Hi,
My Phantom 150cc 2-stroke cuts out after perhaps 20 to 50 Km run. Leaving it for a few minutes to 'cool' results in re-start but then the same will happen again in a few kilometres.

Day-to-day riding, to town and back - maybe 5 or 6 Km each way - causes no problems unless the day is very warm. But I cannot trust the bike to keep going for any longer journey than that.

1/ According to the Temperature gauge, it is NOT overheating: the gauge stays down at the first mark, quarter warm. Once, and once only, on a very hot day the gauge climbed to the halfway mark. On that occasion the engine wasn't 'happy' but it didn't quit before I got home.

2/ The ignition coil has 'failed' (Thai diagnosis) and has been replaced 3 times this year.
3/ Often, the ignition-switch is quite hot to the touch after just a few Km.

I wonder if the "whatever is the modern version of contact-breaker" is closed for too long, allowing excess current through the ignition system, causing overheated coil etc etc?

4/ The carburetor has been stripped-and-cleaned more times than I can count. This has no lasting effect after the first five Km, so I don't think that's the problem.

5/ Honda's local dealer replaced the spark-plug yesterday - I got a whole 2 Km before the engine cut-out. Needless to say, I returned to Honda and asked them to find the problem.

6/ The bike is about ten-years-old and has about 32,500 Km on the clock.

Can anyone help to throw some light on this, please?

Geoff

Geoff,

Generally if it cuts out suddenly it is electrical. If it stops slowly it is fuel related.

Carry a spare spark plug. Next time it cuts out pull off the spark plug lead, plug in the spare plug, rest the plug on something metal on the engine kick it over and see if you have a spark.

No spark it is electrical. Have spark it is fuel related.

Does Phantom have a side stand switch to prevent starting with stand down? I don't think my NSR 150RR did but....maybe it is malfunctioning.
Is there a neutral switch and a clutch switch. If not in neutral do you have to pull in the clutch to start? Again maybe not but....
Does the bike have an inline fuel filter between the tank and the carburettor? Sometimes they get plugged and exhibit intermittent symptoms.

Also see PM.

Geoff,

Have you checked the auto lube system. Does the mark on the quadrant line up with the mark on the crankcase? You did say the old plug was "soggy" . Are you using the correct plug? B9 somethin EC. Can't remember exactly.

You still haven't told us if it is the key ignition switch or the kill switch which is hot.

Do you ride slowly or with some spirit. Two strokes need to be "ridden" not simply used.

I'm still with electrical fault or fuel filter. Unplug and re connect every connector you can find on the harness. Check every wire that is near any part of the frame for abrasion. Does it or did it ever have an alarm system? My NSR did and it wouldn't start one day. Until I found the alarm system was grounding the ignition system, even though it was turned off.

Nobody yet answered the side stand or neutral switch question.

Phew, so much to think about that my brain hurts ...

@ Flying Squirrel
The main key-switch gets hot, not the kill-switch.
The bike doesn't have a stand-switch nor a neutral-switch so far as I can tell - I have occasionally kicked-started her, in gear with the clutch hauled in.

As for security systems, she doesn't have any now but I really don't know about the past. There are various dangly bits of wiring near the main fuse holder, though the ends look to be neatly 'clipped' rather than frayed as though they had fallen off. Could be the remains of a security system, I don't know.

"Have you checked the auto lube system. Does the mark on the quadrant line up with the mark on the crankcase? " Crikey, what's that?

My driving certainly has some "spirit", though as an "older person" I like to think I temper my speed surges with enough sense to stay alive. I've only been driving for 48 years (mostly cars), the last ten years have been on little Honda 'step-through' machines until I bought the Phantom a year ago.

The fuel consumption, by the way, varies between about 26 and 20 km per litre and has averaged 23.59 (66 miles per gallon) since last December. It seems thirsty to me, especially compared to my girlfriend's Scoopy, which returns about 200 mpg. On the other hand she drives rather more sedately than I do!

@ Matty
My driving routine sounds pretty much like yours, ten minutes to town, do some shopping - stop, start, stop, start - then home along an open road. The drive home is often quite "spirited" to vent the frustrations of town driving.

I try to make sure to use the recommended plug - "B9 something EC" to quote Flying Squirrel (it's written on a label on the tank-top) - and Champion brand for quality and that seems to last quite well. Your suggestion of an Irridium plug reminded me of about 45 years ago when a friend of my father brought along some aircraft-engine plugs for my pre-war side-valve car. They were later marketed as "Ring of Fire", I believe.

Meantime, I've put her into the Honda dealers with the request to "Fix It". At the last visit, they are ordering a new "control box", which at 4000 baht makes my wallet wince. I sincerely hope it works!

Cheers,

Geoff

Waaaay too big

My car was a pre-war Morris 8, 800cc side-valve. Definately in the "Rolls Canardly" class (Rolls downhill, can-hardly get up them) Used to use reverse gear to get up steep hills, 'cos that was a lower gear than first.

Ahhh, them were the days.

Geoff