lost my piston circlips!!
- Thread starter dave89b
- Start date
If you enjoy being thrifty when pulling the top end, and do not want to replace the rings, leave the piston in the bore. Once removed, the microscopic grooves will NEVER line back up EXACTLY with where it was before. They will prematurely fail, just like used cir clips. Vintage Bob
How does he replace the piston pin circlips without taking the cylinder off of the piston??whenfoxforks-ruled said:
I wouldn't be overly concerned with re-using the same rings; they're located by pins in the ring lands and will go right back in the same place. If there are "grooves" in the bore large enough to have an effect on ring seal, the cylinder should be honed and new rings installed before he buttons everything up.
dave89b said:
Jesus Christ man you'll walk out to the mail box tomorrow and the clips will be there, I know your kicking yourself, but I'd like to come join in too..... the only thing we didn't do is write a Eulogy for your poor engine :whoa:
I'd really love to have an air cooled kdx (its kinda on my bucket list)...so how much $$ would it take to buy/bail out those poor kxd's?
I can meet you half way...maybe Pennsylvania??
- Thread starter
- #35
nope it happened. its all real. i haven't even checked the mail yet because i know they will be there.
but seriously, i've been an outboard mechanic for years and have re-used cir-clips plenty of times. and those engines are STILL running great.
at least it didn't happen 30 miles from my house where it would have probably happened if i didn't have it running all day to break it in, and just broke it in on the trail. and its COLD out tonight that would have sucked.
but seriously, i've been an outboard mechanic for years and have re-used cir-clips plenty of times. and those engines are STILL running great.
at least it didn't happen 30 miles from my house where it would have probably happened if i didn't have it running all day to break it in, and just broke it in on the trail. and its COLD out tonight that would have sucked.
- Thread starter
- #37
after riding around for about an hour today only using 1st and 2nd trying to break it in. i let it sit there idling for like an hour and was idling perfecct . then i went around some more and after about 10 minutes of puttinng around i gave it a little bit throttle in 3rd before i put it away and as i was slowly coming back in 1st gear then it happened. 20 feet from shop door
reepicheep
Member
- Apr 3, 2009
- 670
- 2
You roll the dice and you take your chances. Dave's not whining, and if what he did was the most expensive stupid thing I have done in my lifetime, I would be a happy man.
Post pictures of the mechanical post-mortum... It'll be entertaining if nothing else.
(and nobody here will ever be tempted to reuse circlips again... ;) )
Post pictures of the mechanical post-mortum... It'll be entertaining if nothing else.
(and nobody here will ever be tempted to reuse circlips again... ;) )
Wrong! Re-using the rings once removed, is just as bad as re-using the cir clips. They will NEVER EXACTLY line up again, NEVER. They will prematurely wear out. I just recalled on some other forum, where a boat mechanic discovered that we are stupid for running expensive 2 stroke dirt bike premix oils. Boat engines run a lot hotter, he "figures", so marine premix oil is a lot better, he had never had a problem, so he "figures". WRONG, I am not retelling my "figuring", or at least I am doing my best in a sea of ignorance. Damn near every Micky mouse plan you can think of, myself or others HAVE already tried, with failures. So why perpetuate ignorance? There is solid data available to prove it, so why argue it? Back to the used cir clips poster, Dave89b, you can send your top end to a reputable shop, and have the top end fixed, for about what a used, questionable condition top end will cost. Cost per hours of fun, against cost per hour of fixing it? A good KDX top end should last a really longtime! People do leave the piston in the bore, and remove the cir clips, so as to not replace the rings. Not a lot of fun, till you have done it a couple of times, go figure? Vintage Bobmudpack said:
reepicheep
Member
- Apr 3, 2009
- 670
- 2
I get the "don't reuse circlips"... they have a really hard job, and are really minimal, and installing and removing them seems like it is likely to exceed youngs modulus and "un springy" them. And they are cheap.
But getting a used bike and pulling the jug, inspecting the piston / bore / head (without removing any rings or circlips) and bolting it back together doesn't seem like it should require rings to be replaced (unless they are worn out of spec).
The rings float (constrained by the pin) anyway, right? So they don't really "line up" with anything besides the pins that keep them from lining up with each other. I'd say even on the pin, compressed in the cylinder, they have a good 1/8th inch of rotation play.
And looking at the piston here on my desk, which had been abused to heck on the 95 I bought used (to the point where the piston skirt was cracked and scored, and the cylinder bore was grooved and galled), the piston rings (which were worn on the thrust surface to at least *half* of their original thickness) are mirror smooth all the way around. That cylinder was badly scored, the rings are mirror smooth.
I'm not trying to discount hard won experience... But on three (soon to be four, my 9 year old is going to have a *really* merry christmas :) ) bike I have bought or helped buy, I pulled the jug to inspect the condition of things then bolted it back together with no problems. Two of the three times, everything looked perfect and it went back together and continues to work perfectly. The third time the piston skirt was cracked and the rings were badly worn, and it got a full top end rebuild.
But getting a used bike and pulling the jug, inspecting the piston / bore / head (without removing any rings or circlips) and bolting it back together doesn't seem like it should require rings to be replaced (unless they are worn out of spec).
