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Where to Start When the 90/6 Won't Start

txedomoon

New member
The History: Was on my way to the Red River Valley MOA Chapter Fall Classic on Saturday when I got caught up in a pretty good rain -- turned out to be an all day soaker. By the time I made the 20-minute ride back home I was wet and so was the bike. Thinking more of myself than my machine I went inside and dried off. Went out an hour later and took all the wet bags, etc off the bike and got involved in family errands that had been put on hold due to the rally I was scheduled to be at.
The Current Dilemna: Went to start the bike this morning and NOTHING. I get all lights when I turn on the key, but that is it. I press the starter button and not even a CLICK.

Where do I start????:dunno

thanks in advance for any tips, ideas, suggestions or grief for putting my bike away wet.
 
Check the easy stuff...especially the kill switch. After than, I wonder about the starter relay.
 
Check the easy stuff...especially the kill switch. After than, I wonder about the starter relay.

Yep, Kill switch turns on and off the dash lights. Still no starter activity. Will start looking at connections on relay.
According to Clymers there is no way of testing the relay other than at a dealership.. is this true?
 
I think it's pretty easy to test the relay. You'd have to study the diagrams, but two of the pins are used to bring 12v in to the relay. The other two pins are normally open with no voltage on the other two pins...infinite ohms. Then when you apply 12v, you hear a click and the two pins go from infinite ohms to near 0 ohms.

Before you do much physical testing, try just unplugging and replugging the relay a few times...scrap off some possible corrosion.
 
Battery gone bad? Maybe the rain didn't have anything to do with it.

Did you try putting a voltmeter across the battery and seeing if the voltage drops way down when you press the starter button?

Seems like it is always worth ruling out the battery as step one to electrical problems.

Barron
 
All these are pretty good ideas.

Here is mine. I agree that the relays are a culprit, and easy to test. If the bike was running when you parked it and it was all wet, I suspect that moisture/water has drained in from somewhere and caused something not to electrically connect. If you can, isolate certain items (kill switch, ignition switch, etc.) and then test/try starting.

One thing I have done is to put bike in a dry garage, and get a portable heater (electric) and direct towards engine so that you can get it warm over a period of time and hopefully get it to dry out any extra moisture. Also using a blow drier (wife's hair dryer - just don't let her know!!) or I own one that I used to use when building RC airplanes, and direct it carefully at locations where moisture could be (handlebar switches, ignition switch, various relays, coil connections, etc.).

If you can get these areas dried out, you may have success.

Also, check fuses. I guess it could be possible that moisture go in somewhere and shorted out blowing a fuse.
 
Does your bike have a clutch override switch (starter won't engage unless the clutch is in)? If so, and the switch had failed, the bike would run fine until you turn it off, then it won't start again.
 
Does your bike have a clutch override switch (starter won't engage unless the clutch is in)? If so, and the switch had failed, the bike would run fine until you turn it off, then it won't start again.

Great suggestion. I have had situations where I or someone happened to mess with the bike and either bump it into gear (thus won't start) or hit the kill switch thus not starting.
 
The OP has an R90/6 which experience with the machine tells one that it has not a clutch/starter overide and will engage the starter if in gear and give on an exciting moment as it pulls forward off the sidestand or pulling the operator off balance.

Yes, the battery could be failing as one will get lights/idiot lights with even a weak battery; but when one engages the starter it can go ahead and do NOTHING. No noise, click, etc. Usually with this condition the lights will go ahead and fail when one does this. Have you got a spare battery or really good charger that gives a "start boost" to jump the existing battery with?

You were riding in the rain and got a heavy soaking. Have you made sure the battery cables are tight? Is the ground on the transmission clean, dry, and tight? Often times a dousing with plain ol rubbing alcohol will disperse water from a switch or area. Do you have a syringe to use to inject a bit into switches and relays? WD-40 specifically is made for water dispersement and limited repelling into switches and relay type devices. For me, I use Kroil or PJ Blaster for penetrating/lubricating but WD-40 is perhaps better for this use. Anyway, check your connections really good as something tells me it is that simple..........God bless...........Dennis
 
The OP has an R90/6 which experience with the machine tells one that it has not a clutch/starter overide and will engage the starter if in gear and give on an exciting moment as it pulls forward off the sidestand or pulling the operator off balance.

I guess the R90/6 is different from the R75/6? When my clutch override switch failed, I had the symptoms that were on the OP. All lights worked fine; everything worked except when I pushed the start button, nothing happened. Once I fixed the switch, it went back to normal. A soaking rain might be just the thing to fry that switch considering the exposure (again, at least on my R75/6). I don't know if I have a neutral override switch as well. I have never attempted to start the bike when it wasn't in neutral.

Chip
 
The OP has an R90/6 which experience with the machine tells one that it has not a clutch/starter overide and will engage the starter if in gear and give on an exciting moment as it pulls forward off the sidestand or pulling the operator off balance.

I guess the R90/6 is different from the R75/6? When my clutch override switch failed, I had the symptoms that were on the OP. All lights worked fine; everything worked except when I pushed the start button, nothing happened. Once I fixed the switch, it went back to normal. A soaking rain might be just the thing to fry that switch considering the exposure (again, at least on my R75/6). I don't know if I have a neutral override switch as well. I have never attempted to start the bike when it wasn't in neutral.

Chip

The R90/6 DOES have a clutch switch (at least since the '75 models), but it doesn't need to be present for the bike to run. Mine was broken and disconnected for years before I finally replaced it, just had to start the bike in neutral for those years. There is a neutral switch, but when that goes the neutral light won't come on but it seems like it does for the OP.

