Hi Guys, I have an 07 Bonneville (Last of Carbi model) I'm having trouble with it dying mid ride, no sputtering just stops, when I flick the petcock over to reserve, she fires back up and runs fine, this happens intermittently. We have cleaned the petcock, no dirt all really apart from a few specs, looked at electrical, I thought perhaps the breather on petrol tank cap was not working and causing a vacuum, so I am stumped, I taken to 2 bike shops for repair but to no avail. Any suggestions would be appreciated, thanks and cheers. Bernie
Hi Bernie and welcome in I also have an 07 Carb Bonnie, but I'm sorry I'm not technically knowledgeable enough to help you. However I'm sure one of the forum gurus will be along soon with advice.
I had similar problems with my 07 carbed bonnie, it was a combination of rust in the carbs, but also the ecu was failing and after cleaning the carbs and fitting a new crank sensor, coils and ecu all is well
From memory there is also a little filter within the T piece that feeds the carbs. Worth cleaning that too.
The part about "no puttering, just stops" would lead me to believe the problem is more likely to be electrical. Maybe your playing with the petcock is just coincidental. Usually if an engine runs out of fuel, especally one with more than one carburetor, it will do so unevenly as one carb goes dry then the other. ...J.D.
I’m with Wire-Wheels on this one. Carbs would likely stutter with fuel starvation much as when switching to reserve. Sudden stop smacks of electrics and switching to reserve maybe just allows a component to cool enough to re-connect. Your issue is isolating the dodgy part. Ignition and pick up coils are notoriously prone to internal breakage, initially intermittent. Plenty of stuff to Google if you have a multimeter to measure resistance values.
I have 3 of these Hinckley era, carburetted Triumphs. I have had coil failures on 2 of them. Carburetors get a bad rap. I have never had a carburetor or fuel systrm problem of any kind keep a bike from running. Could also be the crank sensor. But my money is still on electrical. I'd "bet the farm on it". ...J.D.
After thing about this last night, I agree no coughing or spluttering as if staving for fuel, I guess the leads us to potential coil issues or someone else mentioned Engine Speed Sensor, any tips for checking these? Thank you all for your assistance its a great help. Cheers
The crank position sensor is under the RH triangular side cover. If you follow the twin black wire from its grommet via the plastic loop up under the side cover you will find a 2 pin connector hard up against the battery. You should get about 570 ohms resistance.
