Sign in to follow this  

Engine Maintenance Guidelines

Recommended Posts

Following are some rough guidelines to help establish a maintenance schedule for your 2-stroke ATV.

Recommendations are for a High Performance 2-Stroke ATV engines

TOP END: It is recommended to remove your ATV’s top end (cylinder, head and piston)every 30 to 50 hours, most engines will run to 50 hours under normal conditions, but have started to loose their edge on performance in the 25 to 30 hour range. (NOTE: It takes a good running ATV approximately 24 hours to complete the Baja 1000) While disassembled piston to cylinder wall clearance should be checked and serviced accordingly (clearances needed to be measured by a trained professional with the proper equipment). Reeds should be checked and replaced if worn.

New gaskets and top end bearing should be used upon reassembly.

CARBURETOR: Carburetor should be cleaned at least once per riding season. Ideally it is recommended to thoroughly disassemble and clean your carburetor when servicing the top end.

AIR CLEANER: For machines running with air box lid off, air cleaner should be replaced with a clean unit or washed and oiled after each full day of riding. (See DRI Air Cleaner TECH Sheet)

TRANSMSIION OIL: Transmission oil should be changed every 10 hours. When changing the oil warm engine up to operating temperature before removing drain plug. (The oil is drained when hot to help collect any foreign debris floating through your engine) Be Careful Not to Burn Yourself!

It is always a good idea to drain your oil into a clean dry container, so you may inspect it for foreign debris after it settles.

Make sure that aluminum crush washer on drain plug is replaced at least every third oil change.

COOLANT: Coolant/water solution should be replaced each time the top end is serviced.

CLUTCH: When inspecting clutch, fiber and steel plates, clutch basket, inner hub and pressure plate should be checked.

Racing engines should have clutch checked every 25 hours for MX and XC. Every 5-10 hours for TT and Flat Track. Every 50 hours for Desert.

Recreational engines should have clutch components checked every 75 hours of normal riding. For extreme usage check every 50 hours.

Regularly changing the transmission oil will prolong clutch life.

LOWER END: Lower end inspection consists of crankshaft, bearings and transmission inspection.

Racing engines should have engines lower end disassembled and inspected every 50 hours. Recreational engines should have lower ends disassembled and inspected every 150 to 200 hours.

SPECIAL NOTE: Make sure swing arm pivot bolt and associated bearings, bushing and collars must be kept clean and properly greased. Failure to keep this very important bolt serviced can cause bolt to seize in the swing arm. Causing expensive damage to repair.

Share this post

Link to post
Share on other sites
  •  Like what you are reading? Please help us by sharing this content.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this  

  •  Like what you are reading? Please help us by sharing this content.
  • Similar Content

    • By Jacob Blocker
      I have not been able to start my 300ex that I just got off a guy. I was able to getting it running once, then never again. After a week of trying to make it run I got a compression tester and it is saying about 30 psi. Is this definitely the rings just worn out or can it be something elses? I can't even make it pop when I spray stater fluid in it.
    • By Jacob Blocker
      I have been trying to get my 300ex to start for sometime. a few days i got it to start over and over and then the next day it wont start. I do the value lash and keep the covers off. I was (prob exhaust) smoke coming out of the covers with for the valves. I also noticed that the crank position marker had smoke also coming out, but i just thought it was from the head and it being in the cold. The hole for the position marker also has air come out when it turns over, but it is very light of air flow.
    • By mmgood
      Hey people
      Question for all, just picked a 1986 bayou 300 thinking of going synthetic any thoughts ?
    • By X2Moto4
      Hello. New here. Just picked up a used 350 motor out of a 1991 big bear. Going to put into my 1986 350 moto 4. From what I've read the engines are the same. The only difference so far I've notice is I have to change out transfer case. The moto 4 isn't 4x4. Has anyone done the same swap and any advice before I tackle it.
    • By RCNY1
      Looking for someone reasonable ,HONEST and experienced to rebuild a 2002 Yamaha big bear 400 2 wd
  • Recently Browsing   0 members

    No registered users viewing this page.