Pit Bike YX90 Engine - MANUAL
SPEC:
- Engine CC = 86cc.
- Gearbox = 4 speed all up.
- Clutch Type = Manual
- Ignition = Large road flywheel kit with lighting circuit.
- Wiring Harness Connector Type = Block type
Optional Extra:
- Light weight ignition 520g outer rotor kit fitted.
Item Includes (refer to item picture):
- 1x YX90 Engine
- 1x Manifold and Fittings
PLEASE NOTE
- MINIMAL WARRENTY IS GIVEN. BUYER MUST OBIDE BY TERMS AND CONDTIONS AND RUNNING IN PROCESS
YX90 Engine - MANUAL
WELCOME TO YOUR NEW ENGINE
Before you use, please note the following:
- Your valve clearances have been set by us before dispatch.
- If using a YX Engine then the shipping oil must be drained and replaced before use, we recommend Putoline DX4 10W/40 from our store.
- Correct wiring loom & cdi is used for the type of ignition fitted.
- Exhaust and manifold gaskets are fitted.
- Correct carb & jetting must be used for the engine, failure to do so will result in kickstart gear and shaft damage, only use recommended carbs & data on this sheet.
Engine Data:
- Oil Level – on most pit bike engines they hold 700 – 750ml of oil, please ensure engine is level and flat when using the appropriate measuring device. If using a dipstick then remove, clean and screw all the way back in, then remove to look at the oil level reading. If using a sight glass, then the oil level must be around halfway.
- Valve Clearances – all 2 valve engines use the same valve clearance settings (engine cold) Inlet = 0.10mm & Exhaust = 0.15mm.
If using a DAYTONA 190 4V then the settings are Inlet = 0.05mm & Exhaust = 0.07mm.
If you are unsure on how to time your engine correctly and how to set your valve clearances, then please follow a YouTube tutorial.
Installation:
- We would always recommend installation by a professional qualified person.
- Please ensure the engine breather pipe is fitted to the crank case and the blanking plug removed (if fitted). Ensure there is no kinks in the breather hose and check you can feel the gases escaping when the engine is running.
Oil Coolers:
- We would always recommend using an oil cooler when possible. Using an oil cooler will keep the engine below 190 degrees, even though it is an air-cooled engine, if used under racing conditions then they can become very hot. The cooler will lower the oil temperature which will prolong component life span inside the engine.
- If deciding not to use a cooler then a bypass pipe/hose must be used to link the oil galleries, failure to do this will result in oil starvation to the top of the engine and will cause major damage. This is crucial on Z140 & Z155 engines, DO NOT LEAVE THE BLANKING BOLTS FITTED.
Running In Period:
- We firstly recommend the engine has a few heat cycles before use, this is where you would start the engine for around 5 minutes and then turn off to cool down completely. This allows the piston to bed in and for you to check for any leaks around your oil cooler lines.
- We would then advise about 1 hours use (with breaks) of gentle riding which doesn’t exceed half throttle.
- We would then finally advise for an oil change and to check the valve clearances and adjust if needed.
Warranty:
- We offer our standard 30 days warranty by UK Trading Law on our products. This only is valid on manufacture faults. Issues caused by the user such as incorrectly installed, abusive use, deliberate damage and race use will not be covered.
- 30 Days begins on the date of purchase.
- Regardless of if you have used the engine for 1 hour or 0 hours, once the 30 days has expired it has expired.
- Race Use – We fully understand there is a market here in the UK for motorcycle racing using pit bike engines. Please note anything used under racing conditions is void in warranty as you’re a putting the components under huge stress. These engines were never designed for competition use so please bear this in mind.
- Claims – If you think there is an issue with your engine then please contact us first to discuss your issues, 99% of the time these are always resolved without the need to return the engine and is usually 1 of 2 problems.
- 1 – Incorrect wiring loom and cdi used for that engine.
- 2 – Incorrect Carb used.
In the event of a claim, it is the buyer’s responsibility to return the engine in the original engine moulded box & to cover postage charges.
Upon the return the engine will be inspected by use to see if it is covered under a manufacture error.
Items Not Covered:
Below are some examples of items not covered under warranty as it is related to rider misuse.
- Kickstart Gears (Caused by excessively kicking & incorrect carb setup)
- Clutch Basket Centre Gear (Caused by excessively kicking & incorrect carb setup)
- Barrel & Piston Wear
- Gearbox dogs (Caused by not using the clutch)
- Premature Valve Damaged (Caused by over revving)
Please use common sense when using these engines, please bear in mind these are still Chinese engines and Chinese quality therefore expectations should be made for Chinese standards.
Carburettor Guide:
Below is a data guide of what carb and jetting is recommended to use on the specified engine, failure to use the recommended carb and jetting will void any warranty claim submitted:
- YX140 = GENUINE VM26 135M, 27.5P OR NIBBI 26mm 118M, 40P
- Z140 = GENUINE VM26 130M, 27.5P OR NIBBI 26mm 116M, 40P
- YX160 & Z155 = GENUINE VM26 145M, 30P
- Z190 = PE28 COPY 130M, 42P OR MOLKT 28MM 120M 40P
- DAYTONA 190 = GENUINE PE28 120M TO 125M 40P
- ZS110 = Genuine Mikuni VM24 130M 22.5 P
- ZS125 = Genuine Mikuni VM24 130M 22.5P
- YX90 = Mikuni 22MM Copy – 95/98M 15P
We hope you enjoy your new engine, if you have any questions, please contact us.
