Contact Overland Solutions for all your custom modifications and setup for overland travel.

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. Questions comparing which bike is best etc go in the "Which Bike" forum.
With more than 58 destinations worldwide, Edelweiss Bike Travel is Number 1 in guided motorcycle tours!

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 24 Jul 2008
Registered Users
New on the HUBB
 
Join Date: May 2008
Location: Dumaguete, Philippines
Posts: 17
Unhappy R850R Won't start

Helping a friend try to get his bike going,, got gas, good battery and weak spark,, changed the plugs but still won't go.. cranks good. Pulled the injectors and its getting gas but still won't go.. Is there any way to test the motronic to see if its working correctly?? How much fuel should squirt out of the injectors when cranking??
Reply With Quote
  #2  
Old 24 Jul 2008
Margus's Avatar
Registered Users
Veteran HUBBer
 
Join Date: Sep 2003
Location: Still homeless
Posts: 753
If the spark is weak then probably it's the Hall (ignition) sensor.

Also check the sidestand switch.

Small chance it can also be faulty ignition coil.
Reply With Quote
  #3  
Old 24 Jul 2008
Gecko's Avatar
Slippery when wet
Veteran HUBBer
 
Join Date: Mar 2006
Location: Brussels, Belgium
Posts: 279
I think Margus is right about the Hall sensor - it sounds like it from the symptoms. The side stand isn't likely to be an issue because if it was then the motor wouldn't tunr over - it works like a kill switch.
As for the motronic - alos not likely . This manages the electronic fule injection but if you want to eleminate it you can reset it:
Ignition Off
Remove fuse 5.
Wait a minute.
Replace fuse 5.
Ignition on.
Fully open and close throttle TWICE.
Ignition off.
__________________
...on the road to nowhere...

Biking roads by bikers for bikers www.bestbikingroads.com
Get involved - save a life today www.bmdw.org
Reply With Quote
  #4  
Old 24 Jul 2008
Registered Users
Veteran HUBBer
 
Join Date: Apr 2008
Location: West Yorkshire UK
Posts: 1,044
Unless there has been welding done on the bike you can pretty much forget the mototronic unit. They rarely fail.

I'd suspect one of the above mentioned faults and also check the main earth connection between engine end battery negative. From the plug thread to the battery negative should read zero. If it doesn't because the earth is via a lot of corrosion you need 14 volts in the battery to get a spark.

Andy
Reply With Quote
  #5  
Old 25 Jul 2008
Contributing Member
Veteran HUBBer
 
Join Date: Jul 2002
Location: Sydney, NSW, Australia
Posts: 1,366
If the injectors are squirting petrol in pulses as the motor is turning over then the hall effect switches are functioning ...

How much fuel should they squirt? Well that depends on the temperature (like a choke - it will supply more fuel when the motor is cold). If teh engine temperature sensor goes open circuit (very hight resistance say over 500k ohms) then the bike will get too much fuel and flood teh motor.. been there done that.

Weak spark? check the coil for leakage, shorted turns.
__________________
---
Regards Frank Warner
motorcycles BMW R80 G/S 1981, BMW K11LT 1993, BMW K75 G/S
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
Which Spares To Take, R850r bobbyrandall BMW Tech 5 11 Apr 2008 12:48
Wtb Bmw R850r cdnabn49 TRAVEL Bikes for Sale / Wanted 0 14 Mar 2008 04:30
r850r strange noise bobbyrandall BMW Tech 3 11 May 2007 17:05
r850r backfire problem help please. strodius BMW Tech 4 26 Feb 2007 23:37
Oil seepage R850R Tokoloshe BMW Tech 3 15 Oct 2002 01:54


All times are GMT +1. The time now is 19:43.