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08 300 xcw top end time... piston brand question.

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Ok so its time for a top end. Bike still runs fine but its got some serious hours on it. Its time.

So what the general concensious on piston brand?

I know I know this is like what oil is best. Still

I did some searching here and really didnt find much.

So what are people using. Ive used Wiesco in the past with good results on many other bikes. But those were all Yamaha/hondas. This is my 1st KTM. Do they like something diff?

I was eyeballing this (man are they expensive)

http://www.ktmcyclehutt.com/ktm-parts/ktm-parts.php?sku=00050000009&title=KTM-Piston-Kit&year=&ktm-model=&category=Engine-Parts&fit=Piston-Kits&fitment=bigbikes

probably really cant go wrong with OEM.

Also piston size. I see them some manufactures list them as A,B and C. I know about the slight variations and why they do the abc thing. Is it stamped on the cylinder somewhere what mine is? Never looked before. Why do some offer them as abc and others dont?

http://wossneronline.com/forged_pistons/index.php?main_page=product_info&cPath=50_65_100&products_id=564

If its oem then it is what it is. But if I can save a few $ and use a wossner or Wiesco and it will work just as well then Im all for it. Times are tough and ya gotta stretch them $$'s. ya know how it is.

let the comments fly! :thumbsup:

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Howdy yzman400!

I completed a top end (amoung other things) on my '08 300 XCW this winter. I used a Vertex piston kit...OEM. It went together perfect and was the recommended piston from several KTM service sources.

They all emphasized the importance of setting the X demension as close to 0.00 as possible. I got it very close indeed (piston at the very tip top of the cylinder at TDC). The OEM setting is quite conservative...at least it was on my engine.

When you buy the cylinder base gasket kit, it will come with a few different gasket thicknesses which can be combined as you need to adjust the cylinder so that your X is perfect.

Post up some pics of your piston replacement...it's all cool to see.

-Jay

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Thanks J. that helps. Whats the "X dimension" you speak of? For some reason the little voice in the back of my head says I should know what that is but Im drawing a blank. Sounds like how far the piston is from the top of the cylinder. Ive never had to do that with any other bikes Ive dealt with (yz85,125,250)

Is there a how to on here or is is spelled out in the manual for me? I havent really looked into what all is involved yet with doing a top end on this (after all they are all pretty much the same)

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Thanks J. that helps. Whats the "X dimension" you speak of? For some reason the little voice in the back of my head says I should know what that is but Im drawing a blank. Sounds like how far the piston is from the top of the cylinder. Ive never had to do that with any other bikes Ive dealt with (yz85,125,250)

Is there a how to on here or is is spelled out in the manual for me? I havent really looked into what all is involved yet with doing a top end on this (after all they are all pretty much the same)

Correct. Need to get the piston as close as possible to the top of the cylinder...as close to 0.00mm as you can...at TDC. Using the "standard" cylinder gasket kit I was able to get mine spot on.

There is an illustration in the service manual for how measure...it's very simple really; place a straight edge across the top of the cylinder...run the piston up to TDC and see if you can slide a feeler gauge under the straight edge on top of the piston - or - see if the piston lifts the straight edge up from the top of the cylinder. 300 pistons are flat-top designs so it's very simple to measure.

-Jay

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Correct. Need to get the piston as close as possible to the top of the cylinder...as close to 0.00mm as you can...at TDC. Using the "standard" cylinder gasket kit I was able to get mine spot on.

There is an illustration in the service manual for how measure...it's very simple really; place a straight edge across the top of the cylinder...run the piston up to TDC and see if you can slide a feeler gauge under the straight edge on top of the piston - or - see if the piston lifts the straight edge up from the top of the cylinder. 300 pistons are flat-top designs so it's very simple to measure.

-Jay

Gotcha. that makes sence. And sounds super easy.

What gasket kit did you use? Was it a Vertex kit or OEM KTM or other?

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Vertex is the OEM supplier. Just buy a Vertex piston it is the same one as OE but a lot less.

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Wiseco or Vertex is good. Wiseco is forged, Vertex is cast. There has been lengthy discussion on the differences. Both are good. The forged is lighter and will rev quicker, but you will lose a little bottom end. I know cubera went with a Wiseco and has been pleased.

The Moose kits are good and have everything for your top end job.

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Gotcha. that makes sence. And sounds super easy.

What gasket kit did you use? Was it a Vertex kit or OEM KTM or other?

Any gasket kit will work...I believe mine was OEM...but I don't think it matters.

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Wiseco or Vertex is good. Wiseco is forged, Vertex is cast. There has been lengthy discussion on the differences. Both are good. The forged is lighter and will rev quicker, but you will lose a little bottom end. I know cubera went with a Wiseco and has been pleased.

