Author Topic: Early Sandcast Found......  (Read 89382 times)

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Online BenelliSEI

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Re: Early Sandcast Found......
« Reply #775 on: November 12, 2022, 01:43:20 pm »
Please advise which kind of gaskets you plan to use?

I’ll probably need another Yamiya order, so thinking of trying their’s? I do have 1/2 a dozen open gaskets sets, so may just poke through those. What do you guys recommend?

Offline 71 V12

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Re: Early Sandcast Found......
« Reply #776 on: November 13, 2022, 03:31:23 pm »
Personally, genuine Honda only especially on 682!

Online BenelliSEI

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Re: Early Sandcast Found......
« Reply #777 on: November 13, 2022, 04:49:59 pm »
Personally, genuine Honda only especially on 682!

Good point. Last time I ordered one from Honda Canada it looked +40 years old and had been poorly treated. May try again.....

Offline PeWe

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Re: Early Sandcast Found......
« Reply #778 on: November 13, 2022, 09:40:20 pm »
The sandcast forum might have recommendations about gaskets for a sandcast engine.
Yamiya's kit was good when I used it some years ago.
Blue gaskets with all holes correct like Hondas light green.

I think the head gasket was as  most other newer, 1mm thick and in need of the thicker o-rings Hondaman reminds us about.
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 Prospect

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Re: Early Sandcast Found......
« Reply #779 on: November 21, 2022, 06:25:20 am »
I used Athena gaskets on my k1. Seems to be ok.
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Offline MauiK3

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Re: Early Sandcast Found......
« Reply #780 on: November 21, 2022, 06:45:21 am »
Have to get those barrels off!
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Online BenelliSEI

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Re: Early Sandcast Found......
« Reply #781 on: November 21, 2022, 07:24:32 am »
Have to get those barrels off!

No joy last attempt. Going to build a lifting bar next and suspend it for a few days!

Offline Don R

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Re: Early Sandcast Found......
« Reply #782 on: November 21, 2022, 08:45:14 pm »
 DaNG, a lucky caps lock accident. Sorry to hear they are still hanging on.
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
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Online BenelliSEI

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Re: Early Sandcast Found......
« Reply #783 on: November 24, 2022, 03:28:41 pm »
It’s been “hanging” for a few days. Sent lots of juice down the std holes, and been tapping away. Truthfully, more than tapping......Nothing has budged!

Offline RAFster122s

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Re: Early Sandcast Found......
« Reply #784 on: November 24, 2022, 03:42:59 pm »
It’s been “hanging” for a few days. Sent lots of juice down the std holes, and been tapping away. Truthfully, more than tapping......Nothing has budged!

Talk to an appliance repair shop...tell them of your plight and ask if they have an old beater oven they could sell you or give you for purpose of baking this block and cylinders to get them to separate. Turn it into a powdercoat oven after you finish with it for this purpose.
Baking at 450-500 might get it to free up with a few good smacks...
Just be careful you don't lose or drop a liner out of the cylinders...
David- back in the desert SW!

Online BenelliSEI

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Re: Early Sandcast Found......
« Reply #785 on: November 24, 2022, 04:43:26 pm »
It’s been “hanging” for a few days. Sent lots of juice down the std holes, and been tapping away. Truthfully, more than tapping......Nothing has budged!

Talk to an appliance repair shop...tell them of your plight and ask if they have an old beater oven they could sell you or give you for purpose of baking this block and cylinders to get them to separate. Turn it into a powdercoat oven after you finish with it for this purpose.
Baking at 450-500 might get it to free up with a few good smacks...
Just be careful you don't lose or drop a liner out of the cylinders...

Mmmmm ..... Heating the entire lump would make the expansion of both parts equal? Was thinking of heating from below (propane BBQ) while cooling the barrel with a fan?). Crazy thoughts?

Offline Don R

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Re: Early Sandcast Found......
« Reply #786 on: November 24, 2022, 05:26:57 pm »
 I tried a maap hand torch and a hot air gun on cylinders to remove pistons, not much luck getting things hot.  I was ready to try a rosebud tip on oxy-acetylene. Used my press instead, I put a load on each piston one at a time and went in the house. 
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.

