Destroyed Cylinder Head!!!

[IanDMacDonald]

You can really understand why they peened/staked those butterfly shaft screws after you destroy a head, post-throttle shaft seal replacement, lol.

Things to ponder: I have the Chinese 1179 big bore kit. The engine has run well, but it's up there in mileage. Not sure if the damage to the piston heads is enough to scrap them? I know the cylinder head is toast.

Option 1: Engine swap with something lower in mileage. Hopefully, 2nd gear is not an issue in the replacement engine, as my current engine had 2nd gear fixed.

Option 2: Cylinder head swap

Thoughts?

[cajun31]

I have to ask. Is this the same set of carbs that caused this that you were reluctant to remove the screws from? If so, when you put them back in what did you use to secure them? By the way I would clean those parts up a bit and try them. A dremel to smooth out things.

[IanDMacDonald]

I have to ask. Is this the same set of carbs that caused this that you were reluctant to remove the screws from? If so, when you put them back in what did you use to secure them? By the way I would clean those parts up a bit and try them. A dremel to smooth out things.

Hey, Cajun- Blue locktite. Must not have been cured enough.

i'm not sure any attempts of cleaning the head is worth the risk.

[bikerphil]

Well, if the motor was properly taken care of it should easily last 150K on the mains. If your mileage is much less, I would just change the head.

[Radioguylogs]

Thinking out loud:

• It looks like head gasket surface is not damaged.
• Valve seats are OK.

What would be the negative consequences of using the head and the piston as they are? Some super small percentage larger volume in the cylinder?

I'm not sure hat I would do. I'm usually pretty anal, even when it doesn't matter.

[cajun31]

Thinking out loud:

• It looks like head gasket surface is not damaged.
• Valve seats are OK.

What would be the negative consequences of using the head and the piston as they are? Some super small percentage larger volume in the cylinder?

I'm not sure hat I would do. I'm usually pretty anal, even when it doesn't matter.

That's what I saw too. A little dremel work to polish those spots just a bit and I think it would be good to go.

[cajun31]

Hey, Cajun- Blue locktite. Must not have been cured enough.

i'm not sure any attempts of cleaning the head is worth the risk.

Blue locktite is what I used on all three of my bikes and so far so good. Did the screws feel like they seated ok when you reinstalled them?

[IanDMacDonald]

Blue locktite is what I used on all three of my bikes and so far so good. Did the screws feel like they seated ok when you reinstalled them?

Screws were seated, but I did not wait 24 hours before installing the carbs.

[IanDMacDonald]

I think, I think, I think what I'm gonna, tryna, wanna do is not use this head, and run down to Ohio and pick up a few more XS's, and either use an engine or head off one of those bikes. I'm just not a big fan of putting something that has damage back on the bike.

I should be able to resolve this issue in another week+, and keep it moving. These are incredibly simple and fun bikes to work on.

[Bonz]

Looks like a post or two was deleted in another thread about this. Don't use too much blue loctite, it wicks very easily into the butterfly shafts. In about 10 minutes they don't want to move lol. Don't use a drop of it, use a pinhead size amount of it. That's what I did on my xj750 Seca when I discovered a butterfly plate was not quite closing due to contact with the carb throat. Lightly used steel wool to massage the butterfly plate around the edge till it closed.