Hi. I have a BMW K100RS 1988. I tried to jump start the bike off a car without removing the battery. I had the car started. I put the positive lead on the positive terminal of the bike battery and the negative lead to the bike frame. When I tried to start the k100rs she turned over a few times but would not start up. When I stoped, I saw all the electrics were off. There was no power going to anything. Is there a main fuse somewhere on the bike that I might have blown? Would this have caused something else to burn out? I am not very good with working on motorbikes but I do try to have a go if it's not too 'big of a job'.
One other thing . . . the battery in the bike is not the right one, it's smaller. There is power in it but not enough to start the big engines.
I was hoping someone might be able to help me with this problem. I have been impressed with what i have read on this forum. This is my first time to write to this forum as well.

Greetinga Funbiker looks like its far from fun at the moment.
Just a word of caution never have the car running when jump starting, power spikes can kill components but it is unlikely.
Check all the fuses which are under the left side cover. Check the power to and from the ignition key, Power in is the red wire and all other 3 should have power out with the key on and only on the gray wire in the park position which is the 1st position, you will need to remove the tank to do this. See this link to a how to remove the tank http://www.ibmwr.org/ktech/rt-fairing/k75rt_fairing.shtml
Having too small a battery wont cause these problems but will give problems starting.

Welcome funbiker.
Newbie too.
Knew that I was going to need a new batt when bought the bike and worked fine until it did not.
Yeah about older batteries. Found out too about the starter staying on because of frozen contacts and where to thump it with this crowds posting....(there are still some folks laughing about that episode)
Called friends close to and we jumped it with cables hooked to running car and the bike made way home post haste and then.....with no running lights!. No turn, brake, head, instrument, etc. light.
Said to self, Oh s**t, have fried something and it's probably going to be expensive. Installed new battery and all was/is well. Was sweating that one. Hope your gig works out as well. You probably should not listen to any advice from me....just telling it like it was. Won't jump off of running vehicle again.

....and we too tried to start it with post to frame and post to post contacts with the jumpers and only succeeded when taking the positive lead off of the battery and clamping the jumper lead directly to it.
That's when the bike started happily. Unhooked the jumpers and it still ran. Reattached the battery lead and all was well. Hit first gear and lights went out. Got it home with no lights though.
Have no idea why, except to believe that it was running on alternator alone?

....and when getting gas and trying to put it on it's center stand without looking/proving to be, inept, moved the kill switch just above the green starter button away from straight up and down position.
That was good for about 10 minutes of "oh my, wtf is the problem, why no go?" Only one light lit up then. FWIW.

Belated welcome to the forum RSfunbiker.
We have quite a few K bike owners on the auld sod. There's even one loony who powers a hovercraft with a K engine!
Check out reports and piccies on the the Irish meets under the 'European rides and meetings'. More meet ups in the planning stages for next year.
There's at least a couple of members in the Dublin area. Sometimes having someone there that's more familiar with K's can be a help in diagnosing.
If it wasn't late October I wouldn't be hard to talk into the 80-90 miles for a look at it.
If there is no one local to give you a hand, let me know.
Might still be persuaded before it gets really cold.

Whereabouts in Dublin are you? I'm in the Clonsilla area in west dublin. I can call around with a booster pack, voltmeter and a manual if you wish. I can even leave my laughing hat at home if you wish.

Welcome RSFunbiker. I'm not good on the electrics but there is lots of diagnostic info in the downloads section. You need to PM Crazy Frog to get access but first you've got to stick up an intro in the new members section.
88KE