My idea of the problem would be with the starter relay. Take the tank off, check the connections and clean them, sometimes it just takes removing a terminal and putting it back in to get the connectivity back. I once rode 15 minutes to get gas and after filling my tank got the exact same symptoms as you. In that case I overrode the relay and got home, once home all I did was disconnect everything, clean it up, and everything worked fine again
 
coil connection

Seems that most "I rode in the rain and now my bike won't start" threads place a heavy emphasis on the coils (being cracked or otherwise malfunctioning).

I've never experienced it myself, so I will just give this a +1 from lurking on airhead forums for years.
 
The R90/6 DOES have a clutch switch (at least since the '75 models), but it doesn't need to be present for the bike to run. Mine was broken and disconnected for years before I finally replaced it, just had to start the bike in neutral for those years.

Surely NOT to argue with anyone on here........Just been riding the 1975 R90 now for dont know how many years now. Just went out to check and make sure........lets see: clutch lever out and in neutral the thing starts right up.........In gear with the clutch lever out, engage the starter button and a sudden and sure lurch forward with the starter motor moving the bike just like it always has........hmmmmm ...If I engage the clutch when in a gear she starts right up like it should.........Again, NOT to argue.........

My 83RT and ST's had the switch that you describe and that is but only ONE reason that I keep riding the R90...Now......my Merc 320 SLK has the same type of switch also where one has to engage the clutch in order to start the engine; but I wouldn't get rid of that beauty for anything .......ANYTHING produced now adays.....God bless......Dennis
 
Battery is good/strong shows no sign of draw on voltmeter when I try to start switch.
Starter relay removed and cleaned. Electical contact cleaner and toothbrush, same for
wire-end connectors. Still nothing. No click. Nothing. Will try a hybrid of Dennis' and Jimmylee's ideas
and inject a bit of isopropyl into the starter switch tomorrow morning and then leave the bike out in
the sun for the morning. Maybe the switch just needs a REALLY GOOD dry out.
oh... I can measure voltage going into the coils... haven't checked resistance on the output.
 
The R90/6 DOES have a clutch switch (at least since the '75 models), but it doesn't need to be present for the bike to run. Mine was broken and disconnected for years before I finally replaced it, just had to start the bike in neutral for those years. There is a neutral switch, but when that goes the neutral light won't come on but it seems like it does for the OP.

My idea of the problem would be with the starter relay. Take the tank off, check the connections and clean them, sometimes it just takes removing a terminal and putting it back in to get the connectivity back. I once rode 15 minutes to get gas and after filling my tank got the exact same symptoms as you. In that case I overrode the relay and got home, once home all I did was disconnect everything, clean it up, and everything worked fine again

When you had this experience, were you able to "bump" start the bike? I was curious of it would have run by pushing it in 2nd gear, getting it running and then get home .. or .. was the electric completely shut down so it wouldn't run at all?

I have used bump starting many times!

That's why I really regret it when BMW removed the kick starters. I had one on my R90, now missing it on my R100 !!
 
When you had this experience, were you able to "bump" start the bike? I was curious of it would have run by pushing it in 2nd gear, getting it running and then get home .. or .. was the electric completely shut down so it wouldn't run at all?

I have used bump starting many times!

That's why I really regret it when BMW removed the kick starters. I had one on my R90, now missing it on my R100 !!

I never tried to bump start. When the problem with the override switch first came about, the bike was still in my basement. Jiggling the wires made it work. I guess a loose connection. I would have to trace the override switch circuit to see what it interrupts but by doing that, you should be able to figure out if the bike should start w/o the electric starter. I guess since bump starting requires the clutch to be out, it would have to. Right? Otherwise no bike with that switch could be bump started.
 
First thing I would do is use a volt meter.

1. Check and see if you are getting voltage TO the start button

2. If Yes, then check to see if you are getting voltage FROM the starting button switch TO the starter relay. Remember, there will be a terminal that will show "hot" when ignition is turned on OR hot all the time. It is the relay that connects this hot voltage to the starter to energize it. (I am assuming a generic (sort of) connection here as particular wiring situations may exist - check your particular wiring diagram.

3. If yes, then check to see if you hear the "click" of the relay and are getting voltage OUT of the starter relay.

4. Be sure to also check ALL other "safety" switches that may affect this - like the kill switch, ignition switch, kickstand safeties and clutch safeties.

Just hopefully helpful, because I certainly am not an expert, and have been bedeviled by these German wiring systems. They seem bazaar to me and quite illogical.

For example, just recently my son's K100 had an electrical problem which evidenced itself by HUD display lights and headlight flickering. Loose connecting wire, right? Wrong.

He learned from others on the K-bike forum that the problem was the starter brushes being either dirty or need replacing. He took apart his starter, cleaned the brushes (which didn't need replacing) and commutator and voila! Took about an hour. Everything is again working perfectly! Does that seem logical that the starter brushes needing cleaning would cause the lights to flicker?
 
With the battery good as you say, I would disconnect & thoroughly clean the battery terminals & ground then test. Next with the battery disconnected remove the fuel tank & starter cover, using your wiring diagram for guidance clean & lube all the terminals in that area, relays & all, being careful of the likely brittle insulation on the wires. (good to do anyway)

If still no luck, tracing the wiring from point to point with your voltmeter should lead you to the problem, again the wiring diagram will be key.


I don't see how the suspect coils would prohibit the starter from cranking.
 
If your starter relay is good you'll have power at the two center terminals (heavy red wires). If you only have power on one side it can act like you describe. (Had same problem). You have to use a trouble light though as in my case my voltmeter showed voltage on both, but one side wouldn't light the light.

Load test the battery too just to be safe.

Just my .02 and experience with the worlds most expensive R90/6. ;)
 
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