I just have to spout out about this topic because it is one of my pet peeves with dealerships and garages. Feel free to ignore this if you like!
"Rattle wrenches" or impact wrenches were invented to LOOSEN stuck bolts - and they do an incredibly good job when used as intended.
They work by imparting sudden sharp shocks in a counterclockwise direction in only a tiny fraction of a circle to the nut or bolt they are loosening - this breaks free the (usually) corrosion and other stuff making the bolt stick.
They use special sockets which are hardened so they don't shatter and injure the user - all of the sockets are six point (better grip on the nut/bolt) and they are BLACK. Regular hand sockets are SILVER. You can use an impact socket with a hand wrench but NEVER use a hand socket with an impact wrench - it may shatter and pepper you with
Just about every impact wrench "says" it can be used for tightening fasteners - usually there will be a switch for 3-4 levels of torque - these switches are VERY approximate and NO WAY come near the accuracy of a torque wrench. Dealers and garages like them because they are fast.
As I mentioned in "Tool Time" if you buy a torque wrench this is one of the ways you can do a better job working on your machines than the dealers. I have NEVER seen a dealer or garage mechanic use a torque wrench - NEVER.
As an aside - the absolute best way to measure fastener tension is to use a device which measures how much the bolt is streched when the nut is applied - this is how nuts and bolts work. REAL racers use this method to tighten critical bolts. Here is an example:
http://store.summitracing.com/egnsearch ... 6&D=303846
IF you are going to use an impact wrench to tighten a fastener it should be a hardened steel nut and a hardened steel bolt (or opening).
The Yamaha oil drain bolt unfortunately is a piece of cheesy mild steel.
Furthermore, it is threaded into aluminum alloy.
I found this out when I ran into the same situation as GPSnut - I did my first oil change at 36 miles -and used a torque wrench to fasten the bolt, my second at 604 - a twelve point socket started to round over the bolt's head. Luckily I had a six point socket that fit and worked. Next time I will install a proper six point nut and ground flat washer in place of the stock cheesy bolt-built in washer, and lap the copper crush washer flat.
The next time you go to your dealer go to the service bay and listen - if you hear several impact wrenches going at the same time I will bet you anything you want they are cutting corners. If you Must take your vehicle to a dealer/garage do yourself a favor and buy a set of sockets and a 3/8" torque wrench. When you get home loosen all the fasteners you can that they needed to undo to get the job done and tighten them to the specs in the Yamaha Shop Manual.
I will finish by a personal example - a long time ago (I am an old coot), I had an '84 Toyota Celica that had a tire burst when it hit a rock. I took it to a tire place and had them install a new one. The proper torque was
94 ft-lbs. When I got home - THREE of the lug nuts could be turned by hand - meaning only ONE lug nut was holding on the wheel :shock:
the other was torqued past 200ft-lbs. Thanks for listening to my rant if you have read to this point :lol:
Get a Yamaha shop manual and try doing as much maintence as you feel comfortable with - at first that won't be much - I remeber my terror when I first replaces the brake pads on my GL1200 - but if you work carefully, check your work THREE TIMES, and test it out on a safe piece of open road you will quickly gain confidence, save tons of money, and have the satisfaction that "I did it myself".