GS650 piston rings, ebay aftermarket replacements?

[Chuck78]

Please link your build thread here when you start it!

Also if anyone has a recommendation on a good but affordable dial bore gauge to measure cylinders, please drop me some suggestions.

[Nessism]

[IMG][/IMG]

Crusinimage ebay 850 rings

1st and 2nd compression ring,

Thickness

both 0.046" or 1.18mm

End gaps,

both 0.015" or 0.381mm

Width,

1st ring 0.1095" or 2.78mm
2nd ring 0.107" or 2.76mm

These measurement's were consistent with all 4 ring sets and were all measured in the same freshly de-glazed 850 cylinder, (850 cylinder professionally deglazed on a sunnen honing machine) and are taken around 10mm from bottom of the cylinder,

When I get my other parts back from the machine shop I will be doing a thorough Thread in the Projects section, and will document everything

Please note that the ring width is thicker and I do not have specs for the 850, I do not have a bore gauge to have precise measurement's of the bore and I neither have feeler gauges thin enough to measure Ring to Groove Clearance,

I will ask my machinist to take these measurements next time I'm there.

Cliff's website does have the 850 manual, it's located at the top of the list.

The ring width is supposed to be 1.21-1.23. Your rings are about .001" undersize which isn't too bad. More importantly you need to install the rings onto the piston and measure ring to groove clearance. The spec is .0008-.0022", with the service limit of .0059. My guess is you will be okay.

[one_civic]

Cliff's website does have the 850 manual, it's located at the top of the list.

The ring width is supposed to be 1.21-1.23. Your rings are about .001" undersize which isn't too bad. More importantly you need to install the rings onto the piston and measure ring to groove clearance. The spec is .0008-.0022", with the service limit of .0059. My guess is you will be okay.

Stupid me, lol, I should have checked the top of his site considering his main bike is an 80 850,

[one_civic]

Just checked my Cruinimage ring to groove clearance with my smallest feeler gauges Nessium and 0.002" (0.05mm) fits into both 1st and 2nd compression ring grooves but my 0.003" (0.08mm) does not, so I guess I'm good

[JJ]

Yes you are. Old rings in a freshly honed cylinder will definitely seal better after doing something like the mototune method. I have done this a few times, slapped a crappy top end on to test a transmission before doing a big bore, or throw an engine together for a friend who had no money at all for an engine, or just to get one of my bikes by until I had time to do a proper rebuild. One low miles 750 just had no compression, very little power, it would only go about 70mph or so. Using the kickstarter you couldn't feel any compression at all. I figured it was originally broken in way too easy. Took it apart, nothing wrong inside that could be measured, no wear on the rings or anything. Honed the cylinders and put it back together. Compression isn't all that great at first, not much power, but after blasting on the throttle a while it seals up, gains power, compression test is much better. I don't know why it works but sometimes it does.

Yes, your examples are correct. If the rings aren't worn completely out, chances are good that you can get an reasonable seal and compression using them with freshly honed cylinder walls.

My comments were aimed at a new cylinder walls and rings in a newly rebuilt engine.