
Location: riding the Americas
Posts: 579
Mysterious carbs

What bike do you have exactly?
On the right hand carb there is two connections, (A) one for air pressure = 'connected' to air filter outlet or outside air respectively and, (B) just upstream of the rubber connection to the cyl head there is a connection for a small hose that goes to the mixture enriching device (valve) on the primary carb.

(A) provides the higher pressure on one side of the mebrane to lift the slide of the second stage, as under the slide there wil be lower pressure that is 'communicated' to the other side of the membrane via the small vertical hole in the slide.

If the bike is stationary, ie. you are not loading th engine, there is no way you'll be able to keep the second carb open, as the load is just never sufficient to provide a sufficient airflow through the second carb. So, for me there is no proof your second stage is malfunctioning.

Are the airfilters clean and large enough? Try a short stretch without and see what happens?

I hope the description above is understandable, it is late in the afternoon and description of carbs in text I find difficult at the best of times.

Auke
__________________
Auke
http://aukemarieke.blogspot.com
Reply With Quote
  #4  
Old 6th October 2006
chipompom's Avatar
chipompom chipompom is offline
Registered Users
New on the HUBB
 
Join Date: Sep 2006
Location: uk
Posts: 17
Thanks Auke,

Sorry for the poor description, re read it my self and it only just makes sense

Its a 1991 XTZ660 Tenere, the airbox has been removed and most of the bodywork also.

I've recently had new camchain and guides fitted, but while the guy did a good job on the engine he didn't look at the carbs.

I had the carbs off today and gave them a bit of a clean out and its getting a bit better, i will try it under load on the way home from work tonight. I think the problem was a bit of cack got in there when i ran out of petrol (forgot to take it off reserve)

Again, sorry for being so vauge.

Thanks for the help

Paul
Reply With Quote
  #5  
Old 6th October 2006
Livotlout's Avatar
Livotlout Livotlout is offline
Contributing Member
HUBB regular
 
Join Date: May 2005
Location: Thetford, England
Posts: 88
Thumbs up

Hi Paul

Could be fuel starvation, you did say you ran out of fuel, this may have caused partial blockages - check petcock (and filter if it has one), any in line filters, kinked hose, fuel link hose between primary carb float bowl and secondary carb, finally check filter that sits above the inlet valve to the primary carb float bowl (you will have to remove valve body - one screw, filter sits on top of it).
I'm giving this advice on the assumption your set up is the same as on my MZ Baghira - XTZ660 engine.

Best of luck

Alec
Reply With Quote
  #6  
Old 6th October 2006
Livotlout's Avatar
Livotlout Livotlout is offline
Contributing Member
HUBB regular
 
Join Date: May 2005
Location: Thetford, England
Posts: 88
Smile

Paul

The final item (valve) I refered to in the last post, is item no 43 in the attached pic :-


http://i103.photobucket.com/albums/m...tlout/h-06.gif

Again, best of luck

Alec
Reply With Quote
  #7  
Old 9th October 2006
chipompom's Avatar
chipompom chipompom is offline
Registered Users
New on the HUBB
 
Join Date: Sep 2006
Location: uk
Posts: 17
HI Alec,

Thanks for the help (my works server wont let me look at the pic could you mail it to me on please)

I put a single dose of Redex carb cleaner in and its starting to get better, i think i'll add a bit more before my long ride out this weekend and see how it goes

Thanks for the help all. I hope to return the favour one day

Paul

Last edited by chipompom : 10th October 2006 at 08:05.
Reply With Quote
  #8  
Old 9th October 2006
Livotlout's Avatar
Livotlout Livotlout is offline
Contributing Member
HUBB regular
 
Join Date: May 2005
Location: Thetford, England
Posts: 88
Thumbs up

Hi paul

EMail sent

Alec
Reply With Quote
  #9  
Old 10th October 2006
chipompom's Avatar
chipompom chipompom is offline
Registered Users
New on the HUBB
 
Join Date: Sep 2006
Location: uk
Posts: 17
Cheers Alec, It all make sense now. many thanks

Paul
Reply With Quote
Reply



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

Advanced Search
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

vB 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
Carb' overhaul advice Mark Yamaha Tech 13 24th March 2008 15:05
LC4 Carb ash_d KTM Tech 13 6th October 2005 12:00
carb sync troubles... jim Yamaha Tech 6 22nd June 2004 21:54
carb adjustment ShaunC Yamaha Tech 3 29th April 2004 17:11
Carb questions Finian Yamaha Tech 5 11th May 2003 22:37


All times are GMT +1. The time now is 04:26.

Top of page Top Home Shop the Souk Grant & Susan's RTW Trip Subscribe to the E-zine HUBB Forum Community
Travellers Stories Trip Planning Books Links Search Privacy Policy Advertise on HU

Your comments and questions about the site are welcome. Contact Horizons Unlimited.
All text and photographs are copyright © Grant and Susan Johnson, 1987-, or their respective authors. All Rights Reserved.

Search Engine Optimization by vBSEO 3.0.0 RC6