Online BenelliSEI

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Re: Early Sandcast Found......
« Reply #787 on: November 24, 2022, 06:29:53 pm »
I tried a maap hand torch and a hot air gun on cylinders to remove pistons, not much luck getting things hot.  I was ready to try a rosebud tip on oxy-acetylene. Used my press instead, I put a load on each piston one at a time and went in the house.

Don..... Pistons are free, bores look good, and it had an excellent leak down. I may just leave the damn thing where it is!

Offline RAFster122s

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Re: Early Sandcast Found......
« Reply #788 on: November 25, 2022, 01:05:36 am »
It may not be the expansion that breaks things free but the heat cycles. The pins if stuck are not of aluminum but made of steel, so their expansion won't be the same until the temps stabilize. So bake it and a few smacks while it is hot can get things to move.
David- back in the desert SW!

Online BenelliSEI

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Re: Early Sandcast Found......
« Reply #789 on: November 25, 2022, 05:47:25 am »
It may not be the expansion that breaks things free but the heat cycles. The pins if stuck are not of aluminum but made of steel, so their expansion won't be the same until the temps stabilize. So bake it and a few smacks while it is hot can get things to move.

Very good point! Don’s suggested another good “pulling” tactic, so will combine the two if needed.
Thanks, both of you!

Offline MauiK3

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Re: Early Sandcast Found......
« Reply #790 on: November 25, 2022, 01:57:22 pm »
I think a heat gun will be safer than any form of torch, better heat spread and lower temperature.
It will eventually break loose.
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Re: Early Sandcast Found......
« Reply #791 on: December 01, 2022, 12:58:58 pm »
Built the “Puller” and used a heat gun on the front studs, each end. Really warmed up the area of the two dowel sleeves and it finally popped.

Online BenelliSEI

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Re: Early Sandcast Found......
« Reply #792 on: December 01, 2022, 01:00:23 pm »
Stripped down the head today, ready to try hydro blasting.

Offline newday777

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Re: Early Sandcast Found......
« Reply #793 on: December 01, 2022, 01:57:08 pm »
Stripped down the head today, ready to try hydro blasting.
Clean off all the oils before you hydro blast or the slurry will be contaminated with oil/grease. Less cutting force.
Stu
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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!
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2008 GL1800 my daily ride and cross country runner

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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.....
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Offline MauiK3

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Re: Early Sandcast Found......
« Reply #794 on: December 01, 2022, 02:39:01 pm »
Very clever puller.
It’s really great you are saving another sandcast.
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Online BenelliSEI

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Re: Early Sandcast Found......
« Reply #795 on: December 01, 2022, 04:32:42 pm »
Stripped down the head today, ready to try hydro blasting.
Clean off all the oils before you hydro blast or the slurry will be contaminated with oil/grease. Less cutting force.

Will do.

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Re: Early Sandcast Found......
« Reply #796 on: December 01, 2022, 04:33:57 pm »
Very clever puller.
It’s really great you are saving another sandcast.

Even with a lot of “pre load” and heat, it took a lot of heat and a FBH!

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Re: Early Sandcast Found......
« Reply #797 on: December 07, 2022, 08:04:46 pm »
Top end is stripped and off for vapour blasting. When it returns, I’ll be tackling “fin straightening”.

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Re: Early Sandcast Found......
« Reply #798 on: December 07, 2022, 08:09:37 pm »
I had a good look at the original pipes today. Both side lowers have holes where the “muffler” portion joins the headpipe. The two uppers are in much better shape. None of them have any real dings or dents, so will try and patch and polish these up. I do have a new, still in the boxes, set of Yamiya no# pipes too.

Offline RAFster122s

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Re: Early Sandcast Found......
« Reply #799 on: December 08, 2022, 02:35:13 am »
Top end is stripped and off for vapour blasting. When it returns, I’ll be tackling “fin straightening”.

You really ought to consider straightening and any welding in those before blasting, that way you can have a consistent finish on them as any welds and grinding will be subjected to the same texturing the vapor honing does.

But, depending upon your paint finish thickness it might be a mute point.
David- back in the desert SW!