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2 Stroke Maintence

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Hello I just purchased my first 250 2 stroke and am fairly new to the 2 stroke world as i have previously had a kx250f. So I was curious as to what all maintenance i should do on a rm250 besides top end rebuilds. 

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Pressure test the bottom end to check for crank seal leaks is a good idea. Not something you do on 4-strokes.

Not sure if your KXF had separate tranny and engine oil, in my 2-stroke I use Walmart or similar(cheapest) ATF in the trans and change it at least every two rides. Maybe three if I'm putting around mostly.

Repack your pipe? Mainly if it's got spooge coming out of it. And if it does, it might need to be jetted or change brands of premix.

I think that's about it, besides the normal stuff any bike should get.

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This fits in the thread when do I change my rings..it's cheap and quick so I'll prob just do it. Is there a way to even tell when it's time? Sorry and thanks

Ktm 300

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Trans oil not as often as 4 stroke but every few rides, air filter clean and oil when partly dirty ( 2-3 rides avg?), air in tires every ride, chain and sprockets when the front sprocket gets curvy ( measure chain stretch too), brake pads checked every ride, replace as needed, spokes checked and tightened every few rides, tires swapped out when worn, tubes every other tire change, repack muffler maybe every 100 hours or so, change jetting when weather gets hot/ then cold.......yada yada yada

 

 

Joe

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This fits in the thread when do I change my rings..it's cheap and quick so I'll prob just do it. Is there a way to even tell when it's time? Sorry and thanks

Ktm 300

do compression checks every 5 ish hours to track loss, 160 or less its time for rings or piston and rings, to determine which of the two measure bore and piston.

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do compression checks every 5 ish hours to track loss, 160 or less its time for rings or piston and rings, to determine which of the two measure bore and piston.

Thanks Excitable, sounds easy enough.

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Trans oil not as often as 4 stroke but every few rides, air filter clean and oil when partly dirty ( 2-3 rides avg?), air in tires every ride, chain and sprockets when the front sprocket gets curvy ( measure chain stretch too), brake pads checked every ride, replace as needed, spokes checked and tightened every few rides, tires swapped out when worn, tubes every other tire change, repack muffler maybe every 100 hours or so, change jetting when weather gets hot/ then cold.......yada yada yada

Joe

Yada yada, yup lol.

I check steering head, wheel, linkage/shock bearings every ride too. Takes 2 mins but can save you some major equipment failures

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Hello I just purchased my first 250 2 stroke and am fairly new to the 2 stroke world as i have previously had a kx250f. So I was curious as to what all maintenance i should do on a rm250 besides top end rebuilds. 

Change gear oil every ride.  Keep air filter clean & oiled.

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Clean out the air box, I bet it has lots of gunk in there, Keep the airfilter clean, and grease the mating lip, fresh spark plugs, keep the carb fresh and worn parts rebuilt, flush out the coolant system and replace old fluid. Check linkage and swing arms for cleanliness and grease em up, it might have wear, so be ready to purchase new parts. Wheel bearings may need replacement, spokes may need to be tightened, check for mono shock leaks, check for fork seal leaks, and check all parts mounting hardware, I'm sure you will find some loose bolts somewhere.

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So the previous owner and I were talking today and he said that he ran the bike at a 50:1 ratio, should i be concerned about it running lean and run at like 40:1 or 32:1 ratio. Also he said that the last time the gear oil and radiator coolant were changed 8 hours ago, so I'm guessing i should change them too asap.

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The premix ratio kinda depends on bike usage in a 250. Fast, wide open or skilled rider should use more oil. Trail riding and slower riders can be fine with 50:1. Be aware that in a 2-stroke changing the premix ratio will change the jetting, and probably in the opposite way you may think.

More oil in the ratio = less fuel

Less oil in the mix. = richer fuel condition

Just remember that in a 2-smoke oil AND fuel have to pass thru the jets, so if you increase the oil, you DECREASE the gas and vice versa.

Coolant doesn't need to be changed so often. Tranny oil, probably. Depends on what was used. I use cheap-a$$ ATF and change it every two rides. ATF is on the lighter side of the spectrum and gives good clutch feel. And the theory is its better to change the oil more frequently to remove possible particles, than run expensive oil and not want to change it as often. WalMart or Autozone type F is usually about $3 a quart.

