Bonneville America Forums Forums Technical Forums General Tech Bike cuts out - trying to figure cause.

Well, my 03 speedmaster cuts out after about 3 - 4 miles.

Leave it for about 20 - 30 minutes and it fires up again.

1. The hose from the petrol tank isn't pinched. I checked to make sure it wasn't blocked along the way by popping some wd40 and blowing it through.
2. I put new spark plugs on prior to this happening and they are the specified type and gapped to 0.8mm.
3. The battery when running the engine shows 14v.
4. the air filter (K&N) was recently cleaned and re oiled as per the letter of the instructions.
5. The electrics (lights, indicators) still work.
6. The sidestand switch is fine- still cuts out when in neutral.

The only mods are the AI removed the K&N air filter and Iridium plugs but I have checked with standard plugs also.

I'm thinking that i might have an ignitor issue or possibly ht leads but surely if that was the case would the bike not start up in the first place?

Prior to this the only other issues have been bike cuts out in heavy rain and is rectified by wd on the plugs/ caps and starts up fine again. And that was the cause of the exhaust overheating when I went to Funkletrumpet's BBQ this year.

Any suggestions gratefully received because at the moment I'm

How are the connections at the coils?
Do you happen to have any of the emissions crap they put on bikes meant for California?

I've just checked the connections - they seem fine.

No this is a UK standard bike.

Went back in, started up fine, revvved it up to 2500rpm then 5000rpm for a short while, working fine, let it go on idle and then cuts out again.

i'll pop back and see what happens in about 20 minutes.

Is it safe to assume the hidden fuel filter at the "T" fuel inlet is clean?

TRY TO DETERMINE FUEL OR IGNITION ,IF YOU HAVE AN OLD SPARK PLUG LYING AROUND,STICK IT IN THE PLUG CAP EARTH IT OUT ON ENGINE AND SEE IF IT SPARKS, IF IT DOSENT YOU NEED TO SEE IF THE COILS ARE BEING SWITCHED,SOUNDS LIKE SOME ELECTRICAL CONNECTION IS POOR POSSIBLEY A BLOCK CONNECTOR,THIS WILL CAUSE HEAT AND ARC THE CONNECTION CUTING BIKE OUT ,IT THEN COOLS DOWN 20 MINS READY TO START,

me think pick up coil !!!!

I checked the spark a bit earlier but forgot to say and that is good.

I was kinda thinking about the connector problem because I had a similar issue on my T595 but that was a pretty easy find and fix.

I was wondering about the pickup coil but didn't want to go opening the alternator cover just yet.

I'm back off into the garage with multimeter in hand - first check I think may be the alternator wiring connector.

I am getting fuel to the carbs. Opened up the drains and the flow is there.

I didn't think of checking spark after bike cuts out doh!

That's going to be something to do tomorrow.

Anyhow thanks for all the input guys - it's appreciated.

My bike did the same thing and it wound up being the pick up coil. Good Luck

check for a loose ground on the battery ( guess how I know!) and most likely its the ignition box notoriously know for such things. mine would cut out the right side & then fire back up.

Sorry for the delay on my response but not had chance to really look into bike.

Yep it is the pickup coil. No spark when it cuts out and I have one on order.

So should be back to normal next week.

Thanks again for all your assistance.