Anybody here tried an Athena piston in a KDX220?

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UFS207
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Anybody here tried an Athena piston in a KDX220?

Post by UFS207 »

I'm due for a topend and denniskirk.com sells these in fractional oversizes (+.0004" and +.0008") for $112.99. A good bit more expensive than the wiseco's ($90 from rockymountain) but I might be able to strangle another year or so out my jug with one of oversized athena's before things get really expensive. The plating in my bore looked great but my current wiseco was worn completely out. No scoring anywhere, just a smooth worn surface on the intake side of the piston. Very rough check with feelers revealed .007"-.008" clearance. I'm afraid to bring home a set of mics and check it for fear of what I may discover.

Side note: I've read some very mixed reviews from people getting cylinders bored and replated both here and over at dirtrider.net. Servicehonda.com now sells kawasaki parts and they list the 220 jug for around $380. This is at least $100 cheaper than I've ever seen them go for, bikebandit.com wants well over $500. If my jug is worn over the limit would it be foolish to spend the extra cash on the new OEM cylinder or save the $150 or so and take a chance on a shoddy replate job?

Whoever came up with the idea of plating aluminum cylinders needs punched right in the nuts repeatedly.
dejovi22
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Post by dejovi22 »

I have not tried the Athena pistons but I have tried the Pro X pistons with just a little oversize. I tried this on my RMX and the bike still runs without any problem (sold the bike to a friend two years ago).

If your cylinder is getting to the point which will need service due to wear; why don't you just sent it to get bored out to a 225cc? I guess will not be much more than buying a new cylinder and you will gain performance. I think is worth to take that into consideration.
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Post by KarlP »

I don't know if I would take the chance on an oversized piston to allow for a worn cylinder........
The plating itself is very thin. Any appreciable wear would be through to the aluminum and wear would happen very fast after that, as well as plating failure.
The cylinder/piston seal is formed by the rings, anyway. Tight skirts are NICE, though.

I also had a bad experience with a plating job. The plating and sizing was O.K., the pre-plating pickling damaged the KIPS actuating shaft bores, though. I fixed that with emory cloth wrapped around a drill bit.

Others here are more knowledgable. $380.00 (plus piston) for a sure thing is pretty tempting.
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canyncarvr
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Post by canyncarvr »

I don't know if I would take the chance on an oversized piston to allow for a worn cylinder........
Repeated for emphasis.

But...IF the bore in your cylinder indeed is great..AND you have .007-8", it's indeed your piston that is the problem.

Any 'wear' in a cylinder isn't going to result in a 'round' cylinder, and using an oversize piston is not a good plan.

But...yours isn't worn if the plating is fine.

The 'oversizes' you note equate to the Pro-X size groupings defined by alpha designatinos...the 'A' 'B' 'C' etc. part.

IN THAT CASE, such 'oversizes' won't matter much. Note the alpha mark on your current cylinder..use that as a guide.

I know nothing at all about Athena. I would want to make darn sure..then make sure all over again that they are indeed not an ART or Pro-X piston by another name.

One thing for sure...A Wiseco isn't any of 'em!

**edit** A quick look on the web..and I see NO reference to Athena that does not INCLUDE the word 'forged'. Guess that would take care of the different name on the box idea.........

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Post by scheckaet »

Tight skirts are NICE, though.
Yeah, but only on cute girls :busted:

I'd go with a wiseco and a new cylinder if I don't trust the replating company.
Can still resell your old cylinder on ebay, could probably get a few bux out of it (as long as you mention what is wrong with it), I'm sure someone would try to replate it and may do it successfully.
(BTW, if you're selling it on ebay, PM me 1st, might be interseted :busted: just joking :wink: )
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Post by jowens66 »

>|<>QBB<
canyncarvr wrote:
I don't know if I would take the chance on an oversized piston to allow for a worn cylinder........

I know nothing at all about Athena. I would want to make darn sure..then make sure all over again that they are indeed not an ART or Pro-X piston by another name.

One thing for sure...A Wiseco isn't any of 'em!

**edit** A quick look on the web..and I see NO reference to Athena that does not INCLUDE the word 'forged'. Guess that would take care of the different name on the box idea.........
Athena pistons are top quality. They aren't ART or Pro-X pistons, they are Wossner pistons.

They are forged. Check the Wossner website, and they have one avail. for KDX's also.

I have one in my KTM 300. Its what most Ktm bike repair shops recommend, either that or OEM Ktm which is Vertex.

