Ask The Pro - Answers

Drain On The System

Q My new Triumph Bonneville has a serious problem. If the battery falls below 12.6 volts, the ECU will not let it start. With a fully charged battery, if I stop/start more than two or three times in the city, my bike will not start again. The only way to start it is to remove the left side cover and bridge the solenoid terminals. I have just fitted a new battery, but no change. The dealer from whom I purchased the bike is selling battery chargers with new bikes, so obviously Triumph is aware of the problem.

I just took my bike to my local Triumph dealer, where it passed the following tests: clutch switch operation, earth strap continuity test, charge test and battery condition test. Next we drained the battery to 12.4v, connected a laboratory-standard regulated DC power supply and tried starting it at 12.4v, 12.5v and 12.55v: no start. At 12.6v, it started. This would seem to prove that the ECU is set to disable starting at a battery voltage less than 12.6v.

I passed this info onto Triumph, but I don't expect any joy. They won't acknowledge there is a problem, even though a fix is as simple as reprogramming the ECU. Since posting the details on a number of Australian forums, I have been contacted by riders from the USA and Canada, so it would appear to be a worldwide problem.Brett ParkerPerth, Australia

A _The official response from Triumph Motorcycles America, Ltd. is concise, but something less than satisfying to anyone with a dead Bonneville in the garage: "We have seen the symptom and are currently in the process of gathering factual evidence to determine whether it is a battery condition, a charging situation, a riding style or an ECM/tune item. Once enough data is collected, a proper resolution can then be decided."

In search of a more hands-on explanation, we dialed up Mickey Cohen, Chief Executive Officer, official spokesperson and repository of all knowledge at Mickey Cohen Motorsports ( in Placentia, California, caretakers of Triumph's U.S. press fleet. From his perspective, it all comes down to what your dealer did or didn't do after the bike came out of the crate.

"Unless the idle is set to at least 1000 rpm, the bike won't charge," Cohen says. "So if all you're doing are starts and stops around town, the battery isn't getting enough juice." And you can't always go by what the Bonneville's tachometer is telling you. "It's important to set the idle with Triumph's diagnostic tool or a reference tachometer connected to the coil wire. Like most stock units, the bike's tach may be optimistic."

Then there's the battery itself: "We've all heard about soaking a new battery," says Cohen. "If the dealer just pours acid in the battery and puts the battery in your bike, you'll have issues with it later. After being filled with acid, the battery needs to sit for an hour before it's sealed. After that, Triumph recommends charging a fresh Bonneville battery with a Yuasa 12-volt automatic charger until the green light comes on, which usually takes about 30 minutes."

Urban riding can suck the life out of you and your Bonneville, even if everything is perfect. So hook up the Battery Tender tonight and head up to Port Denison for the weekend. It'll do the both of you a world of good._

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