Since I was the editor for TDM Newsletter for a year, I was asked me to do a review of the the bike. I've never met such a versatile machine in my life, racking up 25,000 truly fun filled miles on my own TDM. This "140mph dirt bike" has taken me 7200 miles to Alaska, six times around the White Rim Trail, six times over Mosquito pass (13,400 foot pass - high­est pass in Colorado), on the insane Ele­phant Ride and over Georgia pass.

Some people bought the TDM to be a nice sport bike. Sport Bike Magazine compared it to the BMW R1100RS, Ducati 900, and the Moto Guzzi 1100 Sport. They compared top gear roll ons from 50 MPH and third gear roll ons from 50. 

In the real world, the TDM walks away from the other big twin sport bikes costing twice as much. The TDM is an 850cc 5-valve per cylinder parallel twin. The engine dynos out around 70 HP and 50 Lbs. of torque. The engine is re­markably smooth. I had a friend that rode it and claimed the engine was smoother than his 4 cylinder 1100. And being a big twin, it has lots of torque. After about 35 MPH, just stick it in high gear and go. One gear for 35 to 135.

So why does this report appear in Dual Sport News?? Well frankly I pick the TDM as my Dual sport bike over a BMW R100GS/PD. This requires some explaining. I tend to buy bikes by the numbers. Back in 1993, your typical "Street" bike had about 4 inches of wheel travel. The BMW R100GS/PD had 8 inches. The TDM had 6 inches. The TDM had a very up to date suspension compared to the BMW. Both ends of the bike were very controlled; the R100GS seemed very soft and frequently bottomed out. The TDM you sit "in" the bike where as the R100GS you are perched on top of the bike and stood tippy toe. The TDM was narrow to be able to slip between rocks and ride close to the side of the trail. The R100GS feels more like a grader going down the trail with those big jugs sticking out. You are very limited where you can place the bike on a trail. Plus the TDMs were selling for $5k and the BMWs were running $8.5K. The only problem was tires!

Tires about drove me crazy. The rims on the TDM were clearly set up for street rubber. At 110/80-18 up front and 150/70-17 in the rear, it was very difficult to find suitable dual sport tires. My first solution was to try an Avon AV24 Gripster on the front. This tire was designed to be a rear tire on small dual sports. It fit, but I had to run a tube. The rear was much more difficult. At the time, only a Pirelli MT60 was available in a 140/70-17. It worked reasonably well. Now with the introduction of the BMW R1100GS, they share the same rear rim size. I also have several choices for front tires, Pirelli MT70, MT60, Michelin Sirac, and the Avon Gripster. They all wear like iron and had the nice side effect of lighten­ing up the turning of the front end. The only thing I can figure is the less rubber contact makes it easier to turn at low speeds. On the rear I now run the Avon AV34 Gripster. Other good choices are Michelin T66, Pirelli MT80, or the Metezler En­duro 4. 

I found several wonderful add ons. First was the Givi Lug­gage. Now I don't purchase a bike unless I can attach these wonderful hard-sided bags. Second, a taller windshield from Clearview in Colorado. I got one of the first prototypes. Third was a center stand from Capitol Cycle. And Last was Crash bars, order from England. Together it makes the perfect bike for me.

My bike has had real problems. From my experiences with the newsletter, most TDMs are extremely reliable and mine is the exception. I have had problems with zero valves, had to have the head reworked at 10,000 miles; one fuel pump, three fork seals (I keep popping them when I get air born off jumps), and one voltage regulator. Even with all those problems, I would buy another one in a minute. I have never had so much fun with a bike in my life!

Originally Published: March 1999

{gallery}ARTICLES/Bikes/Yamaha-TDM850/Gallery{/gallery}