My wife has a Fatboy that she doesn't ride much. About 1K per year. On weekends she seems to always have something else going on. So I change the oil and filter each fall. Was changing the trans and primary fluid ever other year. The trans fluid always looks exactly like what I am putting back in. In other words it looks new. Not being cheap, just seems like a waste of time. The good thing about the bike is it is never started and ridden less than 50 to 100 miles. Just wondering how many years the fluid is good for?

 

Nowadays, depending on if it's a decent oil.. it is a waste of time. Lots of times when you start the bike up it will then burn off any humidity/condensation the oil may have absorbed. I would instead just take the time to start the motor up and cycle the oil on a regular basis. It's actually worse for the bike to just sit unused.

 

If you really want to know, and specifically for her bike and riding profile, send an oil sample to BlackStone Labs. They will give you an oil analysis which should help you determine how long you CAN go... I used to do that for my Vette... I forget, but think they tell you how many more miles the oil could go, given the time/miles/contamination of the sample..

General rule of thumb... oil in the engine & primary get changed due to contamination, not the oil going bad. The trans, if all is working properly, doesn't get nearly the same amount of contaminates that the other two do...

FWIW.... I get to ride all year here in SoCal, and have a couple bikes that don't get as many miles as the bagger... Based on time (with NO winter layup) I go 5K on primary & Engine or 18 months. I go 10K on trans or 2 years. I change the primary earlier than recommended mileage, because the primary is a very dirty place. I replace the trans earlier than recommended mileage, just because...

If I was in an area where the bikes were stored for 3-4 months during winter, I would probably just change all three holes before winter layup....

 

I change my wife's more for contaminates than anything else. She only has 7000 miles in three years, but the bike is stored outside in a carport and is subject to temperature variations, dust and dirt, etc. I'd rather spend the extra few dollars a year and know that the drivetrain will last.

 

All oil producers and vehicle makers have a mileage recommendation for their interval along with the statement "OR ONE YEAR".

Does not seem to be hard to figure that one out.

 

That's only for engine oil. I plainly stated that I change the engine oil annually. Does not seem hard to figure that one out either.

 

 

You have to change engine oil every year because of the contamination from the blowby in the cylinders. The distillates break down the oil. This wont happen in the primary or transmission. There is no reason to change them annually.

 

Showing my age. My first full time job was working in the service department of a Chevrolet dealer in the 60's. In those days, unless there was a problem and you got into a manual transmission, no one ever changed the transmission fluid. And I do mean ever. I spent a year as the oil change guy, and not once did anyone request a transmission fluid change on a manual transmission. I asked our transmission expert about it and he said manual transmission fluid just didn't need changing according to factory schools he had attended. I did go ahead yesterday and change the wifes transmission fluid. At 2 years it looked identical to the new fluid. Think I am going to wait 3 years next time around on the transmission. Like others have said, it is cheap to do. I just don't like wasting my time and energy even if it is cheap.

 

True... except the primary has it's own contaminates from wearing clutch plates... I don't like going the recommended 10K on the primary changes. I do them at 5K and get some dirty fluid out of there, more so than engine oil at 5K or one year...

I will let the trans slip by on time a little bit, now and then...