ring gap specs
- Thread starter jostby
- Start date
Per the Gas Gas book it should be .5mm to .8mm..
If your using an aftermarket piston and rings use the specs it came with.
I'm kind of surprised that people are complaining that the ring gaps aren't right when you take the parts out of the box.
You're supposed to set the ring gap to match your jug. If they shipped it out all set for an "A" bore the gap would be to big for the "D" bore. At least they gave you enough material to work with. Setting gap is a very basic step that must be done with all rebuilds.
There have been a few posts on here and some other sites bitching about ring gap not being right. If you have never had to set ring gap during a rebuild you are either the luckiest man alive or your not doing something right.
Just my .02 for everyone bitching about rings.
If your using an aftermarket piston and rings use the specs it came with.
I'm kind of surprised that people are complaining that the ring gaps aren't right when you take the parts out of the box.
You're supposed to set the ring gap to match your jug. If they shipped it out all set for an "A" bore the gap would be to big for the "D" bore. At least they gave you enough material to work with. Setting gap is a very basic step that must be done with all rebuilds.
There have been a few posts on here and some other sites bitching about ring gap not being right. If you have never had to set ring gap during a rebuild you are either the luckiest man alive or your not doing something right.
Just my .02 for everyone bitching about rings.
widebear
Banned
The piston I was refering to in my previous post is a Honda cr-250 piston , one size only, and thats stnd . I agree with you about measuring first but my complaint is about outsourcing and quality control. Ive done enough top ends over the years and their was a time that I could rely on the quality control being correct out of the box, the reason made in U.S.A. , Germany or Japan quality. Your hearing alot of bitching as you put it is because guys are getting caught by a recent degrade in quality control , not checking and squeeking their engines and its not just the do it yourselfers, but Ive recently seen shops that have allways cut corners in order to make their margins are getting caught too. I,m not happy about the rings in my Wiseco being made in Taiwan, If you are good on you maybee plan on sending you kids to school over there, cuz thats where the future is and tell us all to suck it up!
dave948, I agree that end gap is nothing more than a specification to be adjusted, no differant than setting valves on a 4t except that you only adjust ring gap once. The last bike that I rebuilt I put a B piston (Athena) in my A cylinder and did have to file the rings to meet the GG specs. I don't remember what I started with or ended up at. But...
widebear, you confirmed what I had written in my notes from college in '83 (damn I'm getting old). Automotive industry at that time used .004" min, .010" max. If I had had the info from dave948 I would have used it and probably filed the rings but as it is the A piston from Vertex had .015" gap (.381mm) and that is what I went with. (in a B cylinder rebuilt to A specs by Millenium)
The information that came with the Vertex piston only has specs for piston to cylinder tolerance (.002" - .0025" for anyone that is interested). No ring gap info.
Also, with all the automotive engines I have rebuilt I have never had to file a ring, I think the tolerances are much tighter in the high performance world of single cylinder engines.
Thanks to both of you for the info.
widebear, you confirmed what I had written in my notes from college in '83 (damn I'm getting old). Automotive industry at that time used .004" min, .010" max. If I had had the info from dave948 I would have used it and probably filed the rings but as it is the A piston from Vertex had .015" gap (.381mm) and that is what I went with. (in a B cylinder rebuilt to A specs by Millenium)
The information that came with the Vertex piston only has specs for piston to cylinder tolerance (.002" - .0025" for anyone that is interested). No ring gap info.
Also, with all the automotive engines I have rebuilt I have never had to file a ring, I think the tolerances are much tighter in the high performance world of single cylinder engines.
Thanks to both of you for the info.
widebear... I don't know you from a hole in the wall and you don't know me. So the comment about me sending my kids to Taiwan for school, I've fought overseas for this country so go f yourself...
I stand by my statement of every ring gap must be set except for dumb luck.
I don't care how many rebuilds you've done with out setting it, you did them wrong. I worked as a 2 stroke mechanic for over 15 years in the marine industry and have done hundreds if not thousands of rebuilds.
If your ring gap is right out of the box you got lucky, end of story.
You've spent more time blogging about this than it takes to file the rings. Stop embarrassing yourself by bitching about something you should be doing, like others have said, it's like setting valves ect.
widebear
Banned
dave 948. take it easy buddy .My statement about Taiwan was more to press a point rather than insult, so if you took it the wrong way, sorry. I think your missing the point of my rant and if you read my thread you will see that I agree that you should check your tolerences and we are on the same page in that regard, and I respect you for you professional approch , by all means. My point is, Ive seen quality control diminish since manufacturers and companies started outsourcing and that list includes everthing from piston rings, melamine tainted food products, xlarge shin pads with straps that are to short to go around your calf, all the way to call cntrs in far away places, it goes on and on . Blogging ?I do agree that I'm guilty of inciting a hearty reponse out of you, and others at times, to provoke thought and discussion, fact is but its been kinda of dull and quite around this site recently, how many how do I jet my bike threads or , gee Whally what do you suppose the Beaver mixes his oil at,do we really need?. On your point of luck coming into it I agree with you and I personally dont leave luck to chance but I have seen alot more engines being squeeked as of recent and do believe thats because guys became comfortable with being able to succesfully repace a top end without checking the tolerences and that has somehow changed and I put that down to a degradation in quality control which is now catching up to the sloppy work practices.I cant speak for the marine industry as I have no experiance and I only speak from my own experiance. As a final thought judging by your choice of language it would be great to see you direct some of your passion towards the polititions that have deceaved us into the whole idea of n.a.f.t.a. and such, dont shoot me I'm just the messenger.
GMP
Active member
No insult was intended by widebear and IMO the post was spot on. Reread and I'm sure you will agree. The Asian outsource thing gets under my skin as well.
Please, no personal attacks. If you feel you were insulted read again before you post. If its obviously offensive I will delete it immediately. Thanks.
Please, no personal attacks. If you feel you were insulted read again before you post. If its obviously offensive I will delete it immediately. Thanks.
I don't know why your comment struck a cord with me and set me off but it did. I look back at the posts now and my comment was unnecessary and childish. Not what this forum is for or about.
We do live in a throw away world and the people demand the cheap products that are on the market today. I'll always buy the best I can and wiseco made a good product for a lot of years. I haven't purchased any wiseco products in 2 or 3 years but I'll check them more carefully in the future if you promise to always check and set your ring gap.
We do live in a throw away world and the people demand the cheap products that are on the market today. I'll always buy the best I can and wiseco made a good product for a lot of years. I haven't purchased any wiseco products in 2 or 3 years but I'll check them more carefully in the future if you promise to always check and set your ring gap.
