Bad experience with Wossner pistons...

[CS18]

Finished up my 500AF a month and a half ago and absolutely love it. Unfortunately last time out, at 4.7 hours on the meter (I completely rebuilt the engine before sticking the engine in the AF), I suffered a loss of compression. Just tore the engine down and saw what happened. It seems the locating pin for the bottom ring came out and allowed the ring to turn round until it got to the exhaust port, at which point the ring caught in a big way wrecking piston and barrel. 

I've had bad experience with a four stroke Wossner piston in the past, but decided to give them another go in the 2 smoker. Suffice to say never again...

[Motorrad]

Not what I want to hear..  I was going to try them next..  After my wiseco machining flaws... I didn't want to run wiseco again...   Hmmm

[1989kawasaki]

id say go after wossner and get them to pay for the damages their s**tty product caused

[CS18]

id say go after wossner and get them to pay for the damages their s**tty product caused

Thats the plan anyway...

[kwakman]

good luck with that.......mates 480 engined tdr ate 2 sets of wossner pistons and the barells too....K.

[RoostDaddy]

I dont think its a Wossner problem.  Yes it sucks, but I have had it happen on Wiseco and Pro-X pistons too.  This is always one of the places I inspect on a piston before putting into a bike. (use a small punch and give them a tap to make sure they are seated)  not a guarantee but a good precaution.

[kwakman]

can you be more specific Roost, what are you punching with the tap? K.

scratch that, you mean loc pin.K.

[kwakman]

the hungry tdr made a mess, we think, due to Wossner stating that the thermal expansion of their pistons is reduced enabling a tighter piston to bore clearance.locked up 2 sets. when run at an increased clearance, (but still a smidge tighter than the Wiseco) she runs good.K.

[cbxracer30]

This is what they are going to tell you "The pin fell out do to a too lean condition , send us the piston and we will perform a rockwell hardness test on it this will tell if the piston was run hot for a long period" . I have already been done this road with wiseco and it never went anywhere. Good luck! CBX

[81cr450]

Manufacturers wont cover incidentals, period, even if you do get them to own a defect. I'm doing a trx650 rincon topend right now & didnt want to hear of these problems, but I guess atleast with the 4 stroke no locating pin. Glad to hear some on the tighter fitment spec kwakman, I'll make sure they give her a little more clearance. Anybody tried Namura?

[wpmarineltd]

Vertex all the way !!

[1989kawasaki]

a buddy of mine had the exact same thing happen to his 89 rm250 with a weisco piston and weisco gave him a new piston and resleeved his cylinder and gave him big trailer stickers for free

[Dutch-K5 Fan]

Vertex all the way !!

I've run Vertex in mine CR125 and CR250 for several years, worked perfect.
Have never found one for the KX500.
Do you have them in England then?



Dutchie

[Kiwi500]

Use genuine parts !! Never had one of them fail........cheaper is never better.
G

[weymouth399]

Use genuine parts !! Never had one of them fail........cheaper is never better.
G

Plus 100 on OEM

Bob W