Author Topic: 1974 750 K4 Restoration  (Read 1090 times)

Offline 71 V12

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1974 750 K4 Restoration
« on: February 05, 2018, 11:01:24 AM »
Some time since I last posted so thought I would give a quick update of progress on my K4 restoration. Original bike as bought is the usual US import, left outside in albeit a "dry" climate but weather seized and surface on all chrome parts.

Soaked the cylinders in Diesel for a week (got to do something with the demon stuff now it been condemned), after gentle rocking back and fro the engine freed off. New coils, cleaned carbs, new points and remote fuel, she started and ran well. The noise really pissed of the miserable woman next door which was also fun.

Nonetheless the kick start return spring wasn't returning and given the state of the rest of the bike an engine strip would be in order.

By and large anything electrical needs replacing or restoring. I am going to powder coat switches and see if I can restore them. Calliper and master cylinder seized. But all in all it more or less complete and a good challenge.

Hopefully the video loads?

Offline 71 V12

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Re: 1974 750 K4 Restoration
« Reply #1 on: February 05, 2018, 11:21:59 AM »
So that was where I was.
Since then good progress on all fronts.

 - Frame blasted and powder coated frame, swing arm brackets etc.
 - Wheels stripped. rims re chrome plated, hubs polished and rebuilt with new stainless steel spokes and fitted with new conti tyres.
 - Headlamp shell painted, all missing parts sourced and new halogen unit fitted.
 - Good used original taillight sourced and fitted to re-chromed bracket.

More to follow -

Kevin

Offline MCTID

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Re: 1974 750 K4 Restoration
« Reply #2 on: February 05, 2018, 11:26:23 AM »
Good work Kevin.

Congratulations on two fronts......one for having an even 'ropier' looking K4 than my wreck.....and secondly for making yours look much shinier than mine is now.

Looking forward to seeing yours finished (it might spur me on with mine).
Now: 2008 CB1300S, CB750K4, 1970 Bonneville. Various other 1960's 650 Triumph T120's/ TR6's/ TR6C's (all in bits...many, many bits unfortunately). Previous: 2007 CB600FA, 1976 CB500 Four. BMW F800ST. GS750E. ZZR1100. CB1300 (2). ZXR1200S. VFR800. CB750 Nighthawk. CX500. XS500 Yam. Suzuki GT500. BSA A10. Various Lambrettas. Zundapp Bella (honest).

Offline Rob62

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Re: 1974 750 K4 Restoration
« Reply #3 on: February 05, 2018, 01:14:47 PM »
Nice one, looking good.

I am also doing a USA K4 but mine already runs and is generally only in need of a clean and re-commission... however as such it will not be as shiny as yours when its finished... :o

Offline 71 V12

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Re: 1974 750 K4 Restoration
« Reply #4 on: February 05, 2018, 05:33:21 PM »
As mentioned despite the engine seeming to run well albeit in a static situation, I decided to completely strip the engine given it was weather seized and the kick start spring required replacing. Strip down was straight forward, but having only previous experience of old Triumphs I was impressed by the quality of the engineering, materials and maching. OK the bike had just 5k on the clock, but no wear to any of the bearings.

No wonder the Japanese killed the British motorcycle industry. My 67 Bonnie was really 1940's technology. The only real advance over a near 30 year period was to make the engine a unit design which stopped one source of oil leaks!

One issue that came to light though was corrosion to one of the inlet valves on no 1 cylinder. I guess the bike had been parked up on the side stand and no 1 inlet was closed, some corrosion to the seat but nowhere near as bad. Seat cleaned up with a seat cutter borrowed from work and a new valve bought.

Cases have been soda blast cleaned and repainted with rattle can engine paint. The finish is satin so quite subtle. pretty much a case of reassembly with new seals and gaskets and fingers crossed I have not missed anything during the reassembly.

Offline 71 V12

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Re: 1974 750 K4 Restoration
« Reply #5 on: February 05, 2018, 05:45:27 PM »
Realised at this stage I had mounted the engine to my engine stand the wrong way round, so turned round whilst still manageable. Cylinders and head reassembled with out any dramas. Which pretty much brings me up to date.

New chain tensioner and blade, cylinders, head, cam and rockers  fitted.


Offline 71 V12

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Re: 1974 750 K4 Restoration
« Reply #6 on: February 05, 2018, 05:52:04 PM »
Latest job has been to polish the cases and fit. A decent polishing motor and a good selection of mops and compounds makes the job much easier.

