Noob to this forum

[pauliexjr]

OMG, am I glad I found this site, I was beginning to think I was the only SOHC owner left in the UK!

I'm Paul, I've been riding bikes for more years than I care to remember, I only passed my car test when I was 21 because the then girlfriend refused to ride pillion!

Latest project is a 1977 CB750 F2 with a genuine 10,700 miles on the clock, a true barn find I got off E-bay in November last year. Unfortunately my garage is huge and drafty and a b*gger to heat so I didn't do much over the Winter (we had 2 1/2ft of snow for most of December and a big part of January!) but now things are warming up I'm getting stuck in.

For anyone who's interested this is what I've got to work with:








My humourist son has already nicknamed it 'Project Rising Sun' and you can see I've got some work to do, but I'll post back as it moves along. :-)

[UK Pete]

Hi Paul, welcome to the forum, there are lots of us F2 owners on here, and i have just finished restoring one and put an mot on the bike today
I have learned absolutely loads about the F2 during the last year or so and now know all its faults and all the fixes to the faults, where to get the bits ect,
They are great bikes and in my opinion the best of the SOHC 750's
Keep us posted on how yours is going and keep the photos coming
Pete

[Spitfire]

That looks like fun, seriously it looks a bit like mine did before I breathed new life into it.

Den

[kaceyk2]

Hya pauliexjr, welcome!  You are not alone, there are thousands of us inSOHC4RA (single overhead four restorers anonymous) here, you are "safe" we will not expect you, or advise you to be "in recovery" we will not tell your misses or immediate family just how much you are spending on this project.
We will not tell auntie that you used your christmas present ( that oh so lovely top) for an oil rag or polishing cloth. members here have even dropped off parts to other members under cover of darkness.
Here, we will not try to encourage you give up your new found "addiction" rather we will help you to embrace it by all means at members disposal... There is a wealth of information here, no problems are insurmountable... and some wonderfull folks to help you through the highs and lows of your restoration...
I too have this addiction, I am an addict, I recently "found" more parts that I had hidden in an upstairs wardrobe... I did not buy "project rising sun" of ebay.. I actually bought "The illegitamate beast of Bodmin moor" off ebay.... heres a pic.... Welcome!!!

[pauliexjr]

Thank you for your welcomes guys, much appreciated, I feel a bit like a new visitor to the AA, "My name is Paul, and I am addicted to lost causes!" I keep telling myself it looks worse than it is, but in my heart of hearts I know both my wallet and my leisure time are in for a serious pounding!  But hey, I'll have some fun, and doubtless some skinned knuckles along the way.

This was my last lost cause about 5 years ago, I did say never again, but back to the AA I suppose....

Before:




and after

[kaceyk2]

hey Paul, lovely looking triumph..brings back memories.... I should get me misses to design a cb750 logo combined with a pic of St.Jude the patron saint of lost causes, and get some cloth badges made up!
When I stripped my cb750k2 down (the one in the picture) I believe that I had less usable parts than you may have... well at the least no more!  Are you going to do it all yourself ( I have so far) or will it be off to the powder coaters etc...?

[pauliexjr]

I'm not sure yet. When my son (eventually) gets his jet ski out of my garage I might have a go at stripping and spraying the frame myself. Certainly the engine strip and rebuild will be down to me and as I'm looking at cafe racing it I've made enquiries with The Tank Shop in Dumfries about a custom alloy tank, but I'll need to save the pennies for that one!

[Bryanj]

1st big common problem check the exhaust valve guides
2nd big common problem finding new piston rings

[popwud]

Welcome Paul.

[pauliexjr]

1st big common problem check the exhaust valve guides
2nd big common problem finding new piston rings

Thanks for the welcome guys. I've seen the posts regarding exhaust valve guides, I've just had the head and barrels vapour blasted so I'm in a good place to check those.

The pistons and valves were coked to hell, but that could be because the bike started life in London and was used for lots of short-trip commuting.

I've got a new set of rings from David Silver so no probs on that.

But, how strong is the bottom end on the F2? I don't really want to split the crank, but I also don't want to build the whole thing back up, then be faced with clattering big ends or rumbling mains when I start it up! It's only done 10,700 miles, so how likely is it that the bottom end's been knocked out? I suppose this is really a post for the techies?

[Bryanj]

Bottom ends are fairly bulletproof, anything can be damaged by an a numpty in its previous life tho'.

As its been in a dissasembled state for so long i personaly would strip and clean out the lower checking the primary chain wear first, cranks are not grindable and shells cost a lot so unless bad tend to get reused. Replace cam chain AND ALL THE RUBBER TENSIONER BITS----its over 30 years old and they get hard and break up.

Apart from the guides and being medicaly clean on rebuild (especially the oilways) thats about it.

