Author Topic: Getting my K0 back on the road  (Read 7810 times)

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Offline PeWe

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Re: Getting my K0 back on the road
« Reply #50 on: June 24, 2022, 11:13:31 PM »
Go for the correct diffusers, the picture.
Good sound without the "wool".
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline WideAWAKE

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Re: Getting my K0 back on the road
« Reply #51 on: June 25, 2022, 09:21:02 AM »
Go for the correct diffusers, the picture.
Good sound without the "wool".

I’ll track some down.

Just wanted to confirm they were the correct ones and I wasn’t missing something.

Offline PeWe

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Re: Getting my K0 back on the road
« Reply #52 on: June 25, 2022, 10:36:02 AM »
Go for the correct diffusers, the picture.
Good sound without the "wool".

I’ll track some down.

Just wanted to confirm they were the correct ones and I wasn’t missing something.
Pic with 4-pack Honda, like small bottles
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline WideAWAKE

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Re: Getting my K0 back on the road
« Reply #53 on: June 26, 2022, 06:54:04 PM »
Making some decent progress on the bike itself.

New tires mounted, main harness in, started to get some electrical going.

I believe my rectifier fried itself as it was quite covered in burnt black paint and connections were melted. I got a good used one on the way. Everything else seemed to clean up nicely.

Started to pull my motor apart to do some internal testing and it seems it will need to come apart.

A bump in the road but I’ll get it sorted.

Offline WideAWAKE

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Re: Getting my K0 back on the road
« Reply #54 on: July 02, 2022, 06:32:38 PM »
Got as far as I could cosmetically with the bike and now I need to get to the motor.

For reference here is pretty much what I’m working with

http://forums.sohc4.net/index.php/topic,190226.25.html

I’ll try to keep it all contained here from this point on.

So as of now my top end is pretty much all apart and I started to clean up the head.

Soda blasted and I think it will be all good.

I’ll get the valves tomorrow and lap em and see where I’m at.

Measured the guides and valves themselves and they were in spec.




Offline WideAWAKE

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Re: Getting my K0 back on the road
« Reply #55 on: July 03, 2022, 05:30:23 PM »
Well I thought my motor had never been opened before but it would appear (after scratching my head for a bit, thinking it was totally worn out) I have a 1st over bore.

Barrels still have very good cross hatching, pistons measure good as do all the piston to bore clearances.

But my number 1 piston has 1 ring that has a pretty big gap (.028”) which does not seem kosher.

It seems a light hone and new rings are in order.


Offline PeWe

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Re: Getting my K0 back on the road
« Reply #56 on: July 03, 2022, 09:13:23 PM »
Verify ring lash up-down. If pistons are worn.

0.28mm ring gap had been OK ;D
« Last Edit: July 03, 2022, 09:16:38 PM by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline WideAWAKE

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Re: Getting my K0 back on the road
« Reply #57 on: July 03, 2022, 09:30:48 PM »
Rings all measured good but the gaps on piston 1

It was .028 thou not .28mm.

I ordered new rings with a 3 Piece oil rings.

Pistons and bore all measure good.

Offline WideAWAKE

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Re: Getting my K0 back on the road
« Reply #58 on: July 03, 2022, 09:40:54 PM »
Got all my valves cleaned and lapped em all

Then tested with Prussian blue.

They all seat nicely.

I have some new viton valve seals on the way and once they arrive I’ll put everything back together and do a leak test.

I was surprised to see seals on only the intake side. Went down the rabbit hole to figure that one out haha.

So much to learn about these motors.
« Last Edit: July 03, 2022, 09:47:29 PM by WideAWAKE »

Offline PeWe

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Re: Getting my K0 back on the road
« Reply #59 on: July 03, 2022, 09:49:14 PM »
You might regret if not replacing the ex guides with later using seals. Search forum and find smoker tales. At least smoke at each start-up.

My K2 had an old (K1?) smoker head, old style, no ex seals.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline WideAWAKE

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Re: Getting my K0 back on the road
« Reply #60 on: July 05, 2022, 05:25:24 PM »
Started doing a little cleaning before I finish pulling the motor apart.

Ol’ mr Honda never thought about having to clean deep inside this head! Haha what a pain! Soda blasted and then chemical soaked. It’s almost there. Let us soak tonight and call it good.

Got my chains and tensioners for the primary/cam ordered, new rings and gasket/seal kit.

Hopefully get the rest of it apart this week to be ready for assembly when parts show up.



Offline WideAWAKE

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Re: Getting my K0 back on the road
« Reply #61 on: July 05, 2022, 05:30:28 PM »
And 4 rounds through the ultrasonic cleaner and some poking and prodding to get these oil passages clear.

Offline WideAWAKE

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Re: Getting my K0 back on the road
« Reply #62 on: July 07, 2022, 07:11:59 PM »
Got the cases apart and pulled the chains and tensioners. I did have 1 screw that had it’s head stripped and needed to be drilled out and I got luck cause it was an easy one.

Also gave the barrels a fresh hone.

I will get the rest of the motor cleaned up real nice for paint while I’m waiting on parts to arrive.

Should have everything needed to get it back together in a week or so.

And new rings showed up yesterday. They are a much better fit at .012 inch gap.


Offline newday777

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Re: Getting my K0 back on the road
« Reply #63 on: July 08, 2022, 04:07:55 AM »
If that is still the stock bore, measure the ring end gaps in multiple depths, (use the pistons upside down to push the rings in square to the different depths and measure) as most likely it is bigger now at the bottom of the bore. If it's too big and it'll smoke. If too big end gaps at the bottom, bore time for bigger pistons and rings......
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline PeWe

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Re: Getting my K0 back on the road
« Reply #64 on: July 08, 2022, 04:34:25 AM »
The bore honing has cross hatch pattern? Link for photo.
https://www.precision-surface.com/what-is-honing/

I heard 30 degrees.
If only grinded, oil will not flow correct when piston moves.

