Quick question about piston circlips . . .

Got questions? We got answers....
User avatar
Jeb
Gold Member
Gold Member
Posts: 1894
Joined: 08:01 pm Jul 14 2006
Country:
Location: Cincinnati / Northern Kentucky

Quick question about piston circlips . . .

Post by Jeb »

I've been doing quite a bit of searching on the site and ran across something that's got me worried a little . . . the circlip damage on Inda's bike (saw the pics).

Why did that happen? I looked through the online manual on top end reassembly and it doesn't mention position, so was it seating? Are circlips seating any different than "typical"?

Thanks ahead of time.
"No farmer ever plowed a field by turning it over in his mind" -George E. Woodbury

CLICK FOR PICS!
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

Seat the openings at 6 or 12 O' clock. Not like the manual shows... Sorry, this is a sticking point for me and the manual. Think inertia here.... and make sure they "SNAP" into place.
Even if you are using a Pro-X piston... take one of the circlips down to a good shop and have them match it up with Wiseco circlips. They are much , much stronger and very cheap insurance. I have found stock and Pro-X circlips to distort upon installation.
*** Administrator //***
****'95 KDX 200/****

"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
User avatar
Jeb
Gold Member
Gold Member
Posts: 1894
Joined: 08:01 pm Jul 14 2006
Country:
Location: Cincinnati / Northern Kentucky

Post by Jeb »

. . . so if I've got a Wiseco kit on the way and install the clips w/ openings at 6 or 12 o'clock, and confirm solid seating, I'm fine?
"No farmer ever plowed a field by turning it over in his mind" -George E. Woodbury

CLICK FOR PICS!
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

You got it Jeb! :wink:
*** Administrator //***
****'95 KDX 200/****

"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
User avatar
Jeb
Gold Member
Gold Member
Posts: 1894
Joined: 08:01 pm Jul 14 2006
Country:
Location: Cincinnati / Northern Kentucky

Post by Jeb »

Thanks, bro, I've only owned my bike a week and you've already been quite a help to me
"No farmer ever plowed a field by turning it over in his mind" -George E. Woodbury

CLICK FOR PICS!
liv2ride626
Member
Posts: 35
Joined: 06:26 pm Mar 15 2006
Country:
Location: Redondo Beach, CA

Post by liv2ride626 »

I Just got done putting my bike back together with a proX pison kit and you guys got me worrying about the clips, I positioned them according to the service manual when I installed them. Should I be worried about anything?
marco220
Supporting Member II
Supporting Member II
Posts: 113
Joined: 05:22 pm Mar 29 2006
Country:
Location: NW Chicago Suburbs

Post by marco220 »

I positioned mine per the manual since I hadn't seen/heard anything to the contrary until AFTER I had the bike back together and broken in. I was concerned when I first read about the 12/6 and Inda's point about inertia. I considered tearing it back apart but decided not to since the 200s are most likely put together that way and don't seem to have a problem. I also figured that a forged piston is stronger than cast so it won't distort under load and therefore the holes will stay in shape.
2002 KDX 220
RB'd Carb and Head

I don't crash often... but when I do, I'm going for style points!
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

If you happen to take a clip out to check its position, don't put it back in. THAT would be worse than leaving it in the wrong place.

Never re-use piston clips.

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
User avatar
Colorado Mike
Gold Member
Gold Member
Posts: 1921
Joined: 11:42 am Feb 25 2005
Country:
Location: Colorado

Post by Colorado Mike »

a long long time ago .. (2 seasons) , I put a wiseco in my 220 because of all the bad stuff I heard about the stock ones imitating grenades. I had done a couple heat cycles and was about to go out riding when I found talk on this forum about the clip position. I got feeling uneasy about mine, and new it was gonna drive me nuts, so I tore it down again and found one clip was starting to come out of the groove. It hadn't got far enough out to score the cylinder, but that would have happened the next day most likely. I felt very lucky even before I saw the pix of what happens to your motor when you do what I did.
Mike

Life's tough, it's even tougher if you're stupid.
'04 KDX220
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

The carnage...

Piston damaged by Circlip

Image

Cylinder damaged by wrist pin after circlip failed... RUINED! :mad:

Image
*** Administrator //***
****'95 KDX 200/****

"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
User avatar
RBD
Gold Member
Gold Member
Posts: 210
Joined: 02:00 am Jan 18 2005
Country:
Location: Portland, Oregon USA
Contact:

Post by RBD »

I have been building all types of engines for 35 years and I can guarantee that the opening of a "C" type of piston pin clip 'clock" position does not matter PERIOD!

Yes in the old days of low performance engines that were starting to get into more of the high performance, still using the "G" shaped piston clips, it was always recommended to put the flag of the "G" part of the clip pointing up. The reason being that these clips were very thick in diameter and they were heavy in mass.

Todays clips are about half the mass and have no flag...... In turn it takes a little more skill to insert them without bending them, distorting them into the groove and getting them seated into the groove.

