Head gasket replacement

Worldtrekker

Worldtrekker

Joined
Oct 12, 2025
Messages
10
Age
66
Location
Houston TX
Bike
2008 ST1300
I purchased a 2008 ST1300 last summer with only 15000 miles on it. The bike appeared to be in excellent condition and ran fine. Absolutely love it and have had all the maintenance completed on it. My mechanic did a borescope inspection of the cylinders and discovered it has bad head gaskets at the time the SC was replaced. Apparently it must have overheated in the past. Looking for suggestions for a mechanic in the Houston, Texas area that could do the work. Mine does not feel comfortable doing this. I'm also considering buying a low mileage used engine on Ebay and doing a motor swap. Any suggestions would be appreciated!

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I'm curious how he determined you have a bad head gasket with a borescope exam. Can you explain more about what he saw? Did he take pictures? Head gaskets are not a frequently cited problem on this website. Your quoted mileage - 15k is astoundingly low. The bike hasn't even been broken in. I assume your SC is the Secondary Master Cylider.

I doubt you will find an engine with so few miles. Assuming your engine is in good condition except for the head gaskets, swapping engines on this bike is a major task and is likely to be very expensive unless you diy.
 
SMSW said:
I'm curious how he determined you have a bad head gasket with a borescope exam. Can you explain more about what he saw? Did he take pictures? Head gaskets are not a frequently cited problem on this website. Your quoted mileage - 15k is astoundingly low. The bike hasn't even been broken in. I assume your SC is the Secondary Master Cylider.

I doubt you will find an engine with so few miles. Assuming your engine is in good condition except for the head gaskets, swapping engines on this bike is a major task and is likely to be very expensive unless you diy.
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I appreciate the replies. Good point. I'll post more info tomorrow with photos of the cylinders borescopes and spark plugs. Yes SC meaning the secondary master cylinder.
 
Worldtrekker said:
I appreciate the replies. Good point. I'll post more info tomorrow with photos of the cylinders borescopes and spark plugs. Yes SC meaning the secondary master cylinder.
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over 40 years of wrenching I have never heard of a borescope seeing a bad head gasket. You can't see the gasket with a borescope. It's possible to see a/f entering the cylinder under pressure. There would be other signs of a bad head gasket, a piston top cleaned of all carbon, a/f in the oil, radiator cap off and while cranking over the engine a/f would blow out or a blue water test. So you never experienced any overheating problem? Very odd.
 
By chance, do you have oil leaking around where the head meets the block, on one side or the other. If so, that would indicate a bad head cover gasket.

Hope you have had a good conversation with Larry (igofar)!

Also, engine swapping is NO FUN! BTDT! Still working on it a year later.

20250131_123029.jpg

Stripping out the donor engine.

20250207_133357.jpg

Getting it ready for the project bike.

20250224_150957.jpg

Removing the bad engine.

20250310_164600.jpg

Prepping the install

20250401_EngineOnLift.jpg

Dropping the frame over the engine.

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To where I have gotten to. More work to be done this winter.

20250520_RideAroundBlock2.jpg

I have two good ST1300s, which is why I'm taking my time with it.

20250130_oilChange-2.jpg
 
Al st1100 said:
over 40 years of wrenching I have never heard of a borescope seeing a bad head gasket. You can't see the gasket with a borescope. It's possible to see a/f entering the cylinder under pressure. There would be other signs of a bad head gasket, a piston top cleaned of all carbon, a/f in the oil, radiator cap off and while cranking over the engine a/f would blow out or a blue water test. So you never experienced any overheating problem? Very odd.
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If you have a good bore scope you can see water leaking from a head gasket into the cylinder. I am not saying this is his problem just that its possible.
 
tnbill said:
If you have a good bore scope you can see water leaking from a head gasket into the cylinder. I am not saying this is his problem just that its possible.
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That's what I said. Ford has a TSB for some 4 cylinder engines concerning loss of coolant, small amount over a period of time with misfire on cold start up. Verification was to keep cooling system under pressure overnight and inspect cylinders for a/f the next day. There maybe only a slight amount not enough to hydro lock. So unless the gasket is completely blown would be the only way to see it with a scope. In that case there would be other tell tale signs.
 
