Intake blow by

[vwjedi]

Is anyone else getting oil blow by dripping from the intake tube?

I noticed some oil on the reverse lever under the intake tube and pulled the cover off to look on the weekend. It's dripping from the end of the tube.

After years of working on small turbo engines its something I'm used to but wondering if anyone else has had the issue on the bike.

The clamp holding the tube is a one time use deal so I'll probably pull it and swap for a better clamp.

 

[Anibal]

I have read somewhere that old boxer engines were prone to leak oil into the cylinder chamber, specially the left one due to the side stand leaning angle and cylinder rings worn out which allowed a small amount of oil to be collected on the cylinder chamber once the engine was switched off but I can’t comment on that as I have never experienced such scenario. What I can say is that once on my old M109R I overfilled the engine with oil by just a bit and as soon as I started the engine I could see oil coming out from behind the left air intake. I later learned that these bikes had that tendency if overfilled, hence Suzuki set up a procedure to change the engine oil which involved idling the engine for 15 minutes, let it rest for 2 then removing both drain plugs to ensure the last drop was taken out of the block.
Did you check your oil level?
If it is ok would you think the clamp you mentioned is somehow not longer doing its job?

Keep us on the loop.

 

[Keehn]

The clamp you are referring to is an "Oetker" clamp. These are also used in PEX plumbing and are renowned for their tightness and thoroughness in clamping pressure. BMW has used these hose clamps for, what seems like forever.

Anyways, I presume you'll swap it for a screw-type hose clamp. Ironically, this type is not as secure as "Oetker", but it has the benefit of reusability (and less ) of trying to remove in tight spaces. As for the oil, it's excessive oil built up in the air box that blew past the PCV valve. I haven't yet had this issue on my bike (but I've had this exact issue on previous boxers), but normally, there's a bleed hose on the bottom of the air box that allows oil to gravity drain.

Try locating a gravity drain on the air box and try that first. If there isn't any gravity drain, then it might be a worthy future mod the community might want to explore as more of us inevitably experience this issue.

Mike

 

[Cu Dubh]

Yep, this is typical of the 1150, overfilling the oil will cause blow-by into the airbox. Don't know about the newer bikes but worth checking.

 

[vwjedi]

Thanks for the replies.

It is the left so that makes a ton of sense.

I found the intake box parts diagram and it looks like there is a drain tub with a plug (shocker, on the left side lol). I’ll crawl under the bike tonight and see if I can find it. I’ll take pics and if it’s not overly a pain then pulling the drain plug might become part of maintenance routine.

The oil is at the right level. Been checking it at every fill up since the bikE is still new.

 

[Keehn]

Thanks for the replies.

It is the left so that makes a ton of sense.

I found the intake box parts diagram and it looks like there is a drain tub with a plug (shocker, on the left side lol). I’ll crawl under the bike tonight and see if I can find it. I’ll take pics and if it’s not overly a pain then pulling the drain plug might become part of maintenance routine.

The oil is at the right level. Been checking it at every fill up since the bikE is still new.

Of note.

Recently worked on wifey's 1976 Honda CB500t, and the airbox union between the two carburetors that aids in vacuum equalization and also the PCV suction has...

You guessed it, an excess oil blow by gravity discharge tube.

The reality is that ALL motorcycles that feed oil back into the air intake WILL experience your/our issue. It's just on boxer engines, with the left cylinder lowest to the ground, the left intake boot naturally gets the oily run, if the gravity discharge tube is gunked up. Upright engine designs...I dunno??? I've only spent most of my riding miles in boxers .

Just consider it a "quirk" and carry on.

Edit: I thought I'd add a pic from the microfiche for clarification on the gravity drain location:


I'd say, look for a plug that looks like that underneath the engine. From the way the tube is snaked, it'll be a PITA to replace, come time 10-20 years down the road. But that's not a problem at this moment...

Mike

 

[vwjedi]

Of note.

Recently worked on wifey's 1976 Honda CB500t, and the airbox union between the two carburetors that aids in vacuum equalization and also the PCV suction has...

You guessed it, an excess oil blow by gravity discharge tube.

The reality is that ALL motorcycles that feed oil back into the air intake WILL experience your/our issue. It's just on boxer engines, with the left cylinder lowest to the ground, the left intake boot naturally gets the oily run, if the gravity discharge tube is gunked up. Upright engine designs...I dunno??? I've only spent most of my riding miles in boxers .

Just consider it a "quirk" and carry on.

Edit: I thought I'd add a pic from the microfiche for clarification on the gravity drain location:

View attachment 10772
I'd say, look for a plug that looks like that underneath the engine. From the way the tube is snaked, it'll be a PITA to replace, come time 10-20 years down the road. But that's not a problem at this moment...

Mike

Thanks Mike

Found that diagram and just building up motivation and the appropriate four letter words to find it.