I do have the genuineHonda dealer manual for the K8/F2 scanned to disc if you want a copy, postage plus a beer usually works

Cheers
Bryan

[UK Pete]

Hi Paul, Bryan's reply is spot on as usual, he pretty much knows everything to know about F2,s
I took mine apart right down to every nut and bolt, i found that a previous owner had over tighened nearly every small 6 mm bolt bolt on the engine
some of the engine crank casing bolts were snapped off, and nearly all the head 6mm threads needed a heli coil insert as they were all done up well over the torque settings, as well as that silicon had been used on every gasket surface including the head

Anyway i got there in the end and now have a sweet engine,  i replaced the rubber bits for the cam chain and tensoiner , new rings new vaves, new cam and tower plus all the rockers ,

Here is what i learnt about rebuilding an F2 engine, the main things that wear are the valve guides, and it is really worth getting them done, i got mine from DYnoman in the USA,  the valve tips get indented so take a good look at them, again dynoman or cylex in usa sell these, also the valve spring seats crack so check them thouroughly and if your budget allows upgrade them again from the USA guys, when rebuilding the top end get yourself a parts manual and make sure you have every little rubber seal needed, there are four small rubber rings that go on the 4 inner studs at the bottom of the cylinder these get missed easily, them same four studs go up through the cylinder, and head and in the actual head they are not enclosed and so are open to the elements you will notice they are you rusty studs , when they arrrive at the top of the cylinder head they have to have a dome nut and brass washers on them or you will get an oil leak, also the four cam tower bolts some times are drilled right through and need to be sealed as they can get an oil leak that comes out right by your  spark plugs, make sure you renew all the little o rings under the cam towers as well as the four rubber pucks, and if you can get one use a Original Honda head gasket
If your pistons and bores are good then new rings and a light hone and your good to go

As for the bottom end, i would take it apart and clean it right out of any sludge and nasty deposits, its not to hard to do and it gives you the chance to renew the drive shaft and crank seals, which after 30 or so years will be hard and worn , also the primary chains, and tensioner can be inspected or renewed
Last of all as Bryan says rebuild it in a clinical way no dust dirt whatsoever , these F2 bikes have a real tiny oil restrictor in the head and it will block up with the smallest piece of muck or dirt , and so trash your whole top end.
Pete

[K2-K6]

Hi Paul and welcome to the forum.

Just to pick up on something Pete has alredy said, those 6mm bolts that get stripped threads so easily in the casting are really delicate to assemble in as much as it feels when you tighten them that they could not possibly be tight enough but they are. Use a good quality torque wrench of a very light (low) range to get an accurate feel on them, but you'll see what we mean when you do them as it feels no sooner have you started to tighten them then it's done, DON'T be tempted to add a bit more afterwards.

Looks like you've got most of the main bits to start with so can get along way with the basics.

[cbnovascotia]

Hello, glad to have found this forum, it's a wealth of info! My name is Trent and reside in Halifax, Nova Scotia, Canada. I'm currently rebuilding a 1973 CB750k3 engine to one day(year) to be put into a cafe style custom. In the past, restored a 1972 triumph T100R and a 1977 kz1000a which is still my summer runner. I've only had to do topend rebuilds on  those bikes, this CB is a complete teardown and rebuild. Please have patience with my basic questions and input! Hope you'll accept a fellow CB enthusiast from across the pond! Cheers! - Trent
 

[kaceyk2]

cbnovascotia,
Heres an Odd one (me entirely) I was nearly a Canadian!  My Mam and Dad were out there in the fifties (like many folk who went over) my old man was an aircraft fitter and was on contracts. They lived in Montreal, and Ottawa. My old lady got pregnant with me ( not having the slightest inkling I would later "go wrong")
Time passed,  and when she was due to expell me from her internals, my fathers contract was due to expire.
Fearfull that he would not immediately get another contract, which would leave them having to pay for medical expenses (He was not a Canadian Citizen just yet) my Mam went into severe pregnant lady panic overdrive, and returned home to the UK to have me....which she duly did immediately, if she would have "dropped" me on the flight back, I guess I would have no nationality.... My father went on to gain USA citizenship and he has three valid and legal passports, Canadian, UK, and USA...
He made the papers in Canada over a court case for custody of his daughter ( my half sister who now lives in Mississippi) He was the first man in Canada ever to win Sole custody of a daughter/child.
The photos my mam have are amazing, the reds and oranges of the trees in autumn are just splendid.
She has photos of the Niagera falls frozen over in winter....Frozen... wow, I never knew they did this till she dug those photos out...a few years back.  apparently they dont freeze every year?
She has a photo someone took of her hand frozen to her car door handle..when she forgot to put her gloves on....
One day I would certainly like to see where I was conceived ...and nearly born.