Go Back   Horizons Unlimited - The HUBB > Technical, Bike forums > BMW Tech
BMW Tech BMW Tech Forum - For Questions specific and of interest to BMW riders only.
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 24 Feb 2007
Registered Users
New on the HUBB
 
Join Date: Feb 2007
Location: leighton buzzard beds uk
Posts: 2
r850r backfire problem help please.

Hi need some help please. I have a 95 r850r (25k miles). Owned it for 6 mnths and its been great so far, up until this week when it has suddenly developed terrible backfire under deceleration. Generally by the time it gets down to 2k revs the thing sounds like a shot gun going off. There seems to be a slight misfire/surge when you try to hold a steady throttle as well(I would not describe this as surging it seems to quick).I am worried it will blow the exhaust so am not riding it at the moment. I have changed the plugs, checked all the connections etc and as per advice on this site I have checked both cables are seated correctly. Air filter is good and I have read all the stuff on syncing the TB's and resetting the TPS. Anyone any ideas before I take the plunge and really mess things up?? Cheers. Strodius.(by the way this is an excellent site thanks for all those posting great info)
Reply With Quote
  #2  
Old 24 Feb 2007
Registered Users
HUBB regular
 
Join Date: Oct 2002
Location: uk
Posts: 59
backfire

check the exhaust for leaks, loose joints at the clamps are the usual cause of a backfire. run your hands over the exhaust before it gets too hot you should be able to feel any leaks. if not it could be carb balance or any number of other things
Reply With Quote
  #3  
Old 25 Feb 2007
Registered Users
New on the HUBB
 
Join Date: Feb 2007
Location: leighton buzzard beds uk
Posts: 2
backfire problem solved

Thankfully I have sorted this backfire fire problem. Turned out to be the RHS throttle body out of sync. Used a pair of borrowed vacuum gauges to find the balance was miles out. Tweeked the brass screws which made little effect and then adjusted the cable to recify. Reset brass screws to original settings and hey presto, back to normal running. Will have to buy myself a set of gauges to keep now.
Reply With Quote
  #4  
Old 26 Feb 2007
beddhist's Avatar
Contributing Member
Veteran HUBBer
 
Join Date: Sep 2003
Location: Whangarei, NZ
Posts: 2,214
Since this occurred suddenly I'd check the cables carefully. Perhaps one is about to snap?
__________________
Cheers,
Peter.

Europe to NZ 2006-10
Reply With Quote
  #5  
Old 27 Feb 2007
Registered Users
HUBB regular
 
Join Date: Dec 2006
Posts: 33
Quote:
Originally Posted by strodius View Post
Thankfully I have sorted this backfire fire problem. Turned out to be the RHS throttle body out of sync. Used a pair of borrowed vacuum gauges to find the balance was miles out. Tweeked the brass screws which made little effect and then adjusted the cable to recify. Reset brass screws to original settings and hey presto, back to normal running. Will have to buy myself a set of gauges to keep now.
not gauges...vacuum gauges aren't sensitive/accurate enough.
...make a U tube manometer out of clear plastic hose for pennies (Home Depot, Lowes ect...) a manometer is dead on accurate and instantanious sensitive as it acts on pressure (negative) against pressure. I used red auto trans fluid as the liquid since it's similar to water and easy to see, but you could use any liquid...even water. light water is more sensitive than heavy mercury...the beauty of that is you can carry the compact coiled hose and add liquid on the road when you want to use. I would use 1/4+" ID hose with bushings for the connections...that allows some forgiving from bigger diameter...the danger is sucking the liquid thru if it's way way off to begin with.. the beauty of a manometer is you only have to compare easily seen liquid levels.

this quick easy solution is more accurate than both mercury or gauges.
Reply With Quote
Reply


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
Extra passport pages - no problem or big problem? jj Trip Paperwork 8 15 Dec 2006 09:27
1150 GSA problem Thermal BMW Tech 10 29 Jul 2006 21:15
Tenere reserve tanks problem... TahoeTenere Yamaha Tech 5 5 Jun 2006 23:22
1150GS starting problem? Steve Pickford BMW Tech 4 19 Feb 2006 03:57
Morning Backfire JFL Yamaha Tech 12 14 Mar 2005 17:18

 
 

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
Queensland is back! May 2-5
Ecuador June 13-15
Germany Summer: May 29-June 1
CanWest: July 10-13
Switzerland: Date TBC
Ecuador: Date TBC
Romania: Date TBC
Austria: Sept. 11-14
California: September 18-21
France: September 19-21
Germany Autumn: Oct 30-Nov 2

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!

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 20:23.