Engine Bucking

[poochar]

Hello,

Have had nothing but praise for the 2016 Downtown 300i
.... until today .......... 2,100 miles
Rode the bike down to Walmart today (ran fine)
BUT the ride home engine started "missing" (bucking and sputtering)
at one point it stalled and had trouble starting ..... manage to limp on home
(could still get the RPM up too 5,500 while sputtering)
- certain the gas is good
- bike is still under waranty for another month (but pain to get to the dealer)
- warm day 91 f
- pulled seat and trunk off ....... all seems to connected (hose and wires)

ANY thoughts?

Thanks
Eric

[Stig / Major Tom]

I know you mentioned wires tight....inluding spark plug cap and battery terminals? Yes? Ground wires?
Spark plug not loose?
Tried removing gas cap?....sometimes cap doesn't vent as it should...making fuel delivery difficult when engine hot on warm day.
Hope you resolve it here - but do take to dealer if not fixed ASAP.
Stig

[poochar]

Thanks Stig !!!

You are spot on ............. (with a semi cooler head) .... I checked again.

Spark plug wire was off !!!

At 1,800 miles I checked the valves (had spark plug out to turn over the engine)
I always put dielectric grease on tip of the spark plug (I'm sure that helped with it coming off)

97f degrees and humid in garage now.... so in the morning will clean up spark plug and boot of grease...
(and learn a lesson too)

Thanks,
Eric

[hypophthalmus]

It sounds like you're saying you put the grease on the spark plug terminal?

Dielectric grease is an insulator, and you shouldn't get it on anything that's meant to conduct electricity. A small amount on the boot of the wire will help it release later and prevent corrosion.

If that's not what you did, then disregard this.

[Stig / Major Tom]

From Permatex Dielectric Grease
"Protects electrical connections and wiring from salt, dirt and corrosion
Prevents voltage leaks around any electrical connection
Extends the life of bulb sockets
Required for modern high energy ignition systems
Suggested Applications: Marine and automotive electrical connections, spark plug boots, trailer hitches, battery terminals "

If you have a good/hard electrical connection - this stuff protects that connection, but does not enhance the electrical flow.
Stig

[Stig / Major Tom]

Thanks Stig !!!

You are spot on ............. (with a semi cooler head) .... I checked again.

Spark plug wire was off !!!

At 1,800 miles I checked the valves (had spark plug out to turn over the engine)
I always put dielectric grease on tip of the spark plug (I'm sure that helped with it coming off)

97f degrees and humid in garage now.... so in the morning will clean up spark plug and boot of grease...
(and learn a lesson too)

Thanks,
Eric

Well done Eric!
97 degrees? Heat index will be 110+!

Text us if you can't find your way out!
Stig

[poochar]

Well done Eric!
97 degrees? Heat index will be 110+!

Text us if you can't find your way out!
Stig

I always put a little dab of Dielectric Grease on my spark plugs before I put the wire back on!
(with NO problems)

Braved the heat of the garage ......
wiped down the spark plug and cleaned out the boot with WD-40....

When I push the boot on the only "positive" feel I get is the clicking of the threads
at the top of the spark plug  (then goes no farther)  Guessing that is as far as it goes.....??

Bike starts and runs OK

Eric

[Stig / Major Tom]

I always put a little dab of Dielectric Grease on my spark plugs before I put the wire back on!
(with NO problems)

Braved the heat of the garage ......
wiped down the spark plug and cleaned out the boot with WD-40....

When I push the boot on the only "positive" feel I get is the clicking of the threads
at the top of the spark plug  (then goes no farther)  Guessing that is as far as it goes.....??

Bike starts and runs OK

Eric

Yep, that's all she needs.
Enjoy that practically new scoot...the 300 is a winner.
Heat advisory here, as well. Birds are exploding, that kinda thing
Stig