Oil in frame? How does that work?

[lethalweapon100]

So nessing around on youtube I come across some videos of XR250/400s and how to change oil on them...with the dipstick in the frame and the drain plug on the front of the frame? I used to own an XR100, I guess thats an exception to that system. How does this work? Ive never seen anything like it.

[84XR350]

Nothing weird about the oil in frame bikes when you realize that they are "dry-sump".  The frame tube is the dry-sump reservoir for the engine oil. 

In a dry-sump system, there is no oil sitting in the oil pan when the engine is running and the motor has two oil pumps: 

One is a scavenge pump that is high volume/low pressure that sucks the bottom of the crankcase dry and sends all the oil into the frame reservoir.

Pump two is a high pressure pump in the traditional sense that you are used to from back in the day.  Instead of getting its supply of oil from the bottom of the engine though, it sucks oil from the frame reservoir and sends it out to all the internals that would melt without lubrication.

The idea behind dry sumps is that the crank & rod doesn't have to spin thru oil, shedding power.

The tricky part is checking the oil since you have to get the oil out of the crankcase and into the reservoir before checking.  Read your manual as to how long you have to run the motor, then how long to wait before checking level.

[Landcrab]

Nothing weird about the oil in frame bikes when you realize that they are "dry-sump".  The frame tube is the dry-sump reservoir for the engine oil. 

In a dry-sump system, there is no oil sitting in the oil pan when the engine is running and the motor has two oil pumps: 

One is a scavenge pump that is high volume/low pressure that sucks the bottom of the crankcase dry and sends all the oil into the frame reservoir.

Pump two is a high pressure pump in the traditional sense that you are used to from back in the day.  Instead of getting its supply of oil from the bottom of the engine though, it sucks oil from the frame reservoir and sends it out to all the internals that would melt without lubrication.

The idea behind dry sumps is that the crank & rod doesn't have to spin thru oil, shedding power.

The tricky part is checking the oil since you have to get the oil out of the crankcase and into the reservoir before checking.  Read your manual as to how long you have to run the motor, then how long to wait before checking level.

I wondered why my xr4 always seems low on oil when I check. Even after a nice initial warmup and wait time before checking. I still haven't figured out the best way. Manual you say.....hmmm, maybe time to pick one of those up! Thank you for the great explanation about the dry sump, very informative.

[topaz250]

I wondered why my xr4 always seems low on oil when I check. Even after a nice initial warmup and wait time before checking.

 

probably similar to the DRZ, run for 3mins, wait 3mins, check, don't thread in dipstick.

Try it right after you change the oil, you'll know its full, as a bench mark.

[Chuck.]

The surface area of the frame tubes become an automatic oil cooler.

[Redpoint]

probably similar to the DRZ, run for 3mins, wait 3mins, check, don't thread in dipstick.

Try it right after you change the oil, you'll know its full, as a bench mark.

Not correct on the waiting.  Manual says to run for 5 minutes, then check immediately after turning off the engine.  Most people here (including myself) also strongly suggest to ride the bike and run through the gears before checking.

 

Correct on not threading in the dipstick though.  Unthread, remove, wipe, place back in (without threading), remove & check level.

[topaz250]

Not correct on the waiting.  Manual says to run for 5 minutes, then check immediately after turning off the engine.  Most people here (including myself) also strongly suggest to ride the bike and run through the gears before checking.

 

Correct on not threading in the dipstick though.  Unthread, remove, wipe, place back in (without threading), remove & check level.

 

similar, yes, didn't say it was exactly the same as the drz. ?

[WWalker]

Ah yes....checking oil level on my XR400. Such a fun and precise task. Thankfully these things can most likely run without any oil at all and still be fine. I've found that if you check the oil on a full moon if will be high....and no moon....low. It also fluctuate with the changing of the tides.

[Coolerking]

The best way to do this whole thing has nothing to do with the dipstick.

It has everything to do with knowing how much oil the bike holds, and how to correctly DRAIN all of it out.

Then there is no checking anything with a dipstick....

But if you must use it then, the post above is correct, warm the bike up ride it for 5-10 mins then stop and pull the stick right away, clean and slide it in to the threads and then have a look.

 

[michigan400]

FYI - The OP was just making fun of XR's. He does not need to know how to change oil or check the oil.

[lethalweapon100]

FYI - The OP was just making fun of XR's. He does not need to know how to change oil or check the oil.

No way! I love XRs. Bulletproof machine. I just found it interesting that the oil was in the frame, ive only really ever worked on 250F race bikes before. I had no idea that that existed.