2004 r1100s wouldn't start

Ok group...help me out...bike started no problem this morning, went to gym, came out 90 minutes later...dead (slow cranking like I left something"on"), like the battery couldn’t turn the starter.

Made some calls for a tow, 25 minutes later, bike started up?

Is there something I’m missing, is it possible to leave the hazards or turn signal on to drain the battery?

What are some telltale signs of a bad alternator or starter or battery?

Because the battery is under the tank, how do I jump the bike? Through an accessory port?

Thanks for help in advance

I would start(no pun intended) with battery condition and connections.Batteries on bikes can be fine in AM and done by noon. A loose connection can present start/no start condition as it heats up and cools.

The easiest way on an S model is to remove the starter cover which exposes the positive lead, ground the other lead to engine case. A small set of motorcycle specific cables with smaller clips work way better than the generic huge ones.
There is a GS terminal kit from that era that puts a covered stud at that starter cover location alongside the power outlet.
You can charge thru that accessory outlet, but typically too much current needed to jump thru it

The starter can be a suspect with loose magnets, dirty sticking solenoid plunger, but more often the battery is the higher percentage item.

How old is the battery? Do you have any accessory plugged in/wired in to bike? The S battery is even a bigger pain to me than other models to access.

Your symptoms match a starter problem quite well. Bike runs fine, then battery seems dead, then next time the starter spins it over fine. Loose magnets or more likely an internal grease cover has fallen onto the armature. Pull the starter pull its nose and you’ll see right away if that the problem.seceral threads here show how.

battery first

I'm going to start with the battery and move on from there....battery is old, should have replaced when I did air filter...I will also take a look at the starter...thanks

My experience with these starters is if the planetary gear cover falls onto the armature, the starter will work normally but then at times, it will seem as if the battery has suddenly gone dead, then it will work again. Do a search and you'll find some good threads on this.

You can replace the starter inexpensively. I bought a replacement for the oilhead valeo starter for $60. I bought mine from DB Electrical, but they are available in the usual online storefronts too. No issues, been installed for a year.

starter and battery

Since I have to take off the fairings to replace the battery, I'm just going to replace battery, battery cable (thicker and new ones) and starter. I think I can get this all done in less that 3 hours.....I'll post problems or successes. Thanks

Also, I purchase starter from Euromotelectric, they were very helpful.

For a look at your starter, this Best of Forum has some great info-

https://forums.bmwmoa.org/showthread.php?69483-A-peek-inside-your-starter

OM

replaced starter and battery...all good

Battery was harder to replace than the starter.....Battery was 6+ years old, starter original. Both looked ok. New starter installed easier than the battery which wouldn't be so hard if the fairings didn't need to come off.

Took the opportunity to install a battery tender port accessible under the seat for the upcoming winter.

Battery most likely problem

larrydk said:

Battery was harder to replace than the starter.....Battery was 6+ years old, starter original. Both looked ok. New starter installed easier than the battery which wouldn't be so hard if the fairings didn't need to come off.

Took the opportunity to install a battery tender port accessible under the seat for the upcoming winter.

Click to expand...

I’ve had four oil heads; 96’ R1100RS, 04’ R1100S and two 04’ BCRs. Combined 201,000 miles. They are hard on batteries especially if they sit more than a month without battery charging. A six-year old battery will still work if properly charged by daily riding or tending. The jump-lug kit is well worth it if for no other reason than to have an easy point to check the battery voltage and alternator output. Alternator output should be around 13.6 to 14.0 volts. Battery Tender brand makes a nice, cheap, SAE-connected digital voltage readout for Tender pig tail.

Never had a starter failure on these four bikes.