Topic: CB750 K2 engine + bike project, frame will come

[Terry in Australia]

Ha ha, no worries Per, no rush mate, but I would like it, I'm collecting parts for the T500 for a "Racer for the road" (as opposed to, a yawn, Cafe Racer) and I think with that swingarm and a nicer period front end, it'll look pretty cool.

[PeWe]

I have started to collect parts for this build.

Need to verify all small new parts I have. Time to make an Excel chart.


It will  get this Freedom green tank w sidecovers and maybe this, Alfa 4-1.


Or 4-4 look with Lotus Root pipes if I not reserve them for the blue K6. Photo with the No numbers 4-4.

[MauiK3]

That green is beautiful

[Terry in Australia]

Looking good Per. How do you like the Hindle pipe? My Hindle pipe is sitting in a box Per, I’ll have to build a bike to put it on, but I think by the time I work through my other projects it might have at least one birthday…….

[PeWe]

Yes, the Freedom Green metallic is really nice.

I stumbled on the set for several years ago on an eBay auction April 2013.
A guy in California painted and sold complete sets of old tank with new sidecovers, emblems, petcock etc.

I did not realize back then how this color is a mix between green and blue depending on the light.
It match perfectly well with K2 gauge faces.

The Hindle my blue K6 has work really well. It is not that loud when cruising around in legal speeds. Nice tone when open the throttle!
It has good flow and very good ground clearance.

Not the best looking, but work really fine. Very light, 3.5kg, plus the head spigots so 4kg can be the total.

I was not that convinced about stainless pipes before. I like it more after use. Easy to fix bluish pipes or asphalt residues that sit hard.
Clean and grind-polish  it shiny again. Bronze tone back after a ride or 3.

[Terry in Australia]

That's interesting Per, I "Re-Commissioned" a US import K1 for a guy here a few years ago. He'd bought a set of painted parts (tank, sidecovers, headlight bucket and ears) for the K1. I had the bike running well with the old bodywork, and the last thing I did before he collected it was install the painted tank.

He got home and took it for a ride, and it died in the first mile. Turns out the Ebay painter had sandblasted the tank, and there was blasting grit inside it, which made it into the carbs and blocked the jets. He keeps asking me to fix it, but he doesn't like paying, so I've told him that I no longer work on other peoples bikes......

[PeWe]

I know a guy that had lots of blasting sand inside tank too.
He got carb problems with sudden stops.

I have seen him riding with that tank so probably solved.
I told him to drain tank, upside down on a bench and use it as a drum to make all sand to fall out from the lower tight area where tank bottom and sides meet. Vacuum clean it too.
My tank was not blasted. Not cleaned at all. Filled it completely with vinegar for 5-6 days.

[PeWe]

I got the upper engine case from the shop today. Now prepared for the Billet block's 77 mm "sleeves". (Alu, part of the  block).
It will get a 890cc cylinder to start with.

The other parts on the bench for same bike.

[PeWe]

Keep this thread boiling and easier to find.....
The build is in the collect parts stage.
Engine parts more or less complete unless it will get hardwelded rockers from CycleX.
Primary hub to be sent to Germany for cush rubber replacement. Riveted installation.

Frame, swing arm and battery holder need to be blasted off and painted black. Probably powder.

Got new shiny front fender yesterday. The fenders I have look bad.
NOS Honda front from DSS UK.
I have NOS rear fender on the shelf. K1 style that work with the K2 we had here with earlier rear light.
They both need to be coated inside with black body spray.

It will get the cheap DSS replica seat that look closer the K3-K6 design. Not perfectly dressed but low price.
Here placed over my brown K2 that has another replica seat that cost +50%

The front fender stay need some paint on inside where chrome is not perfect.
A good idea to protect the stays with gray paint, or other anti rust.
They will rust if not protect.
 My brown K2 will get thst next time front wheel is off. Fender insides have black body, I did not protect the stays.

Fork tubes and rebound springs to be ordered to build the fork, K2 with stock brake but better biting pad.

Sidestand too. The old used ones seems often to be bent. Replica is an alternative.

[Stev-o]

Lots of nice new parts!

[PeWe]

Yes,  + the small new parts
Hopefully a roller this year.

The rolling chassi swap with my brown stock K2 will take some extra efforts after the season.

[Terry in Australia]

Where did you buy the more expensive K2 repro seat Per? I have a K2 to build plus two K1's, and I really hate the K3-K6 "ironing board" seats that you see on restored K2's everywhere, to me they just don't look right. I'm not sure if I'll restore it or just "Restificate" it, but I'd like to put a K2 specific seat on it, if I can't find a good used original.

[PeWe]

This is the seat my brown K2 has
https://www.davidsilverspares.co.uk/CB750K2-FOUR-1972/part_275786/

It had no rear Honda print so I had to order a stencile on eBay. Sprayed rustoleum vinyle spray, silver. A few thin dusty layers.

The cheaper one I bought to this build:
https://www.davidsilverspares.co.uk/CB750K2-FOUR-1972/part_105077/

Both seats need more parts.
Hinges x 2
https://www.davidsilverspares.co.uk/CB750K2-FOUR-1972/part_334067/

+ 2 pins
https://www.davidsilverspares.co.uk/CB750K2-FOUR-1972/part_105080/
David silver has but not that complete as Yamiya with washer and cotter pin.

