TOPIC:

pretty tough motors...bet it is more good than bad from here.....

Those holes could help cooling, but I'm not sure. Could help, could hinder, heat transfer is like that.

Lets see her internals haha.

T_Dub wrote: Those holes could help cooling, but I'm not sure. Could help, could hinder, heat transfer is like that.

Lets see her internals haha.

If you were to measure the surface area that was removed from the fins by drilling (the area of the circle the diameter of the hole x 2 for top and bottom of fin) and compare it to the surface area of the metal exposed by cutting the holes through the fin (which is quite thin), I suspect it’s a fairly even trade off. When you then consider that the air passing down through the holes may be less than the air flowing across the surface of the fins the holes may actually reduce the transfer of heat from the fins to the air. In any case, I doubt the holes improve the cooling of the fins but probably don’t diminish the cooling any appreciable amount. Maybe the previous owner just liked the look of holes in his engine?

650ed wrote:

T_Dub wrote: Those holes could help cooling, but I'm not sure. Could help, could hinder, heat transfer is like that.

Lets see her internals haha.

If you were to measure the surface area that was removed from the fins by drilling (the area of the circle the diameter of the hole x 2 for top and bottom of fin) and compare it to the surface area of the metal exposed by cutting the holes through the fin (which is quite thin), I suspect it’s a fairly even trade off. When you then consider that the air passing down through the holes may be less than the air flowing across the surface of the fins the holes may actually reduce the transfer of heat from the fins to the air. In any case, I doubt the holes improve the cooling of the fins but probably don’t diminish the cooling any appreciable amount. Maybe the previous owner just liked the look of holes in his engine?

Well there's something else going on too. Sometimes in electronics you'll see heat sinks where the fins are all chopped up. This improves cooling somewhat because the longer a flat plate is, the less cooling you get when you flow air across it. Has to do with the thermal boundary layer growth and such. basically aerodynamics principles. So the holes could have a similar effect, improving cooling. I'm sure in this case its negligible though.

it looked ricky racer and was easier than real work...imo

POP Yosh used to drill the fins for extra cooling, so i fiured if it was good enough for him, its good enough for me. so i drilled mine too. but he did the block not the head.

i see that your head has been drilled tapped and fitted with allen head bolts ,in the oil galeries. this tells me that it was used in a dry block settup at some time in its life.

Thanks for the advice guys,keep it coming please!

Mark, what is the advantage ( or not !) of a dry head job, i did a search but couldnt find anything on it...is there anything else I should be aware of before I tear into it.i have a Clymer manual
Was going to get busy tonite but just got home from work and I'm pooched!

Cheers
Mick

The KZ's r known for leaks around the cyl block, top and bottom. the oil passes through the bock, via the 4 outer cyl stud holes. Then it goes into the head. Some guys bypass the block with external oil lines that go into the head like yours, to help prevent oil leaks.
It looks kind of trick, but is a luxury more than a necessity. Since this has been done, u may find that some other mods have been done when u get into it, such as porting or under shim buckets and high lift cams. Dry blocking, is a mod that u would do last, rather than first.
I’ll try to find a thread about it for u. there r some good 1’s here.
heres a good post by a member.
kzrider.com/forum/2-engine/324427-how-to...block-your-kz9001000

Thanks Mark, that does look trick. I peeled the cam over off when I got back tonite,the inlet cam says " made in USA " EP 14

And I thought Kawis were made in Japan!!!! I ll dig a little deeper later

Ok experts, what have I got? !
! It says CWC made in USA 1.5 EP14 on the cams with 37.75 lift on both intake and exhaust, slotted cam sprockets.

The valves are 35 mm intake and 30 mm exhaust .

The bore is 72 mm .

I searched on this site,nothing comes up?

1075cc

You have a 1075 with cams. The CWC should be the foundry and the EP14 is the core or blank #. Look for something stamped on the end of the shaft for the manufacturer that ground them. Call Star racing and see if they can give you any info.
Pitstop Performance can repair those holes in the fins if you are restoring it. If not, drill the cylinder fins too.