Bonneville America Forums Forums Technical Forums General Tech Poor running.

A week or so ago, I was riding along, minding my own business, when the bike started playing up: loss of power, ridiculous vibrations, strong smell of fuel. Then it stopped completely.
I checked for obvious signs by the side of the road but couldn't see anything. Somehow, I managed to get it going again and limp my way home.

I had a look again yesterday and she starts OK but after a minute or so, begins runs poorly, with the same symptoms.

6k miles on the bike.

Things I've done to date:

-Changed plugs.
-Checked for spark-fine on both sides, although the sparks are different colours-one's blue, the other is yellowey, should that be relevant, although I don't have feeler gauges so they probably aren't gapped properly.
-Changed air filter. The airbox is clean and dry.
-My leads appear fine, tho I've only done a physical check.
-All rubbers appear fine and I've run it without the fuel cap to eliminate vapour lock.

Observations:
Both the headers appear to heat up the same amount and there's unburnt fuel in both exhausts.

It's under warranty, because it hadn't been serviced by the dealer, I was told that it may impact on what can be done. With it being the start of the riding season over here, there's a 3 week wait before it can be looked at anyway, plus, it'll mean me spending £50 on HT leads, something I really don't wanna do unless absolutely necessary.

Sooo, anything else I can check/do?

Could a blocked fuel filter cause these symptoms? The fuel over here is terrible; when I rejetted, there was a load of rust-coloured crap in the carbs.

You should at least check the hidden filter. Does the cutting out happen more at higher rpm's? If so, that may be the culprit.

It idles only slightly more roughly than normal (you'd be hard pressed to tell) but if I twist the throttle even slightly, it exhibits the symptoms as described above. I daren't rev it too much. Incidentally, will running it as it is for 30 seconds at a time have any long or short-term affect on anything?

If it was a fuelling issue, wouldn't the symptoms of that be different-more akin to running out of fuel?

Don't think it is a filter problem if filter was clogged I don't think there would be raw fuel in the exhausts.

if you had a lot of chum in your bowls, then you may also have a stuck float(s). Drop the bowls and check it out.

I don't think it's fuel either since you had a smell of fuel. That says ignition problem to me,(could be stuck float too if you had gas in both exhaust probably not though) Fuel in the exhaust would be unburned fuel meaning it is getting in the cyl. but not burning. That could be a number of things, burned valve, very bad rings, burned or broken piston (will be a big failure in short order) I really doubt it is any of those however. I would be looking at the ignition, spark should be blue that yellow spark could be a sign of a failing ignition.

I think Ian's got it...try to find someone to swap ignitors.

Update: Since putting the new plugs in, the bike's not moved; it's only been run to fault-find. I pulled them today to gap them properly (I wasn't that far out). One of the plugs is slightly sooty (the other looking new). I tested the spark again and it seems much improved: blue rather than yellow.
I'll be cleaning the carbs tomorrow. Is it something that can be done with the carbs on the bike? I realise that removing them is preferable but the garage is full of crap at the moment (we're cleaning the house out) and, as such, space is very limited. As it is, I have to move my pedal bike out to even get near my Speedie.

Thanks for your suggestions.

Let's hope it is fuel related. Try pulling the choke out when the bike coughs and sputters. if it smooths out then pull the carbs and clean properly. Sounds like space is an issue for you. here's my garage with the highlander backed out. I have a lot of stuff to move to work on anything too! When the wife's suv is parked you have to turn sideways to walk up by it. The jack is under the wheel hanging on the board with hedge trimmers stacked on top next to the lawnmower which is laden with seat cushions for outside chairs. To get to those i have to move two or three bicycles. Heck in this pic i even have my tent hanging on the clothes line in order to dry out from the Arkansas Rally. dangit. Speaking of the tent, just to the left of the tent (out of frame) is thee most important item in any garage: the beer fridge! At least the calendar has a clear view on what is important! Just trying to lighten up your mood is all. You'll tackle this. be methodical and sort through it.

OK, just had a try again.

It's the left-hand cylinder which isn't firing. (Right header hot, left header cool.) I swapped the leads-no change.

I then tried swapping the leads over at the coil end, so the left coil went to the right plug (and vice-versa)-it wouldn't start at all. Is this normal?

I'm away over the weekend so can't try anything major until I get back but, please, keep suggestions coming-I'm transportless without my bike so really can't wait a month til I can get it to the dealers. Obviously, if it is electrical then there aint much I can do.

Oh, and moe, see that space in between all your bikes? That's all the space I have to work in. Your garage (pronounced "Gah-ridge") is HYOOGE compared to what we have over here.

Is it an easy job to check the coils/ignitor with a multimeter or something? If so, can anyone provide step-by-step instructions, including what to set the dial to and what should appear on the readout. I'm hopeless with anything like that. Cheers.

I am experiencing the exact same problem. I took the carbs off. Found the rubber on the left side connecting the carb to the head had a tear in it not visible until carb was off. Massive vacuum leak

Cheers, Kenny, I'll go check them now. I've had a cursory glance but I mainly focused on the smaller vacuum cap rubber things.

Hey. Me, again. So, things have changed once more. My bike's due into the dealers on Monday so, yesterday, I set about removing my HID system. Whilst I had the tank off, I removed the carb-to-head connectors/manifolds and refitted them, just to rule out vacuum leaks. I pulled every connector I could see and put it back and I removed the hidden fuel filter and put in one of my own, nearer the fuel tap.
Prior to doing this, she was running on one cylinder. This morning, I fired her up and she ran fine. I went for a run of a few miles and she was fine, even at 6k rpm.

So, any thoughts from anyone? I'll be going for a longer run over the weekend.

Also, and a slight aside: sometimes you need to run your bike wit the tank off. What does anyone use as a temporary "tank"? I stuck a funnel into the top of the fuel hose and filled that up but it's hardly safe.

(The hidden fuel filter can be removed with the carbs on; it's not too difficult with long-nosed pliers.)

It's running again!!! Yay!

Basically, I had the bike booked in to be looked at and, aware that the warranty could be affected, I took off the HID system I had fitted. Whilst the tank was off I pulled the carbs apart and refitted them, to rule out an air leak and I also pulled each connector and pushed them back together to ensure a decent connection.
I put it all back together, she fired up first time and ran fine for the 5 miles or so test-ride.