Wiseco pistons have had there share of piston pins that have been a little to long, not allowing the last clip installed to seat into it's groove, allowing it to come loose and pop out.

Please note that it does take some skill to install a piston pin clip and not distort it, bend it and make sure it is seated.

NO! with todays piston and clips clock position is not critical.

Again this is JMO,

Ron
User avatar
Jeb
Gold Member
Gold Member
Posts: 1894
Joined: 08:01 pm Jul 14 2006
Country:
Location: Cincinnati / Northern Kentucky

Post by Jeb »

OK . . .

Is there anything different about my KDX's piston assy than a typical piston assy?

I ask this because I've changed a few pistons on bikes years ago (both 125 and 250 mx bikes). With some finangling the circlips snapped in place and, as far as I remember, that was pretty much it.
"No farmer ever plowed a field by turning it over in his mind" -George E. Woodbury

CLICK FOR PICS!
IdahoCharley
Supporting Member II
Supporting Member II
Posts: 1005
Joined: 06:57 pm Mar 19 2005
Country:

Post by IdahoCharley »

I agree with RBD assessment on this issue/question. I also remember the old clips and we saw problems with this happening with them due to the clip tang. It was somewhat routine in motorcycle and ski-doo shops (common name for snowmachines in the late 60s and early 70s for the younger members) to see the tab or tang on piston clips score a cylinder wall.

Even in that era - the problem was more likely the improper installation or the reinstallation of the clip than the actual clip. Insertion was normally done with a needle nose plier and a twisting action to snap the clip into place. Was easy to permanently distort the clip by being overzealous with the twisting motion.

This "issue" seemed to surfaced when Eric Gorr published his performance handbook and noted that the c-clip opening should be either at 6 or 12 o'clock positions. The fear of inerita dislodging a properly positioned and tensioned c-clip is a non-issue in my book also.
KTM 380EXC Mine
KDX 200 Mark's
TTR 125 L Wife's
KDX 200 Austin's
EC 300 Tyson's
WR430 Husky - mine
User avatar
canyncarvr
Gold Member
Gold Member
Posts: 6943
Joined: 01:07 pm Nov 05 2004
Country: US
Location: The Mythical State of Jefferson

Post by canyncarvr »

Re: Is there anything different?

I don't know if you're asking about something specific or in particular, but, no. The KDX is just like other assemblies. Indeed, the clips, pins and all have to do with the piston, nothing to do with the bike.

Amen to the 'pin too long' part of what Mr. Black said about Wiseco's.

Not to jump on a bandwagon, here, but I've never understood the big deal about clip position in the case of the KDX. I think proof enough of that is the different positions stated as 'right' between the manual and other builiders. It's obviously a matter of preference, not a matter of critical import.

Besides that..it seems to me that having a gap at 12/6 'o clock would make the whole idea of mass and things moving worse because the space is what will change if the clip moves, and the space being on the axis of movement, that's where it would change the most.

Still, I think it's mostly a matter of choice.

CM: You said your clip was coming out. Was that due to it not being snapped in in the first place? Was YOUR pin too long?

I've destroyed an engine when a piston clip came out. That clip was NOT a 'G' clip as Ron mentions, but worse than that, having a plier hole on each end.

Image

Note that the term 'circlip' applies to several different configurations of clip that fits into slot.

The above type clips generally have a radiused (rounded) face and a flat face, the rounded face goes toward the pin, the flat face faces outward (toward the piston).

An item of note I haven't seen on this thread....regardless of where you think the gap should be, don't put it at the window in the piston pin bore. That positioning makes it very difficult to get the clip out next time you wanna.

Consider the source
Using a perceived level of knowledge to boost my self worth.
Non impediti ratione cogitationis

bike profile: !clicky!
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

Ya'll ever hear of a guy named Eric Gorr? :hmm:

Seems he agrees with me. :wink:
*** Administrator //***
****'95 KDX 200/****

"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
User avatar
Colorado Mike
Gold Member
Gold Member
Posts: 1921
Joined: 11:42 am Feb 25 2005
Country:
Location: Colorado

Post by Colorado Mike »

Well, now I don't know why the clip was coming out. Maybe the wrist pin is a little too long. I had a tough time getting the clip in on the second tear down, so I built me a little squarshing device out of a woodworking clamp and a socket to get the pin seated tightly against the clip on the other side , then I got it in. seemed like it would be a lot easier if the wrist pin was 1.5 RCH to 1 BCH shorter.
Mike

Life's tough, it's even tougher if you're stupid.
'04 KDX220
IdahoCharley
Supporting Member II
Supporting Member II
Posts: 1005
Joined: 06:57 pm Mar 19 2005
Country:

Post by IdahoCharley »

CM - Sounds like your wrist pin was too long - normally there will be a few thousands gap (WAG .010 in). That piston will grow a little as it heats up and contract a little as it cools. The wrist pin will not grow or contract quiet as fast as the aluminum piston. I believe the clearance is there to allow for the growth/contraction.

