Author Topic: gaping rings  (Read 2225 times)

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Offline Scott

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gaping rings
« on: August 01, 2019, 11:29:54 AM »
Hi there

I've never set the gap on rings before and was wondering if a good quality file is OK to use or if it is better to get one of the tools I see on ebay that looks like a grinding wheel that is turned over by hand crank.

Thanks for your thoughts
Scott

Offline Scott

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Re: gaping rings
« Reply #1 on: August 01, 2019, 11:51:35 AM »
Sorry, but I think I have a few questions.

These are the pistons and rings I’m using.

Offline Scott

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Re: gaping rings
« Reply #2 on: August 01, 2019, 11:53:28 AM »
Is this the top ring?  It has rounder edges than the other ring.

The gap is currently.007

Offline Scott

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Re: gaping rings
« Reply #3 on: August 01, 2019, 11:55:40 AM »
This is the ring with square edges.

It’s gap is .016

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: gaping rings
« Reply #4 on: August 01, 2019, 12:02:37 PM »
The tool you refer to can be pretty aggressive before you realize it. If you can get by otherwise you should be fine.
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Offline Scott

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Re: gaping rings
« Reply #5 on: August 01, 2019, 12:04:41 PM »
Oil rings are .017 and the expander oil ring ends are far from touching when I hold it in the cylinder with my fingers spreading it out.

Offline Scott

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Re: gaping rings
« Reply #6 on: August 01, 2019, 12:17:51 PM »
I have a file that I think will be suitable and I'm quite patient.

The instructions say to use a stone to finish off with, but my stone is quite big and may be hard to use.  Can I use wet and dry sand paper?  Or maybe one of those Paddle Pop stick things shelias do their nails with?

Thanks again for your time
Scott

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: gaping rings
« Reply #7 on: August 01, 2019, 01:29:48 PM »
Whatever it takes really. Just be sure to lightly file all 4 edges of the side(s) you cut.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline Scott

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Re: gaping rings
« Reply #8 on: August 01, 2019, 01:42:33 PM »
Cool, thanks

Offline PeWe

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Re: gaping rings
« Reply #9 on: August 01, 2019, 09:38:22 PM »
I used a flat needle file sitting in a vise. Holding the ring with gap squeezed together around file and move ring. Only one direction, from outside to inside.

If you have modern piston with very thin oil rings, the rails need to get the inner end corner rounded to make it easier to compress them.
The sharp corners of the rails can hook into the expander and not compress enough when bore need to go on. The rail can get pinched and you need to order new. If not discover that forcing the bore on you will harm the bore.
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Offline jgger

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Re: gaping rings
« Reply #10 on: August 01, 2019, 10:11:26 PM »
You know to use the piston turned upside down to place the rings square to the bore, right? Just push them as far as the ring grooves are on the piston to measure. If the ring is crooked you won't get an accurate measurement.
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Offline PeWe

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Re: gaping rings
« Reply #11 on: August 02, 2019, 03:31:51 AM »
You know to use the piston turned upside down to place the rings square to the bore, right? Just push them as far as the ring grooves are on the piston to measure. If the ring is crooked you won't get an accurate measurement.
+3.  Important to do that.
I usually push rings to different locations of the piston rings working range just for sure to see if gap change . It should not with new bored cylinder.
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: gaping rings
« Reply #12 on: August 02, 2019, 05:58:08 AM »
You know to use the piston turned upside down to place the rings square to the bore, right? Just push them as far as the ring grooves are on the piston to measure. If the ring is crooked you won't get an accurate measurement.
Insert 2 wrist pins in the piston to keep the ring square in the bore (pins will hit the deck at the same time keeping it square).
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Offline Scott

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Re: gaping rings
« Reply #13 on: August 02, 2019, 02:33:19 PM »
You know to use the piston turned upside down to place the rings square to the bore, right? Just push them as far as the ring grooves are on the piston to measure. If the ring is crooked you won't get an accurate measurement.
+3.  Important to do that.
I usually push rings to different locations of the piston rings working range just for sure to see if gap change . It should not with new bored cylinder.

Thankyou
I had been pushing the ring with the piston and by chance I used the oil ring landing as a gauge.

These are fresh cylinders prepared by Mike for another customer that I ended up buying them off , so I haven't measured gap at different positions in the cylinders

Offline Scott

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Re: gaping rings
« Reply #14 on: August 02, 2019, 02:34:47 PM »
You know to use the piston turned upside down to place the rings square to the bore, right? Just push them as far as the ring grooves are on the piston to measure. If the ring is crooked you won't get an accurate measurement.
Insert 2 wrist pins in the piston to keep the ring square in the bore (pins will hit the deck at the same time keeping it square).

I will use this stopper method from now on.  It seems so easy now that you have pointed it out.

Cheers

Offline Scott

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Re: gaping rings
« Reply #15 on: August 02, 2019, 02:36:05 PM »
Is the ring with the curved edges the top ring?

Offline CBJoe

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Re: gaping rings
« Reply #16 on: August 02, 2019, 03:27:01 PM »
Insert 2 wrist pins in the piston to keep the ring square in the bore (pins will hit the deck at the same time keeping it square).

Ooh...thats a good trick.  Did this myself recently and that would have been handy.
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Offline Don R

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Re: gaping rings
« Reply #17 on: August 03, 2019, 09:51:35 AM »
 Check the instructions there for top and second ring. Is one silver?  Often they are packaged in the order they go on but it's also good to check.
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Offline Scott

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Re: gaping rings
« Reply #18 on: August 04, 2019, 01:14:54 AM »
I’ll open the other packs and have a look.

I checked the instructions but I’ll do it again for sure. There’s no silver ring, but maybe a bronze clour

Offline MRieck

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Re: gaping rings
« Reply #19 on: August 04, 2019, 05:15:45 AM »
Bronze ring is top ring, black ring is second ring. Be sure the markings are facing up when you install them.
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Offline Scott

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Re: gaping rings
« Reply #20 on: August 04, 2019, 11:35:57 PM »
Sweet

Thanks