Offline haynes66

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Re: 1974 750 K4 Restoration
« Reply #7 on: February 05, 2018, 08:31:05 PM »
nice work. is that a convertible under the tarp?
honda firestorm
silverwing 600 scooter
honda britain project
phil read rep project
YGS1 80cc yamaha
LE Velocette

Offline philward

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Re: 1974 750 K4 Restoration
« Reply #8 on: February 05, 2018, 10:07:52 PM »
Really looking good - progressing well
Current Bikes:-
Honda CB750K2 (1975)
Honda CB500K2 (12/1972)
Honda CR750 Replica (1972)
Honda CB350K0 (1969)
Kawasaki ZZR1100D3 (1995)
Kawasaki ZZR250 (1990) Project (Going on eBay ASAP)

Offline 71 V12

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Re: 1974 750 K4 Restoration
« Reply #9 on: February 06, 2018, 11:22:53 AM »
nice work. is that a convertible under the tarp?

Thank you for the kind feedback.

I am badly afflicted by the restoration bug. Its a TR6 under the cover. Another US import from California and genuinely rust free. The rear of the chassis and under panels still had original factory paint on them, protected by a thick layer of spiders webs!

Dash veneer was also destroyed by the sun. I found the wiring had burnt out due to a bodge to a live feed to the light switch. I assume this is what caused the car to be sold.

Every piece of rubber or plastic was rotted due to ozone or temperature. There were a few dents in the bonnet and the boot lid had been drilled to take luggage rack. But every panel is genuine factory and original to the car, rare for any TR6.

So the TR6 was a nice project and worthy present for my wife finishing her degree as a mature student! The car won best TR6 at the TR register midlands concourse in 2013.

Over the years I have restored in order:

1965 MK1 Morris Cooper S. The only car I regret selling. Bought a basket case TR6 in 1980 with cash.
1971 TR6. Sold in 2000 to buy a basket case E Type. Last seen on antiques roadshow being driven by Michael Aspel I have the video.
1965 Triumph Herald. Sold to an American girl living in Stratford on Avon about 1993. Last seen on The Cars the Star being driven by ex chancellor Sir Geoffrey Howe. I have the video.
1970 Triumph Daytona. Sold at auction about 1993 to pay for a bathroom!
1967 Daimler V8 250. Still owned by my mum.
1967 Triumph Bonneville. Sold to a guy from Sussex.
1986 Daimler Sovereign S3. Originally sold new to the MD of Pirelli UK. I sold it to a guy in Walsall.
1974 Triumph Stag. Stolen from my driveway and never recovered.
1971 V12 E Type. Keeper.
1974 Triumph TR6. Still LHD and owned by my better half.
1991 Kawasaki Zephyr, also a keeper.

The CB750 is my first Honda, and I am really enjoying the challenge of it. The complexity of the engine has surprised me given how old the design is. I assume Honda must have started the CB750 K project around 1966/67. The tooling for the cases and as I mentioned the quality of the machining are impressive given the vintage.

So l love a project, and bikes are more manageable now. Still lots to do on the 750 to keep me busy - for now!

Offline K2-K6

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Re: 1974 750 K4 Restoration
« Reply #10 on: February 06, 2018, 01:07:53 PM »
The CB750 is my first Honda, and I am really enjoying the challenge of it. The complexity of the engine has surprised me given how old the design is. I assume Honda must have started the CB750 K project around 1966/67. The tooling for the cases and as I mentioned the quality of the machining are impressive given the vintage. (edit; that is a quote from 71 V12 above but I've wrongly copied it,.  :) )

Interesting comparison. For a long time I've looked at these not as old bikes,  but as a precursor to much more modern car engines. They where doing things,  as you note, back in the sixties that ultimately becomes the accuracy and sophistication of much more current vehicles. Truly far ahead of their time and no wonder they really took over from older bike manufacturers all over the world.

Nice work on the K4,  I'm sure you're going to enjoy riding that when done.

The TR6 is one of the best looking Triumph cars made I think. Lovely proportions,  stance and sound. Something unusual about Triumphs that such a large proportion of their range are interesting designs. All the TR's,  Spitfire, GT6, Herald,  Vitesse,  Dolomite Sprint,  when others made run of the mill,  all of these are interesting and worth owning.

I like the TR8 also, especially in rally guise,  but that's often dismissed by hardened Triumph-isters.
« Last Edit: February 06, 2018, 02:03:46 PM by K2-K6 »

 

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