Hello everyone,



My K100RS has never been the easiest bike in the world to start. However, over the last few days she has become even worse, yesterday I had to bump start her. Once running her behavoiur is really unacceptable. At low revs (1,500 - 2,500) she bunny hops which the severity lessens as the motor warms up. Once above 3K things smooth out.



Has anyone had a similar situation with there bike?



Thanks in advance, Martin

I have had the same issue with my 75. It seems to have a mind of my own and does whatever it wants when it wants! I have replaced everything I can think of on this thing and have cleaned all the connections with Deoxit and have set and reset the Air flow sensor and throttle body vacuum and still cannot get consistant performance from my bike...I am playing around with trading it on aan R1150RS even though I love this bike!

there are some simple basics guys ....go to the efi trouble shooting page on the portal interface and go throught the steps ....

mabe the ecu isnt getting the right signals...same for the efi unit which ties together ....

there are many possibilities ....but recently we have seen intermittent switches , corroded and piched cables and the like causing rather eroneous problems .



just work through the list .....you cant say that you have fixed it till you have checked and properly pinpointed the fault among the various bits and pieces .

just a thought

Thanks for the advice, although I really don't think I have the electrical skills necessary to do the tests in the troubleshooting sheet.

I cam into work by bike tosay, she was difficult to start, no surprise there. However, after the run along the motorway (+/- 50 kms) the engine was smooth throughout the rev range.

Could thsi problem have any connection with the water/engine temperature? The water temp sensor on my bike was changed this time last year.

hhmmm maybe in the connector that joins the temp sensor to the rest of the bike ......a strong possibility ....deoxIT is your friend

dont forget that the temp sensor is double ended , the two cables that connect to it are off each end .....the third connection is to the frame at the sender , down pipe (aluminium of corse ) might even be worthwhile taking out one of the bolts that holds the riser/down tube and cleaning it up (could be just corroded down there )



just a thought from a silly old fart

Never thought of the coolant tube connection at he head ....Thanks for the thought! Poor grounding on the temp sensor body. That might explain why my problem is intermittent and so erratic

hey guys,

i have a similar problem - the colder it is outsside, the richer my bike gets while cold - so rich that in the first 12-40s. it rattles like crazy and is easy to flood (if i open the throtlle immediately, it dies). where is the temp sensor connection? under the tank?

i would be grateful for any advice
cheers!

For those who didn`t sleep in the german lessons, this could be some help.

Inge K.

it does not open... but the name itself says it can be a good trail

The link does open at my PC, you live to close to the german border, the server thinks you can come and pick it up yourself.

Inge K.

luckily it worked and i didn't have to go and pick it up myself mate;)

a good source of information, thanks a bunch!

That document in German could be quite useful. Although I don't speak German myself I do know someone who does and, of course, pictures don't need translating.

After some investigation this weekend, it appears that cylinders 2 and 3 are not firing. Other than the obvious ignition coil, is there anything else I should look at?

yes definatly the plug leads martin

you dont have to pull them out just undo them at the coil and the plug tops and measure with you multimeter ,,,also change the plugs if you havent already done so ,ost leads these days are resistive ...so 5000 ohms wouldnt be a bad thing to find .....but open circuit is bad ...moove them around to see if there is any change .

whilst the meter is in your hand try and measure the high voltage connections on the coil between each other ..(you might need to get a couple of paper clips to get in deep enough to make good contact )

they should mesure 10.000 ohms or there about .

the primary of the coils has 2 connections ....plus an earth the primary should be about 2.4 ohms

i guess thee is a remote chance that the hall pickup may have failed ....but it would be a positive move to follow the cables up from the ignition pickups to under the tank ...and clean the contacts that connects that cable to the loom ....whilst there check the plug to the ignition control unit at the front of frame under the tank ......check/clean those contacts as well

hope this helps

please report your findings back here

2 and 3 get their signal from one of the coils of the hall sensors. Everything in between is suspect. Have a good look at the low voltage connections under the coils, they can weather and give poor contacts.

Quick check, change the primary leads on the coils; black/red and black/blue to change and see what happens - still 2 and 3 out or now 1 and 4??

This weekend I got time to have another look at the K100. Before taking anything mechanical apart, I'm hopeless with electrics, I thought I'd change the plugs. They were a little dirty but not duly so. After, cranking the egine over a few times it caught. Upon taking the bike for a spin, around 5 kms, it seems all the silly behaviour was down to worn plugs! I'd never seem that kind of behaviour in a bike with worn plugs, and I've had my fair share of bikes of all shapes and sizes! Later on this week, I'll come into work with her and see how she behaves after a long motorway run. Hopefully, she'll stay sweet.

I had a CB750 Honda that ate plugs at every opportunity until I changed the coils and then all was OK. It seemed that the coils were bad and new plugs would be OK for a while but play up as soon as they got a bit old (2000k) but new coils did the trick and I started to get 10,000k from plugs.

I think these plugs had been in for around 30K kms, they really did need to be changed.

I would say the plugs in my K100 have done 50,000k. The CDIs will give a good spark with even really bad plugs but a crook CDI will still fire a plug but if the spark is weak then the plugs will give out first and need replacing but the real cause isn't the plugs. I hope all is OK but be prepared for more problems, I would say there is a good chance of it.

aye !!! measure the coils martin .....should be 10 k output to output

we have seen many corroded high tension sockets on these things i even bought some myself ....doh ! that measured to infinity ...but still sparked ....aparently ok ....yeah right !!!!