Wiseco ring rotation?

[Blaner]

hey! time for another top end rebuild, funny thing is i just did one 7months/240km ago. Bikes been running beautifully for that time but a few weeks ago on an outting i noticed a strange knocking sound, the same day i snapped my kickstart spring, so i put two and two together and thought the bit of spring floating in the oil was the source of the noise. I stopped as soon as i noticed it. Alas, after fixing the spring and an axle bearing recon, i took it around the block to test the axle but the knocking was still there she died after about 100m!

Upon inspection, i found that both rings had their ends facing the exhaust port and naturally pressing out into the port on each stroke! this causes the top ring to get hooked and that messed everything up.

Now, im puzzled beacuse when i installed the rings i followed my manual and made 120% sure the rings were located at the stopper/locator marks in the ring grooves which are staggered with an offset from the intake and made sure they were the right way up. I know i did it right and my clearance was very very good, a bit tight if anything. Now my suspicions lead me to think my father (who is actually a exceptionally skilled and precise mechanic) changed it after i slipped the piston and rings into the jug... After i assembled, i told him to have a look before i torqued the barrel Thinking i may have missed something.

So, I ask you...is it AT ALL possible for the wiseco rings to rotate from the correct location position with very good clearance? or did my dad forget to upgrade his spectacle prescription and meddle his polarity and move them back to front? I am 100% confident i had it right. I didnt see if he fiddled or not but as far as i can see, its the only explanation. He says he is not sure if they were right implying that he did something! eish...any input?

 

[sheeblast]

look at the piston, is the ring locator pin bent? i bent a couple on my zilla, both with wiseco.

 

[Blaner]

mmm i dont think so, il check in the morn and let u know, but why would the pin bend in the first place?

 

[sheeblast]

well many reasons
bad part
pre det
bad install

 

[sicivicdude]

A ring would bend if there were forces on it pushing it to spin. Namely a poor porting job with the exhaust port being too much of the total circumference of the bore or a cranks shaft out of runout causing a twisting motion on the piston.

It could just be total coincidence too. How bad did it tear up the piston and bore?

 

[Blaner]

i have not enlarged the exhaust port at all, only get rid of casting flaws and areas where the gasses were eddying. so cant be that. I have enlarged the intake ports but the rings do not run into the port area at BDC. Runout is in spec, checked that after i got it back in june 2010.jetting is good, pretty sure its spot on and no signs of pre detonation. the barrel is not too bad, just a 0,25mm bore will fix it, piston got the top ring mashed into it down the skirt so its shot. perhaps i must chamfer the ports more. but it still doesnt explain the rotation. When the ring is located on the piston and under compression from the fitting into the barrel surely it is impossible for them to move, the ring butt will just stop up against the pin, both clockwise and counterclockwise. il inspect those pins more closely...

 

[sicivicdude]

Did you mess with the boost port width?

 

[liljatownboy]

Did you mess with the boost port width?

you mean transfer ports?

 

[blast3r06]

let me know if you find out why those rings spun on you i have a 06 blaster and my factory piston did the same thing

 

[liljatownboy]

they would spin if

wrong size rings

poor instillation

ring pins are defective

 

[sicivicdude]

No, the boost port width. The pins ride precariously close to each side of the boost port and he said that he "enlarged the intake ports". If he took the boost port width out too far, the end of the ring can pop out into it and snag. Once it does that, it's all over with.

 

[scotj77]

maybe the locator pins fell out and i don't think your dad couda screwed up bc the piston shouldn't fit into the cylinder with teh rings not aligned properly

 

[liljatownboy]

No, the boost port width. The pins ride precariously close to each side of the boost port and he said that he "enlarged the intake ports". If he took the boost port width out too far, the end of the ring can pop out into it and snag. Once it does that, it's all over with.

^true the port above the two intake could be to wide if you messed with them

 

[sheeblast]

maybe the locator pins fell out and i don't think your dad couda screwed up bc the piston shouldn't fit into the cylinder with teh rings not aligned properly

but the piston could be backwards. did you check the piston to see which way the locator pins were facing after it blew up?

 

[Blaner]

yes piston is in the correct way. i did not enlarge the boost port above the two large intakes for the reason Sicivicdude mentioned. Even if it did hook there, why did they both end up with the gaps facing the exhaust? you can see it hooked on the exhaust, there is a score running up from the top edge of the exhaust port caused by the mashed ring. still havent inspected pins. will do that now! thanx for input so far

 

[Blaner]

Got some pics fo u guys can see... the pins are still there...dont look bad, im not sure...i think i will do more of a chamfer on the exhaust this time round.

 

[sheeblast]

i didn't see the pin in any of those pictures. but that isn't that bad, when mine did it, i had a decent piece of piston missing and a .25mm overbore didn't fix the problem i had to go 1mm.

 

[brandoz28]

hmmmm were the rings flat like that on the ends when you installed them? the ones with my wiseco were cut on the ends

 

[sheeblast]

hmmmm were the rings flat like that on the ends when you installed them? the ones with my wiseco were cut on the ends

ya, just noticed that when you said it, my were notched to have a little bit of the ring going over the pin.

 

[Blaner]

here you can see the pin in both the top and bottom grooves. that is not the end of the ring, the rings are out in these two pics. best i can do in terms of photography... If they are not normal for wiseco let me know! ive ordered my new one so guess i can compare in a while, takes ten days ordering from the states...

the rings did have a notch/step on them when they were installed.