08 SD990 Dies and Restarts

Hey fellas,

Couple of months ago I topped off the oil as it was showing a tic above min. Brought it up to mid-level and was rewarded with a grand misting of oil over everything south of the ECM. Blow-by breather sits between it and the front jug.

Cleaned it, connections and all... B12, contact cleaner, dielectric grease where applicable.

A week ago, from a stop, 1st gear @ 4k, it died and instantly barked back to life.

Yesterday, in a long right curve, 2nd gear @ 5k...same thing. Before the tach even swept to zero...bam!...back to life.

Now, that one got my attention. Pucker factor 9.65!

I've ridden over some incredibly bad road trying to recreate it...no dice.

No other issues, at all. I love this thing.

Duke is my daily ride, so I am trying to tackle everything at once. Been reading the site pretty solid this week to make sure I am on track.

If the dying failure rings a bell, please hit me. If you can add to my list, I appreciate ya.

Clutch switch
BGC
Battery connections
Any of the connections outside of the battery box.
Rectifier?
TPS
Tilt/tip switch

Thanks much,

Rob

Total electrical power loss suggests items 3 and 4 on your list plus ignition switch, related diode in headlamp unit and kill switch - the others plus possibly dodgy crank sensor, side stand switch, etc and/or respective wiring/connectors wouldn't result in power loss to clocks, lights, etc but would result in engine cutting out.

So would suggest double checking these first including main relay and fuse - could also be one of relays under seat but would need to check wiring diagram to remind me if anyone one of them is on the main power side.

Had only one similar problem on my ex-race SDR and that was down to a breaking wire in the middle of the dense wiring loom under rear of tank/front of seat - that took a while to find........

Have you got tuneecu cable?
If you haven't got one get one so you can check any fault codes.
Maybe Try 15 min reset and see what happens.

sabre's bike did this one year at crashfest - would start run then suddenly die - we unplugged the tilt switch and it cured it. IIRC with the tilt switch unplugged it just sees the circuit as "the right way up" the whole time....

Does the tilt switch kill all electrics or just the engine?

So, Rob - total electrical power loss or just engine cut-out?

If it's total power loss, tach will drop to zero and diplay will go blank - power back and tach will do full sweep and display will be as per when ignition turned on ie tach, for example, won't just pick up again instantly.

Sounds like just engine is cutting out - if so, it's back to your full list plus items mentioned above.

A couple of years ago my bike started cutting out on a ride. I realised it was doing it when going over a bump or landing a wheelie heavily.
In this case it turned out to be one of the battery terminals that had actually broken off and was only being held in place.
Hopefully you'll find its something straightforward like that.

one more thing......

My SD was cutting out at Cadwell one year - eventually think i traced the problem to a loose connection in behind the headlight.

Drop the headlight forward and on the LHS as you look from the front there are a series of white connectors that connect the loom through a mounting plate, seem to remember that one of these, (possibly the second down on the LHS) was loose and had partially unclipped making an intermittent open circuit. It was making the bike cut out as you describe according to my wife who was piloting it at the time.....

^^^^^^^^ x 2 with that as I've also had that problem with the middle of the vertical bank of three connectors (no idea why they need to be restrained in a metal bracket) but I'm also assuming that it's likely to be one of the wires/connectors that were taken apart to be cleaned - could be this or something else wholly unrelated to the cleaning op.

Of course work has picked up, never fails.

I have all body parts, seat and tank removed. Will start at the headlamp and head south.
I'll holler with questions/finds.
Really appreciate the direction.

Best,

Rob

I once pulled the dash and chased a short on a '78 Caddy. I swear it was easier. lol.

Had some luck though. No.47 and the Reaper nailed that connection behind the headlamp. Looser than a New Jersey cheerleader.

Some kind soul already removed my tilt switch.

Also found that I could slip the Positive battery connection, with slight pressure. The Neg side had a bit of goose pate grown on it. Will clean and replace bolts/nuts with stainless nylocks.

A couple of the connections outside of the battery box looked a little oily from that blow-by affair.

BGC is good.

I cannot hear the clutch switch click, but it is working.

Kickstand switch is good. All the grounds are solid. Everything else I checked was tight.

Think I'll grease and repair what I have found. Get back on the road.

Sure appreciate ya for the help.

Best,

Rob

So, sorted?

Put some miles on, today.

Yes'sir...sorted!

Thanks to all.

Best,

Rob

Great result I'll note this one down.