YZ400F Oil Leak???

[PAULZ]

OK...Decided to work on my YZ400F today and my goal was to find out where this oil leak was coming from and fix it. It wound up that it was coming from the crank case cover. To fix this I took it off and siliconed it. It seems to have solved the problem but I have heard that this is a bad thing and there should be no oil in there. What do I do? Is this okay or am I going to do damage like this?

[642MX]

OK...Decided to work on my YZ400F today and my goal was to find out where this oil leak was coming from and fix it. It wound up that it was coming from the crank case cover. To fix this I took it off and siliconed it. It seems to have solved the problem but I have heard that this is a bad thing and there should be no oil in there. What do I do? Is this okay or am I going to do damage like this?

You mean the mag cover? (I think). If so, oil should be in there. Silicone is not a good fix. I'd recommend getting a new gasket. ?

[PAULZ]

Not exactly sue what you mean by mag cover...but its the cover on the left of the bike. Right next to the shift lever.

And why is silicone not a good sealant? Its high heat

[642MX]

Not exactly sue what you mean by mag cover...but its the cover on the left of the bike. Right next to the shift lever.

And why is silicone not a good sealant? Its high heat

The left side cover has many names: mag cover, flywheel cover, stator cover, ect... Anyways, we're on the same page.

I don't care for silicone for the following reasons: looks like hell, most of the time the it will leak anyways, (if it does hold) it will be a real pain to get back off.

Without oil, a YZF will seize up in seconds. Its not worth the risk for me.

[grayracer513]

Silicon sealer is great for all kinds of things. Gasket sealer isn't one of them. I prefer to assemble the crankcase cover gaskets on either side of a YZF with no sealer. The gasket can only be reused if it's not damaged in any way, and when using a new one, ALL of the old one must be removed.

Silicon will only seal on a completely clean, entirely oil free surface, and there's no way to do that with an old gasket there.

[Jay Chasin DaBag]

On my yz400 I am experiencing an oil leak on the right side, right above the brake... how do I fix this issue? Or is it even something I can fix.... 

[kx450f06]

On 11/2/2020 at 9:51 AM, Jay Chasin DaBag said:

On my yz400 I am experiencing an oil leak on the right side, right above the brake... how do I fix this issue? Or is it even something I can fix.... 

Picture would be helpful. And you might start a new thread this one is so old your more likely to get a reply on your own.

[Jay Chasin DaBag]

That Is where the leak is coming from 

Edited November 5, 2020 by Jay Chasin DaBag

[Jay Chasin DaBag]

[Mitch FTB]

17 hours ago, Jay Chasin DaBag said:

That's pointing to a coolant hose, if its leaking around there it's probably a coolant leak.. if that hose is old and cracked replace the hose and refill with coolant.

[Jay Chasin DaBag]

6 hours ago, Mitch FTB said:

That's pointing to a coolant hose, if its leaking around there it's probably a coolant leak.. if that hose is old and cracked replace the hose and refill with coolant.

Okay! Thank you very much... am new to this dirtbike stuff, lol... really appreciate it!