Cracked block near chain tensioner - KZ750 L3

I bought a new engine recently for parts, so at least I can replace the block if I have to. I wish I didn't have to get a new set of gaskets and do the whole razor-cleaning of the surfaces all over again. That was a real pain.

While I'm in there I'll re-check those bolts per your recommendation.

The guy I bought the engine off of said that not fully removing the cam chain tensioner before reinstalling it could strip those threads, so I'll be more careful next time.

Before tightening a bolt into a dead-end threaded hole, it's usually a good idea to first assure the hole is clean and free of any sediment, oil, etc., even when the bolt is correct length (i.e., not too long).

Would think any good volatile spray cleaner, such as brake cleaner or carb cleaner, would be okay for this purpose.

For example, failure to clear receiving cam bolt holes may exacerbate tendency to strip their threads when torquing the bolts.

Good Fortune!

Dont think its liquids,

just had a look at my cyl 750 block and the holes for the bolts form the head and from the chain tensioner do meet!

Really odd, looks like kawi engineers run out of space there as having the two holes connected like that certainly weakens the casting at that point, not a good engineering practice in my book, is it like that in the 1000's too?

it would be really important to have both bolts the right length, longer ones will simply touch each other and it would be easy to create a crack like yours even by just torquing them to spec, its like driving a wedge!

Check the bolts you took out of there, wouldnt be surprised if the threads are marked from rubbing steel against steel.

Good to know....

Very useful info. I suspected as much, given where all those bolts go. I think I know what did it, then:

The OEM bolts are threaded at the bottom and tapered in along the middle. I'll guess that's to take up the last few millimeters of tensioner bolt, and since I used a regular fully-threaded bolt for the head, the top tensioner bolt pressed right up on those threads. Good thing stainless is hard, or I'd have to guess I'd smashed the threads on the head bolt.

Fortunately I saved the original bolt that didn't shatter on me, so I'll use that for the rebuild when good weather comes.

staniel wrote:

I wish I didn't have to get a new set of gaskets and do the whole razor-cleaning of the surfaces all over again. That was a real pain.

Buy a good quality liquid gasket remover and let it work on the gaskets before you try to scrape them off. It will be TONS easier!

staniel wrote:

Fortunately I saved the original bolt that didn't shatter on me, so I'll use that for the rebuild when good weather comes.

rebuilds are done in bad weather, good weather is for riding

turboguzzi wrote:

rebuilds are done in bad weather, good weather is for riding

This is true for those fortunate enough to have a garage. I live in Seattle with no workspace. Please don't make fun.. the situation is sad enough

TerryK, I used liquid gasket remover the last time I did it and it was still an epic PITA. Maybe it'll be easier since the gaskets are 5 months old instead of 27 years. I guess it's a fair assumption that I'll need all new gaskets for this project? Can't reuse a head gasket if I used Permatex?

I'll surely post updates when I do all the work again.

Thank you all for the help. If any of you lives in Seattle and has a place to work, please let me know!

gee man, you dont put no permatex in a head gasket

who told you to do so?

Dangit. My Clymer manual said to put some around the two dowel bolts! I used the black stuff, though, so maybe it'll peel off with a wet rag...

staniel wrote:

turboguzzi wrote:

rebuilds are done in bad weather, good weather is for riding

This is true for those fortunate enough to have a garage. I live in Seattle with no workspace. Please don't make fun.. the situation is sad enough

TerryK, I used liquid gasket remover the last time I did it and it was still an epic PITA. Maybe it'll be easier since the gaskets are 5 months old instead of 27 years. I guess it's a fair assumption that I'll need all new gaskets for this project? Can't reuse a head gasket if I used Permatex?

I'll surely post updates when I do all the work again.

Thank you all for the help. If any of you lives in Seattle and has a place to work, please let me know!

If you peel most of the gaskets off before you put on the gasket remover it shouldn't be much of a problem...however I don't think it will touch permatex. A little sealer around the dowels is fine, as long as its a LITTLE bit and not a blob. If you have sealer on it all I can say is: happy scraping!!

staniel wrote:

Dangit. My Clymer manual said to put some around the two dowel bolts! I used the black stuff, though, so maybe it'll peel off with a wet rag...

as long you didnt smear ALL OVER the gasket then your ok