Seat lock
https://www.davidsilverspares.co.uk/parts/by-part-number/partnumber_77220340003/

I had to order the seat lock bracket for frame too. Cost less here. Stock finish is nicer except for the price.
This one is painted black

https://www.davidsilverspares.co.uk/CB750K2-FOUR-1972/part_320178/

I miss ign switch and seat lock set for K2, Honda NOS.

I have the old seat lock from my K6 that got a set with same key for Honda ign switch.

Aftermarket ign switch does not have the typical Honda CB750 key.
My K6 had an aftermarket tjat got bad connection after a while. I saw it on my voltage meter while riding. Ignition fed by relay so not affected.

Saw a sudden 0.5V loss. Wiggled the key and voltahe back. Ordered a complete Honda set with all locks.

My brown K2 got NOS ign switch from an eBay seller in Thailand for lower price than the others.

[Stev-o]

This is the seat my brown K2 has
https://www.davidsilverspares.co.uk/CB750K2-FOUR-1972/part_275786/

$121?  That is cheap. 

[PeWe]

This is the seat my brown K2 has
https://www.davidsilverspares.co.uk/CB750K2-FOUR-1972/part_275786/

$121?  That is cheap.

Not that cheap
$ 202.64

[Stev-o]

This is the seat my brown K2 has
https://www.davidsilverspares.co.uk/CB750K2-FOUR-1972/part_275786/

$121?  That is cheap.

Not that cheap
$ 202.64

The price changed!

[PeWe]

Stev-o you were not wrong with that price.
There are 2 links to DSS seats in my earlier post.

It's the cheaper version I bought for this build.
https://www.davidsilverspares.co.uk/CB750K2-FOUR-1972/part_105077/

[Terry in Australia]

This is the seat my brown K2 has
https://www.davidsilverspares.co.uk/CB750K2-FOUR-1972/part_275786/

It had no rear Honda print so I had to order a stencile on eBay. Sprayed rustoleum vinyle spray, silver. A few thin dusty layers.

The cheaper one I bought to this build:
https://www.davidsilverspares.co.uk/CB750K2-FOUR-1972/part_105077/

Both seats need more parts.
Hinges x 2
https://www.davidsilverspares.co.uk/CB750K2-FOUR-1972/part_334067/

+ 2 pins
https://www.davidsilverspares.co.uk/CB750K2-FOUR-1972/part_105080/
David silver has but not that complete as Yamiya with washer and cotter pin.

Seat lock
https://www.davidsilverspares.co.uk/parts/by-part-number/partnumber_77220340003/

I had to order the seat lock bracket for frame too. Cost less here. Stock finish is nicer except for the price.
This one is painted black

https://www.davidsilverspares.co.uk/CB750K2-FOUR-1972/part_320178/

I miss ign switch and seat lock set for K2, Honda NOS.

I have the old seat lock from my K6 that got a set with same key for Honda ign switch.

Aftermarket ign switch does not have the typical Honda CB750 key.
My K6 had an aftermarket tjat got bad connection after a while. I saw it on my voltage meter while riding. Ignition fed by relay so not affected.

Saw a sudden 0.5V loss. Wiggled the key and voltahe back. Ordered a complete Honda set with all locks.

My brown K2 got NOS ign switch from an eBay seller in Thailand for lower price than the others.

Thanks Per, I just bought another BMW today so I'll put my K2 resto on the back burner, but good to know I can find a good repro seat for it.

[PeWe]

BMW restore thread or ready for the road?

[Terry in Australia]

BMW restore thread or ready for the road?

Ready for the road Per. I'm a little worried that my Z1-B might not be ready for the 1000+ mile ride next month, and as much as I could ride several of my other bikes, a BMW R1100RT is a wonderful mile eater, so I found a really nice, really cheap (cheaper than a worn out CB750) example, and am just arranging to have it transported down here from Queensland. (where old bikers go to die...)

[PeWe]

Plan B is to ride your K0, the bike Kawasaki had to beat=Z1-900

You look forward to looooong relaxing rides on a BMW cruiser, right?

[PeWe]

I had to do the final gear swap from the late shaft to correct K shaft for this case.

This to be very sure it fits which it does.

I had to grind a radius in lower case where final gear had contact if gear is pushed max inwards.  This to avoid alu flakes in oil. The gear should fix that in a sec.

Upper case has clearance, around 0.35mm. Lower case- gear 0.15mm feeler gauge ok after massaging that radius.

Only the double row bearing to be mounted. I let the shop  do that when doing the undercut of 2-4.

[PeWe]

Slow going build

Final drive got its double row bearing.
Late final gear on an earlier  shaft to use with the late transmission in an earlier case.

Cases need warmer weather to be cleaned internally with power washer outside on my driveway.  Oil channels nust be absolutely clean. Remove the rubber plug before.

Then paint plus curing time.

Soon time for rod assembly on crank.

[PeWe]

Got the thumb out and finally cleaned the frame. (After 2 years)
Degreaser sprayed everywhere, pressure washed with warm water afterwards.

My plan to sand frame smooth and spray with 2k rattle cans has changed to visit a professional shop.

Let them sandblast frame, swingarm and battery holder. 2k paint. Prime and glossy black. The shop need clean parts

This frame will not be a new CB750 build. It will be the frame for my brown K2 mostly stock that will get new identity with uncut frame.

The brown K2 will get other tank set in freedom green metallic and the engine in this thread. Most likely 890cc.

[SanDogDewey]

Primary hub to be sent to Germany for cush rubber replacement. Riveted installation.

I’ve only seen the cush rubbers held in by the little nubs. Riveted?