Vertex 2-Stroke Piston Kit - Stock Bore

Vertex 2-Stroke Piston Kit - Stock Bore
Vertex 2-Stroke Piston Kit - Stock Bore

$84.98 - $194.98
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  • Description
  • 41 Reviews
  • 30 Questions
  • Fitment
Description
Item #VER0008

The MotoSport.com Vertex 2-Stroke Piston Kit - Stock Bore includes one of each of the following components with the following attributes:

Vertex 2-Stroke Piston Kit:

Important Note: This piston is for a stock sized bore. Please measure your cylinder to check clearance before ordering.

As the O.E. supplier of two-stroke pistons to KTM, Vertex Pistons has an outstanding reputation for quality and performance. Each gravity cast piston is created with only premium aluminum alloys utilizing an 12 - 21% silicon content.

The silicon content in Vertex pistons is crucial to the quality of the piston. Silicon is critical in decreasing thermal expansion which, when an engine reaches normal operating temperatures, can change the geometry of the piston. Controlling this expansion means that a Vertex piston can be run at tighter tolerances for more power, less noise and a longer lifespan of the piston. Plus, the silicon content decreases wear on the piston skirt which also aids in the life of the piston.

In addition to the silicon, each Vertex piston utilizes a unique Molybdenum Disulphide (MOS2) coating which aids in the break-in process and reduces overall wear.

Vertex Piston includes:

  • Premium quality Vertex piston.
  • Complete set of nitride coated or chrome-plated piston rings.
  • Fully case-hardened wrist pin.
  • Circlips.
  • Competitive price!

Hot Rods Needle Bearing:

  • Case-hardened and silver coated, the bearings are just as tough and reliable as all Hot Rods parts.
  • Wrist pin bearing is specially designed with a long shouldered bearing cage to withstand high RPM use.
  • Can be used with Hot Rods connecting rods and O.E. or aftermarket pistons.

Cometic Top End Gasket Kit:

State-of-the-art gaskets is what Cometic has been doing since its inception in 1989. This comes from their dedication to constructing gaskets for the most demanding race circuits like AMA and NASCAR. Today's lightweight engines are producing more horsepower, higher cylinder pressure, clamp load and extreme temperatures. Cometic's commitment is to provide innovative, quality gaskets while maximizing your engine's power and performance.

Cometic meets the needs of each specific gasket by using materials to match. Even the basic top end gasket kit features different materials for each gasket. The head gasket is constructed from non-asbestos, flexible graphite that is laminated to a stainless steel core. The manifold and base gaskets are constructed from non-asbestos nitride rubber-bound fiber. Cometic also includes copper gaskets where needed.

Cometic designs and builds their gaskets in the U.S.A.

Note: Image is for reference only, actual Kit may vary based on contents and fitment.


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41 Reviews
4.5 out of 5 stars
5 Star   35 4 Star   8 3 Star   0 2 Star   1 1 Star   3
Phil
Dayton, OH, USA
Ease of Installation  
Good kit

Parts seems of good quality. I like that the needle bearing it comes with us hot rod. Haven't ridden with it yet so I can't speak on power or reliability. My only complaint is it didn't come with the copper crush washers for the head bolts that my YZ 250 has. I didn't notice untill reassembly. Had to order them separately. Would rather pay more for the kit and have them included. Other than that it went together great.

Loaner
Verified Purchaser
San Diego, CA, USA
Durability   Ease of Installation   Performance   Power   Style  
Easy Top End Package

This gave me everything i needed to swap out the top end on my KTM. What a dream, no running back to the shop for a gasket, or needle bearing. I highly recommend this kit, and the Vertex pistons have lasted for me with no issues.

pmdparts
Verified Purchaser
Abbeville, SC 29620, USA
Ease of Installation   Performance   Power   Style  
Nice product--but beware of "A" ,"B", or "C"sizes

Ordered this kit for 2013 KTM 85 sx. Description says "standard bore'" but apparently, KTM produces engines with "A", "B", and "C" bores from the factory. These are just three different size pistons that vary by a fraction of a millimeter and are fit to each motor individually to help account for variance in machining and plating of the bores. The piston I received was a "B" unit and it turns out that our bike was fitted with a "C" piston from the factory. I wish that the item description had spelled this out so that I could have gotten the "c" piston instead, but there was no mention of this in Motosport's description. I installed the "b" unit and I'm sure it will be fine since I will replace it in about 20 hours anyway.

Rider13
Verified Purchaser
Modesto, CA, USA
Durability   Ease of Installation   Performance   Power   Style  
Faulty product

Shortly after installation of this piston and break in my engine seized. A large chunk of the top of the piston broke off wedging itself between the head and the remaining piston, destroying not only my new piston, but also my cylinder and head.

DirtLife
Verified Purchaser
DTown Racer
Durability   Ease of Installation   Performance   Power   Style  
First Top end rebuild on 85r Honda

Researched rebuild days before part showed up. Made job easy.

