Triumphrat

advhopeful · 12-02-2012, 03:26 AM

the bike runs and will not sputter unless I accelerate only happens when she is warm. What is my next move? "squatters in the airbox etc)" not familiar with what that means.

thank you all so much for your help with this.

IrlMike · 12-02-2012, 06:47 AM

Re squatters - it's been known for mice to have moved in to an airbox, not for a bike in regular use tho'.

I think it's airbox & carbs off, check & clean, not forgetting the duck bill filter in the fuel line.

petermholmes · 12-02-2012, 03:09 PM

Due to the fact that it's definitely heat related, I'm leaning back towards electrics, specifically a coil or maybe the ECU. When the bike starts to lose power, if you listen carefully, does the sound of the engine change? Does it sound as if it's no longer a triple but a twin (or worse, a single)?

sdanville · 12-02-2012, 05:37 PM

My Guess is ECU.
Hate to say it. Seems if the Miles get to 30,000 the Gill electronic's are near fail point. The bike warms up, the electric's warm up things expand with heat , circuits move a hair, connections lost, spark failure. I hope I am wrong.

petermholmes · 12-02-2012, 06:35 PM

I hope you're wrong too, but I wouldn't be surprised to hear you're right. The problem is electronics that are failing can do such a good job of mimicing one or more carbs running out of gas.

Maybe if he stopped the bike once it's warm enough to be complaining, turned it off but left the fuel tap on, waited for a couple of minutes, and tried again? If the problem is the carbs running out of gas, they might get enough juice to accelerate normally for a couple of runs. Why I say that...I've waltzed off with the tap closed a few times, and in my experience a full set of carbs can run the bike for a couple of miles before they run out of gas. Of course, if it's a coil failing, that may give it just enough time to cool down so that it will act normally for a while too.

For what it's worth, when I lost a coil (not completely, but in a mode similar to what he's experiencing) the resistance of the coil at fault was slightly different than that of the other two. In my case, heavy acceleration with high RPMs would cause the coil to overheat, at which point I'd lose the cylinder to which it was attached. Once that had happened it took about 5-10 minutes of going easy on it for the coil to come back online, at which point, if you accelerated heavily again, the coil would quit again. Could cruise all day long, but could only accelerate heavily when the bike was cold.

Just trying to prevent his having to rip into the carbs if it's avoidable.

Greaser · 12-02-2012, 10:32 PM

Quote:

Originally Posted by petermholmes

...

For what it's worth, when I lost a coil (not completely, but in a mode similar to what he's experiencing) the resistance of the coil at fault was slightly different than that of the other two. In my case, heavy acceleration with high RPMs would cause the coil to overheat, at which point I'd lose the cylinder to which it was attached. Once that had happened it took about 5-10 minutes of going easy on it for the coil to come back online, at which point, if you accelerated heavily again, the coil would quit again. Could cruise all day long, but could only accelerate heavily when the bike was cold.

Just trying to prevent his having to rip into the carbs if it's avoidable.

That sounds like what happened when my coils failed. I was able to compensate a bit by playing around with my air gap at the crank sensor, effectivley varying the dwell angle of the timing.

IrlMike · 12-03-2012, 05:29 AM

Quote:

Originally Posted by petermholmes

I hope you're wrong too, but I wouldn't be surprised to hear you're right. The problem is electronics that are failing can do such a good job of mimicing one or more carbs running out of gas.

Maybe if he stopped the bike once it's warm enough to be complaining, turned it off but left the fuel tap on, waited for a couple of minutes, and tried again? If the problem is the carbs running out of gas, they might get enough juice to accelerate normally for a couple of runs. Why I say that...I've waltzed off with the tap closed a few times, and in my experience a full set of carbs can run the bike for a couple of miles before they run out of gas. Of course, if it's a coil failing, that may give it just enough time to cool down so that it will act normally for a while too.

For what it's worth, when I lost a coil (not completely, but in a mode similar to what he's experiencing) the resistance of the coil at fault was slightly different than that of the other two. In my case, heavy acceleration with high RPMs would cause the coil to overheat, at which point I'd lose the cylinder to which it was attached. Once that had happened it took about 5-10 minutes of going easy on it for the coil to come back online, at which point, if you accelerated heavily again, the coil would quit again. Could cruise all day long, but could only accelerate heavily when the bike was cold.

Just trying to prevent his having to rip into the carbs if it's avoidable.

Well, hearing you recount your own experience here Peter, I'm thinking you may be right - it may not be fuelling.

The coils are certainly a weakness (mainly Gill type?). The more common symptoms of failure are poor low rpm operation/misfiring, then fine above 3k or 4k rpm. But that's obviously not the only way they go. Of course, all the connections, including HT should be pulled & checked.

A strobe light will show up a bad/misfiring coil.

Set up the bike with tank off & extended hose connected, as for carb balancing, run the engine til warm, add a bit of extra hair dryer/heat gun heat (carefully) to coils, check with strobe light?

Otherwise, it's test by substitution? Any of the 885cc T3 series coils will do - all the same, except the dual type on the 4 cyl bikes.

IrlMike · 12-03-2012, 06:08 AM

Quote:

Originally Posted by Greaser

....playing around with my air gap at the crank sensor, effectivley varying the dwell angle of the timing.

The air gap doesn't affect the dwell angle (ignition coil 'on' or 'charging' period) - that's determined by the microprocessor in the igniter, according to rpm. All the sensor is detecting is the zero crossing point of the voltage induced, then receding as a lobe passes the sensor tip.

The gap is important tho', as the amplitude of the sensor output is proportional to rotor/engine speed & it needs to be in the right range - high enough to give a clear signal for start rpm, not too much to swamp the sensor input circuit at high rpm. Out of this range & timing jitter or misfiring could occur.

'Typical' inductive pick up output: (not quite ours, but similar)

The pattern of repeating pos/neg cycles (one for each lobe passing) depends on the actual pattern of lobes on the rotor - 7 lobes in our case

Umm....that's probably more info than anybody wanted, but I'm sat here with a cold this morning & feck all else to do

petermholmes · 12-03-2012, 12:55 PM

Quote:

Originally Posted by IrlMike

Umm....that's probably more info than anybody wanted, but I'm sat here with a cold this morning & feck all else to do

Heck no! I enjoyed the lecture, prof. A good day is any day you learn something new.

CharlieS · 12-03-2012, 01:14 PM

This stuff is gold. It's going right into my troubleshooting favorites.