How to fix the snatchy throttle response on your Yamaha FZ-1

Several FZ1 owners I’ve spoken to have complained about a nasty fuel injection snatch on the transition from a closed throttle to a slightly open one. Coming into a corner, for example, they might be leaned right over and go to get back on the gas, but they’re finding it impossible to get the throttle open without a big jerky power spike to the rear wheel. Annoying and dangerous - but fixable.

It turns out it’s an emissions thing - another example of how ever-tightening environmental legislation is making it tough for manufacturers to keep delivering bikes that are faster, lighter and more powerful than last year’s. The FZ1 EFI system cuts fuel completely on a closed throttle as the revs descend, then adds in a trickle when the revs get down to 4000rpm to support the idle. A carbed engine, by comparison, trickles enough fuel to idle on throughout the whole rev range on a closed throttle.

When the throttle is opened again, it takes a split second to squirt the fuel down into the combustion chamber, where it arrives with a sudden burst of power. This split second causes the hesitation and snatch you feel when riding the bike. Why is the fuel cut? It’s an emissions requirement in the US on all vehicles, in order to reduce the levels of unburned fuel and combustion gases in the exhaust. The Fazer just suffers worse than most for it.

Thankfully the issue is now well understood by the aftermarket - and one product is proving particularly effective in solving the issue, simply by reinstating a small trickle of fuel back into the cylinders on a closed throttle. Ivan’s Fuel Cut Eliminator (FCE) has been recently tested by BIKE magazine on their FZ1N long-termer and results have been spot-on. No more snatch, problem solved. It’s a little magic box that cuts into the wiring near the bike’s ECU. Ivan’s website also has dyno graphs to show the FCE adds around 10hp to the bike’s midrange, which is always a tasty bonus.

For around US$200, plus an hour of your time to fit it, it seems like a no-brainer for current Fazer owners, and it might put the bike back on the desirability list for those initally put off by the flaw. Just don’t tell Al Gore what you’re doing.