1Racing
Verified Purchaser
Texas, USA
Durability   Ease of Installation   Performance   Power   Style  

Great replacement for stock.

Pickle
Verified Purchaser
Atlant Ga
Durability   Ease of Installation   Performance   Power   Style  
Great top end

Never have a problem with this top end in my sons yz-85

speedy
Verified Purchaser
Montana, USA
Durability   Ease of Installation   Performance   Power   Style  
Good kit

everything you need

DirtWarrior
Western PA
Durability   Ease of Installation   Performance   Power   Style  
2 Stroke Power!

This is a great rebuild kit. Very high quality parts. The only improvement that I think could be made is if Cometic decided to put a paper in their gasket kit that labeled each individual gasket and O-ring. Other than that, fantastic product. Just as good, if not better than Wiseco.

brokendad
Verified Purchaser
Edmond, OK
Durability   Ease of Installation   Performance   Power   Style  
Top End Kit

Restore the power in your bike byu using quality parts!

shnedy
Verified Purchaser
Durability   Ease of Installation   Performance   Power   Style  
Great product vertex piston

Got the piston kit for my cr 125 it had no compression.
After i replaced the piston and ring wow what a difference. Before i changed it i was able to start the bike with my hand. Those days are over .
Great product.

Roosty
Verified Purchaser
Salt Lake City, UT, USA
Durability   Ease of Installation   Performance   Power   Style  
As usual motosport delivers

Love these guys! The vertex piston fit perfectly and the cometic gaskets are working as advertised. In fact, the expansion chamber o-rings fit much tighter than OEM so no more oil spooge from exhaust! Thanks motosport!

Tony
Verified Purchaser
Durability   Ease of Installation   Performance   Power   Style  
Great buy!

I will buy again! Installed on a 97 cr 125 that had a dime size hole in the Piston marked clearly fits factory specifications. Gaskets that come with the kit are way better then the oem paper gasket

yzrippa
Louisiana, USA
Durability   Ease of Installation   Performance   Power   Style  
DO NOT BUY!!!!

because this piston is not forged its cast which causes weak spots in the piston and after about 8 hours of run time always on a track with races the skirt of the piston blew off and ruined my cylinder and crank.

Zach
Binghamton, NY
Durability   Ease of Installation   Performance   Power   Style  
Great piston

I decided to do a top end on my cr125 this winter and change it up from my usual Wiseco piston. Now that the snow is melting I can finally get back out and ride and this piston is great in my bike. Would definitely recommend this kit!

Deema00
Verified Purchaser
Napa, CA, USA
Durability   Ease of Installation   Performance   Power   Style  
03 CR250 Top End Build

Super Stoked on the Vertex Top End Kit. The power is back! It came with everything needed for the rebuild. Installation was easy and a breeze. I recommend this set-up for any CR owner. Quality, Super Quick and Great service. From Motosport to my House to My Bike. couldnt be happier to be back riding.

Deema00
Napa, CA, USA
Durability   Ease of Installation   Performance   Power   Style  
03 CR250 Top End

Super stoked on the vertex top end kit, the power is back in my 2stroke. The kit came with everything needed to re-do the top end. Straight from Motosport to my house to my bike! Recommend this set-up to any CR owner. Quick, Convenient, and Quality. Everytime.

John
Verified Purchaser
Phoenix, AZ, USA
Durability   Ease of Installation   Performance   Power   Style  
Great Purchase

I have ordered numerous parts from Motosport for my son's dirt bike. It is easy to order, it always ships on time, and I have never had any issues with the quality of the parts I ordered. I recently ordered a piston kit for his dirt bike. It contained everything I needed to rebuild the top end of his bike. Thank you so much for your service!

DDR26
Verified Purchaser
Daytona Beach, Fl.
Durability   Ease of Installation   Performance   Power   Style  
Vertex piton kit

Very good quality part. Installation was a breeze. Easiest 2 stroke top end I ever did. And Fast shipping too.

Bubba
Verified Purchaser
Durability   Ease of Installation   Performance   Power   Style  
Vertex piston in 99 YZ250

I ran a Wiseco last time and tried Vertex this go round, installation was simple and easy...pin bearing was same as factory so good there. Ran about 5 hours so far and power is excellent, actually feels like improved throttle response over the Wiseco.

