• The Athena 490CC Big Bore kit is the missing source for increasing your motorcycles raw power.
  • The included 490CC cylinder on the Athena Big Bore kit is constructed out of aluminum with a galvanic coating to increase the durability. The water jets have been widened for a higher flow rate, keeping the cylinder cool.
  • Athena built a reliable forged piston that has been molybdenum coated for high performance use and extended wear life.
  • The Athena Big Bore kit includes a specially designed gasket kit to accommodate the big bore features.
  • Another great feature of the Athena Big Bore kit is that it bolts on with no machining needed, and includes easy-to-follow step-by-step installation instructions.
  • The Athena 490CC Big Bore Kit includes: cylinder, piston, ring(s), pin, clips, top end big bore gasket kit.

ATHENA BIG BORE KIT - 490CC

Price Range: $413.77 - $899.99
To purchase this part, please select a ride:
Select from rides that fit this product

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Overall:
5 out of 5
5 out of 5
Ease of Installation:
5 out of 5
Ease of Installation out of 5
Style:
5 out of 5
Style out of 5
Durability:
5 out of 5
Durability out of 5
Performance:
5 out of 5
Performance out of 5
Power:
5 out of 5
Power out of 5
Location: Rio Rancho, NM
LOVE IT!
" This kit is amazing! I have it on my TRX450R and I would NEVER go back! Given then only thing stock on mine is the frame, this made the biggest improvement to my bike! I love it! So, if you are looking for MAJOR power gain, this is the way to go! "
Overall:
5 out of 5
5 out of 5
Location: Orange County, CALIFORNIA
490 Athena
" Thisis an excellant product for the 450R. I have had one on my 04 450R for the last 2 years. The bike hauls with this kit. I am purchasing another kit for another 450R I love it! "
how abt the compression ratio ?
Asked by kidharry, long island
Compression ratio will vary depending on the application. Unfortunately Athena doesn't furnish us with the specs regarding that. The stock jetting will need to be spec'd due to changing the displacement of the engine.
Answered by james718
You should. I did, but I also had it jetted properly due to the Pipe
Answered by Fast450R, Orange County, CA
can i run a high comp piston with the big bore kit
Asked by kawipro
You must run the Athena Piston with this kit.
Answered by racer3114, PDX
Do you have to do some other modification to the bike if we get this kit?
Asked by j450
other than checking clearances and rejetting, no. you should be good to go.
Answered by dirt
yes air intake and ext aslo rev box, jet kit to get all you can get from your big bore kit its worth the money
Answered by rebchris79, quanah tx
Most likely rejet. You may want to run some better fuel. I do.
Answered by Fast450R, Orange County, CA
Is this the kit for the 02-08 CRF450R?
Asked by Dan74v, Palm Desert
We have both kits. You just need to make sure you have your ride chosen when you are picking the item. If you aren't sure you are choosing the correct one feel free to call us and place the order over the phone.
Answered by JesseC, Tualatin
VIBRATION
Asked by moto36
Vibration shouldn't be noticeably greater but keep in mind you are changing the motor to a larger and higher horsepower design than the chassis was designed for so a slight increase in vibration is plausible.
Answered by Nate675, Portland
NO!
Answered by Fast450R, Orange County, CA

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