SP1000

[David 54]

My SP 1000 has been running perfectly, but suddenly is only running on one cylinder (the left) Checked plug, it's wet so assume petrol getting through, checked spark against the block, seemed ok, switched plugs over, no change so it's not the plug............... ...any ideas (all I've done is wash it in between it running perfectly and going onto one cylinder) Thanks in anticipation.

[arveno]

...dont wash it never again lol

Joke aside

I would check if the right spark plug " sparks"
If not , there you have the issue.

check if spark plug wise got loose.

report back result.

I am sure it has to be something simple.

[twhitaker]

Switch spark plug caps to see if the problem follows.

[flangeman_70]

Check these items in this order  :Beating_A_Dead_Hors e_by_liviu :-
1) Chokes/Fuel enrichment.
2) Float that is sunk/stuck.
3) Weak Spark

Report back

Good luck!

Adam

[pehayes]

I have just rolled my SPII back on the road for a similar problem.  It turns out that a coil which has enough ZAP to spark a plug in open atmosphere may NOT have enough to do the same job inside a compressed chamber.  I had to detect it by using a self-powered inductive timing light to see that the secondary wire was actually  running a spark.  If I tested with the plug out it sparked just fine.  Install the plug and no detection of current in the wire.  Seems are rare but not unknown phenomenon.  Apparently takes about 5X the amperage to jump the same gap through compressed air.  Mine were original 1987 coils being triggered by a Dyna-III ignition.  Temporarily wired in a known good Ducati coil and all was well again.  I purchased new 5ohm DYNA coils from MGCycle and just completed the installation.  Purrs like a kitten again.

Patrick Hayes
Fremont CA

[Lannis]

Compression first, fuel second, ignition third, it's always the right troubleshooting order.

My SP starting missing badly on the left cylinder on the highway under load once, on a long trip.   Checked sparks, switched plugs, took carb apart in an I-20 rest area in Alabama ....

... turned out to be overly tight valve lash on the left cylinder holding the valve open when the bike was pulling hard.   Lucky I didn't burn a valve, but if I would have checked that first, I would have saved hours of fruitless debugging of perfectly good ignitions and carbs ....

Lannis

[Arizona Wayne]

I had that happen on my CX100 after we hit rain.  It was water getting into the spark plug cap. The plug would be wet w/fuel.  I'd dry it out...the bike would be OK until the water got into the cap again and short out the spark.

[Cam3512]

Spray som WD40 up into the caps?

[Arizona Wayne]

Spray som WD40 up into the caps?

Mine had a 2 piece all rubber cap on it, not the original metal 1. Had to seal the cap.   NGK caps seem to be the best now.