March 2011

Learn how to: repair a Ski-Doo 600 SDI that keeps shutting down, use battery tendrs, picking the right rage cage and checking the fuel delivery of a '98 Cat ZR 600 EFI.

By AmSnow staff

Published: March 9, 2011

Some folks have had starter module problems, but the key to easy running is a good battery with proper voltage going to the ECU

Ski-Doo 600 SDI shutting down
Q: Recently my sled just started shutting off when I was riding it. It happened not once but several times. There is a starter module that sits on top of the battery. You can see what it looks like in the Nov. 2010 issue, p. 49, top right. If this was going bad, will it make the sled stop? When this happened to me I heard a noise coming from that module and when I tapped it the noise stopped and the sled would start. I replaced it and the sled did not do it again. However, I am not convinced this was necessarily the entire problem and would like some ideas on what you think. - overthehillsgang

A:Ski-Doo owners have had, and continue to have problems with this module. When running most SDI sleds it is important to have an excellent battery and proper voltage going to the ECU. Always check the battery condition and cable connections for corrosion or loose ends. Sometimes battery cable ends will get coated with a dark chalky substance that will insulate the cable end from the battery terminal so make sure you clean all the ends and verify voltage. Try unplugging all connectors and using dielectric grease and make sure all the small pins are in good condition. Another area where the Ski-Doo’s have had issues is the handlebar switch shorting out or getting corroded. – Dyna-tek Racing

There’s a right way to replace the trailing arm on a 2002 Viper and the last piece to attach is the lower bolt on the shock.

2002 Yamaha SX Viper help
Q:I need help replacing the pivot arm on this sled. I have the shock in, but can’t get the bottom two bolts in for the life of me. Any help or ideas? It might be called the swing arm, or w-arm also. – mac3256

A:If you are referring to the trailing arm, the last item to mount will be the lower bolt for the shock. Everything else needs to be bolted in first. Make sure the sled is suspended in the air with the skis off the ground so you can cycle the trailing arm to align that lower shock bolt. – Dyna-tek Racing

Battery Tenders
Q:I have a 2004 Ski-Doo MXZ 800 H.O. with electric start. This is the first year I am going to park it outside. I wanted to put a battery tender on it so I wouldn’t have any problems. Can I leave a tender on it while it’s outside in the elements? I believe that I can leave the charger inside and use extensions to run to the sled. Looking for some input. What type, name brand, is this feasible? Or should I just charge it every so often? - Pemone

A:The best scenario for battery storage is for the battery to be left on a peak charger, often called an “automatic” charger. Automotive chargers are usually not a peak charger and will damage a battery if left on more than 24 hours. The storage temperature of the battery is not a concern if the battery is kept at least at a 75% charge. Most automatic chargers are not completely weatherproof, but are resistant to the elements. These automatic chargers come in different amp ratings. The price goes up considerably with higher amp ratings. Lower amp ratings will not charge a dead battery very quickly (2-3 days), but will perform the same storage protection that a higher amp charger will. UASA, C-TEC, and Battery Tender are the more popular chargers with varying features for different charging applications. But for storage, the importance is that the charger is “automatic”. - Straightline Performance

Rage Cage
Q:I recently purchased a set of Boyesen Rage Cages for my 2007 Ski-Doo MXZ 600 H.O. The instructions say to jet down one size. If the reeds increase airflow, shouldn’t I have to jet up? Conversely, if I need to jet down, doesn’t that mean that airflow has decreased? Did I waste my money? – maxxterminator

A:No, you did not waste your money. If a performance set of reeds is doing its job correctly, air velocity through the carb venturi will be increased and create more vacuum over the needle jet, drawing more fuel out of the float bowl. Your stock 600 might already be jetted down one size from the factory anyway, but with the increased air flow and speed over the jet tube it will pull in more fuel. So, jetting down is usually recommended. With today’s reformulated fuels you may want to leave the jetting stock and do some plug readings first and then jet down after that. – Dyna-tek Racing

Some auto valve fuel pumps, as used on the 550F, will stick closed, but bad fuel is a more common problem, especially as ethanol use has become more widespread.

Ski-Doo 550F won’t remain running
Q:My 2010 Ski-Doo REV XP 550F snowmobile runs for a minute or two and then shuts off. It will shut down slowly and then not restart. However, if you let it sit overnight it will re-fire and run like nothing is wrong. But then, after a few minutes, it will shut down again. I checked the plugs and spark is looking good. Ethanol fuel is being used and it makes me wonder if moisture is getting into the fuel pump and making that valve stick closed.

A:Always start with the basics, spark, compression and fuel delivery. Ski-Doo has been using auto valve fuel pumps for a while now and in some cold weather they will stick closed and limit the fuel to the carbs. It is also possible you may be experiencing phase separation on your ethanol blended fuel. Here the water or ethanol separates and settles on the bottom of the fuel tank. Try draining all the fuel and using fresh stuff. – Dyna-tek Racing

98 Arctic Cat ZR600 EFI starts hard
Q:I have a 1998 ZR600 EFI and it starts very hard outside in the cold. It takes 15 to 20 pulls, but in a heated garage it starts on the first pull! It seems like the computer isn’t enriching it on initial start-up to give it the extra fuel for cold starting. I am thinking it is the temp sending unit, but want to be sure. How can I confirm this? Plus any ideas of what I can check before I have to check the CPU? Also this sled has a new top-end and plenty of compression in both cylinders. It runs great after initial start-up.

A:The first thing we check is fuel delivery pressure at the rail. You can tee in a pressure gauge that reads around 0 to 60 psi and install it on the rail where the rubber fuel line attaches to the injector rail. Our experience usually has shown that on the first pull you get 10 to 20 psi. On the second pull you get 20+ psi and with the motor running it should regulate around 40 psi. There are several things that could be causing your issue. First, the fuel filter or screen may be plugged. Second, and usually the most common, is that the stator has failed. When cranking to start it, it will have low voltage delivery to the fuel pump and cause low fuel pressure. A bad fuel pressure regulator can cause this issue also. The best thing to do is have the right tools to diagnose the problem or you may be spending a lot of money on parts that weren’t needed. It is better to spend money on tools you can use the rest of your life. – Dyna-tek Racing

Powercommander or ECU re-map?
Q:What would be best for a stock Arctic Cat Crossfire running on 94 octane for trail riding? I do some drag racing too. Should I get a Powercommander or an ECU re-map? – rotax583

A:If your budget allows, I would opt for the Powercommander. It is an excellent tuning tool to build a good performance sled trail or racer. If you have the ECU reprogrammed then it would be hard to trail ride. With a race box on the sled there is too much ignition timing. For the summer grass drags you can install a timing key and finish tuning it with the Powercommander. – Dyna-tek Racing

Editors Note: Each issue we take questions from our “Ask The Experts” forum at www.AmSnow.com, to feature in the magazine. Our industry experts consist of staff from Straightline Performance, Speedwerx, Starting Line Products, Dyna-Tek Racing, Aaen Performance, Hauck Powersports, and our own editorial staff. If you have a question you can’t get answered anywhere else, try our Ask The Experts forum and we’ll get you started down the right path.