2-3 years ago Wiesco had a batch of wrist pins that were too long for the Polaris 700-800 sleds' pistons and would not allow the second c-clip to seat. I had a choice of waiting a week for correct lenght pins or grinding mine down to a given length. I went and ground the two pins down to the designated specs. The specs had a +/- spec of .2 mm which leads me to believe overall length is not TOO critical provided it is adequate for clip placement and expansion/contraction concerns.

Indawoods - your RIGHT - Eric Gorr does agree with you in his performance handbooks. :supz: The way I look at it is its hard to break a old dog of good habits/tricks/procedures!! :lol:

Eric Gorr is a very sharp person likely has picked up a lot of excellent practices from others and created quite a few himself over the years: I believe he tries to incorporated them into his every day engine builds and as tips into his books. :supz: This is a practice or tip that should work on all typical wrist pin clips - Right??

Well Almost - I actually didn't see anything wrong with positioning the c-clip at 6 or 12 o'clock UNTILl CCs POST because CC is right IMO: if c-clip "inertia" is the problem being adverted - then 9 and 3 o'clock would be the perferred positions. :mrgreen: :supz:

CC as always your posts leave me wondering/thinking or drinking.

I will ponder this very little actually since I'm like Yamajeb - when the wrist pin has slide into place and both c-clips have snapped soundly into place I let out my breath and slip the cylinder down over the piston with a smile. The rebuild is almost complete and we shall be hearing the sweet sound of a motor firing up before long!! :lol: :lol: :lol:

P.S. Indawoods - That old english bike of yours may have the older piston clips if you are still using OEM pistons. When I had British bikes it always amazed me of the forged or machined domed pistons that were standard in the day - compared to the Japan bikes. i.e. Some of my former mistress 67 BSA Spitfire, 68 BSA Lighting, 79 Triumph Bonney special verses 66 Kawaski W2SS, 75 Yamaha 650 that I have owned.
KTM 380EXC Mine
KDX 200 Mark's
TTR 125 L Wife's
KDX 200 Austin's
EC 300 Tyson's
WR430 Husky - mine
User avatar
Jeb
Gold Member
Gold Member
Posts: 1894
Joined: 08:01 pm Jul 14 2006
Country:
Location: Cincinnati / Northern Kentucky

Post by Jeb »

So . . . .

. . . . how 'bout circlips in the tranny . . . JUST KIDDING!!!

One comment on the dialogue concerning the orientation I can't help but make. IF the orientation did matter because the piston forces were great enough to distort the circlip AND it had nothing to do with incorrect installation or stressing/micro-fractures within the circlip's mass AND there were no flaws in the circlip to start with AND there were no forces exerted on the circlip from the pin pressing on it laterally - and therefore the only force was the action of the piston - the position of the circlip that would provide minimal flexion would indeed be either the 6 o'clock or 12 o'clock position.

It's a matter of physics and where the circlip would tend to start distorting. I would bore you to elaborate but I'll ask you to consider this: If you had a choice in trying to distort a circlip between two of your fingers, how would you orient the circlip? Now, in which direction would the piston forces be acting? See what I mean!! :supz: :supz:
"No farmer ever plowed a field by turning it over in his mind" -George E. Woodbury

CLICK FOR PICS!
IdahoCharley
Supporting Member II
Supporting Member II
Posts: 1005
Joined: 06:57 pm Mar 19 2005
Country:

Post by IdahoCharley »

Yamajeb wrote " It's a matter of physics and where the circlip would tend to start distorting. I would bore you to elaborate but I'll ask you to consider this: If you had a choice in trying to distort a circlip between two of your fingers, how would you orient the circlip? Now, in which direction would the piston forces be acting? See what I mean!! "

Using your finger analogy with the circlip would certainly lead you to that conclusion!! Basically half the wire in a bending moment verses the total wire segment - OK I agree. Just knew that some smart wippersnapper would straighten us old fellows out!! :lol: :grin: (Its a good thing!!)
KTM 380EXC Mine
KDX 200 Mark's
TTR 125 L Wife's
KDX 200 Austin's
EC 300 Tyson's
WR430 Husky - mine
User avatar
Indawoods
Creator and Founder
Creator and Founder
Posts: 9951
Joined: 09:59 am Jun 12 2003
Country:
Location: Midwest

Post by Indawoods »

9 out of 10 times... it probably wouldn't fail. I always fall into the other 1 time... This is why I am very anal about some things and this is one of them.

Here's your next mission.

Go buy a stock Circlip... and buy a Wiseco Circlip (Wiseco dealers carry a selection usually) Now... try Yamajebs test. You will never use anything but Wiseco circlips from here on out.... at least I won't.

This is my experiences, but do what makes you feel good! :wink:
*** Administrator //***
****'95 KDX 200/****

"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
Post Reply