Author Topic: Plating pistons to save a bore job.  (Read 2697 times)

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Offline 754

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Plating pistons to save a bore job.
« on: December 23, 2019, 11:40:20 AM »
There us a process I heard of on CycleDrag,  U.S. Coatings is the name of the place, they have 4 facilities in the USA. They claim good results on I think pro mod cars.
 They build up the piston up to several thousands with a good coating process, then you hone your bores and refit them. 36 bucks per piston.
 Anyone tried this. I wonder if they mask ring grooves and pins. They also do top coatings.
 Pretty interesting.
« Last Edit: December 23, 2019, 12:09:51 PM by 754 »
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline 754

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Re: Plating pistons to save a bore job.
« Reply #1 on: December 23, 2019, 12:43:39 PM »
Sorry, I meant this for Hi Performance section..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline KayOne

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Re: Plating pistons to save a bore job.
« Reply #2 on: December 23, 2019, 01:44:34 PM »
Hi Frank, I’ve had Piston skirts from my SBF coated to get more life out of the bore and piston. Works very well. A supposed benefit is less piston drag and wear on the bore. I’ve also thermal coated the top of the pistons but truly can’t say if there is any benefit. Yes they do mask off the lands somehow. There is a good coating shop in Calgary, couriered my pistons there and had them back the next week.
CB750 K1 restored
1979 CB750Fz - original except for exhaust, 14000km
1984 VF45F Interceptor - all original, 12000 km
1968 S90 - all original, 2100 miles
1973 H2a, Restored
1973 H1D, next project
CB750K1 (sold)
1976 KZ900 (sold)
1981 CB900F (under restoration)
2015 Yamaha FJ09, my appliance rider

Offline gschuld

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Re: Plating pistons to save a bore job.
« Reply #3 on: December 30, 2019, 06:47:34 PM »
Swaintech does a PC9 skirt coating.  They can go thicker if desired.  Mike Rieck has used them with success for the same purposes you are asking about.

George


Offline 754

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Re: Plating pistons to save a bore job.
« Reply #4 on: December 30, 2019, 07:00:31 PM »
Thanks for the info, nice to know we have one that close.  I probably have a few bigbires I can bring back for cheap.
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline PeWe

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Re: Plating pistons to save a bore job.
« Reply #5 on: January 03, 2020, 10:18:44 PM »
How much will the coating build up?
Total bore/ piston clearance.
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 gtmdriver

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Re: Plating pistons to save a bore job.
« Reply #6 on: January 04, 2020, 01:45:22 AM »
I wouldn't think that the process would be successful if there was any ovality in the bores though.

Offline PeWe

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Re: Plating pistons to save a bore job.
« Reply #7 on: January 04, 2020, 08:22:49 AM »
Bores can be honed to correct shape which will need thicker pistons were a coating can do it right.
I guess this is rhe way this is done, right?
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 754

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Re: Plating pistons to save a bore job.
« Reply #8 on: January 04, 2020, 09:53:50 AM »
I am thinking they go a bit oversize,  then you hone and fit to piston.
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline PeWe

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Re: Plating pistons to save a bore job.
« Reply #9 on: January 04, 2020, 12:03:22 PM »
I have heard about pressing a forged piston over the wrist pin sides and let it swell so the skirts fill the bore better. A friend of mine heard that from an experienced mechanic as the last trick to get more life out from the pistons and their bores.

My friend had a cylinder where one of the forged pistons had sloppier fitment. Piston into a vice and press some. That helped!
He had a wristpin in just for sure to ensure how the piston change when deforming it.
« Last Edit: January 08, 2020, 10:33:39 AM 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 wwsummersjr

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Re: Plating pistons to save a bore job.
« Reply #10 on: January 04, 2020, 03:20:25 PM »
What about ring gaps after honing cylinders to fit piston skirts?

