Shopping For:
  1. Manage Saved Rides
  2. Change Your Selected Ride

Athena Big Bore Kit - 490cc

Retail: $757.99 - $999.99
$699.99 - $899.99
Please Select a Ride:
Or, select from rides that fit this product
 
It appears you may have cookies turned off in your web browser, or are using a browser that does not support cookies. You must accept cookies to use our site. For questions call us at 1-888-676-8853.

Need Assistance?

Call 1-888-676-8853

You may also like

Cylinder Works Big Bore Kit - 488Cc - Athena Big Bore Kit - 490cc
Cylinder Works Big Bore Kit - 488Cc
$589.99
You Save: $60.00
Athena Big Bore Piston - 490cc - Athena Big Bore Kit - 490cc
Athena Big Bore Piston - 490cc
$179.99 - $219.99
Wiseco 500cc Big Bore Kit 12.5:1 Compression - Athena Big Bore Kit - 490cc
Wiseco 500cc Big Bore Kit 12.5:1 Compression
$959.99
You Save: $99.00
Athena Big Bore Kit - 490cc - Main
zoom: + −

Product Description

  • 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.
  • Customer Reviews
  • Ask an Expert
  • Also Offered For
(2)
5.0 out of 5 stars
5 star   2
4 star 0
3 star 0
2 star 0
1 star 0
Write a Review
“ This kit is amazing! I have it on my TRX450R and I would NEVER go back! Given then only thing stock o... ”
karr Location: Rio Rancho, NM
1-2 of 2
Overall
Durability
Ease of Installation
Performance
Power
Style
Array
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
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!
1-2 of 2
Total Questions (6)
Questions with answers:
  6
Questions without answers:
0
Have a question?
“ I HAVE A 06 TRX450R AND WANT TO KNOW WHERE TO START OUT JETTING YOUR BIKE AFTER INSTALLING A BIG BORE... ”
CVL202
“ How abt the compression ratio ?... ”
kidharry Location: long island
1-6 of 6
CVL202 Over 3 years ago
I HAVE A 06 TRX450R AND WANT TO KNOW WHERE TO START OUT JETTING YOUR BIKE AFTER INSTALLING A BIG BORE KIT??
MotoSport Staff Expert
Over 3 years ago Location: Tualatin, Or
Jetting is going to very from place to place. So you will just have to play with it until you get it right
Over 3 years ago Location: quanah tx
when putting a big bore kit on any bike or quad you will need more air so go to an aftermarket air filter (also consider aftermarket ext). , then start with the stock jets and work your way up from there to the point were you bike runs well on start up as well as high rpm and you thotal response should me crisp and quick also consider you altatuied and ambiant temp of air this makes big diffrance
Answer this Question
moto36 Over 3 years ago
VIBRATION?
DOES GOING WITH THE BIG BORE KIT MAKE THE BIKE VIBRATE OR HAVE A ROUGHER FEEL
Top 10 Contributor
Over 3 years ago Location: Portland
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.
Top 500 Contributor
Over 3 years ago Location: Orange County, CA
NO!
Answer this Question
Dan74v Over 4 years ago Location: Palm Desert
Is this the kit for the 02-08 CRF450R?
The reason why I ask is that on the website it says it fits the 450X model as well. The cylinders on the X and the R are different so Athena Makes two kits: CRF450X'02-07 - Athena 490cc Big Bore Kit; and CRF450R'02-08 - Athena 490cc Big Bore Kit They are different part numbers. Please update the website to reflect the correct information.
MotoSport Staff
Over 4 years ago Location: Tualatin
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.
Answer this Question
j450 Over 4 years ago
Do you have to do some other modification to the bike if we get this kit?
Expert MotoSport Staff
Over 4 years ago
other than checking clearances and rejetting, no. you should be good to go.
Over 3 years ago Location: quanah tx
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
Top 500 Contributor
Over 3 years ago Location: Orange County, CA
Most likely rejet. You may want to run some better fuel. I do.
Answer this Question
kawipro Over 4 years ago
Can i run a high comp piston with the big bore kit?
MotoSport Staff Expert
Over 4 years ago Location: PDX
You must run the Athena Piston with this kit.
Answer this Question
kidharry Over 5 years ago Location: long island
How abt the compression ratio ?
was the jetting changed for this mod. ? thanks
MotoSport Staff Expert
Over 5 years ago
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.
Top 500 Contributor
Over 3 years ago Location: Orange County, CA
You should. I did, but I also had it jetted properly due to the Pipe
Answer this Question
1-6 of 6
* required entry

Forgot your password?