Topic: Dating my engine. Help please?

[My73andme]

CB750E - 2437088

I don’t have my frame vin at the moment but I’m wondering if my engine possibly got swapped over the years with a new one as I’m having trouble with the countershaft seal.

I found this chart online...maybe my engine is a 76..?

[My73andme]

Oh Frame and it’s registration are 1973

[Bowswell]

http://www.sohc4.net/cb750k-serial-numbers/

[ekpent]

 It does look to be a 1976. Saw your other thread and that year did not come with an automatic chain oiler. I like this chart  http://www.hondachopper.com/engine/engine_timeline/timeline.html

[My73andme]

Thanks bowswell but that chat isn’t helpful I think maybe cause I’m on my phone but it cuts off the end of the cart.

Ekpent: yea crazy hahaha I bought all kinds of stuff for a 73 engine like a clutch gasket, seal and screws for the covers. Any idea you know if they can still be used on a 76 engine (thread the same) ?? Could this be a reason why my countershaft seals won’t push in correctly (difference of a mm or something)? I also bought a 4 into 4 carb set up that I hope will be ok but I’ll contact murray about that. Looking to also get exhaust....I guess It would be ideal to find out what year exactly engine I have so that I can order parts and tins appropriately ya know.

Are there any other major differences I should know about if my frame is a 73 and my engine is a 76???

Thanks guys!!!

[My73andme]

Ok so would a “k3” be a 1973 and a “k6” mean a 1976? When was F? There’s talk about the 79 engine not being a great one..doesn’t matter for this just trying to understand this whole dating game.

[ekpent]

 It just works out that the a K1 for example is a 1971,K3 is a 1973,K6 is a 1976. As for parts most of them will work for all K model 1971-76 like screws, gaskets,round top carbs with correct jetting etc.. There may be a slight difference in the 1976 clutch plates and basket though from earlier years.
  A 1979 CB750 engine is a whole other beast as it is a double overhead cam design and totally different then the previous years.

[MikeSimon]

Well, there should be absolutely no doubt the the engine with  a 24.. leading the serial number is a 1976 engine.

1976 was the first year Honda actually called the bike a "K'76". Previous years were K1 through K5 for 1971 through 1975. The first year 1969/1970 was just CB750 and later a "K0" was unofficially adopted.

The "F" was a different animal. Introduced in 1975 as a CB750F with a 4-1 exhaust and a "sportier" styling. Also officially called a F'76 (F'77, F'78 etc) from 1976 on.

[My73andme]

You all are the best!!!!!

MikeSimon so do I have a k76 or an f76??

[Jerry Rxman Griffin aka MuthaF'er]

It is NOT a F

[PeWe]

It just works out that the a K1 for example is a 1971,K3 is a 1973,K6 is a 1976. As for parts most of them will work for all K model 1971-76 like screws, gaskets,round top carbs with correct jetting etc.. There may be a slight difference in the 1976 clutch plates and basket though from earlier years.
  A 1979 CB750 engine is a whole other beast as it is a double overhead cam design and totally different then the previous years.

My K6 is like the earlier but has the later clutch fibers. Not with double metal in the middle. The clutch aluminum parts are same as the earlier K2-K5.
The outer fiber disc has wider tabs and slanted.
I use EBC CK1145 in my K6. (CB 750 K6/K7/F2 1976-78). My K6 has the oiler stuff too for drive chain which can start to splash oil each time I remove front sprocket and forget to tighten the small screw that push a rubber inside.
K7/F2 has deeper clutch hub to house the double metal.

[kmb69]

Well, there should be absolutely no doubt the the engine with  a 24.. leading the serial number is a 1976 engine.

1976 was the first year Honda actually called the bike a "K'76". Previous years were K1 through K5 for 1971 through 1975. The first year 1969/1970 was just CB750 and later a "K0" was unofficially adopted.

The "F" was a different animal. Introduced in 1975 as a CB750F with a 4-1 exhaust and a "sportier" styling. Also officially called a F'76 (F'77, F'78 etc) from 1976 on.

It's amazing to me how some people can dream this kind of crap up!
Honda never used the K? designation on CB750's until K1. The K0 was unofficially adopted to differentiate CB750 Sandcast and Diecast, the latter being called K0.
Honda was required by US DOT to assign specific models to specific years and had to put the year model on their VIN tags beginning 1976.
The K6 was never called a K'76 by Honda. They referenced ('76) in their shop manuals but they were officially designated CB750 K6 models.
The K7 was never called a K'77 by Honda. They referenced ('77) in their shop manuals but they were officially designated CB750 K7 models.
The K8 was never called a K'78 by Honda. They referenced ('78) in their shop manuals but they were officially designated CB750 K8 models.
The F1 was never called a F'76 by Honda. Could not find ('76) referenced in their manuals but they were officially designated CB750 F1 models.
The F2 was never called a F'77 by Honda. They referenced ('77) in their shop manuals but they were officially designated CB750 F2 models.
The F3 was never called a F'78 by Honda. They referenced ('78) in their shop manuals but they were officially designated CB750 F3 models.

Examples attached.