Wiseco Engine Rebuild Kits for 2-Stroke and 4-Stroke Dirt Bikes

January 18, 2018 / by Kevin Bailey

Wiseco's new engine rebuild kits offer everything you need for a bottom and top end rebuild in one box. Here we take a look at the components included, and the technology behind them.

So, the time has come for an engine rebuild. Hopefully it’s being done as a practice of proper maintenance, but for many it will be because of an engine failure. Whether the bottom end, top end, or both went out, the first step is to disassemble and inspect. After determining any damage done to engine cases or the cylinder, and arranging for those to be repaired/replaced, you’re faced with choosing what internal engine components to buy, where to get them, and how much the costs are going to add up.

Rebuilding a dirt bike engine is an involved job, requiring many parts to be replaced. Missing one seal or gasket can put the whole rebuild on hold.

A full engine rebuild is a serious job and requires a lot of parts to be replaced, especially in four-strokes. You have to think of bottom end bearings and seals, a crankshaft assembly, piston, rings, clips, wristpin, and the plethora of gaskets required for reassembly. If you’re doing this rebuild yourself, or having your local shop do the labor, chances are you don’t have a factory team budget to spend on parts. However, you know you want high-quality and durable parts because you don’t want to find yourself doing this again anytime soon.

You can source all the different parts you need from different vendors to find the best combination of quality and affordability. But, it can get frustrating when 6 different packages are coming from 6 different vendors at different times, and each one relies on the next for you to complete your rebuild.

Wiseco is one of the vendors that has been offering top end kits (including piston, rings, clips, gaskets, and seals) all in one box, under one part number for many years. Complete bottom end rebuild kits are another thing Wiseco offers with all necessary parts under one part number. So, it seemed like a no brainer to combine the top and bottom end kits to create a single-solution engine rebuild kit.

Top-end piston kits (left) and bottom-end kits (right) come together to create Wiseco engine rebuild kits.

Wiseco engine rebuild kits come with all parts needed to rebuild the bottom and top end, plus an hour meter to track critical maintenance intervals on your freshly rebuilt motor. The kits include:

  • Crankshaft assembly
  • OEM quality main bearings
  • All engine gaskets, seals, and O-rings
  • Wiseco standard series forged piston kit (piston, ring(s), pin, clips)
  • Cam chain (for four-strokes)
  • Hour meter with mounting bracket

2-stroke and 4-stroke

Whether your machine of choice is a 2-stroke or a 4-stroke, Wiseco can help you with your rebuild. 2-stroke Wiseco engine rebuild kits include everything listed above, along with a small-end needle bearing. 2-stroke fans often brag about the ability to rebuild their bikes so much cheaper than their 4-stroke counterparts, and they’ll have even more ammo for bragging now with these kits starting in the $400s.

A Wiseco 2-stroke engine rebuild kit includes all the parts you'll need for piston and crankshaft replacement, plus an hour meter to track your next maintenance intervals.

However, don’t abandon your 4-stroke yet. Many riders cringe (and rightfully so) at the thought of rebuilding their 4-stroke because of the costs associated, but Wiseco 4-stroke engine rebuild kits starting in the $600s takes a lot of sting off your rebuild project. They even include a new timing chain.

A Wiseco 4-stroke engine rebuild kit includes all the parts you'll need for piston and crankshaft replacement, including a cam chain and an hour meter.

Ease of ordering

Wiseco engine rebuild kits come with the listed parts boxed up in one box, and listed under one part number, which makes it nice to not have to worry about if you might’ve missed something when ordering.


Head over to wiseco.com to see options for your bike.

Quality performance

Ordering convenience doesn’t make a difference if the parts do not provide quality and reliability. Wiseco crankshafts are designed completely by in-house engineers, who determine all assembled dimensions, clearances, materials, and specifications. These specifications have been determined from R&D tests such as hand inspection, dyno, and failure analysis.

Once Wiseco cranks have been manufactured to exact specifications and are received by Wiseco, samples from each batch are inspected, measuring critical tolerances and dimensions to be sure the designs have been executed correctly. Major inspections done are for run-out and trueness. Crankshafts must operate within a small tolerance of run-out and trueness to last long and perform well.

Bearings are another critical point of inspection. Wiseco has worked to build relationships with bearing suppliers to provide a long lasting, low-friction, clean product. Debris in a bearing can lead to very fast wear, and Wiseco makes it a point to inspect batches of bearings for cleanliness and proper operation.

Wiseco crankshafts and bearings are manufactured and tested according to strict tolerances and clearances, including run-out and trueness. Crankshaft designs are also tested for 4 hours at WOT.

After going through hand inspection, executed crankshaft designs are dyno-tested at wide open throttle for 4 consecutive hours. This is a benchmark test, and crankshafts must pass this test to be deemed worthy of going to the end user.

Watch our crank R&D and inspection process.

The top end kits that come in the engine rebuild kits feature a classic Wiseco forged piston, which are designed forged, and machined completely in-house. Forged aluminum has an undeniable advantage in strength over cast pistons, thanks to the high tensile strength qualities of aluminum with aligned grain flow.

Read more about the forging process.

All Wiseco pistons are forged in-house from aluminum. Forging gives the alloy a better grain flow, which in turns creates more tensile strength, or the ability to bend without breaking. Some pistons may also come with ArmorGlide skirt coating, and some 2-stroke pistons may already exhaust bridge lubrication holes pre-drilled.

All pistons are machined on state-of-the-art CNC machine equipment, then hand finished and inspected for quality. The forged pistons come complete with wrist pin, clips, and high-performance rings.

Lastly, all gaskets and seals are made by OEM quality manufactures. Sealing components are not something to ever go cheap on, because no matter how high-quality your moving components are, if your engine is not sealing properly, it’s coming back apart.

Gaskets and seals provided in Wiseco engine rebuild kits are OEM quality, ensuring your freshly rebuilt engine is properly sealed.

Topics: NEW PRODUCTS, featured, Powersports, Tech

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