Motocross
Yamaha YZ85
The junior race bike most Australian kids grow up on. Standard and big wheel (LW) versions, a bulletproof two stroke and the cheapest parts in the class. Sold in Australia from 2002 to 2026, 25 model years.
About the Yamaha YZ85
The YZ85 is the bike in the 85cc class that dealers always have parts for and that every club has ten of. It got a proper update in 2019 with a power valve engine and a new frame, and again in 2021 and 2022 with a new fork and bodywork. The LW big wheel version adds a 19 inch front and 16 inch rear for taller kids.
It suits a junior from about 11 to 15 moving up from a 65, or a lightweight rider who wants a cheap and simple race bike. The KTM 85 SX has the edge on outright speed but the Yamaha is easier to ride, easier to own and cheaper used.
What changed by year
- 2002 to 2018
- The original bike: no power valve, simple and reliable. Plenty around and cheap, but noticeably slower than the 2019 onwards.
- 2019 onwards
- Power valve (YPVS) engine, new frame and suspension, much stronger mid range. Later years brought a new fork and updated bodywork. The bike to buy for a racing junior.
Servicing a YZ85
Premix at 32:1 to 40:1, gearbox oil every 5 to 10 hours (about 500 ml), air filter every ride. An 85 lives at full throttle, so a racing junior wants rings every 10 to 15 hours and a piston every 20 to 30. Clean the power valve on the 2019 onwards bikes at every top end.
Check the spokes and the chain adjusters often, because these bikes get ridden hard and adjusted rarely. Grease the linkage and steering head every few months.
Parts that fit a YZ85
Motul 800 2T 4L$179.90 · members $152.92
H/D Tube 275/300-17$32.00 · members $27.20
Tube Vee Rubber 275/300-17$16.90 · members $14.36
Motul Transoil Expert 10W40 4L$99.99 · members $84.99
Tube 250/275-17$16.95 · members $14.41
Tube Uhd 300/325-16$35.00 · members $29.75
Tube 225/250-17$16.90 · members $14.36
Standard Tube 300/325-16$16.90 · members $14.36
DID 428 Fj XRing Chain - Gold$148.95 · members $126.61
SPP Alloy Fork Support Adj$34.95 · members $29.71
Maxima Cool-Aide Pre Mixed Note..$19.95 · members $16.96
Tube 325/350-16$17.90 · members $15.21
Buying a used Yamaha YZ85
Buy a bike that a family raced and serviced, with receipts. A compression test tells you most of what you need to know about the engine. Check the frame around the footpeg mounts, the subframe and the radiators for crash damage. Most YZ85s have been down many times; the question is whether anything is bent.
The 2019 onwards bikes hold their value well. Recent sold prices are on the Marketplace page linked below.
Used Yamaha YZ85s for sale
None listed right now. Selling one? List it free →
Yamaha YZ85 known issues
Top ends
The cost of an 85. Budget for one a season if the kid races.
Clutch and gearbox
Learner riders are hard on clutches. Feel for a notchy lever and check the gearbox oil for metal.
Crash damage
Bent bars, subframes and radiators are common. Check the bike is straight before worrying about the plastics.
Yamaha YZ85 questions
- What age is a YZ85 for?
- Roughly 11 to 15 depending on size and experience. The LW big wheel version suits taller kids.
- YZ85 or YZ85LW?
- Same bike with bigger wheels on the LW. Pick by the rider height and the class they race.
- How often does a YZ85 need a top end?
- Rings every 10 to 15 hours and a piston every 20 to 30 for a race bike.
- What premix ratio does a YZ85 use?
- 32:1 to 40:1 with a good full synthetic two stroke oil.