The Moose kits are good and have everything for your top end job.

I debated going with Wiseco since they are a forged piston and technically stronger than a cast unit. However...in the end, I went with a cast unit since it's the OEM piston and is highly rated. The coated skirt on the Vertex piston is nice also.

-Jay

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Wiseco or Vertex is good. Wiseco is forged, Vertex is cast. There has been lengthy discussion on the differences. Both are good. The forged is lighter and will rev quicker, but you will lose a little bottom end. I know cubera went with a Wiseco and has been pleased.

The Moose kits are good and have everything for your top end job.

I assume your talking about the Moose Gasket Kit? pn#0934-1691 they dont seem to offer a piston kit for the 300 (they do others)

I like Moose products. Been using them quite a bit lattely as I get a good price on there stuff.

Does the Moose kit come with the diff thickness base gaskets?

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I assume your talking about the Moose Gasket Kit? pn#0934-1691 they dont seem to offer a piston kit for the 300 (they do others)

I like Moose products. Been using them quite a bit lattely as I get a good price on there stuff.

Does the Moose kit come with the diff thickness base gaskets?

yes, Moose gasket kit. Mine came with two different gaskets. You can use them together or separate. I have found I haven't needed to get that precise and what they provided got me where I needed to be.

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If I had to do it all over again I would go with a Vertex size B piston and rings on the stock cylinder if it had 50 or so hours on it. Fewer than 50 hours I would probably stay with the size A. This is what I tried to do on the first rebuild on my 300 but it sucked the base gasket at the aft part of the gasket where the engine cases join and seized with only 6 hours on it. I then went with a Wiseco ProLite replacement and ran the peouss out of it for about 60 hours. I replaced it (just in time because it had a crack at the left wrist pin underside) with another ProLite. That one finally seized destroying the cylinder. This time I'm running an OEM size A with brand new cylinder. FWIW, after 220ish hours and 5(?) pistons on the 300 I'm back to my old stubborn ways of keeping engines as close to stock as possible and with all OEM replacement parts whenever possible. This philosophy has kept me out of trouble in the past and so I'll stick with what works for me. I've since parted ways with my beloved 300 and am now trying to kill a 530. :ride::lol::ride::thumbsup:

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If I had to do it all over again I would go with a Vertex size B piston and rings on the stock cylinder if it had 50 or so hours on it. Fewer than 50 hours I would probably stay with the size A. This is what I tried to do on the first rebuild on my 300 but it sucked the base gasket at the aft part of the gasket where the engine cases join and seized with only 6 hours on it. I then went with a Wiseco ProLite replacement and ran the peouss out of it for about 60 hours. I replaced it (just in time because it had a crack at the left wrist pin underside) with another ProLite. That one finally seized destroying the cylinder. This time I'm running an OEM size A with brand new cylinder. FWIW, after 220ish hours and 5(?) pistons on the 300 I'm back to my old stubborn ways of keeping engines as close to stock as possible and with all OEM replacement parts whenever possible. This philosophy has kept me out of trouble in the past and so I'll stick with what works for me. I've since parted ways with my beloved 300 and am now trying to kill a 530. :ride::lol::banana::ride:

Your case is not the norm, though. haha :D

My 05 had a fresh Wiseco in it when I bought it. I put 2+ years of use on it, about 200+ hrs before replacing it. Sucked some dirt after 60 hours on a new Wiseco, and reinstalled the original Wiseco (due to budget constraints) since it was in better shape, with the newer rings, and ran it till I sold it many hours later. Neither is that the norm.... :thumbsup:

I wouldn't normally do that, but the piston held up well and still made good power...

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just out of curiosity what does everyone think of the athena pistons. if i remember right i think they are forged and have the moly coating as well. anyone ever run one?

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just out of curiosity what does everyone think of the athena pistons. if i remember right i think they are forged and have the moly coating as well. anyone ever run one?

When I did my research, I couldn't find an Athena piston kit for a later (2004 or newer) model 300. They have them for 200cc up to 2009, however. Made in Germany and look exactly like Vertex pistons...exactly.

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...glad this was posted, as i asked the same thing a while back and got no answer. it is a topic thats been debated quite a bit, but when you need to find the answer....you cant. so thanks for bringing it up

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priced out a Vertex piston kit and Moose Gasket kit. Approx $175. Done deal. Will still need to get a $15 wrist pin bearing from my KTM dealer as it doesnt come with the piston kit.

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priced out a Vertex piston kit and Moose Gasket kit. Approx $175. Done deal. Will still need to get a $15 wrist pin bearing from my KTM dealer as it doesnt come with the piston kit.

Check the ktmtalk classifieds as Andrew Cooksey is selling the top end kits complete at a very competitive price. He is also an excellent bottom end rebuilder.

His AD. linky

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