Wiseco wrist pin circlips

[F-16Guy]

All you wiseco (or prospective wiseco) guys listen up. I put my top end together last month, broke my bike in, and put about 5 hours on it when it started to smoke. I thought "Hmm, maybe the rings didn't seat right, or maybe I got some shoddy machine work", so I tore it down. When I got it apart, I was shocked and angered to find that one of the circlips had worked loose! The wrist pin slid out and gouged my fresh bore beyond repair, and now I have circlip fragments floating God knows where. When I was putting it together, I noticed that one of the clips didn't seem to "snap" in like they normally do. I removed and reinstalled it, and it seemed secure (apparently it wasn't) so I finished the assembly. This is not my first motor build by any means, and to Wiseco's credit, I've never had a problem with there products in the past (2 or 4 stroke). The groove for the clip in question is hogged out, as if the clip was moving around in it. I suspect that I got the wrong clips (or defective clips) with my kit. I have called Wiseco, but there QA guy is on vacation, or something. When I get further info, I'll post it. Until then, make sure your clips fit properly and are tight. All you Ross and JE guys insert comments........... now!;)

[MIKE400EX]

Something to check: If the bore is not perpendicular (square) to the case or bottom of the jug/cylinder, the piston pin will bang back and forth against the circlips. Usually the end result is either a scuffed piston side or a circlip that comes out. If that was a round wire clip then I'd be willing to bet that the clip was damaged when you put it in the last time, but unfortunately it wasn't visible.

[RAPTORAZ]

Originally posted by F-16Guy
All you Ross and JE guys insert comments........... now!;)

Here's my jab! J/K:D

[nakomis0]

If it didn't snap it that sounds like your problem.

Theres a special position the clip has to be in, or else the up and down force of the piston will pop it out.

Right now I can't remember what poistion that is but...:rolleyes:

[powerslider]

The circlip gap should be either at the 12 or 6 o clock positions, high rpm can sometimes dislodge them if they are installed with the gap near the 3 or 9 o clock positions. You should never reuse them once they have been installed as the radial tension is decreased.

[Predator36]

Originally posted by powerslider
The circlip gap should be either at the 12 or 6 o clock positions, high rpm can sometimes dislodge them if they are installed with the gap near the 3 or 9 o clock positions. You should never reuse them once they have been installed as the radial tension is decreased.

You are on the money, I have seen the results of not doing it properly several times (yes it was me).

Another thing to look out for - I have seen the crank knocked out of true on several 400ex engines. When this happens the rod rocks back and forth on every stroke of the engine which in turn hammers the wrist pin into the clips till something has to give.