Al st1100 said:
That's what I said. Ford ....
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The bore scopes I've seen are not all that flexible and are aimable only by twisting and pushing the scope in the confined space (cylinder). Given these limitations, what are you looking for - a drop or two of liquid or more than that?
 
SMSW said:
The bore scopes I've seen are not all that flexible and are aimable only by twisting and pushing the scope in the confined space (cylinder). Given these limitations, what are you looking for - a drop or two of liquid or more than that?
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yes, ford does not specify just any small amount. When the piston is down it's easy to spot a/f.
 
Worldtrekker said:
I purchased a 2008 ST1300 last summer with only 15000 miles on it. The bike appeared to be in excellent condition and ran fine. Absolutely love it and have had all the maintenance completed on it. My mechanic did a borescope inspection of the cylinders and discovered it has bad head gaskets at the time the SC was replaced. Apparently it must have overheated in the past. Looking for suggestions for a mechanic in the Houston, Texas area that could do the work. Mine does not feel comfortable doing this. I'm also considering buying a low mileage used engine on Ebay and doing a motor swap. Any suggestions would be appreciated!

IMG_0207a.jpg
Click to expand...


I appreciate the replies! I uploaded the photos from the borescope inspection, spark plugs and mechanic notes:
https://u.pcloud.link/publink/show?code=kZjKuK5Z0b2z8Bpx0Q7UpCrvSwDs4uhz8RHk
 
Igofar said:
I sent you a private message, give me a call when you get time.
Igofar
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Correction, I meant the clutch slave cylinder (SC).
SMSW said:
I'm curious how he determined you have a bad head gasket with a borescope exam. Can you explain more about what he saw? Did he take pictures? Head gaskets are not a frequently cited problem on this website. Your quoted mileage - 15k is astoundingly low. The bike hasn't even been broken in. I assume your SC is the Secondary Master Cylider.

I doubt you will find an engine with so few miles. Assuming your engine is in good condition except for the head gaskets, swapping engines on this bike is a major task and is likely to be very expensive unless you diy.
Click to expand...
 
I would also be very hesitant to go on the head gasket route without further testing. It's really just not that likely (although still possible).

What other symptoms do you see/hear/feel? If it's just from a borescope I wouldn't even bother thinking about it anymore, and keep on eye on your coolant levels.
 
Joeywhat said:
I would also be very hesitant to go on the head gasket route without further testing. It's really just not that likely (although still possible).

What other symptoms do you see/hear/feel? If it's just from a borescope I wouldn't even bother thinking about it anymore, and keep on eye on your coolant levels.
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The bike runs great and have not ridden it enough to notice coolant levels.
 
SupraSabre said:
By chance, do you have oil leaking around where the head meets the block, on one side or the other. If so, that would indicate a bad head cover gasket.

Hope you have had a good conversation with Larry (igofar)!

Also, engine swapping is NO FUN! BTDT! Still working on it a year later.

20250131_123029.jpg

Stripping out the donor engine.

20250207_133357.jpg

Getting it ready for the project bike.

20250224_150957.jpg

Removing the bad engine.

20250310_164600.jpg

Prepping the install

20250401_EngineOnLift.jpg

Dropping the frame over the engine.

20250430_2tractorLowerFrame.jpg

To where I have gotten to. More work to be done this winter.

20250520_RideAroundBlock2.jpg

I have two good ST1300s, which is why I'm taking my time with it.

20250130_oilChange-2.jpg
Click to expand...

Thanks for the photos. Yes good conversation with Larry. That's quite a project!
 
Okay, the oil showing around the sparkplugs & head gasket are the valve cover gaskets leaking into the sparkplug well, and draining from the sparkplug well. There is a drain for the sparkplug wells so they do not fill with oil. Replace the Valve Cover gaskets (which include around the sparkplug wells, and you will be fine. I had that problem last spring with the left side of my 2004.
 
SupraSabre said:
Okay, the oil showing around the sparkplugs & head gasket are the valve cover gaskets leaking into the sparkplug well, and draining from the sparkplug well. There is a drain for the sparkplug wells so they do not fill with oil. Replace the Valve Cover gaskets (which include around the sparkplug wells, and you will be fine. I had that problem last spring with the left side of my 2004.
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That's what Larry was saying as well. Thanks!
 
I ordered the valve cover gaskets. Based on what I'm seeing to only do this. Then monitor oil consumption and coolant level changes.
 
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