1-20 of 41

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30 Questions
Answered:   29
Not Yet:   1
dandan
Q: Will this fit on a 2000 YZ250 2 stroke?
9 days 16 hours ago
hi have a 2000 yz250 2 stroke and I jus wanted to know what size i needed or if i needed a certain letter on the piston for my bike. thanks!
Kelson
Q: Is this the exact stock piston that comes in the bike 2014 ktm 250 sx?
3 months 3 days ago
Loaner
3 months 1 day ago
A: It exactly matched my 11 300xc & 12 250xc, so i bet it is.
Deland
Location: Orangeburg, SC, USA
Q: May I use this piston kit with the Athena cylinder?
4 months ago
MotoSportExpert
MotoSport Staff Expert
3 months 22 days ago
A: Yes this Vertex 2-Stroke Piston Kit - Stock Bore would work with a stock bore Athena Cylinder.
Dylan22
Location: Georgia, USA
Q: Will a size c fit a 2004 KTM 125sx that has had a stock piston in it?
Over 7 months ago
I have a 2004 KTM 125sx and I would like to know if there Is a real big difference in piston sizes for this bike. The piston hasn't been changed before I don't think.
MotoSportExpert
Expert MotoSport Staff
Over 7 months ago
A: Vertex offers A, B, C, D, sizes so that the customer can properly fit each piston to the cylinder. The difference in the sizes is 0.01mm (0.0004") increments with A being the smallest and D the biggest. When a cylinder wears, the customer can choose the next larger piston size to regain the proper factory fitment. If you are just replacing the piston, then you need to first know the bore of the cylinder. This can be done by using a bore gauge to find the diameter or by reading the owner’s manual to find the bore specifications. Ultimately, the bore should be measured for the best possible results. After the diameter is known, then you can pick which size piston will work best in your cylinder. Remember to maintain about a 0.05mm (0.002”) piston to cylinder clearance, depending on application. If you are having a cylinder re-plated, then you will want to choose a piston of the OE bore size (an A or B size is probably best). When you send the piston and cylinder away to get re-plated, the plating facility will match the cylinder bore to piston diameter. If you have a cast iron bore cylinder and you are sending the piston and cylinder off to a machinist to be bored out, then you will want a piston that is oversized from the current diameter. For example: If your current bore is 64.00mm, then you will want to choose a 64.50mm or similar oversized piston. The machinist boring the cylinder will bore and hone the cylinder to match the piston size.
Also, feel free to give us a call at 888-676-8853 and we would be happy to help you out with your order.
Moe987
Location: Reno
Q: Piston size.?
Over 8 months ago
I just returned a kit that came with a piston that was 66.40. Will this fit mine which needs a max of 66.35?
MotoSportExpert
MotoSport Staff Expert
Over 8 months ago
A: The stock bore Vertex 2-Stroke Piston Kit (22584B) for your 2004 Yamaha YZ250 would be 66.35mm. Also, feel free to give us a call at 888-676-8853 and we would be happy to help you out with your order.
cartwright
Q: What size bore is a 99 yz125?
Over 8 months ago
Im trying to bore over my 99 yz 125 but I don't know if I need a big bore kit or can I just get a bigger piston and resize my own cylinder. I need to know what size is my stock cylinder.
MotoSportExpert
Expert MotoSport Staff
Over 8 months ago
A: Stock bore on the 1999 Yamaha YZ125 would be 54.00mm. Feel free to give us a call at 888-676-8853 and we would be happy to help you out with your order.
edd653
Location: London, UK
Q: Oversized pistons?
Over 9 months ago
Are you able to get 0.5/1.0mm oversized pistons for yz 125 (05)
MotoSportExpert
MotoSport Staff Expert
Over 9 months ago
A: If the part is available through one of our suppliers, we would be happy to order it for you. Please contact one of our sales professionals to inquire about special orders and availability.
Dirt Bike / ATV: 1-888-676-8853
Kawasaki
Q: What is the stock size for a 2004 kx 125?
Over 10 months ago
I ordered a vertex piston and just rid the cylinder and got it re-sized and the piston wiggles side to side is that ok?
MotoSportExpert
MotoSport Staff Expert
Over 10 months ago
A: This stock bore Vertex Piston would be 53.96mm. You need to first know the bore of the cylinder. This can be done by using a bore gauge to find the diameter or by asking the machine shop who did the work. If you had the cylinder bored and replated you would need to go to the next size up.
Remember you want to maintain about a 0.05mm (0.002”) piston to cylinder clearance.
Javon
Location: Jamaica
Q: Can this fit my 03 Yamaha yz 125 2 stroke ? My piston only has 1 ring?
Over 10 months ago
MotoSportExpert
MotoSport Staff Expert
Over 10 months ago
A: Yes this Vertex 2-Stroke Piston Kit will fit your 2003 Yamaha YZ125. Just be sure to correctly select the Year/Make/Model of your bike before ordering so we can be sure to send you the correct kit for your bike. Also, feel free to give us a call at 888-676-8853 and we would be happy to help you out with your order.
*The image is a generic image supplied by the manufacturer for reference only. It may not be displaying the exact part for your bike.
wireman
Location: Kentucky, USA
Q: I have a cr 125 02 does it come with two rings?
Over 11 months ago
MotoSportExpert
MotoSport Staff Expert
Over 10 months ago
A: For your 2002 Honda CR125 it would be a single ring.
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