Ok. My TTR has developed an annoying habit. It has cut out a dozen times at idle over the past few weeks, so I'm asking for ideas on what might be causing it.
Today I took it for a 10-15 minute urban run at 30-40 mph, a 2 mile return trip up a dual carriage way at +60 mph, and finished off with start / stop, 1/4 mile dawdle in traffic. I stopped at some traffic light and after a few seconds at idle the engine cut out. The bike wouldn't restart even though it spun over as normal. I pushed the bike 100 yards to get it off the main road, and looked it over for anything obvious. After 10 minutes I tried the starter again, and it started. I rode about another 200 yards and as I coasted down a short hill it cut out again. This time it was close enough to keep rolling down the hill until I got home.
I pulled the plug out expecting it to be oiled up but it was totally clean, not even wet? Up until today I thought the cutting out was down to a voltage problem. The bike only gets used for a 3 mile commute once or twice a week, so I thought the maybe I was losing the spark at low revs, and then not being able to restart because of a low battery. Today though the battery had been on charge before I started the test run. So now I'm thinking maybe its a fuel problem?
I've pulled the carb off and stripped it down today but it looks pretty clean. Tomorrow I'll drain the tank and check the fuel tap.
Does anyone have any other ideas what could be causing the cutting out?
The tank had some paper towel in it, but it would have be in there for a good few years. It could have been blocking the fuel tap as the fuel dropped but strange it's just started doing it?
The float height was about 22mm instead of the 27mm in the Haynes manual. I haven't checked the fuel height with a tube. That's a job for later this week.
I fitted a carb kit, but nothing I swapped out looked dirty or worn. I've got a diaphragm on order, the old one did look a bit thin and the surface was cracked.
I've got a new battery ready to go as well.
Hopefully I'll get it running next weekend.
Its now the next weekend and its still not running. :(
After being put back together with a new diaphragm and fuel level fixed, it still struggled to start. When it did it ran for a few seconds with the throttle open but didn't want to idle.
I'm sure the fuel side is now in a far better place than it was, so I decided to check out the electrical system. The first smoking gun was the coil. Despite the bike briefly running 10 minutes earlier, the secondary winding came up as open circuit? I've ordered a new coil but carried on with the multi-meter.
The next test was the stator windings. I checked it as per the service manual and didn't get the expected readings. Position 1 to 2 read 33.5 ohms, 1 to 3 read 32.7 ohms, but 2 to 3 read the expected 1 ohm?
So first question to the forum.
Is 32 ohms close enough or should I dig a bit deeper and find what's increased the resistance?
Second question, the wires from the stator look yellow rather than white so I'm wondering if a previous owner has rewired it an put the positive wire to position 2 instead on position 3, would this explain the readings?
Last question would this matter or does the regulator not care which is the positive wire is anyway?
Hopefully at least the coil will get me running again.
-- Edited by Dan-in-a-Van on Sunday 6th of October 2024 09:07:35 PM
-- Edited by Dan-in-a-Van on Saturday 12th of October 2024 06:27:53 PM
The symptoms had me thinking fuel supply. Either a partially blocked breather or an obstruction between the tank and the carb.
I've had both.
I've pulled fuel caps & taps apart to not find an obstruction. I found it in the breather / overflow hose. The negative pressure, over a period of years, sucked up dust into the breather - of course Triumph positioned it just ahead of the rear wheel. Bit of moisture too and it finally blocked it. Riding along until it started to die then opening the fuel cap put me in the correct direction.
Next time I had the same problem, I immediately went to the breather. Yeah, nah.
While I had the tank off doing whatever, a big bug had crawled into the fuel line and died. Fuel dribbled out fast enough to let me ride it around town only. Or re-fill the fuel bowls as I slowed down and turned it off (but there is fuel in the bowls???!!!) Open the throttle to maintain more than 80km/h and it ran out of fuel.
Isn't home maintenance interesting and fun.
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In the Riverina.
'73 RD250, '80 XS1100, '81 RD373LC, '96 Tiger 900/sidecar, '02 TTR250, and another XS11 - this time a chain drive Period 5 race bike that may be ready to race eventually.