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So the previous owner and I were talking today and he said that he ran the bike at a 50:1 ratio, should i be concerned about it running lean and run at like 40:1 or 32:1 ratio. Also he said that the last time the gear oil and radiator coolant were changed 8 hours ago, so I'm guessing i should change them too asap.

 

There are oils that are designed to be run at ratios like 50:1 or even 100:1. However, 32:1 is what the bike manufacture recommends so that is the mix ratio that should be used. The gear oil should be changed. Do not use ATF, instead use 10w40 motor oil or 80w gear oil that is compatible with a wet clutch. Shell Rotella T is a good cheap oil to use.

The coolant doesn't need changed, just top it off. 

 

Here is an article about mixture ratios: http://www.maximausa.com/pdf/Oil%20Migration%20Sheet.pdf

Edited by ManBearPig.

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ATF is compatible with a wet clutch that's for damn sure. But I'll leave this horse alone, because it's been beaten to death a million times over...

And if the previous owner was running 50:1 and you go to 32:1, your jetting may need to be changed accordingly.

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There are oils that are designed to be run at ratios like 50:1 or even 100:1. However, 32:1 is what the bike manufacture recommends so that is the mix ratio that should be used. The gear oil should be changed. Do not use ATF, instead use 10w40 motor oil or 80w gear oil that is compatible with a wet clutch. Shell Rotella T is a good cheap oil to use.

The coolant doesn't need changed, just top it off. 

 

Here is an article about mixture ratios: http://www.maximausa.com/pdf/Oil%20Migration%20Sheet.pdf

 

 

I beg to differ on premix ratios and ATF. As it says in the article, your fuel/oil ratio depends on usage rather than whatever the manufacturer claims. If the bike is seeing sustain/frequent high rpms, then the 32:1 makes since. However, if you rarely go past 1/2 throttle, 32:1 is just wasting oil and creating a lot of spooge. 

 

...as far as ATF, there isn't a reason not to run it.

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I beg to differ on premix ratios and ATF. As it says in the article, your fuel/oil ratio depends on usage rather than whatever the manufacturer claims. If the bike is seeing sustain/frequent high rpms, then the 32:1 makes since. However, if you rarely go past 1/2 throttle, 32:1 is just wasting oil and creating a lot of spooge. 

 

...as far as ATF, there isn't a reason not to run it.

 

 

Instead of trying to anticipate how the bike is going to be ridin, using a 32:1 ratio covers the lubrication needs for any scenario. Why bother deviating? The amount of oil saved is insignificant and so is the amount of spooge created.

 

If ATF meets the manufactures requirements for gearbox oil or there is an article that states ATF isn't bad for your gearbox/clutch, then it could be a valid recommendation. Until that happens it should not be recommended regardless of anyone's opinions because it could possibly ruin a clutch.

 

 http://ebcbrakes.com/product/standard-ck-series/

http://www.motosport.com/blog/a-guide-to-dirt-bike-oils-2-stroke-4-stroke

 

Please base recommendations off of facts rather than opinions. That is how bad maintenance practices are born.

Edited by ManBearPig.

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To the OP and others who may want to devote many minutes of their lives to the argument, just search oil debate on here. With thousands of posts, it's on the level of the gun debate or trump right now!

Here's the short version:

Oil in a 2-stroke gearbox needs to cool the wet clutch plates, not reduce friction in them, and provide protection against shear forces(the two gear teeth literally trying to cut the oil molecules in half under load). Do you think a dirtbike with a max torque in the low double digits has even a chance in cold hell at putting out the power of a V8 truck or car from a dead standstill launch? An automatic trans has clutch plates that work identically to a motorcycle wet clutch, and ford specs ATF in a lot of their manual transmissions, truck to be specific. Both containing shear forces and heat that a dirtbike will never produce. Not even with 200 HP.

ATF has more detergents than engine oil, though, which is why it's known that it should be changed frequently in comparison since it suspends particles. Auto transmissions have filters, unlike gearboxes. Using gearbox oil will keep more solids in a sludge on the bottom, which don't always drain out well. I have changed gearbox oil and ATF hundreds of times in auto and moto applications. The gearbox oil will always leave a sandy sludge inside the case that can be wiped off with a finger, but the oil will not carry it out.

If the OP just wants to just follow what every manufacturer tells him that's fine. If he wants to know why he must use brand X to formulate his own opinions, he will have some trouble finding real evidence that ATF will ruin a dirt bike trans.

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