Crack in cylinder head when tacho gear removed

Hi,
I got a crack in the cylinder head when I removed the mechanically driven tachometer gear. The crack caused bits to fall off the mounting hole of the tacho gear.

When I put it back in the rubber seal barely covers the gap caused by the missing bit in the cylinder head.

Any ideas how to fix this ?
I dont really want to replace the whole cylinder head.


Image: [img size=(01-499)]H:\My Documents\My Pictures\Z750\Kawa 750 taco.jpg[/img]

is it leaking? got a picture?

take the head in to a good welder and get him to weld it up then get an autometer motorcycle tach and trigger it off your ignition coils.

Dont know if its leaking since I just pulled the engine out. I dont want to glas blaster and polish the cykinder head and then find out that it leaks oil.

Image: [img size=(01-499)]H:\My Documents\My Pictures\Z750\Kawa 750 head 2.jpg[/img]

Sounds like a good option Timebomb..

Do you have any experiense off chemiacal metal ?
One alternative is to put it back in and then seal it up with that stuff. Or weld seal it up with weld.

Got some time to make up my mind. It´s winter in sweden now so I have 5 months to fix it.

I have used JB WELD to repair cracks in cylinder heads and water plates in outboard boat engines. And it holds. Just as long as the crack is properly prepared and the JB Weld is mixed and applied as directed, you shouldn't have any problems. Sanding and filing of a JB weld repair usually can be done with a Dremel tool and finished up by a good old fashioned hand sanding to match surface contours. TIG welding is another fix, but depending on the severity and location of the crack, will depend on how much machining work will be needed afterwards. - Good Luck!

i hae found over the years it is almost impossible to keep the tach drive area sealed up for an extended period of time also the cables are a hassle i have spun more than a few out so i just normally block that off and either go with out or if it was important then i'd go with an electronic set-up if your doing a resto on the bike then you would have to fix it but if your hotrodding it then do what ever works for you.

Unomike, will check JB Weld out and see if I can get it in Sweden. Might find something similar.
Is it two components that are mixed before application ?

Time, I get you, less hassle to weld i shut and go with a modern tacho.

I´m building a modern cafe racer...sort of. Will do the modifications that I feel like. Planning a GS swing, wide back tire and some glas blastering since I just bought one
Would like to keep the original tacho since it keeps the retro feel.

Heres some pix:
#1. The bike when I fist saw it.
#2. After first reduild
#3. Breake down, winter reno

Arnold wrote:

Unomike, will check JB Weld out and see if I can get it in Sweden. Might find something similar.
Is it two components that are mixed before application?

Yes, Part A and B. Good Stuff. Should be available in your country. There are other products out there that claim to be as good as JB Weld. But I have had the best results with JB Weld. Keep me posted with the repair!

Hey Uno,

Did a search and saw that JB Weld is the only one that works for temp up to 260 degrees Celsius.

Found it at the US Ebay at first and then a small importer in Sweden that stocks it !
Will buy this and some other stuff.

Will get back to you with some pix when I´m done. Will take some time since this is the last thing I´ll do with the cylinder head.

Thanks again,
Arnold

Fixed the crack up wiht JB weld. Rock hard stuff..I feel 100 % confident that this will hold.

Before:


Aftter:

Before: