Author Topic: CB500 K1 – 1972 – Everyone’s building one, so I’ll give it a try !  (Read 6912 times)

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Offline cantarauk

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A short introduction to me and the build I am taking on.

Growing up I was exposed to all sorts of motor vehicles (mainly cars) as my father was in the car trade who had a great passion for petrol and speed. He also raced various models over the years from fairly modern to classics. So with his passion for all things petrol it was only natural that would pick up somethings from him. I was fortunate enough to be exposed to some bikes growing up for a few years had one of my own.

After moving to the UK from warmer pastures I lost any interest in bikes sue to the weather and now 20 years later feel I have finally acclimatized.

So it is now time to get back on that saddle so to speak.

The idea is to get a donor bike from the 70’s which will need a complete rebuild and brought back to life as a Café race. What I must add at this point that I have very limited mechanical experience when it comes to bikes and fabrication but hopefully all the help I require will be found here amongst the members.

So my project starts with a donor 1972 UK Honda CB500 purchased for £600 which will be torn down and rebuild. There are so many great ideas out there of which I will probably be stealing quite a few. THIS WILL BE A SLOW BUILD AS AND WHEN I HAVE THE TIME.

The game so far is rough but looks like -

-   Strip bike down to frame
-   Strip engine down with a view to replace worn parts

Frame and exterior
-   Shave unused tabs off
-   Weld where required for seat / electrical box
-   Strip paint from tank and fix any imperfections
-   New petcock, cap and latch
-   Custom seat / cowl from BCR
-   Fill and shave top triple tree clamp
-   Black clip-on bars
-   Short 4 into 2 exhaust system from cycle x or other
-   Powder coat all parts

Engine
-   Stripped, paint removed (black) and vapor blasted
-   New pistons and rings only if required
-   Cylinder honed and ported if required and suggested
-   New seals, gaskets etc
-   New valve springs
-   Full carb rebuild
-   New cam chain and cam tensioners
-   Bottom end rebuild with new seals
-   New tappet covers since I do not like the once currently there

Braking & Suspension
-   Rebuild forks and new sanctions (rusted badly)
-   Hagon or other shocks )all black)
-   Bronze swingarm bushings
-   Rebuilt Front and Rear brakes new cables and piston
-   Drilled brake rotor
-   All Ballz tapered headset bearings
-   All Ballz sealed wheel bearings
-   Avon tires
-   Rebuilt wheels with original rims and new spokes

Electrical:

-   New cable harness for all electrical connections
-   New modern Reg/Rec Combo
-   Looking into LED lighting throughout (will review this choice)
-   Triumph headlight with shortened ears
-   Mini tack/speedo
-   Antigravity 4 cell battery
-   Dyna S Ignition with black 5 OHM coils and Dyna wires

I am sure there are a lot of tasks that I have missed or need to think harder about and welcome any comments.

Also below is the picture of the donor.


« Last Edit: November 14, 2020, 05:17:41 am by cantarauk »

Offline Mace

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From a fellow brit to a fellow brit, welcome!

I'm in the process of doing the same thing you are, except mines a 75 cb500. Its a great looking project you have there, and no doubt you have many things to get on with!

Just some advice to you which I never got. Carburetors are a NIGHTMARE to rebuild and reassemble. If you're going to do it yourself then dedicate a month or so to learning how they work.

Get yourself the manual as well,they're worth their weight in gold.

Lastly, don't forget to post picture updates, the members her love pictures.

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Offline Stev-o

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Welcome from Texas.  Looks like a decent bike to start with, how many K's on the clock and is it in running condition?

These motors have been known to run for 100,000 miles without a rebuild, you may be tearing t=down the engine when not needed.
'74 "Big Bang" Honda 750K [836].....'71 Honda 750K project.....'76 Honda 550F.....K3 Park Racer.....K5 Fiddy Dolla Special!......and a Bomber!............plus plus plus.........

Offline cantarauk

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Hi, Thank you both.

The bike has 39k on the clock but not sure how true that is since there is no speedo and tac cable. I have been told that this was running not so long ago but I have my doubts on this as the coil cables are broken and there is no fuel lines into the carbs and the electrics look like they have been eaten by mice or something in one section of the harness.

The thinking around tearing the engine down is based on me seeing different screws,bolts and nuts on the engine itself so I am not sure if this has been disassembled before. Also one way to learn I suppose.

Mace - Following your post looks great. I will be looking at the carb rebuild as I need to move these from the current stay plate as it is broken on the plate and one of the swing arms. I have have a spare pair just in case that I picked up for £30 which is my fallback plan.

See image of carbs that I have taken off


Offline Mace

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Those are some healthy looking cracks you've got there!

If you're going to do the carbs yourself, then I strongly recommend getting an ultrasonic cleaner. http://r.ebay.com/8fXGis
I got this one with some machine parts fluid. Absolutely brilliant bit of kit, and fantastic at cleaning the interiors of the main carb.
Or you could pay someone £200 to do it :-?

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Offline Mace

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Also, don't hesitate to bin stuff you think is past its use by date.

My wiring harness was so manky it practically fell apart in my hand when I yanked it off! Needless to say she got binned!

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Offline cantarauk

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Hi Mace,

Thanks for the advice.

There is going to be a few items that go straight to the bin on initial investigation I am sure of it. I have sourced a guy up North who is willing to paint strip the engine and then vapour blast the engine once in bits and also vapour blast the carbs and then sonic clean them. Needless to say everything has to be stripped down. He will do the lot for £200 which  seems really good.

He has a few examples he has done so will see what quality I can expect before taking him up on this.

Also a question for the community as I am unsure which route to go due to mixed feedback. Should I get the engine bead blasted or just vapour blasted. I would like to get it as clean as possible and then not have to spay it of possible.


Offline martin99

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You moved to the UK for warmer pastures?? What are you, an Eskimo? ;D

Seriously, welcome and good luck with the bike.
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 cantarauk

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Lol - mis-type "From" was ment to be

Offline Bankerdanny

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The carbs aren't that hard to deal with. But invest in a set of proper JIS screwdrivers. The bolts all look like conventional Philips, but they are JIS. Proper screwdrivers will save you some stripped heads.

The biggest pain with respect to the carbs are the tiny screws that hold the slides to the mechanism, which must be removed to get the needles out. They are prone to sticking and stripping.

My experience is that cleaning the carbs and replacing the gaskets takes the better part of a weekend. Reuse your existing jets and needles. They don't generally wear out and you can't trust the brass in the various carb kits to be the sizes they say they are.

That manifold is repairable by a good welder, but it shouldn't be too hard to find a replacement.
"The problem with quotes on the Internet is that you never know if they're true" - Abraham Lincoln

Current: '76 CB750F. Previous:  '75 CB550F, 2007 Yamaha Vino 125 Scooter, '75 Harley FXE Superglide, '77 GL1000, '77 CB550k, '68 Suzuki 80 (K11 probably, it's been 30 years), '68 Yamaha YR2, '69 BMW R69S, '71 Honda SL175, '02 Royal Enfield Bullet 500, '89 Yamaha FJ1200

Offline cantarauk

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Hi Bankerdanny,

Cheers for the advice. I have a set of JIS screwdrivers as it is one thing I picked up from reading numerous posts on this site and thought is a good idea. You are correct on the small screws as I have done some stripping this evening to get the carbs down to bodies ready for a vapour/bead blast then sonic clean and in the process have stripped one. Do you know what size these are so I can replace once I have drilled out ?


Offline cantarauk

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UPDATE -

I have made a start at stripping down this yesterday and this evening and have so far managed to get the carbs out and one of the carbs stripped down. This did not go to plan as mentioned above.

So from the strip down I have removed the fuel tank, seat (held on by a nail I may add) , carbs, front brake callipers (no fluid in so will require a full rebuild), headlight, rear fender, front fender and brake light.

Some images attached but so far off to a good start.


Offline Stev-o

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I'm rebuilding a 750 and had the cases, cylinders and head bead blasted, then vapor blasted.  They came out beautiful!

When it comes to the carbs, I will not bead blast them, just vapor & sonic clean.

Good luck.
'74 "Big Bang" Honda 750K [836].....'71 Honda 750K project.....'76 Honda 550F.....K3 Park Racer.....K5 Fiddy Dolla Special!......and a Bomber!............plus plus plus.........

Offline cantarauk

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Hi Stev-o

Cheers that sounds like the best way to do it. Did you strip it all down to get it done as parts when you have both engine and carbs done.

Also once cleaned have you applied any protected to keep from oxidising or just left it as is ?

Glenn

Offline calj737

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Whether bead or vapor blasted, aluminum will oxidize no matter what. Whether it become neglected looking is dependent entirely upon the care you put into them afterwards. You can polish them with aluminum cleaners regularly, or even use "treatments" to thwart heavy oxidation. But they will oxidize some unless coated.

Personally, I love the look of vapor blasted and cared for aluminum. But if you want a lower maintenance machine, paint or powder coat is probably best. After blasting, an ultrasonic cleaning of the carbs is mandatory, and some effort of the cases too. All oil galleys need to be unplugged and purged with compressed air and fluids. Be mindful to use a non-caustic fluid that won't discolor the aluminum though. Acetone is useful, though a tad pricey in large volumes.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

*** Currently experiencing life at 60 WTFs per hour ***
I always thought getting old would take longer

Offline Stev-o

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Hi Stev-o

Cheers that sounds like the best way to do it. Did you strip it all down to get it done as parts when you have both engine and carbs done.

Also once cleaned have you applied any protected to keep from oxidising or just left it as is ?


Yes, everything needs to be stripped down to parts when blasted. 

No protective products have been applied to my motor, it will be assembled this Fall. 

