Suzuki DR250, DR350 Repair Manual 1990-1994

The 1990-1994 Suzuki DR250, DR350 repair manual by Clymer, covers the following dual-purpose models:

• Suzuki DR250, 1990-1993
• Suzuki DR250S, 1990-1994
• Suzuki DR350, 1990-1994
• Suzuki DR350S, 1990-1994

Book Excerpt: 1990-1994 Suzuki DR250, DR350 Repair Manual ENGINE LOWER END

This chapter describes service procedures for the following lower end components:

1. Crankcases.
2. Crankshaft.
3. Connecting rod.
4. Transmission (removal and installation).
5. Internal shift mechanism (removal and installation).
6. Balancer shaft.
7. Oil pump.
8. Starter reduction gears (models so equipped).

Prior to removing and disassembling the crankcase, clean the entire engine and frame with a good grade commercial degreaser, like Gunk or Bel-Ray engine degreaser or equivalent. It is easier to work on a clean engine you will do a better job.

TRANSMISSION AND INTERNAL SHIFT MECHANISM

TRANSMISSION OPERATION The basic transmission has 5 pairs of constantly meshed gears on the main shaft (A, Figure 1) and countershaft (B, Figure 1). Each pair of meshed gears gives one gear ratio. In each pair, one of the gears is locked to its shaft and always turns with it. The other gear is not locked to its shaft and can spin freely on it. Next to each free spinning gear is a third gear which is splined to the same shaft, always turning with it. This third gear can slide from side to side along the shaft splines. The side of the sliding gear and the free spinning gear have mating "dogs" (Figure 2 and "slots" (Figure 3). When the sliding gear moves up against the free spinning gear, the 2 gears are locked together, locking the free spinning gear to its shaft. Since both meshed main shaft and countershaft gears are now locked to their shafts, power is transmitted at that gear ratio.
TRANSMISSION OVERHAUL: REMOVAL/INSTALLATION Remove and install the transmission and internal shift mechanism as described under Crankcase Disassembly and Crankcase Assembly in Chapter Five.

Subject: 1990, 1991, 1992, 1993, 1994 Suzuki DR250, DR350 service, maintenance, repair. ISBN-10: 0892876026 | ISBN-13: 9780892876020 | Clymer M476