Hey I'm new here, I bought my first bike a 87 k100rt a few months before winter with 25k. I replaced the cracked intake boot and it rode fine up until I started having starter problems. I didn't really ride much after that but I did find out I could pop start it but I don't think I remember the headlight coming on so maybe it was a starter grounding problem?

anyway, winter came and I painted the frame/cowl/tank etc polished up lots of aluminum put on super bike bars, 7" headlight, bar end mirrors and replaced the starter.

I just got everything except the lights put together and I'm not really getting anything out of it. The only think I get coming on is the clock on the dash, the ignition/key switch doesn't do anything and the kill switch starter button needs to be replaced but I couldn't get that to get power to the bike. I checked all my connections and fuses but I don't see anything wrong. Hopefully going back and cleaning all of the electrical connections with an emery board and applying dielectric grease will sort out my problems but right now I'm stumped. I have a multimeter and have enough voltage at the battery I'm stumped at what this could be. Hopefully I can gets some tips to get back on the road.
thanks in advance,
James

Hi James there are a couple of leads you have discovered which will move you forward. First you mention the starter motor problems, The BMW relies on good grounding of the load shed relay through the starter motor brushes. So your first job is take the starter out and change the brushes and do a general clean and service of the starter motor.

You say the battery has enough voltage but is that under load. What voltage do you get when you measure it with the load of a lit headlight bulb across it? A problem with meters and batteries they can show good voltage under no load because the meter draws almost no current but under load it drops down to 8 volts so not capable of starting the bike.

Lastly don't use dielectric grease that is an insulator the best treatment is to use DeoxIT from Caig.com there will be a local stockist. Follow their clean-up instruction to get the terminals really clean. I am not an enthusiast of emery as it can leave particles behind which act as insulators, a fine wire brush is better if you have to remove heavy deposits of say acid corrosion on battery terminals.
Regards,
K-BIKE

I tried opening the original starter but the screws just stripped and It was easier to replace it. If the problem persists after cleaning the connections I'll try cleaning up the new/used one.

The battery is new so I think that is ok
I've heard about DeoxIT on here before. I'll order up some up as soon as I can and clean everything up.

Is there a way to test the load shed relays ground through the starter?

thanks

hi james.... welcome to the forum

k-bike has some excelent advice .

i notice on my bike that the "kill switch " when activated removes any indication that the bike is alive (neutral switch light , bulb warning light.... starter etc ..) could it be that you infact have several issues ?

...possibly the kill switch ...could the ignition switch also be a possible candidate for a pull down and clean up . we have seen some issues with the ignition switch previously .

i personally would be checking all the connections under the tank for possible corrosion to the connectors going to the handle bars as well

good luck !

The simple check of the load shed relay is does it operate the headlights when all is tuned on if it does not and the battery is strong then it is safe to say it is not pulling in. If the new starter is perfect fine but if it is second-hand I would be inclined to refurbish it so you know it is in perfect condition.

Do check the battery under load, you say it is new was it a dry charged battery that you poured the acid into? If so you should give it a conditioning charge before using it if you want maximum life from it. Then do load test it, without a load test it is just a guess if the battery is OK or not.
Regards,
K-BIKE

Alright lots of good tips just what I was looking for, now I'm pretty sure cleaning up the connections will solve my problems. I do have several electrical problems. I'll be back in progress in a week or two after I get the kill switch sorted, ignition switch tested, and clean all the connections with DeoxIT. Again thanks, hopefully next time we talk I'll have pictures and everything will be up and running

Do a quick check to see if yours had the sidestand switch that stops the fuel pump running if it is down. Mine has and it can be a real worry when it won't start until you cotton on to the fact it is down, flip it up and away she goes on the starter.
Regards,
K-BIKE

I don't know if I should make a new post about this. I'll just continue it here.

I got the bike all together, cleaned up all the contacts and retro-fitted a turn signal/horn switch into an on/off and starter switch. I did had the bike turn on with this setup a few days ago and I tested the starter and the engine turned over. To get to turn on however I had to mess around with the kill switch fuse and it would only work when I had it certain way.

Today I tested the on/off starter switch and fuse box with a multimeter and everything seems correct. I was thinking about replacing the fuse box with something aftermarket but it seems to be working according to the multimeter. I also tried plugging fuses in the back to get a better connection but nothing happened.

The only thing that I could think of is the fuse box is showing continuity with the multimeter but not enough to allow the bike to be on. What do you think?

