[c-king]

Hello Monster-knowledgeable folks-

Short version: My M796 ABS seems to have an oil leak coming from a bolt head directly behind the body of the starter motor. Looking at the shop manual and parts diagram, it shows a grub screw ("dowel" in the parts diagram), a gasket, and a bolt over the top, but doesn't say what it is for.

Is it feasible that this is the source of my leak? Searching this and other boards has not found other people with this same issue, so I'm a bit dubious. What is this thing, and do I have to pull the case apart and remove the starter to get at it?

Longer version:

I picked up my 2013 Monster 796 ABS last summer, and it had a small oil leak. A visible drop of oil hanging from the bottom of the oil filter after a long ride, but no measurable oil loss.

It was looked at by a dealer, and they said it was coming from the oil filter which was too loose. They tightened it to spec and said problem solved. But when I got it home and ran it, it was still leaking. Thinking that perhaps I had a bad filter or gasket, I put on a new filter and tightened to spec. Still leaking. So I cleaned the whole bottom of the engine with brake cleaner and then sprayed with baby powder, and it looks like its coming from a bolt head up behind the starter. Photos attached.

Looks like a tough thing to get at, so for the short term, I squirted Permatex all around the bolt head, forming a continuous barrier around the apparent source. Cleaned everything again, and no more leak. Until this summer, when after running hot there's a slight film of oil on the bottom of the motor.

So, what is this thing, have you ever seen a leak here before? I'm all set to drain the oil, pull the cases apart, remove the starter and replace these parts (grub screw, gasket, bolt) to torque, in hopes that will solve the problem, but I'd hate to do all that and then discover that this could not possibly be the source, or that there's an easier fix. Above that point looks clean, but is there a typical leak above I should look more closely at?

Any thoughts?

Thanks in advance! Photos and part diagrams attached.


Sure appreciate any help you can give!

 

[johnnycay57]

Impressive research. I'm betting you are correct.

 

[QLDs4]

My supersport project had a slight leak and the main problem was the starter motor gasket (metal).
That plug, the starter and the join between the engine casing and horizontal cylinder are the only things hidden down there hidden by the starter motor.
To get to the plug you suspect you'll have to drop the starter anyway so make sure you get a new starter gasket and good sealant to re attach it.
Sadly the starter will have a bolt inside the engine so you'll need to pull the alternator cover to access it.
Not a big job but you should get a cover puller tool to take it off nicely, make sure you mark the alignment of your gear shift lever to the shaft it mounts to.

 

[c-king]

That's helpful, thanks; I didn't realize I would need a new starter gasket to put it back together.
I have the puller for the alternator cover and some Yamabond.
Shame it's such a lot of work to essentially tighten a bolt.
I would really like to know what that bolt/gasket/dowel is for, though!

c-king

 

[QLDs4]

need a new starter gasket to put it back together.

You might be able to reuse it but they're not expensive.

 

[LeFraussie]

That's helpful, thanks; I didn't realize I would need a new starter gasket to put it back together.
I have the puller for the alternator cover and some Yamabond.
Shame it's such a lot of work to essentially tighten a bolt.
I would really like to know what that bolt/gasket/dowel is for, though!

c-king

I have reused my starter gasket without issues.
You will need to remove the flywheel also. There is a special tool and an impact wrench is a must.

 

[QLDs4]

You will need to remove the flywheel also.

I've never seen inside a 796 but on on the 750ie I just rotated it all until the I could get at that internal bolt through the hole in the starter driven gear.

 

[c-king]

From what I've seen I'm expecting a similar access hole for the third starter bolt on the 796. Hopefully I can leave the flywheel alone!
Do I need to pull the plugs in order to rotate the engine to get the access hole to line up?

Thanks!

C-King

 

[Chrisbo18]

A lot of times, holes like that are made for other internal machining like oil passages, ball/spring detents, etc., then they're capped afterwards. Good luck!

 

[QLDs4]

Do I need to pull the plugs in order to rotate the engine to get the access hole to line up?

Off memory that gear should move by hand easily in one direction as the the starter sprag clutch should only push the flywheel in one direction and free spin the other way.

A lot of times, holes like that are made for other internal machining like oil passages, ball/spring detents, etc

These are holes through the gear that is driven by the starter, not engine cases or anything like that.