Author Topic: 1977 CB750F1 Project UK  (Read 4350 times)

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Offline martin_uk

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1977 CB750F1 Project UK
« on: April 26, 2014, 01:36:19 AM »
I recently bought this bike from a friend, who initially purchased via Ebay, primarily  for the engine, as his had blown.

The bike had a replacement engine fitted  and also came with the original which had seized whilst standing.

He thought it would just need a strip, light hone and new rings.

I viewed rolling frame and didnt seem too bad with rusting and deterioration to be expected and nearly new tyres :)

It appeared largely original and had only 16,000 miles recorded. My plan was to do a full restore and keep original spec and genuine parts where possible.

I have partially restored a CB400f beforeand spent quite alot correcting problems by PO, so was pleased this was largely unmolested.

I have restored a few other bikes  and am just finishing a C90 that sat outside for 25 years, so was a bit doubtful that engine would need minimal work.

I had not seen the engine as it was at his workshop.

A price was agreed and he would drop off bike and engine.

When I saw engine, it looked quite corroded and plugs were removed, so my doubts increased, but I like a challenge!

I started stripping the bike and sorting into piles for powder coating, chroming, zinc plating and parts that needed no work.

There wasnt much in the no work required, apart from number plate, ignition switch and keys :(

Lists were started and I began to research prices.

I have had a few Hondas and currently have 4 in various states of repair, so have used David Silver quite alot.

Parts prices seem to be going up very quickly and before I new it I had ordere over £1200 of parts and that did not include engine as not yet stripped! Images to follow. 
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #1 on: April 26, 2014, 01:52:15 AM »
« Last Edit: May 01, 2014, 11:02:01 AM by martin_uk »
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #2 on: April 26, 2014, 01:58:13 AM »
« Last Edit: May 01, 2014, 11:03:17 AM by martin_uk »
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #3 on: April 26, 2014, 02:12:27 AM »
« Last Edit: May 01, 2014, 11:08:20 AM by martin_uk »
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

Offline Hon3ybadger

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Re: 1977 CB750F1 Project UK
« Reply #4 on: April 26, 2014, 02:13:25 AM »
what is that worm looking thing in the cylinder?

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #5 on: April 26, 2014, 02:15:55 AM »
what is that worm looking thing in the cylinder?

Dont they all have them? Was quite a surprise to me too!

It is grease someone squirted in.
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #6 on: April 26, 2014, 02:19:16 AM »
https://flic.kr/p/njw95C

Still trying, will delete once I find best way to display image
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #7 on: April 26, 2014, 02:28:16 AM »
what is that worm looking thing in the cylinder?

I have been told its an early worm drive  8)
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

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Re: 1977 CB750F1 Project UK
« Reply #8 on: April 26, 2014, 07:58:09 AM »
That engine will be a project but, given your past experience, nothing you cannot handle.

Looking forward to your restoration as is David Silver Spares' profit margin!
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #9 on: April 26, 2014, 03:25:35 PM »
An overnight soak in diesel and a bit of persuasion with a 2x2 block of wood and a dead blow hammer and the Number 3 piston came out.

I have just ordered the 836cc piston kit from Cruzin Image on Ebay.

Bit of a gamble as price seems very cheap at $149, but willing to take a gamble.

Crankcase front right mounting had a piece broken off. Will see if it can be built up with weld once I have split cases.

2014_0425cb750B40030 by nitram2010, on Flickr
2014_0426cb750B40008 by nitram2010, on Flickr
2014_0426cb750B40010 by nitram2010, on Flickr

« Last Edit: May 01, 2014, 11:12:01 AM by martin_uk »
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #10 on: April 26, 2014, 03:37:27 PM »
An overnight soak in diesel and a bit of persuasion with a 2x2 block of wood and a dead blow hammer and the Number 3 piston came out.

I have just ordered the 836cc piston kit from Cruzin Image on Ebay.

Bit of a gamble as price seems very cheap at $149, but willing to take a gamble.

Crankcase front right mounting had a piece broken off. Will see if it can be built up with weld once I have split cases.

[/url]2014_0426cb750B40001 by nitram2010, on Flickr[/img]

[/url]2014_0426cb750B40008 by nitram2010, on Flickr[/img]

[/url]2014_0426cb750B40010 by nitram2010, on Flickr[/img]

[/url]2014_0426cb750B40011 by nitram2010, on Flickr[/img]
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #11 on: May 01, 2014, 11:15:51 AM »
Unfortunately combustion chamber has badly corroded and eaten into edge of valve seat, may be too expensive to repair
2014_0425cb750B40023 by nitram2010, on Flickr

2014_0427cb750B40009 by nitram2010, on Flickr

Anyone got a head?
« Last Edit: May 01, 2014, 11:23:06 AM by martin_uk »
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #12 on: May 02, 2014, 12:58:49 PM »
Frame stripped and off to strip and powder coat
2014_0502cb750B40053 by nitram2010, on Flickr

2014_0502cb750B40057 by nitram2010, on Flickr

Before and after engine mounting mod to allow easier fitment.
2014_0502cb750B40041 by nitram2010, on Flickr

2014_0502cb750B40049 by nitram2010, on Flickr
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #13 on: May 02, 2014, 01:31:29 PM »
Not sure if crankcase can be repaired as right front mounting damaged.
2014_0502cb750B40096 by nitram2010, on Flickr

2014_0502cb750B40094 by nitram2010, on Flickr
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #14 on: May 02, 2014, 01:35:55 PM »
Nice surprise as centre stand pin was not siezed  :)

2014_0502cb750B40050 by nitram2010, on Flickr

Was going to struggle to remove spring first, but decided to drift pin out with spring fitted.

