[Chris610]

I just rebuilt my 2011 brute force 750's engine as it spun a bearing and blew a piston. I bough i in that condition about a month ago. But after I got back from a short ride there was a lot of steam in the exhaust and water leaking out of the front exhaust manifold where it meets the head. The engine was pretty warm but not all the way up to temp. whenever it starts steaming the engine bogs down and dies. Does anyone know what is causing this? Thanks. Here is a video of the water leaking out of the exhaust.

 

[NMKAWIERIDER]

Either a blown head gasket or cracked head. It's top-end time.

 

[kickstart]

Did you use a fresh oem head gasket?

 

[mastrblastr]

Head gasket is a likely culprit but I’m going with a cracked head. If it doesn’t do it too badly when it’s cold, it’s because the aluminum has shrunk to its normal size. As soon as it starts to warm up, the aluminum expands and the crack opens up. Either way, you gotta tear it apart again.

 

[Chris610]

I bought a rebuild kit that came with new head gaskets. Can you remove the head without removing the engine? And is there any way to repair the leak or do I need to replace the head?

 

[kickstart]

I bought a rebuild kit that came with new head gaskets. Can you remove the head without removing the engine? And is there any way to repair the leak or do I need to replace the head?

I don't trust aftermarket head gaskets, but that's just me.
No, you don't have to remove the engine.
Take the head off and see if it's a bad gasket or a cracked/warped head.

 

[jg650]

You can pressure test the coolant system and do leak down test to help diagnose the issue before you take off the head.

 

[Chris610]

well I removed the head and saw some black staining on the gasket surface of the cylinder in one place. The gasket seemed to be in good condition. Does this mean it is the gasket or is there still a possibility there is a crack in the head? If so I will buy a product to check for cracks.

 

[mastrblastr]

IMO looking at that picture, I would say gasket, but just to be sure I would get some dye penetrant and developer, and check the head and the cylinder just to be sure. Are you sure you torqued that head down properly when you assembled that engine?

 

[kickstart]

I would check that head for warpage, deck it 2 or 3 thou, slap an OEM gasket on there, then torque the head bolts to 20 ftlbs in sequence, then again to 36 ftlbs. Done.

 

[Chris610]

I am sure I torqued it down, before I took the head off I checked the torque on the bolts. How do you check the head for warpage?

 

[jg650]

A straight edge and feeler gauge to check for flatness also could take it to a machine shop and have them check it. I run Cometic gaskets on my build and have over heated many times without blowing one.

 

[Chris610]

Okay, I think it was the head gaskets because the rear cylinder is leaking as well. But I well check just in case.

 

[big d]

A straight edge and feeler gauge to check for flatness also could take it to a machine shop and have them check it. I run Cometic gaskets on my build and have over heated many times without blowing one

[QUOTE="jg650, post: 1690424, member: 26
[/QUOTE]
i have had luck using a good piece of glass and 400 wet dry sand paper and by hand rubbing the head surface over it until surface is uniform.

 

[Chris610]

Well I checked the head and it is warped. I assume the rear is as well since its doing the same thing. I am going to get the heads machined by a shop. Thanks for the help.

 

[big d]

Trying to save you a little money. Get some 400 wet dry paper and a piece of glass from home depot or whatever and spend a little time rubbing the head surface over it. Keep the paper wet. Change paper frequently. It will work.you can mark lines on the head surface with permanent marker and when they disappear the surface is flat.

 

[mastrblastr]

Trying to save you a little money. Get some 400 wet dry paper and a piece of glass from home depot or whatever and spend a little time rubbing the head surface over it. Keep the paper wet. Change paper frequently. It will work.you can mark lines on the head surface with permanent marker and when they disappear the surface is flat.

I've never had a warped head or jug, so I've never had an issue where I needed to deck anything, but that is a great tip big d. You could use some layout dye as well instead of permanent marker. My buddy makes knives and uses layout dye all the time. Just spray it on and you're done. That being said, I have a pair of ported heads sitting here ready to go on and I never checked them for warpage as they worked flawlessly before. Might as well check them while they're off.