Cracked head, but not what you think

Jhortz · May 4, 2026

Hi guys,

I recently made a horrific discovery, the head on my 2011 Roadster is cracked. I initially thought I had a leaking rocker cover gasket, so I changed it as i had to check valve clearances anyway. I changed the gasket but there is still oil there, and the leak is slowly getting worse. On closer inspection it looks remarkably like there is a crack in the right hand rear corner of the head, you can see a faint crack and the oil pools there when the bike has been run. I hope it is just a superficial crack letting oil run out of the top of the head and not cracked through to an oil gallery.

Has anyone seen this before, is this common?
Has anyone got any alternative theories?
Has anyone got any repair recommendations? (I think I might try smearing some black RTV silicone in there first and see how it goes.)

Gerald · May 4, 2026

Jhortz said:
Hi guys,

I recently made a horrific discovery, the head on my 2011 Roadster is cracked. I initially thought I had a leaking rocker cover gasket, so I changed it as i had to check valve clearances anyway. I changed the gasket but there is still oil there, and the leak is slowly getting worse. On closer inspection it looks remarkably like there is a crack in the right hand rear corner of the head, you can see a faint crack and the oil pools there when the bike has been run. I hope it is just a superficial crack letting oil run out of the top of the head and not cracked through to an oil gallery.

Has anyone seen this before, is this common?
Has anyone got any alternative theories?
Has anyone got any repair recommendations? (I think I might try smearing some black RTV silicone in there first and see how it goes.)

I've heard of this several times but seems to always be a leaking gasket or faulty valve cover. Make a thorough inspection to be certain and if it actually is a crack, I'd vee it out lightly with a dremel tool or something similar and fill with a good epoxy and sand/ file smooth.

Jhortz · May 7, 2026

Gerald said:
I've heard of this several times but seems to always be a leaking gasket or faulty valve cover. Make a thorough inspection to be certain and if it actually is a crack, I'd vee it out lightly with a dremel tool or something similar and fill with a good epoxy and sand/ file smooth.

Thanks mate, I've given it a good clean and it is dry all around the gasket but oil is pooling in the corner. SO unfortunately it looks like I've got a crack, I just hope it is oil seeping out from the cam cavity and not oil being pumped out through a crack that goes into a pressurized oil gallery. I've got some work planned on the bike soon so I will get the rocker cover off and have look inside to see if I can see the inside f the crack, that will help guide me on what to do. But i'm bracing myself to at least have to take the head off to get the crack welded if a shonky backyard repair won't work.

I was hoping for several replies saying it is a known issue with an easy repair, I'm guessing from the silence that I've hit the jackpot for unusual issues that you would only see on a triumph

. I've seen similar issues on engine blocks of large industrial engine when there has been an inclusion in the casting, I'm guessing that's what has gone on here as the crack isn't at a stress point.

Gerald · May 7, 2026

Jhortz said:
Thanks mate, I've given it a good clean and it is dry all around the gasket but oil is pooling in the corner. SO unfortunately it looks like I've got a crack, I just hope it is oil seeping out from the cam cavity and not oil being pumped out through a crack that goes into a pressurized oil gallery. I've got some work planned on the bike soon so I will get the rocker cover off and have look inside to see if I can see the inside f the crack, that will help guide me on what to do. But i'm bracing myself to at least have to take the head off to get the crack welded if a shonky backyard repair won't work.

I was hoping for several replies saying it is a known issue with an easy repair, I'm guessing from the silence that I've hit the jackpot for unusual issues that you would only see on a triumph. I've seen similar issues on engine blocks of large industrial engine when there has been an inclusion in the casting, I'm guessing that's what has gone on here as the crack isn't at a stress point.

I don't believe it's a pressure leak or you would have more leakage. I'd try several fixes before pulling the head inside the frame tubes.