Seemed to work OK so will try doing this on reassembly rather than the washer method.
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

Offline martin99

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Re: 1977 CB750F1 Project UK
« Reply #15 on: May 02, 2014, 03:41:46 PM »
Hello mate, from one Martin in the UK to another :)

That's one serious project you've got there with that engine! Can't you rob the head and cases off your spare or are they not compatible?

Here's hoping you don't find too many more nasty surprises as you continue. Watching with interest, good luck!
Build threads:
77 750F2 Refresh Project http://forums.sohc4.net/index.php?topic=144075.0
TRIBSA http://forums.sohc4.net/index.php/topic,160296.0.html

1977 CB750 F2
1958 Norton Model 99
2011 Triumph Street Triple 675

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #16 on: May 03, 2014, 05:43:25 AM »
Hello mate, from one Martin in the UK to another :)

That's one serious project you've got there with that engine! Can't you rob the head and cases off your spare or are they not compatible?

Here's hoping you don't find too many more nasty surprises as you continue. Watching with interest, good luck!

Unfortunately, my friend kept the engine that was fitted in the bike and I am trying to resurrect the seized one !
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #17 on: May 11, 2014, 02:49:52 AM »
Cylinders dropped off to rebore to 836cc (65mm)

I was a bit concerned about taking that much out, but machinist used to do these in the past and had no concerns, but extra cost as normal rebore was £120 and overbore £160

Cleaned up second hand head I bought on Ebay, valves and seats look OK.

Surprised at how rough original  casting is on one inlet tract, may get it smoothed out.
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #18 on: May 11, 2014, 02:59:15 AM »
I bought a new set of DID rims and aftermarket spokes from DS.

Decided to have a go at doing wheel  rebuild my self.

2014_0504cb750B40010 by nitram2010, on Flickr

2014_0504cb750B40018 by nitram2010, on Flickr

2014_0504cb750B40027 by nitram2010, on Flickr

Started on front first and looked OK until I started tightening and spokes were pushing through nipples.

I did not have angles right, so stripped and started again, I blame the wine I had drunk :-[

Worked OK in the end and rear only took an hour :)

2014_0507cb750B40031 by nitram2010, on Flickr

2014_0507cb750B40033 by nitram2010, on Flickr
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #19 on: May 11, 2014, 03:04:40 AM »
Rear wheel bearing  retainer woes.



Retainer was very tight all the way out, made a tool to turn but would only move with a punch hammered at an angle.

Ended up destroying retainer.

2014_0507cb750B40025 by nitram2010, on Flickr

2014_0507cb750B40023 by nitram2010, on Flickr

Looks like corroded in.

CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

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Re: 1977 CB750F1 Project UK
« Reply #20 on: May 11, 2014, 08:15:43 AM »
Nice job on the wheels.  Next time (if there is one) you might try a soak in penetrating oil and then some heat.
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #21 on: May 13, 2014, 11:05:44 AM »
Nice job on the wheels.  Next time (if there is one) you might try a soak in penetrating oil and then some heat.

Thats what I thought would help, but still a struggle despite this :'(
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

Offline martin99

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Re: 1977 CB750F1 Project UK
« Reply #22 on: May 13, 2014, 11:42:52 AM »
For future reference, next time drill out the centre-punch stakes around the retainer. Doesn't look like you did this from the pics ::)
Build threads:
77 750F2 Refresh Project http://forums.sohc4.net/index.php?topic=144075.0
TRIBSA http://forums.sohc4.net/index.php/topic,160296.0.html

1977 CB750 F2
1958 Norton Model 99
2011 Triumph Street Triple 675

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #23 on: May 16, 2014, 12:57:58 PM »
Just picked up cylinders after borede out to 65mm.

Will add some pics later

Managed to get broken bolt out of right front engine mount, now need to get crankcase welded up.
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA

Offline martin_uk

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Re: 1977 CB750F1 Project UK
« Reply #24 on: May 25, 2014, 12:21:12 AM »
A quick update.
Frame back from blast and powder coat.

2014_0519eng0017 by nitram2010, on Flickr

Tank in primer and complete.

tank in primer by nitram2010, on Flickr

Tank underside almost finished by nitram2010, on Flickr

Tank almost finished by nitram2010, on Flickr

Ready to fit up.
tank with decals004 by nitram2010, on Flickr
Zinc plating
2014_0519eng0015 by nitram2010, on Flickr
« Last Edit: May 25, 2014, 12:25:53 AM by martin_uk »
CB750F1, CB750K8,  Triumph Street Triple R, AJS 350, Triumph 3TA