By Troy Siahaan
This week on Church of MO, we turn the clock back to 1998 and the Yamaha TDM 850. Long before Yamaha’s FZ-07 had the marketing department abuzz with the words “crossplane concept” in regards to its 270º firing order, the TDM 850 was already doing the same thing. In fact, it was doing it with more valves, too – five valves per cylinder instead of the four on the FZ-07. As for how it and the rest of the bike works, here’s Colin MacKellar from MO’s Dutch Desk (I didn’t know we had a Dutch Desk).
Yamaha TDM 850
By Colin MacKellar, Dutch Desk Aug. 20, 1998
Yamaha’s latest version of its five-year-old “Adventure Sports” model, the TDM 850, has undergone a transformation as subtle as a Mike Tyson proposition. The yellow and silver colour scheme adopted for this year makes the TDM one of the most striking motorcycles Yamaha has ever produced. Yamaha has taken a page out of the book of the Euro design houses that have resulted in such design “masterpieces” as the Bimota Mantra and Aprilia Moto 6.5. Yamaha has produced a bike whose looks match the image it is trying to project and raise the expectations of prospective owners. Perhaps these expectations have been raised a touch too high, as the TDM, whilst a blast to ride, still suffers from a few of the nagging problems that compromised its success in the past.
The most significant engineering change to the TDM can be found in the 10-valve 849cc vertical twin cylinder power plant. In a move to improve power delivery, the former 360-degree crank design has been replaced by a “big bang” configuration with 270-degree crank pin timing. The closer firing interval of the cylinders should result in …read more
Source:: Church Of MO Yamaha TDM 850