2-Stroke Maintenence?

I have a 2003 CR125. I'm new to the whole maintaining bikes think. Can someone tell me how to maintain it and what I should do after so many hours? Thanks !!:bonk::excuseme:

Do yourself a huge favor and get a manual for the bike.

It is money well spent.

Change the oil often.

Clean the air filter after every ride.

Get the manual for everything else.

What oil do you change?

The Trans oil.

And it only take a few minutes to change the oil...no excuses!

The shop manual will save you LOTS of TIME and MONEY. Get one.

rockstar, +2 on the manual, however unless you are constantly racing your bike, i would not recommend the published service intervals. CRAZY $$$$

I trial ride my KX, I change the tranny oil twice per season. Forks / brake fluid once per season. chain and sprockets (as a set) once the chain fails a "strech" inspection. Cables / wires / fastners the monent i see any sign of damage.

the biggest thing is just to check your bike before and after each ride.

if you don't like what you see, fix it. This will keep your bike in good operational state.

The most important, and they are both equally important is;

Air filter

Transmission oil

Make sure that air filter is sealed, even if it's dirty the worst that can happen is poor performance, but make sure that it seals nicely inside the airbox so that unfiltered air cannot bypass it. These engines are so sensitive to dirt, and all it takes is a day of riding with an unsealed filter to see damage being done to the engine.

The transmission oil is another one, alot of people say that the check bolt is not good enough. Make sure you drain it and fill it with exactly what the crankcase specifies instead of what the check bolt tells you. My engine is 750ml of oil, so when it's drained I put in exactly that amount.

The manual calls for 10W 30 SAE engine oil for the tranny, alot of other people here use just gear oil, or ATF, and they all seem to work fine.

If you change your oil after every trip (so say you go for riding for a few days, one oil change is good enough) that's usually sufficient, some people will probably say too much but that's what I do.

...change your oil after every trip....

Better yet, change your oil after every ride while the oil is still hot.

Maintainence will depend a lot on how you ride. If you ride dusty tracks and are a very good/aggressive rider, you'll need to follow the obsessive "everything after every ride" schedule.


Gearcase oil changes will depend on how you use your clutch. More clutch abuse, more oil changes required.

Air filter will depend on how dusty the area your riding in is. After your ride, take the seat/ cover off and have a look at it. If there's very little to nothing on it, don't worry about cleaning it. If it's dirty, clean it.

Another thing to do every 2-3 rides is lube and adjust your throttle/clutch cables.

Keep your chain adjusted and lubed. Especially needed on non o-ring "race" chains.

Get yourself a shop manual and a good torque wrench! Best two items you can buy to get started.

2 strokes are so easy to keep up. Just a very small amount of work and they'll run forever.:banghead:

clean the power valve

What oil, there is no oil just ride her till she dies


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