Chapter Four; Engine; Engine Number Identification - Yamaha MM700A Manual

This chapter describes service procedures for the
The engine is equipped with ball-type main crankshaft
bearings, except at the flywheel end, which is supported
by a roller bearing. Needle bearings are located in both
ends of the connecting rods. Crankshaft components are
available as individual parts. However, other than replac-
ing the outer seals, it is recommended that the crankshaft
work be entrusted to a dealership or other competent en-
This chapter provides routine top-end service as well as
crankcase disassembly and crankshaft inspection. Work
on the snowmobile engine requires considerable mechan-
ical ability. You should carefully consider your own capa-
bilities before attempting any operation involving major
disassembly of the engine.
Much of the labor charge for dealership repairs involves
the removal and disassembly of other parts to reach the
defective component. Even if you decide not to tackle the
entire engine overhaul after studying the text and illustra-
tions i n this chapter, it can be less expensive to perform
the preliminary operations and then taking the engine to
the dealership. Since dealerships have lengthy waiting

Chapter Four

Engine

lists for service (especially during the fall and winter sea-
son), this practice can reduce the time a unit is in the shop.
If much of the preliminary work is done, the repairs can be
scheduled and performed much quicker.
General engine specifications are listed in Table 1. En-
gine service specifications are listed in Table 2 and Table
3. Tables 1-4 are at the end of this chapter.

ENGINE NUMBER IDENTIFICATION

The engine serial number is stamped into the right end
of the engine crankcase (Figure 1). Refer to Table 1 for
model listing and original engine application.
Record the serial numbers and model numbers that are
applicable to the machine and have these numbers when
ordering parts. Always order parts by year, model and se-
rial number. If possible, compare the old parts with the
new ones before purchasing them. If the parts are not
alike, determine the reason for the difference and insist on
assurance that the new part is correct and will fit.
For convenience, record all the frame and engine identi-
fication numbers in the front of this book.