Time will tell, but I do not believe I will need it. I don't like near the sea (freshwater lake, yes) nor in a super humid climate. I have polished aluminum engine covers that still look good after a few years after being polished.
'74 "Big Bang" Honda 750K [836].....'71 Honda 750K project.....'76 Honda 550F.....K3 Park Racer.....K5 Fiddy Dolla Special!......and a Bomber!............plus plus plus.........

Offline eddiebpool

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Hello from (not so) sunny Scotland!

With regards to the engine painting issue, I want for a mix of paint and polish.  The paint I used is VHT Engine Enamel.  The paint colour "Aluminium" is very close to a classic Honda paint though I went for "Cast Aluminium" instead.  It doesn't look much different when its dull but sparkles in the sun.  Not a "stock" look but I really like it.  It is a 3 part - primer, colour and lacquer.  You will probably need two cans of each for an engine.  I would heartily recommend baking all parts before you rebuild the engine.  The paint isn't properly hardened until it has been through a heat cycle.  You can get away with heating it while running, as long as you don't anything stupid like spill fuel on it before its hard (yes, I did it).  The requirement to heat it is a bit of a pain.  However, the paint goes on really easy and looks great.  You have to be very clumsy to make a mess of it.  You can see some of the results in my build thread:

http://forums.sohc4.net/index.php/topic,137248.0.html

Best of luck, and welcome!

Offline cantarauk

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Hi,

Eddiepool - Thank you for sending a run down of the process you followed for your bikes engine refresh. I have had a look through your post and the engine looks really great especially from where it was when you got the bike. I have been reading a bit today on the VHT paints and this does seem like the best option if I was going to do it myself rather than spend money.

 
Stev-o / Calj737- Going to do the strip down so will have the parts ready for blasting and then think about paint of not to paint once I get them back. I have a feeling that paint may be the way to go as you can see from the condition of Eddiepool's bike when he took receipt the weather in the UK is not that forgiving.



 

Offline cantarauk

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I received a replacement carb stay plate today which will replace the one that is broken. Thank you mickwinf from sohc.co.uk.



Over the past two days I have managed to get some more of the bike stripped down and am glad not to have fond any more mechanical surprises.

The electric on the other hand have seen better days with 2 of the spark cables falling off the coils when lightly touched. There is also a mess as far as the cabling goes with quite a few cables cut and left in the harness which I imaging is not unusual. Also some looks as if they have been eaten by something so I am going o have to do a new wire job.

More picture on the progress


« Last Edit: September 17, 2016, 01:51:04 pm by cantarauk »

Offline cantarauk

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UPDATE -

Strip down continued. I now have a few bags labelled up with parts and components that have come off ready for cleaning/replacing. I have got the bike to the stage where the engine will be coming out next week. Reading the forums I am going to do the old on the side approach to get the motor out. Is there anything I should be aware of when doing this besides draining the bike completely which is already done ?

Once I get the motor out my plan is to slowly start a dry build adding all the new components and making tweak/adjustments. Parts will be coming is slowly as I find the exact component I am after. I have been in contact with BCR and am in the process of designing a seat/cowl that I hope would look good on the bike. I do not plan to make any changes like cutting tabs, welding trays or welding splash guards until I have the seat.   

Id there are any comments or suggestions to my approach I welcome them


Offline calj737

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I find it just as easy to remove the engine single-handed, by removing the oil filter housing, and putting a floor jack under the oil pan (slab of wood between). Lift the motor just enough to relieve the pressure on the mounting bolts, lift the engine up, grab it and pull it straight out onto some towels. It's not unbearably heavy, and you're not carrying it, just liberating it.

Lifting the frame works well too, but it's a bit more gangly. Defintely preferred method for installing, but removal, shucks, jerk that thing outta there!
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

*** Currently experiencing life at 60 WTFs per hour ***
I always thought getting old would take longer

Offline Stev-o

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I prefer the "lay the thing on it's side" method to remove the motor.
I use moving blankets on the floor.
'74 "Big Bang" Honda 750K [836].....'71 Honda 750K project.....'76 Honda 550F.....K3 Park Racer.....K5 Fiddy Dolla Special!......and a Bomber!............plus plus plus.........

Offline SOHC4 Cafe Racer Fan

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Putting it back in requires much more care. I still don't the lay on its side after draining the oil and removing the filter housing.
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)
2014 MV Agusta Brutale Dragster 800
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.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)

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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
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Offline Mace

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Does anyone rebuild the engine in the frame? Seems like an uncommon approach from what I've seen.

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Offline cantarauk

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I have been in contact with Benjie from BCR and he is going to build my seat for me. There has been a lot of email back and forth discussing what I am looking for and we are hopefully on the same page now. He has started the work which I have added comment on and requires some re-work to shorten the cowl. The images attached are the initial start of the seat and it will be looking different after the re-work.

I have also made a start at tripping the fuel tank using paint strippers first. This has been a very sticky and messy process but I seem to be getting somewhere as you can see from the images.
« Last Edit: September 26, 2016, 12:49:03 pm by cantarauk »