Gregger · May 8, 2026

Could you take a pic from a bit further away. It's hard to see where the leak is on the engine? That way we can zoom in after looking at the surrounding area. I don't think I have ever heard of someone having a crack on the head/valve cover mating surface. I wonder if there is some porosity there??? You will need to remove the valve cover and check closely. I don't think that area is stressed and if there is a crack, you should be able to grind it out and fill with Devcon Plastic Steel or some other metal impregnated epoxy. One other item is that there is a hole drilled from each spark plug location to the side of the engine. This is a drain hole and if the vc gasket around the spark plug is leaking, it will show up as an oil leak under the valve cover.

IFIXSHlT · Monday at 9:43 AM

I’ve had this exact leak on my 2005 in the exact same place. It’s a bad casting. The oil is under pressure in that location which is why nothing you do on the outside will stop it from leaking. I’ve tried everything from RTV to grinding it out and filling it with JB weld and epoxy paint and primer. In the end, it continued to leak. I ultimately ended up changing the engine out due to a bad fourth gear.

Jhortz · Monday at 8:03 PM

IFIXSHlT said:
I’ve had this exact leak on my 2005 in the exact same place. It’s a bad casting. The oil is under pressure in that location which is why nothing you do on the outside will stop it from leaking. I’ve tried everything from RTV to grinding it out and filling it with JB weld and epoxy paint and primer. In the end, it continued to leak. I ultimately ended up changing the engine out due to a bad fourth gear.

Thanks, this is actually exactly the reply I thought I would get (even though it is horrible news). I suspected I wasn't the first person to have this drama, the location and being that close to a head bolt made me very suspicious. The slowly increasing volume of oil leaking also made me worry that the crack goes into a pressurized oil gallery too. I've got a good local bike mechanic (he owns a rocket too

) who I will go see. I'll check out the transmission condition, if it is ok then I'm guessing I'll have to get the head off and sent to get properly repaired if that is economical.

** I've just had a good look at your picture again, is that a tiny drilling in the middle of the crack? is that the drain for the valve cover gasket?

IFIXSHlT · Monday at 8:15 PM

Jhortz said:
Thanks, this is actually exactly the reply I thought I would get (even though it is horrible news). I suspected I wasn't the first person to have this drama, the location and being that close to a head bolt made me very suspicious. The slowly increasing volume of oil leaking also made me worry that the crack goes into a pressurized oil gallery too. I've got a good local bike mechanic (he owns a rocket too ) who I will go see. I'll check out the transmission condition, if it is ok then I'm guessing I'll have to get the head off and sent to get properly repaired if that is economical.

** I've just had a good look at your picture again, is that a tiny drilling in the middle of the crack? is that the drain for the valve cover gasket?

I don’t believe so. If it is, it wasn’t done by me. When I was doing my research on this, I was reading about porosity issues with these heads. I guess back in a day triumph had a fix for this that involved removing the head and sending it to a company to have it sealed from the inside out.

Gerald · Monday at 11:23 PM

Jhortz said:
Thanks, this is actually exactly the reply I thought I would get (even though it is horrible news). I suspected I wasn't the first person to have this drama, the location and being that close to a head bolt made me very suspicious. The slowly increasing volume of oil leaking also made me worry that the crack goes into a pressurized oil gallery too. I've got a good local bike mechanic (he owns a rocket too ) who I will go see. I'll check out the transmission condition, if it is ok then I'm guessing I'll have to get the head off and sent to get properly repaired if that is economical.

** I've just had a good look at your picture again, is that a tiny drilling in the middle of the crack? is that the drain for the valve cover gasket?

I wouldn't have thought there would be an oil passage anywhere close, still believe could follow the line with a disc or burr and then fill with a good grade epoxy or possibly silver solder.

Jhortz · Tuesday at 1:09 AM

Gerald said:
I wouldn't have thought there would be an oil passage anywhere close, still believe could follow the line with a disc or burr and then fill with a good grade epoxy or possibly silver solder.

From what I can make out from the manual, parts book, and pictures on the internet there looks to be a single gallery sending oil to the head. From the look of it the gallery sits at the rear on the left hand side of the engine and my crack is on the rear at the right so hopefully the crack doesn't go to a gallery. Hopefully someone who has had an engine apart can chime in with a definite answer on this one.

Cracked head, but not what you think

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