Barrels pistons rings questions... 1978 GS750

[martin_montreal]

Pics link says it all. Please let me know if access fails. Thx.
Rebuilt head is ready with shims from the old one in there to be swapped around after install...
4 middle studs made barrel removal tough but it's off. Will clean them and thought I'd smear anti-seize on them before re-installing the block which I will clean up and hone.
Are those pistons original. When I did wet compression test, it made no difference. Do I need rings? If so, how do I know which ones to buy?
I need to find all the seals. Do I treat them and / or the o-ring with either Anaerobic gasket or the Right Stuff (shop manual on latter said Suzuki bond but it's from 1978,..
Anything else re the abo? Thanks!

 

[Grimly]

New rings, be foolish not to.
If OEM are out of stock or out of reach, www.cruzinimage.net will have them.
Assuming the pistons are standard (most likely)...
https://www.cruzinimage.net/2017/08/30/77-79-suzuki-gs750-standard-piston-rings-set-4-piston-rings/
However, you need to check that accurately. Piston size, bore size, and go from there.

 

[martin_montreal]

New rings, be foolish not to.
If OEM are out of stock or out of reach, www.cruzinimage.net will have them.
Assuming the pistons are standard (most likely)...
https://www.cruzinimage.net/2017/08/30/77-79-suzuki-gs750-standard-piston-rings-set-4-piston-rings/
However, you need to check that accurately. Piston size, bore size, and go from there.

There was a picture with piston size but I forgot to write it. Diameter is 2.38" or 60.452. Suzuki don't make them anymore.. I will check your supplier. Tha.ks.

 

[Grimly]

There was a picture with piston size but I forgot to write it. Diameter is 2.38" or 60.452. Suzuki don't make them anymore.. I will check your supplier. Tha.ks.

I can't the picture of your measuring stick to show up full size, but anyway that's no use.
You need to accurately measure the pistons at several points and the bores likewise, so that you KNOW how good or not they both are.
Get the manual.

 

[martin_montreal]

I can't the picture of your measuring stick to show up full size, but anyway that's no use.
You need to accurately measure the pistons at several points and the bores likewise, so that you KNOW how good or not they both are.
Get the manual.

Pictures added in directly with measurements of pistons but trying to remove them to bring them with the block to a machine shop specializing in motorcycle engine rebuilds for block measuring and some work if needed beyond honing that I would otherwise do. For the record, my original post quoted the shop manual, and I have both, 1978 Suzuki and Clymers, none of my questions were answered and abuse is not required. Now I will go back to fighting with the circlips / snap rings. Are there no longer decent people with positive attitudes, helpful and non-condescending posts here or should I stop hoping for the way people used to be? I am trying to save the bike, have very little money, a certain level of experience and a bunch of tools, a lot of other maintenance on other vehicles. When I can, I help others and I do this a lot, through many groups. When I need help, because I go deeper as I need to here, it seems there are only nasty comments. Thank you for your input.

 

[rphillips]

Aw heck martin, hang in there, it's not just here, there's all kinds of folks everywhere. Many here are very professional & do things in a very professional way. Nothing wrong with that. Sometimes wish I had the resources to always do things that way. Then there's others that are much thriftier. I rebuild my pet cocks instead of buying new, I clean my carbs with aerosol cans of carb cleaner & starting fluid, & may run brake rotors that are under spec & tires that may be out of date. Nothing wrong with that either... Just listen, pay attention, then make your best decision for your circumstances... It's all good.

 

[allojohn]

... none of my questions were answered and abuse is not required.... Are there no longer decent people with positive attitudes, helpful and non-condescending posts here or should I stop hoping for the way people used to be? ......it seems there are only nasty comments....

Jeez man get over yourself!... Dave (Grimly) is helping you. Others will follow....

 

[Rich82GS750TZ]

Yeah, lighten up, Dave has more miles on these bike than most of will see in a lifetime and is one of the most helpful guys on the forum. Tone is often not conveyed nor understood in writing. Having been here a little while, I know he wouldn’t bother to answer except to try to be helpful. I think you took offense where there really was non intended. Granted, it can sometimes be a fine line between offering a strong opinion and condescension.

 

[Grimly]

Pictures added in directly with measurements of pistons but trying to remove them to bring them with the block to a machine shop specializing in motorcycle engine rebuilds for block measuring and some work if needed beyond honing that I would otherwise do. For the record, my original post quoted the shop manual, and I have both, 1978 Suzuki and Clymers, none of my questions were answered and abuse is not required. Now I will go back to fighting with the circlips / snap rings. Are there no longer decent people with positive attitudes, helpful and non-condescending posts here or should I stop hoping for the way people used to be? I am trying to save the bike, have very little money, a certain level of experience and a bunch of tools, a lot of other maintenance on other vehicles. When I can, I help others and I do this a lot, through many groups. When I need help, because I go deeper as I need to here, it seems there are only nasty comments. Thank you for your input.

Please yourself. I'm done here.

 

[bitzz]

There was a picture with piston size but I forgot to write it. Diameter is 2.38" or 60.452. Suzuki don't make them anymore.. I will check your supplier. Tha.ks.

You have a picture of you measuring a piston, just under the rings, in line with the pin, with a caliper.
That measurement means nothing.
To measure the piston, use a micrometer. A caliper is not accurate enough.
Measure the piston at the SKIRT, in three directions, start at 90 degrees from the pin and compare that to stock sizes.

Then using a bore gauge and a micrometer: measure each bore at three levels, (top, middle and bottom) in three directions and compare that to your piston measurements and the specs in the manual. (I almost guarantee your 45 year old cylinder walls are not parallel)
...you know, like it says in the manual.... ANY manual.

Any less and you're just pissin' upwind and wasting good beer drinking time and money
Not everyone has the experience, talent and equipment to build motors... and those that DO know that we can't help build a motor over an internet connection. WAY TOO MUCH manual manipulation and measurement of parts required.
... so IF you're looking for advice: Take it to someone that knows what they're doing
No condescension, trying to help... BUT ask stupid questions and you're gonna get called out on it.