When the battery is plugged in the clock comes on btw.

The bike doesn't have a side stand switch.

nkdK wrote:To get to turn on however I had to mess around with the kill switch fuse and it would only work when I had it certain way.

Don`t quite follow you on that one, be a bit more specific, please.

Inge K.

That does sound confusing. I couldn't do it today but when I twisted out the 1st fuse a little bit (fi relay, kill switch) everything would work. That's why I thought the fuse box was sketchy. I also received the bike without a side cover or a cover over the fuses. I don't know though. It was a few days ago I got it to do that and I tested everything, and it all seemed like it would run.

Tomorrow I'll get back to it and try to at least get the bike electronics to turn on.

nkdK wrote: I couldn't do it today but when I twisted out the 1st fuse a little bit (fi relay, kill switch) everything would work.

Fuse #1 powers up starter push button, instruments, BMU and brake light switches.
FI relay and kill switch is in the same circuit, but connected before the fuse.
You have to read the current flow in the reverse direction, related to what you first tought.

But anyhow this fuse needs a proper connection to get signal to the starter relay.
The bad connection could be caused by corrosion or to less tension at the female terminal(s).
It could be that someone previously have substituted the fuse with something quite else,
and widened the gap on the terminals.
Do you feel some resistance (at both sides) when moving the fuse in and out?
(compare with the other fuses).

The single female terminals can be pushed in to the relay box, and then inspected/cleaned.
It`s a small retaining tounge at the top and bottom of the female terminals.
Push in two pieces of wire of suitable diameter to fold back both these tounges momentarily.
Be gentle so you don`t destroy the small tounges.
Then the female terminal can be pushed in to the relay box (disconnect the battery first).



Inge K

Have you check the color diagrams ?
This can help.

That diagram was exactly what I needed. The connectors on my bike only had retaining clips on the top. It was pretty hard getting them out at first but after I figured out the first one I sorta got it.

I scrubbed the female terminals on a brass brush and everything worked flawlessly. They didn't look too bad, but were a lot shinier after.

I got it out and tried to start it up, it just turned over and ignited a little bit but wouldn't start up all the way. I saw some smoke come out of the exhaust. I also saw bubbling around where the throttle assembly hoses connects to the engine and air box. I uses zip ties on these when I reassembled so that is a problem. I'm going to order replacements.

I used zip ties because I couldn't find a hose clamp thin enough. Have you replaced these? It's part 11611460940 . Do you know if these bmw replacements are the screw type or the ones that need a tool like the stock ones?

In this thread you find both info about tools for the genuine clamps and some Suzuki clamps that should fit. And yes, you need a tool to fit the genuine replacement clamps.

Inge K.

Thanks, that thread helped. I can get a set of clamps, that's no problem. I do already see the problem of having the throttle assembly installed and needing to get the clamps over the boots (whatever they're called). I should have just did it right the first time. I have to get them though, and hopefully then the bike will start up. thanks again

Some hours of work is ahead, isn`t it nice....then you won`t be sitting in the armchair looking at the
sealing..getting bored and wondering what to do......good luck....hope she`s firing up this time.

Inge K.

nkdk ...can i add ....(our resident doctor of "good connections --blakey ) hasnt chimed in yet .....

we in the forum have found a wonderfull product called "deoxit"

it is primarlily designed to be used with "pro grade" music electronics for the purpose of cleaning and restoring electrical connections ....

there are lots of threads about this product and comes highly recommended by many here

great advice inge ...once again you hit the nail on the head ...

enjoy restoring that bike of yours nkdk ...cheers

thanks charlie, I did use deoxit on all the connections after it was recommended here, I don't have the electronic problems I originally had.

Last night I charged up the battery and tried to start the bike again today. When I engage the starter it turns over a few times and then I get a pop and puff of smoke from the furthest forward throttle body. I think this is what I was mistaking for air bubbles yesterday, since I only tried to start it a couple of times. The weird thing is it looks like it's coming from in between the engine and the boot that goes to the throttle body. I can't really tell though since it happens so fast and I'm reluctant to try and start it more. A bit buff comes out from the exhaust as well.

It has a chemical smell to it as well as smelling like burnt gas. I should add that I made the mistake of putting too much oil in the bike, I didn't see it come over the sight glass. I had corrected that before I tried to start it though. I also checked the spark plugs and they were light brown and were firing. This might be a result of using zip ties instead of the correct clamp, I'm going to be ordering those soon.

