Engine Trouble - intermittently won't start! Any ideas on what to look for?

[mecsw500]

Peter
Today I checked the battery and the connection's looked good. Attached my Fluke meter and checked voltage.
Resting voltage - 13.2 volt
Ignition on - 12.8 volt
Than I used the min/max feature on my meter.
Min voltage during starting - 9.4 volt
Max voltage after starting - 13.4 volt
Avg voltage 13.2 volt
The voltage on the battery terminal really didn’t rise above 13.4 volt
Looks like the battery is ok.

If you are getting down into the mid 9 volt range on starting it’s very possible that the ECU and other modules are not getting sufficient voltage to operate reliably. It might not be the voltage level it drops to, but how it drops to that level. Lithium batteries can drop off suddenly rather than smoothly under load. They have a different operational capability that might be at home on a modern four cylinder sport bike, but trying to kick an big old lump of a Rotax V twin into life Might not be the best match of technologies. Old air and air/oil cooled BMW bikes can suffer the same problem.

Rather than chase your tail constantly, perhaps get a new traditional AGM battery, charge it up and then try it.

These bikes and their electronics were designed around the way voltage drops under load with a lead acid battery. A good AGM battery falls into that category. Lithium technology batteries have their uses, but not trying to fire up a large V twin motor with electronics designed over a decade and a half ago.

 

[EdMat]

These bikes and their electronics were designed around the way voltage drops under load with a lead acid battery. A good AGM battery falls into that category. Lithium technology batteries have their uses, but not trying to fire up a large V twin motor with electronics designed over a decade and a half ago.

If that's the case, then the lithium battery is undersized or its useful life is over for various reasons.

 

[mecsw500]

If thats the case then the lithium battery is undersized or its useful life is over for various reasons.

Not necessarily a good battery with those figures. Lithium batteries has a very difference voltage degradation curve under load. An AGM lead acid battery will decay voltage in a different manner than the sudden voltage drop off of a Lithium battery. 9.5 volts minimum looks too low to me.

Whilst it’s possible your Lithium unit is technically the right size battery and still working within the parameters of its design, it’s just possibly the wrong battery technology for the application on a 998 Rotax big twin on an early Spyder.

The bike was designed long before anyone would be expected to use a Lithium technology battery. I’d play it safe and return to an AGM version which was the original fitment.

I’d get one with at least 350 cold cranking amps.

The Yuasa YTX24HL-BS I think was the OEM fitment.

I know they are $130 from Amazon but I think returning everything to stock is the best way forward to eliminate the battery as an issue.

If the battery is the problem you could chase your tail constantly and indefinitely. A new Yuasa battery is less than one hour of a BRP dealers shop time.

I suspect you have spent many hours on this so far.