Wednesday, November 25, 2009



Hi Dr. Phil,
I have some comments and questions relating to my most recent bike purchase. I hadn't planned to get myself a DR-Z400 since the guys I ride with have DR650s but it was such a bargain I couldn't pass it up. Anyway, my first job was to replace the 14T front sprocket with a 15T one to reduce the revs on the highway. Whilst this has made a bit of difference I was wondering if the bike could handle two less teeth on the back sprocket? We don't do any seriously steep stuff so I'm thinking the taller gearing shouldn't cause any major problems. Next job was to get a decent sized fuel tank and the 17L Safari tank was just the ticket. It actually holds 20L from empty so that gives the bike a great range. Here comes my next question, what difference the fuel type? I've run the bike on both standard unleaded and 95+ octane and can't say that I've noticed any difference. Am I missing something or just not riding hard enough to pick a difference? When I got the bike it had been de-restricted and I found the exhaust note a bit loud for my old ears. So I put some muffler packing in the back half of the stock muffler and it has made a bit of difference but I think it's still a bit on the noisy side. I was thinking about one of the Ballards “quiet” end pipes. I'm assuming they work by restricting the gas flow? If so will I need to re-work the carby to suit? We are planning to do the Flinders Ranges in autumn next year so I've fitted a B&B rack to the back which looks very neat. You guys have recommended Motzo Tractionator tyres for the ranges but none of my local dealers stock them. Can you recommend anything else that would handle the trip? Finally I've also had to change the battery. After only 15 months life it no longer holds a charge. What's going on, are they too fragile for offroad work, pity if that's the case. I've had the bike for six months now and only had one minor get off. The trip to the doctor cost me more than the repair to the bike! Other than that having a great time. Guess that's it for now, thanks for a great mag.
-- Dave Westmoreland, via

Thanks for your email, Dave. Yes, your bike will easily handle two less teeth on the rear sprocket, though just confirm you like the modified gearing prior to doing a big multi-day ride with it. Don’t cheap-out with your choice of fuel quality! Run 98 whenever you can, when it’s not available use 95 or 92 but switch back to 98 afterwards. Most tech gurus agree BP Ultimate 98 octane is better than the rest. You may not be able to notice the difference between 98 and 92 or 91 but you will after you’re more used to your bike, and besides, your engine WILL notice it even if you don’t.  Contact Motoz Australia direct on 02 9905 5155, mention you’ve contacted us and see what they can offer about getting tyres to you direct or through one of your dealers. If you go the quiet end pipe in the muffler, just ask Ballard's when you buy it, as they will know what jetting specs are recommended. Unfortunately we’ve had many letters about dodgy batteries in DR-Zs, we even had a dead battery on a new bike that was delivered to us for testing! As far as we know, Suzuki will replace batteries for free if the bike is still under warranty. Certainly the DR-Z battery is older technology compared to today’s modern sealed-cell batteries used on most late-model 450cc enduro machines. A replacement battery is all well and good, but that won’t help a rider when they are on the trail without a kick-starter and with a flat or dead battery!! I don’t believe the battery is too fragile, perhaps we’re looking at a quality-control issue at the battery production plant. Enjoy your ride!
-- Dr Phil,

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