Had to happen - bike drop

[lukasgrech]

Dropped my bike today. Pulled into a side road to stop for a break, road turned out to be made of 1" deep gravel, slowed down to stop, last bit of braking locked the front wheel, no traction, bike fell onto its left hand side. Picked it up quickly and allowed myself a couple of minutes to be angry with myself. After a quick check that the bike was still solid, I rode it home slowly and had a close look once it was parked.

As I was picking the bike up after the drop, I noticed that oil was spewing out of the gaps between the transmission, airbox and engine. The oil seems to be gear oil by look and smell, but I checked the levels (engine oil too) and I could not see any paricular level change.

Now for my noob-y questions, forgive me, this is the first time I've dropped it and I want to make sure I'm not damaging the engine or any components if I ride it now.

1. Why would oil leak from this place? Is this common?

2. I assume I have to check and probably replace the airfilter, because if oil came out of the airbox, it has probably left a nice coat on the filter (although on the ride home, I couldn't smell any oil burning or notice any change in engine function).

It might be my imagination caused by worrying about the drop, but it seemed to me while riding it home, that the forks were more compressed - although I can't see how this could be a result of the drop since that part of the bike wasn't under any force during the fall.

3. So, how can I check that they are the proper length without taking them apart? Manuals only state free length of spring

4. When I roll the bike and pull on the brake, there is a release of air from the top of the fork tube as they compress, and what sounds like air bubbling through a fluid - should I be worried?



You can kindof see where the oil has run out between the airbox and the transmission in the photo above.




Sorry for the barrage of questions - just want to make sure I haven't damaged my baby

Lukas

[nhmaf]

Does the oil smell like hypoid gear oil (the gearbox oil has a distinctive smell - if you open up a container of hypoid gear oil and take a whiff you'll know what the smell is)..   It might be possible that if the bike was tipped over far enough that some gearbox oil might leak through the little screw on the top of the transmission that holds an internal plate in place (do not EVER remove that screw!) or the bolt that holds the  bar to retain the clamshell cover(s), but I suspect it is more likely some engine oil that sloshed up through the crankcase breather and ran down the tube that is supposed to carry the crankcase gases into the air filter assembly to be taken up by the carbs and burned in the cylinders.    How far over did the bike tip?   I wouldn't have expected to have oil slosh up that high  (the breather valve is under the starter motor cover on the top of the engine) if the bike was resting on a cylinder (not totally horizontal).

What does the oil level read in your crankcase?   To read it correct, put bike on centerstand in a level/flat place, unscrew the dipstick, take it out&wipe it off, and then just rest it in place on top of the threads (do not screw it back in)...  Then take it out again to read the measurement.

The gearbox oil level is correct if you remove the fill plug (on the side of the gearbox near the shift lever) with the bike in the same position, and you observe that the gear oil level reaches the bottom of the threads in the hole - or may just begin to dribble out..

[Barry]

Pulled into a side road to stop for a break, road turned out to be made of 1" deep gravel, slowed down to stop, last bit of braking locked the front wheel, no traction,  

We've all done that and although I've never dropped it the senario you describe is the nearest I've come on several occasions.

I suppose it could be gear oil although the normal oil level in the gearbox is very low and not more than 1/3rd full.  If it's not gear oil it could be engine oil that's leaked from the breather.

If you measure your fork length from two recognizable points I can nip out to the car park and measure mine for comparison.

[lukasgrech]

The oil seems to be engine oil, and looks like it came through the breather - took the airbox apart to take a good look around and clean up the oil that had pooled at the top of the transmission.

I'm unsure about the air filter - It has definitely made contact with the oil, but the paper of the seems untouched and relatively clean. Should I change it?



Barry, measurement of my forks from the top of fork slider dust cap to the top of the lower triple tree is 20cm/8"

[Barry]

20cm is spot on Lukas

Air filters last a long time. BMW specifies every 10,000 miles but I think they are good for 20,000.  Your filter looks dirty but that might just be the photo.  If it's dry and you know the mileage I'd vac it off and reuse it.

[lukasgrech]

Brilliant. Cheers Barry!