Triumphrat

rrunk

After solving some earlier problems, I finally took my '66 T120r for a "longer" ride (30 minutes). I'm noticing that as the bike warms, it stalls in lower RPMs, and it takes more and more throttle to get it going from a stop. After 30 minutes, the bike dies just by me pulling in the clutch. To pull away from a stop, it takes 1/3 or more throttle. The bike starts first kick, even when I'm experience this issue. Once I get going, and at higher RPMs, the bike runs okay.

I've ruled out fuel delivery - when this happens, the bowls have fuel. I pulled the fuel line from the carbs and and fuel flows fine.

I don't think it is an air leak. I've checked for leaks at the carb manifold and the air filter joints.

I've completely taken the carbs apart and cleaned them out, including the pilot jets, a couple times - the jets, gaskets, floats, needles are all new. The float heights are set correcty, the carbs are balanced. There is a chance it is running lean. I use 190 mains, 106 needle, #3 slide, needle at the bottom slot.

I've tried new plugs (Champion N3).

I'm starting to think this is an issue with electrical. It has a Boyer ignition, but I'm embarrased to say I don't know if it is 6v or 12v. Another thought is that it is related to timing.

I'm mostly new at this, so I'm not sure what systems to check, but there is obviously something that changes as the bike gets hot.

Any help on where to look next?

Plewsy

Hi rrunk,
It sounds like it could be a tad rich, after your 1/2hour run thats when you should fiddle with the air screws and tickover.
Try dropping the needle to middle slot.
What colour are the plugs?

rrunk

Thanks. I've done two 30 minutes runs on new plugs and in both cases I've had this same problem. The plugs look okay - they are tan and dry. They don't look burnt and they don't look sooty.

I figured the bike to be lean, not rich, based on other things I've read about people with similar symptoms. But I'm really not qualified to say.

Plewsy

I see you are running 190's std jets for 650 are180's so you are a little big there.
When it is a bit rich you will find the starting very good from cold,
but as it gets hot its more like having the choke on and running will become heavy and choked.
Plugs dark brown to black, sooty not wet.

With a weak mix you would suffer from popping and blow back through the carbs especially
when cold which will improve as engine gets hot, but then it will get too hot to the point of stinking.
Plugs will end up white with dots on.

As your plugs seem about right just try dropping the needles, you can soon pop them back.

rrunk

Thanks Plewsy, I'll give it a try.

68TR6R

My bike ('68 tr6r) does something similar. After nice and hot after long rides the engine will die when I pull in the clutch, then start right back up. I always come nearly to a stop before pulling in the clutch (engine braking), and that's when it does it. Lately I've been experimenting with flipping it into neutral instead of clutching, and it seems not to die (only tried it once so far). My clutch IS a little tight, and I need to fix that, so I wonder if when it gets hot with oil sloshing around in there makes the plates stick a little. I need lighten the pressure on my clutch, but I hate buying gaskets at $8+ a pop.!
P.S. Plewsy,
I like your primary gasket video, I just might have to try it. How is it working so far? I guess the worst thing it will do is leak (like it doesn't do that anyway!)

pookybear

rrunk,

Well check your voltage as that ignition system like full voltage.
If your system is low that maybe your problem.

Also as stated, a dragging clutch--- a Triumph curse. If you can
not get neutral with easy, adjust your clutch.

The 190 main would only be a problem higher up the rpm scale
as the needle jet and needle work the lower end. And even
at that a rich main would show up as "eight stroking". So I do
not think that is the problem here. Also stated was the fact
that the carburators have been cleaned several time. A bit of
grit stuck in the polit could be the problem, but I think it would
have been cleaned out after several go arounds.

Pookybear

RetroRod

Hi all,

There has been a fair amount of focus on the carby tuning, and this may well turn out to be the cause.

There have been so many issues with Boyer EIs on this and other forums, with all sorts of "funny" things going on just to cause confusion. I would not dismiss the Boyer as the gremlin here. Also, it is not unknown for coils to carry on a bit when they warm up, so if fiddling with the carbie does not not fix this problem, a diagnostic check of the Boyer and coil/s would be a reasonable next step.

Just remember, one change at a time, too many changes at once can get you very muddled, very quickly. RR

rrunk

Thanks everyone. I moved the needle to the middle groove (was in bottom) but that didn't help - after 25-30 minutes of riding, same problem. Plugs still look good, not dark at all.

As far as the clutch, I have a very hard time finding neutral - sometimes I need to reach down and use my hand. I figured that was just me getting used to the bike. I also notice that when sitting idle for a couple minutes (long stoplight, etc) the bike seems to want to creep every so slightly, even though I have the clutch disengaged. Could this be related?

Tomorrow I'll check the voltage, and if that seems okay, I'll look into adjusting the clutch.

Plewsy

rrunk,
The clutch dragging will not help at all, so you should adjust the push rod
.
At lights and things I have a habit of snicking it into neutral just as I come to a stop,
as I don't like running with my clutch in (it gets enough abuse)

You will find it difficult to engage neutral when bike is fully stopped (engine running)
letting the clutch out a bit! while lightly operating gear lever will help, or rock the bike.

You say your plugs look a good colour, drop them needles again,
when nice and hot, give them air screws a twiddle,
If it runs worse, the middle position is about right or
It might run better you never know.

Give your battery a good overnight charge (low amps)
I disconnect the earth when charging.

Hi 68TR6R,
I've done a couple of thundered miles now, and got one drip but thats off my sump plugs apart from that shes oil tight..... for now