Offline Steve_K

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Re: Plating pistons to save a bore job.
« Reply #11 on: January 04, 2020, 04:15:34 PM »
When I was working in a bike shop, the shop owner knurled the pistons for a British twin.  The bike owner did not have the cash for a full rebuild, so the owner did that.  Back then, I think a rebuild cost $700 to $800 for that.   Remember, Brit bikes needed to be rebuilt after 10.000 miles.
I don't know how well I worked, but the shop owner was a very good tuner for BSA twins for dirt track.
Steve
Steve_K

76 CB 550, 73CB750, 86 GSX-R750, 16 Slingshot
Old rides:305 Honda, CL350, 74 CB550
 05 SV1000S, 88 CBR600,92 VFR, 88 Hawk GT, 96 Ducati 900SS, 98 Kaw ZX6R, SV650

Offline PeWe

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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 Terry in Australia

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Re: Plating pistons to save a bore job.
« Reply #13 on: January 05, 2020, 02:50:20 AM »
I bought an antique piston knurler on Ebay many years ago, my cousin (vintage car and bike mechanic) told me all about it, it was a common procedure back in the Great Depression, when people had no money for rebuilds. I actually tried it on some CB750 836cc pistons to get rid of a "piston slap" issue using a standard knurling tool in my lathe, and it worked fine. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline PeWe

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Re: Plating pistons to save a bore job.
« Reply #14 on: January 05, 2020, 04:40:21 AM »
More piston coating
https://www.line2linecoatings.com/slickCC.html
They have several products for pistons

It would be nice with a product that can be applied on pistons and baked in oven when wife is away :)
My oven can be set to max 300°C  (570°F ).
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 MRieck

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Re: Plating pistons to save a bore job.
« Reply #15 on: January 06, 2020, 07:32:16 AM »
I have not heard that so I searched.  There are som pics of knurled pistons.

https://www.google.com/search?q=knurled+piston&client=ms-unknown&prmd=isvn&sxsrf=ACYBGNT1aYiBwtiTVo8ovWM-xJ3TSdfdLw:1578204562264&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjGy8OS5uvmAhXKo4sKHfpBCTsQ_AUoAXoECA0QAQ&biw=355&bih=620
If the piston taper has been worn out I can't see how knurling would bring it back. I can see it expanding the OD a bit but not reestablishing taper.
Owner of the "Million Dollar CB"

Offline PeWe

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Re: Plating pistons to save a bore job.
« Reply #16 on: January 06, 2020, 11:47:02 AM »
I have not heard that so I searched.  There are som pics of knurled pistons.

https://www.google.com/search?q=knurled+piston&client=ms-unknown&prmd=isvn&sxsrf=ACYBGNT1aYiBwtiTVo8ovWM-xJ3TSdfdLw:1578204562264&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjGy8OS5uvmAhXKo4sKHfpBCTsQ_AUoAXoECA0QAQ&biw=355&bih=620
If the piston taper has been worn out I can't see how knurling would bring it back. I can see it expanding the OD a bit but not reestablishing taper.
New for me,  seems to  have been done for years.
It might reduce rattling pistons due to skirt bore clearance.
« Last Edit: January 06, 2020, 12:19:45 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 Terry in Australia

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Re: Plating pistons to save a bore job.
« Reply #17 on: January 08, 2020, 02:37:23 AM »
Exactly, it wasn't a permanent fix, it was just done to get a few more miles out of a tired engine. Expanding pistons, on the other hand was a common fix for 2 strokes that would regularly "nip up" if the ridden mercilessly, or with poor quality 2 stroke oil. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline PeWe

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Re: Plating pistons to save a bore job.
« Reply #18 on: January 08, 2020, 10:15:37 AM »
Another coating provider
https://techlinecoatings.com/tech-line-coatings/hi-performance-coatings/internal-engine-coatings/

This might be something for sloppy bores.

TLMB POLYPHEN BASE BUILD-UP COATING

High load durable thin film lubricant.

Primarily used to build up piston skirts.

Used in very high RPM engines or where very long rods are run.

Top coat with either TLML or PKSX.
Solvent based, cleanup with Acetone or similar.

Requires oven curing at 300°F for 1 hour.

Part #TLMB available in Quart & Gallon. For professional applicators only.

I have not verified "professional applicators".
Spray gear or workshop?

Would be perfect if available on rattle cans.

The juicy ribs will taste different  shortly after a piston job ;)
Extra spicy rub needed....
Women in general do not like engine parts in oven. :)
New roller bearing in the freezer OK.
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 johno

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Re: Plating pistons to save a bore job.
« Reply #19 on: January 09, 2020, 10:03:50 PM »
Like your style and Love your humour PeWe ;D ;D ;D
GRASSHOPPER SOHC HONDAS ARE THE MEANING OF LIFE.