Rebuild Motorcycle Engine Step by Step

Today we’re preparing to do a Motorcycle Engine Rebuild and we’re starting off using an Impact Driver to remove the Engine Case. Screws We’ll use the Impact driver to loosen all of the crankcase screws. This is the left side cover and holds the Stator Coil. The Rotor and Stator generate AC, alternating current carried by the three wires here for our charging and operating current.

The Alternating Current runs through the Rectifier which converts it to DC or Direct Current Most motorcycles have a separate lighting coil, but on this particular off-road model lights and the lighting coil, it’s self are not installed.

The Green Wire you see here with the small screw is the Neutral Sensor.

Wire Here is another look at the Stator Coil and Rotor. A Compressor and Air Impact tool make quick work of removing the Rotor Bolt. We need to start the threads of the puller by hand. To be sure there is no cross-threading that would permanently damage both the Rotor and the Puller With the Rotor removed. We can see that the back side is also a Starter Clutch. The small electric 12 Volt starter motor turns the small gear. The small gear then turns the larger Starter Gear. When the Starter Gear is driving, the Rotor, the Rollers are clamped onto the Crankshaft Gear and Hub As soon as the Engine starts, the rotational speed and load releases, the Rollers and centrifugal force keeps them pulled up and away from the crankshaft gear. We remove the Woodruff Key and gears the starter pinion shaft

Now we’re ready to turn this assembly over and disassemble the other side.
Working now on the Right Side, we’ll remove the Crankcase cover and expose the Clutch and Oil Pump Using the same Impact screwdriver we loosen and remove the case screws.

We remove the Oil Filter, Cover and Filter. We remove the Electric Starter Light tapping around the cover with a plastic mallet and the cover is easily removed. This is the Clutch Assembly we’re looking at the Clutch Pressure. Plate Basket, Friction Disc and Clutch Plates We’ll start by removing the Springs that are held in-place by these 6mm bolts. I like to remove the tension on the screws evenly.

The Clutch Pressure Plate comes off. First, then, the friction disc and clutch plates We’ll cover these parts and how they work in a separate video
The locking tabs for the nut are opened so that we can remove the large Basket Nut.

Using the Clutch Holding Tool, we can use our Air Impact Wrench to remove our Basket Nut. We can then remove the Inner Clutch Hub and the Clutch Basket itself. The locking tabs are opened and the correct socket chosen.

We pull the sparkplug from the cylinder head so that we can rotate the crankshaft and gain access to the Oil Pump screws Using the Air Impact Wrench, the crankshaft and engine balancer shaft nuts are removed, The Woodruff Key is removed from the Crankshaft. We pull the Shifter Shaft and the attached Detent the Centering Spring Guide and Ratchet Assembly. Removing the Oil Pump screws is easier now and we work through the holes in the drive gear. We lift the Oil Pump away and remove the displacement. Rotor crankshaft gear is now removed.

We position our engine in the Engine, Stand so that access to the cylinder, head and cylinders is easily
This repositioning demonstrates why this economical, DIY Motorcycle Engine Stand, helps in every phase of the tear down. We remove the Camshaft Sprocket nut and then the sprocket itself. The cam chain is pulled down through the cylinder. The cam chain tensioner is removed. We reposition the engine in our stand to access the head bolts, The head bolts are loosened evenly and carefully so as not to warp the head.


You want to remove that tension about the same on each bolt as you go. Bolts are removed, along with their special Copper washers. It’S very important. These Copper washers are a soft metal that provides sealing for the engine oil

Two 8mm bolts along the side removed The head, just lifts off and exposes the head gasket locating dowels and the special sealing dowels that carry oil to the top end. The small 6mm bolts are loosened and removed from the base of the cylinder With the small bolts removed.

We can lift the cylinder off the case and piston The rubber cam chain guides pull out too. A quick look at the cylinder bore shows, wear and vertical scratches, which usually means dirty or contaminated oil and improper lubrication. We position the engine in our engine stand, so we can access the Center crankcase screws. This is the next step before splitting the case.
We remove the cam chain guide Back to our Impact driver and remove all of the case screws.

A soft rubber hammer helps to loosen the case halves. A flat tip screwdriver in the factory spaces finishes the separation. We can now lift off the left case. Half The right case, half contains the transmission balancer crankshaft shift drum, connecting rod and the piston. We start by pulling the Shift Fork Shafts so that we can move the transmission shafts.

Turning the engine balancer allows the transmission to pull up and out of the right case, half The transmission is removed, The crankshaft is then removed. Then the engine balancer Thanks for watching. We hope that you liked what we’ve shown you and will Like Share and others Join us next time. We’ll show you, the transmission and a working model of the shifting motions.

We’Ll also cover the Clutch and pushers used on this and many other models..


Perform general repair and maintenance work on motorcycles Assist with washing and detailing motorbikes Diagnose problems with motorbike transmissions Troubleshoot issues with knocking and shimmying Handle maintenance tasks on fuel lines and tires Perform fluid change tasks and ensure that bolts are lubricated properly Confer with customers to determine problems with motorcycles to determine issues Start motorbikes in order to assess impending problems Inspect motorbikes to figure out repair needs Work with apprentices and mechanics in order to diagnose and fix problems Perform both preventative and regular maintenance on motorcycles and mopeds Select appropriate tools to handle repair procedures

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