YZ90 (National Engine) Stroker

Motorcycles Yamaha Kit

Please call to order 608-842-0680

Availability: In stock.

Regular Price: $1,725.00

Special Price: $1,475.00


Quick Overview

YZ90 Stroker Specifications:
Fits 2001-2008 YZ80 and YZ85


Choose option:

Send us your engine and get a 90cc stroker kit instead

Spare YZ105/112 top end for later use in supermini classes (prices vary by year): $ 1400.00



Product Description

Bore: No

Stroke: Yes

Actual Displacement = 89.18cc

Engine Modifications Required:

Cylinder: De-Bore, Port and Replate with Ceramic Nickel Bore coating.

Power Valves: N/A

Head: Rechamber to work with the stroker crank. 100 octane suggested for most conditions.

Crankshaft: Stroked and balanced.

Crankcase: Modified to clear stroker crank. Additional case mods needed to clear YZ112 Piston.

Blueprint: Calculate deck height, squish clearance, trapped volume, port timing and compression ratio and list on your perminant Spec-Sheet.

Notes: This kit requires you to send us your entire engine for modification, with kickstarter and shifter.

Notes: This is a national level engine package. The power delivery is designed to build confidence for young riders. It delivers torque and hook up that are un-paralleled in the industry that carrys to a screaming top end pull. This kit just makes all riders faster because it is smooth, easy to ride, and does not fall off the pipe like other engines out there.

Notes: This is the same bottom end as our YZ105 and YZ112 kits. We can also build you a YZ105/112 top end for later use in the supermini classes.

Notes: Prices listed are to install stroker kit parts in good condition engine. Should your engine need rebuild parts there will be additional charges. We will call for approval before we install any parts that will have additional charges. (example: rod kit, mains, main seals, trans parts)


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