The oil seal was leaking so I replaced it with a new OEM Honda seal last week. Took the 350 out yesterday for a day of riding and found that it was leaking again. It looks to be seated properly.

Did I install the seal incorrectly?

Did you pressure test the Engine ensure the seal is in fact leaking? Looks like oil coming from the balancer case vent to me.

Did you install the seal flush with the cases?

Did you grease the seal before installing?

Was their a grove in the crank shaft where the seal rides?

Looks like the vent mod has not been done.... I would say that is were you are getting the balencer oil from....
I would leak test the Engine and perform the mod to the balencer vent breather.....

I second that. The seal isnt leaking its your balancer oil from the vent hole.

Vent hole they are talking about

What cause's the oil to come through the vent hole? How is the balancer case mod done?

You put a screw in the vent hole and then add a vent to the balancer gear case as I did or others are modifying there dip stick.

Thanks for the information Rarerat. Drilling the hole for the vent hose makes me nervous. Could anyone tell me how the dipstick vent is installed?

Mine has a brass threaded fitting with a hose barb coming out. You'll want to run a long hose with a fuel filter high on the frame. Some guys actually mod the dipstick. Either works fine but I'm not sure exactly what they do to the dipstick. I carry my dipstick in the toolbox so I can check my oil level any time. Good luck

Edit: if you look at the first pic in this thread you can see the fitting I speak of. I recommend using one with a 90 degree bend. You can use the hose barb as a lever to remove without tools for ease of checking oil.

viewtopic.php?f=1&t=9826" ."..

What did you use for the dipstick mod?

there is a drain plug from a ford truck radiator of some kind that will screw right where the dipstick goes and you can modify it so that a brass nipple threads right on it. at lwast this way doeant make you ruin the dipstick. ill see if i can dig up the mod. i believe randy at odysseysalvage.com is who came up with it, or at least how i heard of it.

My dipstick is now carried in the side tool compartment. The brass fitting on mine threads in right where the dipstick goes. Click on that link I'm my earlier post. Lower right hand side. See the short hose? That's it. Ill get a closeup tonight if you need?

here is the post i was looking for, i guess it was Randman that came up with no no case mod method, not Randy from Odyssey Salvage. Here you guys go

http://pilotodyssey.com/PO/viewtopic.php?t=6309

A close up would be helpful. The more pictures the better. Thanks

Thanks for posting this thread Nitro. Going to start on this tomorrow evening.

Doing this mod, does the air vent above the starter have to be plugged?

No, the only vent you plug is this one

That looks very nice. Good work

Thanks Fatcat

Just took it around the block. Looks like oil is coming out of the filter......

Checked the oil level looks a bit high, could that be why?

I have never had the oil go past the filter, but I use 3/8 hose & filters & I also run a length of hose past the filter. Check your oil and see how much you over filled it and drain some back out. I run both of my 350 Odys on the top full line and have never lost a drop out the vent hoses.

i had the same issue with it pushing oil out my vent mod, that's why i went ahead and got the rubber bellows thing so the oil wouldn't come out.

I'll check the oil tonight.

Rubber bellows? Could you post detailed pictures of your setup?