The Hinckley Triumph Bonneville Ignition Pickup Coil

Towards the end of last summer, I was plagued with a problem where my motorcycle would shut down while on the road. It's a pretty hairy when your engine just gives out all of a sudden on the highway. The bike would eventually start back up after resting for a bit. That is how the problem started. Eventually it got worst and worst where it would shut down after riding for 10 minutes and fails to start that I had to push the bike back home.

Let me tell you, nothing kills the romanticism of a motorcycle than having to push it uphill.  One thing about motorcycle problems, you just can't ignore it. It just gets worst. From the little I know about motorcycles, I assumed the problem was with my carburetor. So this winter I took apart, cleaned and rebuilt my carburetors. I thought I was BMOC when I was able to put it together and got the bike started this Spring. Until the bike summarily shut down and I had it to push it back home. Thankfully it was a short test ride.

I needed help. The best place to get advice for a Triumph Bonneville owner is Triumphrat.net. The members in this board are knowledgeable and very helpful. The feedback I got led me to look into the ignition pickup coil. I had a problem about three years ago that turned out to be the coil. At that time, I had a mechanic troubleshoot the problem and eventually led to replacing that part. This time, I was determined to do this myself.

What is the Ignition Pickup Coil?

The Ignition Pickup Coil is part of a feedback mechanism that sends crankshaft position and speed to the igniter. It's located inside the right-hand side crank case (alternator). It's mounted near the alternator rotor. The magnetic signal is "picked-up" when raised protrusions comes close to the pickup coil as the alternator turns. This signal, along with other feedback (e.g. throttle position sensor) is used by the igniter to calculate the correct ignition timing it sends to the ignition HT coil. The ignition HT coil in turns signals the spark plugs when to fire.

Check Coil Resistance

Igniter Side Connector

The first and easiest thing to check is the coil's resistance. The coil connector is located under the seat. Remove the seat and look for a connector that is connected to a cable with a black and red wire running down into the right-hand side crank case. Measure across the connector's two points.

Pickup Coil Connector

The resistance should measure around 600 ohms. When I measured mine, it was only reading 100 ohms. That's pretty bad. At this point, there is nothing to do buy and install a new one.

Check Gap

If the resistance is good, the next thing to check is the spacing between the ignition pickup coil and the protrusions on the alternator. You'll have to open up alternator cover and line up the top of one of the protrusions with the bottom of the coil. When opening the alternator cover, put the bike on it's side stand. This will keep the oil from spilling out of the engine. Expect a drop or two to come out but no more. Also, have a rubber mallet handy to help loosen it off. There will also some resistance from the alternator magnets so a bit of elbow grease is needed to get the cover off. To line up the coil with a protrusion, put the bike on 5th gear and rotate the back tire by pushing the bike forward. Do not stand the bike up or you'll have an oily mess on the floor. The gap should measure 0.8 mm.

Replacing the Ignition Pickup Coil

You can buy a new ignition pickup coil from the dealer. You can also get it online at Bikebandit. It's going to cost about $73. It's Triumph part number T1290131. You may also need a new alternator cover gasket (part number T1260968). The ignition pickup coil is attached with two T30 torx screws. These screws are on tight. Be careful when taking the screws off as not to hit  the rotor below. Once the coil has loosened, it's a simple matter of unhooking it off the restraint and disconnecting it. Connect the new part and attached it with the original screws. Measure the ignition coil gap as noted earlier before replacing the cover.

Going Forward

This is the second time that I had to replace the ignition pickup coil in the seven years that I've owned my bike. I am going to buy an extra coil to make sure I have the part on hand if ever I need it (more than likely I will). Also, as part of my yearly bike check up I will make sure to check the ignition pick up coil resistance.