hi guys in new to this site and bmw motorbikes ,but i have a years of experiance of the oriental stuff.. my bike is a 1991 model k100rs 19v which has covered 29000 miles approx.ive been out a couple of times on my bike since i got it and ive had this fault both times,i was out a run yesterday and did about 20 miles when i rolled of the thottle coming into a 30mph limit and the bike lost power and backfired so i diped the clutch and freewheeld into a fuel station that just happend to be close by..started the bike up but she ran roughly and would not take the thottle,so i let her idle for a few minutes and the engine note changed and she ran smoothly again and woud throttle no problem.so i did the rest of my journey abot 60 miles without any more problems.the riding was varied from 60 mph to 95mph as roads were patchy in places:wet:.ive serviced the bike with new plugs set to correct gap,all new fillters and oil,i have also replaced the coils for gen new units and ive drained the tank as well ,there was very little crud at the bottom and the fine filter on the end of the pump was almost spotless.i have done a lot of head scratching over this,an intermitant fault like this seems almost impossible to diagnose,or i will have to let the fault develop,but i would rather solve this problem in case it does damage.any hints or tips would be much appreciated. .toecutter

Things to check are the ignition switch and the 4 pin plug that joins the tank to the harness. The switch may need cleaning and the 4 pin plug cleaning as well and also check that the pins and receptors are in good condition and not out of shape from someone trying to remove the tank and not unpluging first. Also just give every connector a going over with an electrical contact cleaner like Deoxit.
It will more than likely be a bad connector or switch. As the Ks age we are seeing more and more electrical problems like this.
Make sure the multipin plug on the ECU is plugged in properly, make sure it clicks home.

hi rick thanks for the info,ive been thru all the connections with a a fine tooth comb,ive also checked ignition switch all the contacts are sound and clean.ive had the bike running and tried all the connectors as well to see if i can replicate the fault but to no avail,looks as if i will have to let the problem develop.ive been leaning towards the hall efect sensors ,but this is a pricey item if that is not the fault ,its very difficult for joe public to get specs on individual parts,we re always pointed in the direction of mr bmw,but their prices are highway robbery

Hi,

Google Honeywell 2AV54 for replacement sensors and supporting data sheets.

Also have a look at:

http://advwisdom.hogranch.com/Wisdom/oilhead_hall_sensors.pdf

Mike

thanks for the info mike ,ive bookmarked it to save for later,i take it i can do this repair with my k100 as well,it looks fairly involved ,but i think iam uto the job.many thanks to all,and i will post a progress report

Same sensor used since the introduction of the electronic bean can on the 1980 Boxers.

The sensor wiring is where to look, as it suffers from heat and then breaks down. The usual symptom is failing when hot. You can sometimes provide a fix by pouring cold water over the casing.

Getting hold of the sensor can sometimes prove difficult.


Mike

mike d wrote:Hi,

Google Honeywell 2AV54 for replacement sensors and supporting data sheets.

Also have a look at:

http://advwisdom.hogranch.com/Wisdom/oilhead_hall_sensors.pdf

Mike

just had an email from our uk supplier,the quoted sensors are no longer avalible,so i cant rebild my hes assembly,this means i will have to purchase a new new unit from motorworks at a cost of approx £350,which makes the eyes smart a bit and the old wallet cringe ,will have to do a bit of saving ,but i should be back on the road again in the springtime with any luck,as the weather in this part of scotland is rubbish for biking,and the salt thats poured onto the roads murders bikes with corrosin to alluminium parts as well as the electrics,the local councils pour the salt on even if there is the slightest chance of frost ,public liability and all that,mind you the gritter drivers love it with all the overtime just in time for santa claus,thats it for now guys will keep you posted with any updates

toecutter wrote: just had an email from our uk supplier,the quoted sensors are no longer avalible,

Have you tried this one?

Did you try James Sherlock?

www.octopart.com shows a couple suppliers in the USA with stock. Maybe a second choice to the supplier to which Inge linked. Call for pricing.

Thanks for the tips guys,looks promising,should be able to do an overhaul now,and much cheaper than the 350 quoted from motorworks,which makes the eyes smart a bit,the other half says,how is there 350 in that small part,,i say theres not ,but thats the the price dearest,its difficult to convice a woman sometimes,but if i can source the componants myself it will be a much easier sell to the wife,all should be good now.thanks to all .Toecutter