Yamaha Raptor 700R Engine Build - Bottom End Build
Welcome to the first part of our project to completely assemble the engine for a Yamaha Raptor 700R.
The complete series walks you through every step from two empty crankcase halves to a fully rebuilt engine that runs like new. Watch our Yamaha Raptor 700R engine build video above, and follow the steps below to build a Raptor ATV motor.
Tools and Parts Needed – Yamaha Raptor Engine Build
NOTE: For the entire engine build, you’ll need everything found in a well-stocked toolbox: ratchets and socket set, Allen set, wrenches, screwdrivers, pliers, torque wrench, etc. As for the bottom end portion, you’ll need the special tools listed above. Your parts list will vary depending on whether you’re completely rebuilding your Raptor’s engine, or just replacing certain worn OEM Yamaha Raptor 700R parts.
Yamaha Raptor 700R Engine Build: Installing the Bearings
Step 1. Thoroughly clean the inside of the two crankcase halves using parts cleaner and a microfiber towel. Remove every trace of oil, dirt and corrosion.
PRO TIP: You should still clean the crankcase even if it’s new, as there will be some residual contaminants from the Yamaha factory inside the casings.
Step 2. Chill the crankshaft bearing to contract it slightly by putting it in your freezer for at least an hour.
Step 3. Heat the right half of the crankcase to expand it slightly.
PRO TIP: Either heat the bearing housing in the crankcase with a blowtorch to about 250-degrees or put the crankcase in your oven, preheated to 275 degrees for about 20 minutes.
Step 4. Take the chilled crankshaft bearing and install it into the hot crankcase.
PRO TIP: The bearing should drop down right into place, but if it doesn’t fully seat, you’ll have to press it in the rest of the way. If you have to press the crankshaft bearing into place, support the outer side of the crankcase with a piece of wood to prevent it from delaminating as you press down on the bearing. Use a bearing driver that covers the bearing’s outer race, not one that presses on the inner race only, as it’ll damage the bearing.
Watch the clip below to see the crankshaft bearing installation segment of our Yamaha Raptor 700R engine build video.
Step 5. Press the five smaller crankcase bearings into the right half of the crankcase.
NOTE: Use bearing drivers that cover the bearings’ outer races.
Step 6. Press the four crankcase bearings into the left half of the crankcase.
NOTE: The output shaft bearing must be installed with its seal facing outward from the crankcase, and the upper counterbalance bearing has a separate seal that must be installed into the crankcase before the bearing itself.
Step 7. Apply red threadlocker to the bearing retainers’ T30 screws before installing them to ensure they remain locked in place once the engine is fully assembled. Torque the screws to 8 foot-pounds, then stake the edge of each screw with a hammer and punch.
Watch the clip below to see the crankcase bearings installation segment of our Yamaha Raptor 700R engine build video.
Yamaha Raptor 700R Engine Build: Installing the Crankshaft
Step 1. Chill the crankshaft assembly in your freezer for about an hour to contract it slightly.
Step 2. Lay a sheet of metal across the crankcase, and use a crankshaft puller to pull the crankshaft assembly into the left side of the crankcase.
PRO TIP: To determine that the crankshaft is pulled into the crankcase completely, use a feeler gauge to check that there’s no gap between the crankshaft bearing and the crankcase.
Step 3. Spray the crankshaft assembly with silicone spray to prevent it from rusting.
Watch the clip below to see the crankshaft installation segment of our Yamaha Raptor 700R engine build video.
Step 2. Take the main axle and install the gear pinions, washers, collars and circlips onto it. Oil each individual part with 20W50 Yamaha motorcycle oil as you install it.
PRO TIP: As you install them, check that each gear pinion spins freely and that there are no burrs or obstructions.
Step 3. Take the drive axle and install the gear pinions (fifth, third, fourth and second gears), washers, collars and circlips. Oil every individual part with 20W-50 Yamaha motorcycle oil as you install it.
Watch the clip below to see the transmission assembly segment of our Yamaha Raptor 700R engine build video.
Yamaha Raptor 700R Engine Build: Installing the Transmission
Step 1. Install the shifter bracket assembly into the left-side crankcase. First install the oil seal on the outside of the crankcase, then install the bracket and washer on the inside of the crankcase, followed by the washer and retaining circlip on the outside of the crankcase.
Step 2. Oil the left-side crankcase bearings with 20W50 Yamaha motorcycle oil.
Step 3. Install the assembled primary and output shafts into the left-side crankcase.
Step 4. Slide the first shift fork onto the output shaft, but don’t insert the shift fork’s guide into the crankcase just yet.
Step 5. Slide the second and third shift forks onto the primary shaft and output shaft respectively, but don’t insert shift forks’ guides into the left-side crankcase just yet.
Step 6. Install the shift cam.
Step 7. Lift the gear pinions slightly so the shift forks can slide into place, then slot the other end of the forks into the shift cam, and drop the shift forks’ guides into the left-side crankcase.
Watch the clip below to see the shift forks installation segment of our Yamaha Raptor 700R engine build video.
Step 8. Remove the circlip, and the uppermost gear pinion and washer from the output shaft, and install the counter axle assembly into the crankcase. Next, reinstall the gear pinion, washer and circlip.
Step 9. Install the two counterbalance weights into the left-side crankcase.
Watch the clip below to see the counter axle and counterbalance installation segment of our Yamaha Raptor 700R engine build video.
Yamaha Raptor 700R Engine Build: Prepping the Crankcase
Step 1. Install the oil strainer housing assembly into the right-side crankcase. Apply blue threadlocker to the assembly’s bolts to ensure they don’t get loose once the engine is fully assembled.
Step 2. Install the oil-passthrough dowel pin and O-ring into bottom of the left-side crankcase.
Step 3. Install the two dowel pins at either end of the left-side crankcase.
PRO TIP: To add strength to the crankcase once it’s assembled, you can also install two additional dowel pins to the crankcase in the locations shown above. The additional dowel pins are the same as those used at the base of the cylinder (part #17 in the exploded parts diagram at the top of this section).
Watch the clip below to see crankcase prepping segment of our Yamaha Raptor 700R engine build video.
Yamaha Raptor 700R Engine Build: Joining the Crankcase
Step 1. Thoroughly clean the mating surfaces of the two halves of the crankcase.
Step 2. Apply a thin bead of Yamabond liquid gasket to the mating surfaces of the right-side crankcase, then smear the Yamabond to ensure the mating surfaces are adequately covered.
Step 3. Oil the right-side crankcase bearings with 20W50 Yamaha motorcycle oil.
Step 4. Join the two crankcase halves together, then install the three bolts into the right-side of the crankcase and torque them to 8 foot-pounds. Apply red threadlocker to the rearmost bolt.
Step 5. Install the fourteen bolts into the right-side of the crankcase, and torque them to 8 foot-pounds.
Watch the clip below to see the crankcase joining segment of our Yamaha Raptor 700R engine build video.
Watch the complete Yamaha Raptor 700 engine build below. Highlights include:
- Crankshaft - 5:00
- Transmission - 14:21
- Clutch - 32:00
- Flywheel - 48:00
- Piston rings - 1:00:00
- Cylinder assembly - 1:12:00
- Valve Lapping - 1:15:00
- Head Assembly - 1:21:00
- Cam Timing - 1:28:00
- Valve Lash - 1:35:00