Topic: I'm learning more about K0's every day!

[Terry in Australia]

Well I think it's interesting, but I am easily amused, I guess?

Today I received 2 large boxes today from Hondaman (Thanks for shipping them for me Mark, your packing skills are first class!) containing my latest EBay bargains, a set of (like new) 836cc pistons (probably an "Action Fours" kit) and bored cylinders, a ported head with stainless steel valves, an Andrews "K" grind cam in "as new" condition, cam towers, rockers, cam cover, oil filter cover, nuts and bolts, etc etc. All in all, a bargain for 100 bucks! (plus shipping, boo hoo................)

Now the seller (not HM) said they were from a 1975 "Supersport" drag bike, but on closer inspection, I saw that this couldn't be correct, because the cylinder block didn't have the deeper holes for the sealing rings that all the 750 engines had after 1974, (?) and then on closer, closer inspection, realised that there was no centre front hole for the 6mm bolt that secures the head to the cylinder block on all engines from the K1, so it's a K0 head and cylinder block!

I've never disassembled a K0 before, but I knew about the one less 6mm screw etc, but what I didn't know.............. (hang on to your collective hats) ................ is ................ (drum roll)......................... there are no removable oil jets on the K0 head! There is a depression in the casting, and I presume that you still fit two little "O" rings in there like you do on the end ones, but all there is, is two tiny drillings in the depression, and that's it!

Did you know that? Oh, you did? Well why didn't you tell me? Ha ha, Cheers, Terry.    

[754]

What the heck was that listed as
 I even went and looked back then..did not find.

Did you ship to HM because they were US only?..and/or to get it looked over to see if it was worth sending over the pond??


Speaking on KO.. my last name ends with KO..!! HAH!!!

Parts coulda been on later bike, some buy exchange cylinders.. and heads..

[Terry in Australia]

Geez mate, what's your surname? I knew a bloke called Kovko, but that's the only name I know that ends in KO, ha ha!

Here's a link to the auction, I should get in touch with the seller and see if he still has the crankcases, I wouldn't mind a spare complete K0 engine. Cheers, Terry.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=140165853448

[BobbyR]

Well you can imagine that a KO engine would be different than the later models. They designed and built the motor in a about a year so after a lot of miles out on the real world they found areas that needed a change.   

[Terry in Australia]

Yeah, as the head's already been modified (porting) I'm thinking about drilling the head for oil jets like the later engines. As I can't remove the "jet" at the moment, I can't see whether there's any crud (like a blob of silicone) blocking the other side, just waiting to eat these expensive components, in a spiteful act of mechanical terrorism against a poor harmless Aussie!

[bryanj]

OK Terry, i looked in my early parts book and the orify (12238-300-010) are fitted to K2 and after and there are 3 heads 12200-300-060 (CB750); 12200-300-070(K1) but these both supercede to 12200-300-405

These numbers are from an American Honda parts book dated January 1974, if you insist i will try and get time to scan it to a cd

[754]

LOL @ orify... R U sure its not orifi?

[Terry in Australia]

OK Terry, i looked in my early parts book and the orify (12238-300-010) are fitted to K2 and after and there are 3 heads 12200-300-060 (CB750); 12200-300-070(K1) but these both supercede to 12200-300-405

These numbers are from an American Honda parts book dated January 1974, if you insist i will try and get time to scan it to a cd

G'Day Bryan, so are you saying that the oil jets weren't fitted to the K1 either? But the K1 has the front centre 6mm bolt that secured the head to the cylinder block, unlike the K0, right? Hmmnnn............ I've got a reprint of a parts manual somewhere, so I'll check it out! Cheers, Terry.

[Bob Wessner]

But the K1 has the front centre 6mm bolt that secured the head to the cylinder block, unlike the K0,

I thought this center bolt was introduced at some point along the K0 production run? All very confusing.

[bryanj]

well, the book i have shows the bolt for all the listed bikes although it does chenge part number to make it a "flange" bolt.
Was it only the very eary that didnt have it?

[Terry in Australia]

well, the book i have shows the bolt for all the listed bikes although it does chenge part number to make it a "flange" bolt.
Was it only the very eary that didnt have it?

My "Diecast" K0 doesn't have the flange bolt, it's a January 1970 build. I had a K1 years ago, and swapped the head with that from a K2, so I'm guessing it did? (My current K1 is a "bitser", with a K6 engine)

[oldfart]

Well I think it's interesting, but I am easily amused, I guess?

Today I received 2 large boxes today from Hondaman (Thanks for shipping them for me Mark, your packing skills are first class!) containing my latest EBay bargains, a set of (like new) 836cc pistons (probably an "Action Fours" kit) and bored cylinders, a ported head with stainless steel valves, an Andrews "K" grind cam in "as new" condition, cam towers, rockers, cam cover, oil filter cover, nuts and bolts, etc etc. All in all, a bargain for 100 bucks! (plus shipping, boo hoo................)

Now the seller (not HM) said they were from a 1975 "Supersport" drag bike, but on closer inspection, I saw that this couldn't be correct, because the cylinder block didn't have the deeper holes for the sealing rings that all the 750 engines had after 1974, (?) and then on closer, closer inspection, realised that there was no centre front hole for the 6mm bolt that secures the head to the cylinder block on all engines from the K1, so it's a K0 head and cylinder block!

I've never disassembled a K0 before, but I knew about the one less 6mm screw etc, but what I didn't know.............. (hang on to your collective hats) ................ is ................ (drum roll)......................... there are no removable oil jets on the K0 head! There is a depression in the casting, and I presume that you still fit two little "O" rings in there like you do on the end ones, but all there is, is two tiny drillings in the depression, and that's it!

Did you know that? Oh, you did? Well why didn't you tell me? Ha ha, Cheers, Terry.    

Terry -- It isn't just KO heads.  The removable oil jets didn't appear til at least 72.  Check the factory parts book. 

[CB750F2]

G'Day Terry. Just to make things more confusing the head on my K1 motor has the removeable orifices. Mind you the head may not be K1 but check out the part nos in this web site - http://www.crotchrocket.com/fiche_select.asp?vcc=Motorcycles&mfg=Honda&year=1973 Are there any distinguishing marks on these heads? Pat