Shop Talk | Tech Questions & Answers

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Guru Voodoo

**It’s a good thing today’s bikes are such great works of technology. Otherwise, I would be bugging you all the time, and of course, the complicated nature of their systems just adds to your exalted status as a motorcycle guru.

A couple of quick questions:

Both my Nomad 1500 and Drifter 1500 use standard NGK spark plugs (DPR6EA-9). What is your take on platinum and iridium plugs—are they worth the extra money?

The other question is about EFI: My Nomad 1500 is one of the early models with fuel injection (2000). I was surprised the other day when I somehow flooded it trying to start it in the morning. (I had to take the spark plugs out, clean and dry them to get it to start.) I should also mention that it smells like it’s running a bit rich if I let it idle very long. I don’t think that’s ever happened to me before with a fuel-injected bike. Any steps I should take to quell the light aroma of gas at idle and keep from flooding it again?**

Doug Mercer
Via email

_As far as the plugs go, the high zoot models do last longer, but whether they are worth the extra dough when the bike is in a relatively low state of tune is debatable. For my money they aren’t.

When an EFI-equipped bike floods, or more correctly develops a rich condition at small throttle openings, it usually indicates a sensor or mapping problem. Very often, it’s the temp or ambient air sensor that’s failing or occasionally the O2 sensor, if your bike has one. When they fail, the “limp home” side of the map reverts to a rich condition to prevent overheating or lean misfire damage. I’ve seen a few of them do just that and carbon the valves so badly the engine lost compression. Alternatively, the bike might be mapped too rich. In any event, a few minutes pulling codes should prove worthwhile._


I ride a 2008 Yamaha 1300 V-Star Tourer, and am planning on installing Vance and Hines 2-into-1 pipes and a Barons BAK with the inch and a half K&N air filter. I was wondering if you heard about the new Cobra Fi2000 PowrPro, which auto tunes up to 80 times per second and eliminates the need for the dyno. This would also allow you to add a part at a time if it does as it says (auto adjusts). Also, Dynojet makes a Power Commander III USB with attachment for auto tune. Which is better for performance or are they essentially the same? Also, what is the difference between opened and closed loop when it comes to fuel management?**

Robert V.
Via email

_I’ve haven’t tried an Fi2000 PowrPro yet (Cobra just released this product; see an informational video on, but based on past experience my guess is that it’ll do exactly what Cobra claims it will, though whether it will completely eliminate the need for a dyno remains to be seen. What you’re doing is a tried-and-true bolt on pipe/air box mod, so no need to be overly concerned; almost anything you use will work fine, though the PowrPro may make it easier if you decide to change things around down the road. As far as performance goes, it’s six of one, half dozen of the other. The pipe and air kit predicate performance, and the cheater box just makes sure the mapping is correct.

As to the difference between closed and open loop; closed loop EFI systems use oxygen sensors to monitor the amount of oxygen in the exhaust gas—the sensors relay the information to the ECU, (engine control unit) which adjusts the mixture accordingly.

Open loop EFI systems use a fixed map. There are no O2 sensors in the system so the ECU cannot adjust the mixture based on the exhaust gas makeup.  It can only supply fuel based on predetermined parameters programmed into the ECU._

**No Easy Answer

I’m looking for a solution to an electrical gremlin that’s affecting my 2002 Suzuki Intruder LC. Last year, during a ride it suddenly began to misfire. The dash lights started acting weird and it was as if one cylinder had shut down. It backfired and finally died. I turned off the ignition and turned it back on, and there was nothing. I wiggled some wires near the main fuse and suddenly it started again. A little later, I tried it again and it was dead as a stone. Again, I wiggled wires and it came back on.

I had the system checked and all wiring connections gone over and the mechanic seemed to think it was fixed. The other day it did it again and now, it won’t even turn over. I just had the battery checked and it is fine. The ignition switch has been tested and it’s fine. Any ideas?**

John J
Via email

_Unfortunately John, in this case there are no simple “replace the connector” type answers, but on the bright side, a total, permanent electrical failure is much easier to track down and repair than an intermittent one.

Since the battery and switch are good, it’s obvious that the problem lays in the wiring that carries battery current to the switch. To figure out where, start at the battery, and using a test light or voltmeter along with a wiring diagram, trace the current path from the battery to the switch. Somewhere along that path, you’re going to find a bad connection or component._