Heard at my shop nearby.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline WideAWAKE

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Re: Getting my K0 back on the road
« Reply #65 on: July 08, 2022, 07:18:39 AM »
It’s got a very nice cross hatch pattern.

When I was younger I worked at a 2 stroke restoration shop. Pretty much thought all my theory and basics of engine building from the owner, a former Kawasaki race team mechanic.

I hone all my cylinders the way I was thought there.

Gives a nice cross hatch, which proved quite difficult to capture yesterday as the light would reflect off the barrels.

Try to get a better pic later today.

Offline WideAWAKE

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Re: Getting my K0 back on the road
« Reply #66 on: July 08, 2022, 07:46:15 PM »
Parts showed up today.

Took a chance on some CMS “kits” chain and tensioner packages and to my surprise all genuine Honda parts.

Got my valve seals in and started building my head. Gave it a fluid test for about an hour will no loss so I think we’re good to go.

Got my cases all cleaned and prepped for paint tomorrow. I found this steamer worked quite well to flush out all the nooks and crannies after I scrubbed em.

Should have em all painted, cleared and ready for assembly tomorrow.

***And attached a cleaner pic of cross hatching.

Offline newday777

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Re: Getting my K0 back on the road
« Reply #67 on: July 09, 2022, 03:02:07 AM »
How long did the shipping take from CMS?
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline WideAWAKE

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Re: Getting my K0 back on the road
« Reply #68 on: July 09, 2022, 08:54:18 AM »
Ordered at 4pm on Tuesday, Deliver yesterday. They shipped it Wednesday. So pretty much 2 days shipping.

I’m in California. Shipping was free.

Shipping went through France, then Florida, then California.

I had 2 shipments from them a few months ago ship through Germany, Memphis Tennessee, then California and both of those shipment were held up at customs and shipping was delayed due to lack of paperwork.

I’d called CMS and they were very honest, said they were super understaffed and shipping wasn’t up to par with what it should be. Both those times it took about 2-3 days to get paperwork cleared.

Even with the customs delay, shipping was still quick.



Offline HondaMan

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Re: Getting my K0 back on the road
« Reply #69 on: July 09, 2022, 10:58:05 AM »
About the head: if the exhaust guides are the pointy type that don't take oil seals, they are the ones to die for! Those are made from Stellite and last over 100,000 miles if good oils are used. Mine went 131k miles and were just approaching 'worn' status when I changed them for bronze in 2013.

If you can: take the cylinders in for a 0.010" flat-grind on the deck, and have the head flat-ground to "minimum takeoff" depth (this is usually around 0.002"-0.005"). This will ensure no oil leaks and preclude any possible warpage later. The metals are cured now, so they won't move around and distort like they already have during curing in use.
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
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Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline WideAWAKE

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Re: Getting my K0 back on the road
« Reply #70 on: July 09, 2022, 12:52:26 PM »
About the head: if the exhaust guides are the pointy type that don't take oil seals, they are the ones to die for! Those are made from Stellite and last over 100,000 miles if good oils are used. Mine went 131k miles and were just approaching 'worn' status when I changed them for bronze in 2013.

If you can: take the cylinders in for a 0.010" flat-grind on the deck, and have the head flat-ground to "minimum takeoff" depth (this is usually around 0.002"-0.005"). This will ensure no oil leaks and preclude any possible warpage later. The metals are cured now, so they won't move around and distort like they already have during curing in use.


Here is a pic of the exhaust guides.

They are a very good fit to the valves, forget the measurements off the top of my head, but was quite pleased when I checked em.

As for the cylinder and head, unfortunately I don’t have access to a mill to deck em.

I can knock em flat on a large piece of glass though. A bit old school.


Offline MauiK3

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Re: Getting my K0 back on the road
« Reply #71 on: July 09, 2022, 02:17:17 PM »
The minimal material removal will bump compression a tiny bit too? Probably unnoticeable
1973 CB 750 K3
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Offline newday777

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Re: Getting my K0 back on the road
« Reply #72 on: July 10, 2022, 04:40:17 AM »
Ordered at 4pm on Tuesday, Deliver yesterday. They shipped it Wednesday. So pretty much 2 days shipping.

I’m in California. Shipping was free.

Shipping went through France, then Florida, then California.

I had 2 shipments from them a few months ago ship through Germany, Memphis Tennessee, then California and both of those shipment were held up at customs and shipping was delayed due to lack of paperwork.

I’d called CMS and they were very honest, said they were super understaffed and shipping wasn’t up to par with what it should be. Both those times it took about 2-3 days to get paperwork cleared.

Even with the customs delay, shipping was still quick.
Cool. 😊
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline PeWe

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Re: Getting my K0 back on the road
« Reply #73 on: July 10, 2022, 08:12:22 AM »
Very nice with fast shipping.
I ordered small parts from Webike Japan last Monday evening, got it Friday noon same week delivered at my door. Shoe box size.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline WideAWAKE

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Re: Getting my K0 back on the road
« Reply #74 on: July 10, 2022, 05:47:05 PM »
Very nice with fast shipping.
I ordered small parts from Webike Japan last Monday evening, got it Friday noon same week delivered at my door. Shoe box size.

Pretty crazy how you can get free shipping that takes 3 days from the other side of the globe but it costs an arm, a leg and week to get something a few states away.

I shipped body work from CMS to the us and it was free.

I got a quote for a member here to ship a gas tank to the Netherlands and ups quoted me over 700 bucks!!! And 12-14 days. Wild.