The rings float (constrained by the pin) anyway, right? So they don't really "line up" with anything besides the pins that keep them from lining up with each other. I'd say even on the pin, compressed in the cylinder, they have a good 1/8th inch of rotation play.
And looking at the piston here on my desk, which had been abused to heck on the 95 I bought used (to the point where the piston skirt was cracked and scored, and the cylinder bore was grooved and galled), the piston rings (which were worn on the thrust surface to at least *half* of their original thickness) are mirror smooth all the way around. That cylinder was badly scored, the rings are mirror smooth.
I'm not trying to discount hard won experience... But on three (soon to be four, my 9 year old is going to have a *really* merry christmas :) ) bike I have bought or helped buy, I pulled the jug to inspect the condition of things then bolted it back together with no problems. Two of the three times, everything looked perfect and it went back together and continues to work perfectly. The third time the piston skirt was cracked and the rings were badly worn, and it got a full top end rebuild.
I agree. And further more, if the cylinder is in good shape with crosshatching in place, rings would re-seat again just as they were seated during the initial break in. Replacing new rings just because you had to pull the jug for some other reason (such as to inspect the piston), is just silly. I have never seen any of this "solid data" that proves there are microscopic grooves that would never line up again. Likewise, I have never had a problem with ring seal after pulling the jug off a new to me used bike to inspect the piston and rings on a supposed "fresh top end". Heck, even the service manual has instructions for removing the jug, checking tolerances, and stitching back up. No mention of replacing rings any time the jug is removed.
I can't even imagine a way that this would be possible without at the VERY least unbolting the cylinder and turning it so that you could get to the circlips via the exhaust port or intake on the cylinder. How would this be any different than removing the jug and replacing it? You're still twisting the cylinder on the piston which will put the rings in a different position on reassembly, by your figuring at least...
jessica456
Member
- May 5, 2009
- 10
- 0
you should just buy some new ones if u cant find the ones u lostdave89b said:
Quit "looking" at something you would need a microscope to "see". The kdx forum can have more chest thumping and hormones flying around than the womens forum? Vintage Bob
I'm not trying to be homonal, lol. I'm just sayin, I've never once had a problem pulling a jug, checking things out, and putting it back on. I will certainly take your advice to heart next time the situation arises though. Seriously, that's the first time I've ever heard anyone say that you shouldn't put the same rings in if you have to pull the jug off for any reason. Assuming the rings are still in spec, of course....
Did some quick google searches just for fun, and everything I find seems to say if the rings are still in spec, they are fine to re-use as long as they have not been REMOVED from the piston. I'll keep looking for your "solid data" though. ;). This seems to pretty much agree with what all my service manuals say. In spec, check and reassemble, out of spec, replace.
J.
Did some quick google searches just for fun, and everything I find seems to say if the rings are still in spec, they are fine to re-use as long as they have not been REMOVED from the piston. I'll keep looking for your "solid data" though. ;). This seems to pretty much agree with what all my service manuals say. In spec, check and reassemble, out of spec, replace.
J.
- Jul 20, 2009
- 417
- 0
When I was racing MX as a teenager it was normal to replace the rings if the jug was removed and that's what I did regardless of condition. I would not do it now if the rings were less than a couple of hours old.
Back to Dave's seized bike: I bet the circlips are still intact, I would expect my bike to seize if I ran it in like Dave said he did.
Riding for an hour in 1st and 2nd gear, followed by an hour of it sitting idling, followed by 10 minutes of putting round, a little bit of throttle in 3rd, followed by slowly riding in 1st, followed by seizure. What is wrong with this picture? No cooling airflow, where's the mystery? I may be wrong, but that's my take on it. Treating a motor like that is just plain cruel and if you don't instinctively know that, you are in for an expensive hobby. That's why I said find another sport. Also, the same goes for if you are going to reuse an item that can be replaced for a few cents, thats just crazy. I don't mean any disrespect Dave, but if you are going to continue riding you really should take advice from the guys on here, as the advice is free and bike parts are expensive.
Back to Dave's seized bike: I bet the circlips are still intact, I would expect my bike to seize if I ran it in like Dave said he did.
Riding for an hour in 1st and 2nd gear, followed by an hour of it sitting idling, followed by 10 minutes of putting round, a little bit of throttle in 3rd, followed by slowly riding in 1st, followed by seizure. What is wrong with this picture? No cooling airflow, where's the mystery? I may be wrong, but that's my take on it. Treating a motor like that is just plain cruel and if you don't instinctively know that, you are in for an expensive hobby. That's why I said find another sport. Also, the same goes for if you are going to reuse an item that can be replaced for a few cents, thats just crazy. I don't mean any disrespect Dave, but if you are going to continue riding you really should take advice from the guys on here, as the advice is free and bike parts are expensive.
- Thread starter
- #49
the bike DEFINITLY didn't overheat, its really cold here and i was watching it every second of it idling. it was running very cool.
i took a chance and knew what the consequences COULD be. i'm not pissed off or anything its all just part of tinkering.
next time i put it together i KNOW it will be done right.
i took a chance and knew what the consequences COULD be. i'm not pissed off or anything its all just part of tinkering.
next time i put it together i KNOW it will be done right.