The Athena (Wossner) pistons for my Ktm were weighed. I can't remember exact weights, but Weisco Pro Lite was the lightest, Athena next, and Vertex was the heaviest.
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Post by UFS207 »

Finally got a chance to mic the bore and everything is within spec. "C" cylinder and mic'ing several places I got anywhere from 69.03 - 69.05mm. Guess I'll just go with a new wiseco since it's cheapest and call it good.

My old wiseco had over .008" clearance; close to double what the service manual recommends. I could just about throw the piston through the bore, lots of slop. Interestingly enough I still had good compression right up until I pulled the jug and the motor ran nice and quiet, no slap. I'd roughly guesstimate I had around 180-200hrs on this topend (nearly 3 years of riding nearly every other weekend year-round). I guess one can't gauge rebuild times on having good compression and being able to turn the KIPS freely by hand with the actuator shaft disconnected. Probably should have pulled the jug at around 120-130 hrs max. Only carbon build-up was on the face of the main powervalve in the exhaust port. I've always used Yamalube R2 mixed @ 36:1 and cleaned the filter every single ride.

Is 120 hrs or so an acceptable lifespan for a forged wiseco? Would going with a full synthetic premix make any real difference? I've already established that 180+ hrs was way too long with my current setup.
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Post by Jeb »

>|<>QBB<
UFS207 wrote:Finally got a chance to mic the bore and everything is within spec. "C" cylinder and mic'ing several places I got anywhere from 69.03 - 69.05mm. Guess I'll just go with a new wiseco since it's cheapest and call it good.

My old wiseco had over .008" clearance; close to double what the service manual recommends. I could just about throw the piston through the bore, lots of slop. Interestingly enough I still had good compression right up until I pulled the jug and the motor ran nice and quiet, no slap. I'd roughly guesstimate I had around 180-200hrs on this topend (nearly 3 years of riding nearly every other weekend year-round). I guess one can't gauge rebuild times on having good compression and being able to turn the KIPS freely by hand with the actuator shaft disconnected. Probably should have pulled the jug at around 120-130 hrs max. Only carbon build-up was on the face of the main powervalve in the exhaust port. I've always used Yamalube R2 mixed @ 36:1 and cleaned the filter every single ride.

Is 120 hrs or so an acceptable lifespan for a forged wiseco? Would going with a full synthetic premix make any real difference? I've already established that 180+ hrs was way too long with my current setup.
What were your initial measurements anyway?

I put in new rings this month and measured somewhere between .004' -.005" (closer to .005" but I don't trust my accuracy to give another significant figure). When I installed the Wiseco a year ago I measured much closer to .004". I estimate my riding time to be in the neighborhood of between 90-110 hrs between the months of March and mid-September.

So that's roughly .001 for 100hrs, probably a little less.

Wear would certainly depend on how one rides. I rode about half of those hours on an mx track with my youngin' and a farm - where there's more wide-open field edges and trails - and I tended to wring the snot out of my bike and ran mostly in the mid-to-high RPMs (incidentally, this is where I'd like to be on a 250 and, by the way, where Ron's higher compression head seems to really shine IMO). The other half were more on trails so I ran more low RPMs but predominately mid range.

Some BTWs (may-or-may-not-be significant stuff):
  • *I "broke in" the new piston/rings last year with ONE heat cycle - warmed up thoroughly at minimum idle, shut off, allowed to cool completely, warmed back up throughly and ran it pretty hard.
    *I'm pretty good at allowing the engine to warm thoroughly.
    *I use Amsoil Interceptor at 32:1
    *I used straight pump gas up until I got the higher-compression version of Ron's head mods and since mix 50/50 VP110/premium pump. I only had about a month of ride-time on the race-gas head.
Don't know if this helps much, but I DO appreciate your feedback on the matter. I'll keep good records and probably crack the jug again and check things out mid-summer - maybe overkill but I DO have additional stresses/wear from the mods.
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Post by canyncarvr »

Is a 220 Wiseco piston 69mm? Meaning 69.000? (That mostly along the line of what Jeb already asked, 'What were your initial measurements anyway?', but specifically about the piston.)

Are they round? Probably not, but I've never heard one way t'other.

Curious, where was the largest diameter on the bore, and how does that relate to the largest diameter of a new piston?

An interesting thread with some real reasoned, fact-based input! Good reading!!

Thanks!

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