Check that the spark plug cap is pushed fully home on that cylinder, also check and measure the resistance on this spark plug wire.

You could also remove that spark plug and dry it with an open flame, as it now probably is wet.
(compare with the others).

Inge K.

I didn't check the resistance on the wires, but you were correct about them being wet. Two of the plugs had drips on them. I tried to start it again and It seems like it wants to start. I know it's really sensitive to vacuum leaks and those ties might be the problem. I'll just have to wait and see.

If the other wet plug was at cylinder #4, you might have a problem with the front coil or it`s connections.

Inge K.

Hey, I got my package of parts including most importantly the Oetiker clamps, and I got the $10 dollar tool from home depot, recommended here. It's all installed, those clamps are worlds tighter than a zip tie.

Now when I try to start it it sounds a bit better and it even ran for a second but I failed to keep it running. I get a few backfires and puffs of white smoke from the exhaust. I waited 20 minutes to start it again and the same thing, backfires or nothing. I think the next thing I'll replace is the spark plugs if I still can't get it going. I'm not sure where to go from here. I've got the battery charging up and I'll go try it again in a little while.

I checked the coil connections and they seem right, I labeled the wires when I took it apart, I can take a picture/video of anything if needed. Are there any connections I should double check since I had the entire wiring harness out at one point, I might have missed something, but I tried my best not to. I even got the brake light working properly today.

White smoke means oil, check your oil level. Sometimes the sight glass is tricky to see through and you think it's empty so you put more in(how do I know?).
Overfull will screw up a lot of things, not electrical of course but the firing of plugs.RT

Deleted, text similar to next post.

Inge K.

RT wrote:White smoke means oil, check your oil level.

White smoke means water, blue smoke means oil and black smoke means fuel.

Inge K.

Yeah I had that problem at the beginning of the week, I drained it and filled it to the top of the line before I tried to start it though.

I recharged the battery and tried to start it up again. It backfired a lot of times each time, and then the starter stopped after 2 seconds as if I stopped pressing the button. I'm not sure how easy it is to burn out a starter so I was trying to start it for 3-4 seconds and letting it sit for a minute.

I'll go check out the spark plugs and see which ones are wet.

I think the white smoke was just steam.

YES! Inge you were absolutely correct. I had the coils wired wrong, it started right up and idle's but when I give it any gas it dies. Feels good though, I haven't heard it run since last summer when the starter died.

I really should have figured that out when you told me to check the connections the first time. And, the layout is labeled on the coil, in the book, and I had my own labels. Don't know how that happened.

nkdK wrote: it started right up and idle's but when I give it any gas it dies.

Could indicate a intake leak at the hose between airfilter housing and plenum.

Inge K.

When I got the bike that hose was split and it was doing the same thing. I'll check all of my connections, maybe it's not properly seated.

Double checked all the places I could have an air leak and I don't think that's it, especially since I just put all those clamps on today. It won't even idle for a second, but it does start right away. I'm thinking I need to triple check all of my electrical connections.

nkdK wrote: it started right up and idle's but when I give it any gas it dies.

And now it won`t even idle?

Inge K.

No, now it won't even idle. It dies as soon as I let go of the starter. It was idling for a few seconds the first few times though. I'll try again tomorrow.

Thanks for all the help inge K, I'm James btw.

This is sounding like a fuel problem. Check the flow by removing the filter and hold the line into the tank and press the starter button, see if there is a good flow of fuel. Then put the filter onto the line making sure it is the right way round for the flow and try it again there may be a big difference in flow. If there is a big difference then replace the filter. This sounds like a problem I had recently. Bike sitting for a while and the filter on its last legs and when you go to start cough choke gasp wheeze. The backfiring could be from unburned fuel igniting on the exaust stroke with the wasted spark.

I looked inside the tank and all the hoses are intact. I'll change the filter next, Is there any reason an e30/e36 fuel filter wouldn't work besides not fitting through the port hole? I didn't really see how it's mounted though, it's just easier and cheaper to get one of those.

I looked at the plugs and they were all wet with oil. Checked oil level by leaning the bike and it was over the line a little bit, I drained it until it was a bit over the red dot.

I put 2 gallons of fresh premium, since the gas I put in the tank was a few months old.

Changed the spark plugs with NGK 7912. I didn't gap them since I couldn't find what to gap them to in the haynes, but the gap was small like .33 or something. They also didn't have a terminal nut but the old nkg's didn't either and research tells me that's okay.

