 |

6 Jan 2015
|
Registered Users
New on the HUBB
|
|
Join Date: Dec 2014
Posts: 4
|
|
R80 GS Miss fire
Hello there . New to this forum but not to BMW bikes . This is my problem . The bike ( 1994 BMW 80 GS) started to lose power to the point of not being able to drive forward and stalling . It would restart and rev ( with lots of throttle required ) but misfiring with no power . checked fuel and drained float bowls but just the same . A resorcefull AA man rigged up an twin out put coil and leads ( different plugs ) and then a different ignition amplifier all with no change . this pointed to the hall sensor so after recovery I fitted a new hall sensor .
The bike now starts easily and revs with normal throttle but has a slight misfire at idle to 1000 rpm but one cylinder drops out completly as the revs rise to full advance . I have fiitted a New coil and ignition amplifier and plugs . Using a strobe light showed that the Right hand pot was not firing at all above 1500 ( strobe not firing ) .
I reversed the input wires on coil and the left hand pot then started to miss in the same way ? ? The timing appears to be set correctly and advances to full advance .
there is a good supply to the coil .
Any ideas anyone ?
Last edited by gengisfx; 6 Jan 2015 at 20:53.
Reason: spelling error
|

6 Jan 2015
|
Registered Users
Veteran HUBBer
|
|
Join Date: Feb 2002
Location: Wessex, UK
Posts: 2,136
|
|
Hello gengisfx and welcome,
I have had a misfire on my GS caused by one of the terminals in the block connector which goes onto the amplifier coming lose and not making contact properly. It could only be seen by looking into the block when removed and it appeared slightly further back than the others, also check the plug from the bean can as I have seen the same thing happen there.
|

6 Jan 2015
|
Registered Users
New on the HUBB
|
|
Join Date: Dec 2014
Posts: 4
|
|
Thank you Mark,
I will check that out at the week end .
|

6 Jan 2015
|
Registered Users
Veteran HUBBer
|
|
Join Date: Aug 2012
Location: Australia
Posts: 1,131
|
|
As the hall effect switch, amplifier and coil are all common to both sides .. I suspect it is not them. I've be checking the spark plugs, spark plug caps, HT leads.
Of course the miss could be fuel related, or valves ..
|

7 Jan 2015
|
Registered Users
New on the HUBB
|
|
Join Date: Dec 2014
Posts: 4
|
|
Thanks for the ideas Warin ,
I've changed the fuel and I'm thinking it must
Be electrical because the misfire changes side when I reverse
The coil input wires ( which makes me think ht leads
And plugs ok ) I can't think what would make the coil
Produce a missfire on one output ?
|

8 Jan 2015
|
Registered Users
Veteran HUBBer
|
|
Join Date: Aug 2012
Location: Australia
Posts: 1,131
|
|
You got the standard bmw set up? One coil?
When you say 'coil input' you mean the low voltage connections - one to ground, the other to the amplifier? Or do you mean the HT leads - thick wires leading to the plugs (these would be termed 'output' rather than 'input')?
Swapping the HT leads from one side to the other can isolate - the spark plug .. if swapped at the spark plug
- the HT lead or spark plug cap .. if swapped at the coil .. and the above test OKed the spark plugs
IF it truly is the coil .. it would be unusual. No cracks on the coil? Easy test for cracks on the coil .. pour water over it. Or look at it working in the dark to see if there are any fire works around the coil.
|
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
HTML code is Off
|
|
|
|
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...
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)

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 Rescue Travel Insurance™ combines into a single integrated program the best evacuation and rescue with the premier travel insurance coverages designed for adventurers and travel is covered on motorcycles of all sizes.
(ONLY US RESIDENTS and currently has a limit of 60 days.)
Ripcord Evacuation Insurance is available for ALL nationalities.
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!

Every book a diary
Every chapter a day
Every day a journey
Refreshingly honest and compelling tales: the hights and lows of a life on the road. Solo, unsupported, budget journeys of discovery.
Authentic, engaging and evocative travel memoirs, overland, around the world and through life.
All 8 books available from the author or as eBooks and audio books
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.
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.
|
|
|