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DOH!!!!!! Grrrrrrrrrr.......

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Man I am floored right now....I am such a dork!!!

When I did my top end last night...I looked all over the piston ring for the "R" mark...did not see one...but I am now positive there must be a very faint one I did not see...

I put the top end back on, but I am not sure that the ring is in right, so now I have to pull it back down, that's like another hour of work...but for peace of mind I must. I only got the carb back on, so really it is not alot of work, remove carb, remove cam box, unbolt head and pull the jug...but still. :D

The inner top edge of the ring is beveled so that under combustion pressure the ring will be forced to expand against the cylinder wall, if the thing is in backwards, lots of blowby wil occur, and the ring will most likely not seat to the cylinder wall properly. I see this on the old ring, if I had just looked at the ring a bit closer I would have seen the physical difference...

...or if I had RTFM a bit closer... :):D :D

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For sure check it out.

Hey, don't feel that bad.......I do stuff like that all the time. :)

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Man, some guys have all the luck. Now you get to spend another hour or two in the garage tinkering with an awesome bike. :D

I have to put a new sprayer on the kitchen sink tonight. :)

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from the title of this post i thought he slipped & fell on some special sausage :)

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Man what a dumb ass :)

Hmmmm...at least I have the skills to do something like this...twice. Practice makes perfect they say... :D

In this case, when I look at the ring, if it DOESN'T have the "R" mark I am gonna be vindicated...

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Man don't feel bad. When I had my 96 cr 250 I was doing the top end, just a freshen up. Well all my buddies called me and said they were riding early the next morning. It was 11 pm and I had only pulled the carb and air box off. I had planned to finish the job the next day. Well I rushed everything Pulled the jug off removed the piston, slapped the new one on new rings slid every thing back together and fired her up. My joy of having my new top end lasted about 15 secounds, braaaap, braaaaaaaaaaap, braaaaaaaaaaaaaaaaaaaapCRUNKKK. Yes folks In my haist to get my bike back together I did the most stupid thing you could do. I put the piston in backwards. What a dummy I am.

So don't feel about the rings.

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yeh, i almost did the same thing until my son walks up and said, "Dad, you got to look at it with the light reflecting off of it, then you will see the little r. If you are holding the ring with the gap away from you it will be on the left side of the gap about 1/8 inch away from the gap." Sure enough it was there. Get it done and ride it. We went one tooth smaller on the rear once we took it out with the new 04 piston in it. Let me know what you adjust.

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CR2CRF....you hit the nail on the head. The flo light I was using was shining from the side. I swear there was no "R" on that damn ring...but I would bet there really is. On the old ring I did not even see it until this morning while at work showing my piston to a car racing buddy of mine.

Funnier thing is, last night I was thinking there should be a mark, just like on my last bike. When it did not stand out I just went with it instead of looking CLOSELY. Hell, I did not even read the manual, must have installed 50 pistons over the years and this is the FIRST time I had put a ring in upside down :):D

What will really get me is, when I pull it down and find the ring is in the right orientation hahahah...but a 50/50 chance is too big for me.

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The ring may not have a mark on it at all. If it doesent it can go in either way. On my XR650 the ring is like this. Just make sure you have the right ring in the right grove. Typically, the ring land is deeper on one ring than it is for another.

Your correct on the blow-by...don't ask me how I discovered all of this. :)

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Kids say the darnest things!

Measure once, cut the hell out of it till its the right length!! (my motto)

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The_Dave ---> the CRF450 ring has a straight, single, compression ring. The only reason it has a direction is because of the beveled inner corner that allows compression forces on top of the rin to force it outwards into the cylinder wall. My old 426 had the lands where you could obviously tell...

The XR650 has 2 compression rings?

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The XR has a compression ring, and Oil scraper ring, and oil control ring assembly. I understand about the compression ring and its design. Some of those bevels are really small and hard to determine with the nakid eye. What I found out is if a ring does not have a mark indicating "top" it can be installed either way. Like I said, on the 650 the ring lands are deeper for the oil scraper ring than it is for the compression ring. The ring width corresponds with the depth of the ring land.

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I have a friend that had McGraths 92' Peak CR250. He did the same thing. Even after Pro Circuit ported a new barrel, it never ran the same.

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