Buell xb12xt oil drips unknown area

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Hypefxx

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Sep 20, 2022
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I just bought a 2009 Buell xb12xt 25k miles

Been doing some fixes. Bought a Buell tooth as well and reading a lot on this forum. This is my first post here.

Can anyone please help my target where this oil drip is coming from? It looks like it’s near the belt pulley area. It’s not the rear cylinder head or the pcv valve.

EACDF33C-E878-4415-8DBB-B1B8B2FD2068.jpgEACDF33C-E878-4415-8DBB-B1B8B2FD2068.jpg0C5BD50E-5B06-4C82-A539-1C9F332A43F5.jpg

I do have a slight melt on the trans breather hose but I don’t think the oil is from there.
 
Two possible sources - the rear valve cover PCV grommet (or the hose connection to the PCV), and the breather hose - up inside where it might be touching the rear exhaust pipe. My '08 had all three.

I didn't find the last one until I changed the starter.
 
Possibilities:
Primary/trans breather hose loose at fitting
Primary/trans fluid level way too high
Starter motor sealing ring leak
Rear cylinder rocker box lid breather grommet/breather assembly cracked or grommet bad or hose dislodged
Oil pressure switch leaking
Tighten all the cam/pump cover bolts in sequence-Cam/pump cover is the large oval array on right side with "thunderstorm" decal affixed to same
 
I’ve been reading on the forum where a guy had a similar problem and it was the starter. I don’t know why some people call it a “stator” I may be wrong. Is that a costly fix? Thank you
 
Hypefxx said:
I’ve been reading on the forum where a guy had a similar problem and it was the starter. I don’t know why some people call it a “stator” I may be wrong. Is that a costly fix? Thank you
Click to expand...

The starter motor is a Mitsubishi Electric component. It is bolted onto the left side engine case and engages the ring gear on the outside of the hub assembly, spinning the engine over to start it. Has its own sealing gasket/O-ring and if leaking, will leak in vicinity of your green circled area.
Your XB has an alternator assembly virtually identical to Harley Davidson XL/XR models. It consists of a magnetized rotor spinning around the outside of an AC voltage stator. The stator is affixed to the engine case via hardware. These components are contained INSIDE of the primary cover towards the front. The starter motor is externally mounted. Capiche?
 
Very well explained. Thanks so much. I did find that the trans breather bolt kind of loose. I was able to turn it twice to tighten it up. I just degreased everything and will go for a drive and see if oils are still dripping.

This is such a great forum. I will keep you guys updated on the issue
 
Update

Drove 20 miles after degreasing it yesterday.
Still have oil leaking same area but slightly less.
I bought a UV dye from Amazon and will get it soon. Hopefully an easy repair
 
So I’m still investigating where this oil is coming from. It’s probably the starter gasket seal potentially. But when I was removing the airbox and I see the last owner did the breather mod wrong.

He had the front pcv into a tee and into another tee connecting the rear pcv and crank together.

Basically the pcv is spitting out oil into the crank breather hose which is probably why the oil overflow trickles in that area. That is just a theory.

I will Speedtest the crank hose from the pcv tee now and see if that helps
 
Can anybody confirm that the crank breather hose is just a hose open ended at the tip no filter or valve?
 
Hypefxx said:
Can anybody confirm that the crank breather hose is just a hose open ended at the tip no filter or valve?
Click to expand...

Whatever are you talking about? There is no "crank breather hose".

There are 4 breather/vent hoses

Front cylinder to air cleaner through the PCV valve
Rear cylinder to air cleaner through the PCV valve
Gear case/cam cover to the rear swingarm
Transmission vent to the rear shock area. This is the only one (from the engine case) that vents to atmosphere.

Lastly, the fuel vent/overfill/overflow hose, which also vents to atmosphere.

I recommend downloading a free service manual from buellmods.com
 
Trans breather hose sorry. Should there be some sort of filter or nozzle at the end of the hose or is it just an open hose. Seems like stuff can fall into it.
 
Hypefxx said:
Trans breather hose sorry. Should there be some sort of filter or nozzle at the end of the hose or is it just an open hose. Seems like stuff can fall into it.
Click to expand...

Its an open hose to atmosphere. Under most circumstances, while running there will be slight positive pressure in the transmission keeping things being pushed out of the vent hose. Can something "fall in"? Yeah, well sure... it would need to defy gravity and work its away all the way down the hose and into the transmission case.



If you're really worried about that happening, you could put an inline fuel filter on the hose or a diff vent cap on there, but the other 99.99% of people just leave it open.

Sorry Barrett, I couldnt find an Office reference.
 
Last edited:
I appreciate the detail answer. I bought the bike used so it’s trying to figure what was done or stock was kind of a pain.
 

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