Model Identification and bearing issues

[Saddler77]

Hi people, I am looking for some advice as I am rebuilding a CB750. First issue I have is identifying the exact model, I believe it is a CB750 f2 (1977) but the frame number and engine numbers do not tally with anything I can find on the internet.

Frame number is CB750G-1000116
Engine Number is B750GF-1000024

If it is a CB750F2 though, those numbers do not match what I am finding on various websites.

The other question I have relates to steering bearings, according to the parts file I have it should have standard bearings fitted but mine has tapered ones. The reason I ask is even though I have replaced the bearings and tightened everything up there is still a bit of play in the yoke. I am use to working on modern bikes where this sort of play would be excessive but is this normal for a CB750??

I am sure I will be coming up with more questions but any advice on the other 2 questions would be much appreciated

[Spitfire]

Hi there, can't help with the Chassis and engine numbers (are you in the UK ?), an expert is bound to be passing soon, I have an F2 (1977 S Reg) and the engine and frame numbers are pretty similar to yours.
As far as steering head bearings go most people change the standard bearings to taper roller ones, you can get kits from various dealers. If fitted correctly there should be no excessive play at all, do a search on the site for taper roller bearings you get some interesting results. Here are a couple of them:

http://www.sohc.co.uk/index.php?topic=2734.msg8460#msg8460

http://www.sohc.co.uk/index.php?topic=2501.msg6892#msg6892

Cheers

Den

[SteveD CB500K0]

A photo will help us to identify the model too! (We like photos)

Steve

[Bryanj]

That engine number should be GE and the "G" denotes a probable UK model tho' its supposed to mean general export and don't show up on searches as most of those are based on US models

[UK Pete]

My F2 enginge starts B750GE and frame cb750G ,I think you will find all UK models have this numbering, but USA ones dont
Pete

 

[Spitfire]

Just checked my frame and engine numbers are:

Frame number : CB750G-1000XXX
Engine number : B750GE-1000XXX


Cheers

Den

[Seamus]

Just a thought regarding the taper bearings and play in the head. Possible the spacer has been missed out.

[Saddler77]

Cheers for the advice guys, it would appear it is what I thought then. Just the US frame numbers confusing me. I have attached a couple of pics, sorry about the quality but they were took on my mobile and now the bike is a bare frame so not much to see there!

As for the bearings I am certain I have all the spacers there, I have tightened everything up as much as I dare and it seems OK. I have got a mate who worked for Honda in the 70's coming down to look at it on Saturday so hopefully he will give me a clue

[Hinomaru]

Hi people, I am looking for some advice as I am rebuilding a CB750. First issue I have is identifying the exact model, I believe it is a CB750 f2 (1977) but the frame number and engine numbers do not tally with anything I can find on the internet.

Frame number is CB750G-1000116
Engine Number is B750GF-1000024

If it is a CB750F2 though, those numbers do not match what I am finding on various websites.

The USA numbers are different, note the frame and engine numbers on the UK 750 F2:
 
http://www.cmsnl.com/honda-cb750f2-supersport-england_model14689/partslist/

Many more CB750 models here: http://www.cmsnl.com/honda-cb750-four_model14344/
 

[Bryanj]

Its an F2, bet the exhaust valve guides are worn out!!

[F2 Paul 876]

Hi here is the frame and engine numbers for F2's from the Honda parts book.
Hope it helps, looks like a F2 but if imported from the states it could be a F3 which was there version.
Paul

[kaceyk2]

Bryanji, this may interest on the topic of worn out f2 valve guides....on taking my f2 head to the engineering shop (when I had an f2 ) and presenting him with the head and proudly handing him a band new set of phospher bronze guides, my joy was short lived. "you dont want those in there" he said. I asked why? he said that the phospher bronze ones are the same as they use in some honda cars (the Accord I think) and they dont last compared to the original sintered ones...when I explained that neither do the original ones in the f2 head..he looked at me like I was an alien and clutching the phospher ones and shaking them near my face said "these will last even less, but I will fit them if you insist"  I didnt insist and still have them!

[Yoshi823]

I made some new valve guides out of aluminium-bronze, but not exact copies of the originals...I made my ones slightly longer where they protrude into the exhaust/inlet ports. This did not upset flow but did support the valve stem better. The material that I used was also better for dissipating the heat from the valve stem to the cylinder head far better.