Triumphrat

lindsayt · 07-18-2008, 12:42 PM

Okay, so it's actually not a major issue but I'd like to get it dealt with, especially if I end up doing the 2000+ mile ride I just posted about in the Twins Hangout forum.

So as far as I can observe, I've only seen this problem a few times in the last couple weeks, and it's always when the bike is cold, before it's completely warmed up (though it might be after I'm completely off-choke), first thing in the morning after it's sat for a couple days.

So I start the bike and it's running nice and smooth and suddenly the engine cuts completely out - no hacking or wheezing, no sputter, just completely cuts out. It feels about the same as when you're in gear with the clutch pulled, and you put down the sidestand. But I'm about 99% sure it's not a faulty switch, because it will happen when I'm in neutral, with the clutch out and the sidestand up, and it seems to have no relation to whether or not I'm in gear or sidestand position - so two sensors would have to be simultaneously intermittent for that to be what it is (both the neutral sensor and the sidestand sensor).

What I have noticed is that it *ONLY* happens when I'm completely off the throttle - sometimes it'll just randomly die while the bike is sitting, and other times it will happen when I've come to a stop and am about to give it gas. A couple times I've felt where it "dies" just as I'm rolling on the throttle, so it'll jolt me forward (as it almost dies) and then back as the throttle kicks in and it goes.

A couple more observations:
It seems to be a bit hard to start right after this happens - not really hard, but I have to hold the button in for a couple cranks before it turns over, and it sometimes backfires just a little as it starts in that case.

Recently, when I start the bike cold with full choke it's not racing up the RPMs as it normally does as it warms up - it holds a steady but subdued engine speed. If I start to push in the choke right after starting the cold engine, I can push it in quite a ways without the engine speed changing; only when it's almost closed do the RPMs seem to drop to an irregular pattern. This is always what I've used to gauge that the engine doesn't really need much choke, and so that in itself doesn't seem strange to me; but I do wonder why it's not racing up the RPMs at full choke.

Once the bike's been running for at least ten minutes I'll have no more trouble at all - it runs smooth and strong at idle and any speed up from idle.

My guesses are that the carb is out of synch, or one of the carbs has a slightly clogged idle jet, or perhaps it's just too rich at idle for our current weather. The last point seems unlikely though since I haven't messed with factory jetting (so it should be pretty lean) and temps recently, over which I've observed this behavior, have been pretty varying - anywhere from a high on a morning when it was about 85 (at 9 in the morning! That was a hot day!) to this morning when it was only maybe 65 when I started her.

Anyway, any opinions or ideas? Again, I'm not terribly concerned about it since once the bike's fully warm it's not an issue, but since my morning commute is only 2 miles, I do a fair amount of my daily riding on a cold engine. I tend not to leave it sitting while it warms up, especially in the summer when it doesn't need much choke, but I have been letting it warm up a little more since I've seen this problem - usually waiting to take off until I'm completely off choke.

Opinions?

Baltobonneville · 07-18-2008, 01:22 PM

Mine does something like this too, it's annoying but not really a problem. Others have posted the same issue.

From a completely cold start, it idles slower and slower over about 30-60 seconds until it stops. There's no point to starting it and then putting on my gear, because it's not going to run very long unless I stay on the throttle.

Once warmed up, no problem. And my carbs are well-synched, so I don't believe that's it.

This commenced after I did the air-flow/exhaust/carburetion mods outlined in my signature.

propforward · 07-18-2008, 01:24 PM

Carb synch sure - dirty air filter maybe? My bike did exactly this this morning, but it was because I'd left a %^$ dryer sheet in the snorkel. Similar idea though.

How come Balto always manages to post an instant before I do?

killian101 · 07-18-2008, 01:33 PM

this seems to be happening more and more. Mine does this too. The only difference in my case, 99% of the time, it want to cut out, but doesnt. But there is that 1% when im at a light, then it cuts out.

At first id thought it could be an exhaust leak, or maybe coil, ????

lindsayt · 07-18-2008, 01:59 PM

Quote:

Originally Posted by propforward

Carb synch sure - dirty air filter maybe? My bike did exactly this this morning, but it was because I'd left a %^$ dryer sheet in the snorkel. Similar idea though.

How come Balto always manages to post an instant before I do?

You know, that's a very good point. I haven't cleaned the air filter; probably ought to do that!

lindsayt · 07-24-2008, 11:32 AM

bad gas. Or at least, it appears to have been. The problem started a few days before I started this thread; I'd last gotten gas on July 10, so it wasn't *old* gas, but it seems to have been bad. I filled the tank on Tuesday morning (2.8 gallons, so I burned through most of the old gas before I filled it) and have had no problems whatsoever since then. So we'll see if it reappears, but it seems that the problem was connected to the gas.

Oh, and I checked the air filter by way of determining the problem. Surprisingly clean after 7500 miles - a little gray down at the end, but otherwise looked almost brand-new.

I really don't understand why a gas issue would only cause trouble when the engine was cold; I had no trouble when the engine was fully warmed up, but it could barely idle when it was cold, and after I put in the new gas, it idles just like it always did when cold (a little unevenly, but no inclination to die). I'll keep watching, but I think that was it.

NorthernThrux · 07-24-2008, 01:23 PM

I can add that I've only seen it when rpms were below 1000.

I bet you see it again. I use Esso or Sunoco and still have the problem occasionally. More tellingly, I have FCR carbs, so it's not unique to the CVKs. And I have it happen with both stock NGK and Iridium plugs and both stock and Nology wires. And I have antioxidant conductive grease on all connections, so it's not that.

I have richened my mixture a 1/4 turn as others have suggested, and so far, so good. The FCRs don't have a choke. You give the accelerator pump 5 or 6 twists before starting to get it going. It then idles nicely at 600 and slowly makes its way up to 800 by the time I have my gear on.

NorthernThrux · 07-26-2008, 02:16 PM

Well, that wasn't it. I even richened it up till the idles started to drop and I still get it, actually worse. COmes back to a post I had some time ago. I think it's the ignition system. When the idle is at 1k or below, I think it skips occasionally. I've put my pickup sensor as close as possible (0.8 mm, Triumph's recommendation) so that seems to bring us back to the high voltage module. Anybody with Nology ignitors have this problem ?