When I checked the spark though, I either got a weak spark or nothing I could see. I did this in the sunlight though, that might have skewed what I saw. Also when I pulled the plugs they would always be a little wet with oil, mostly on the ground electrode and a little on the base of the threads. It's also very dark, I think fresh oil is almost clear so I don't know if that's important.

I checked the "stalls after starting" trouble shoot guide in the haynes and the only thing I got from it is I either have a fuel problem which I don't think I do or a weak spark. A weak spark seems a lot more likely.

nkdK wrote:Changed the spark plugs with NGK 7912. I didn't gap them since I couldn't find what to gap them to in the haynes, but the gap was small like .33 or something. They also didn't have a terminal nut but the old nkg's didn't either and research tells me that's okay.

That NGK # is unknown to me, it should be NGK D7EA.

And if you got the genuine caps/wires, you must use the adapters
on the spark plugs.

If you got genuine caps which used w/o adapters, check the connectors inside for corrosion and spark erosion, and clean if necessary.

Inge K.

Ngk 7912 is the same as ngk d7ea as far as I know.

I do have genuine oem caps and wires. By adapters are you talking about the terminal/nipple that screws on the top? They didn't come with those and the parts store didn't have any to sell me, but I could order some online.

The old ones I pulled out were ngk d7ea without a terminal at the top.

Just to check the battery I boosted it of my car and that didn't change anything, other than it idling for maybe a 1/2 second longer.

How would I go about cleaning the inside of the spark plug connectors, do they disassemble?

Is this the adapter? I found a couple I could use.

nkdK wrote:How would I go about cleaning the inside of the spark plug connectors, do they disassemble?

Use a small screwdriver and put some emery paper at the tip, and clean
with a circular motion inside the connector, finish with some contact cleaner.

This is what it should look like on the inside:


Inge K.

nkdK wrote:Is this the adapter? I found a couple I could use.

That`s the correct one.

Inge K.

Thanks inge K. I'll go check that out.

I ended up buying 2 cheap plugs that came with terminals, and I had 2 on hand. It's still not starting or idling but I got lots of spark. The connectors are heavily corroded as well, I didn't get a chance to clean them.

It idled for a second but at really low rpms and stalled. The starter is starting to make a metallic sound as well.

I guess I should I be looking at fuel now.

As you earlier mentioned that the plugs get wet, it seems like it getting fuel.

Did you dry the plugs before the new starting attemps?

The plugs have other working conditions under heavy pressure in the combustion chamber, than in the open air.

Inge K.

Yeah, I wiped them clean/dry. Every time I take them out they are spotted with black oil. Should I gap the plugs?

When I tested the spark on the engine cover gas mist blew out of the hole, I'll assume the fuel system is ok.

Wipe them with a cloth isn`t good enough, as you ain`t able to reach the isolator around the center electrode well.

The current travel along the wet deposits on the isolator to ground, instead of making a spark between the electrodes caused by the more resistance it`s getting from the working conditions in the combustion chamber.

An open flame is the best for drying the plugs, I use a propane torch for this......a cigarette lighter functions as a emergency solution.

Inge K.

I dried them with a lighter, they weren't all too wet or oily, but the same thing keeps happening.

The consolation is probably that you are now a step closer to the goal, when the plug adapters are sorted out...and you got a stronger spark.

Can`t pinpoint you in any direction at the moment, without any more clues.

Inge K.

I agree with fuel supply issues. Disconnect the fuel filter from the supply hose, point the supply hose downward in the tank and hit the starter button. Do you have a strong stream of fuel pushing out? If so, put the filter back on, disconnect the hose on the other side of the filter and try again. Still a strong stream?

nkdK wrote:Yeah, I wiped them clean/dry. Every time I take them out they are spotted with black oil. Should I gap the plugs?

When I tested the spark on the engine cover gas mist blew out of the hole, I'll assume the fuel system is ok.

Could also be that your combustion chambers are soaked with fuel after all the
starting attempts, and your plugs being wet fouled very quickly.

To ventilate the chambers, remove all spark plugs, run the starter 6-8 seconds
two,,,,four times with the throttle almost wide open.

Ground all the spark plugs when doing this, or you`re in the risk of damaging
the ignition ECU.

Also have a look in Bert`s excellent troubleshooting guide in the portal,
and see how to check and measure this and that.

Inge K.