Cylinder Works Big Bore Kit

Cylinder Works Big Bore Kit
Cylinder Works Big Bore Kit

$379.99 - $599.99
13% Off - Save up to $89.96

Description See Also: 7 Reviews 29 Questions Fitment
Item #CYW0003

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7 Reviews
4.3 out of 5 stars
5 Star   5 4 Star   0 3 Star   1 2 Star   0 1 Star   1
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All Reviews
Poe1
Johnstown, PA, USA
Durability 5/5 Ease of Installation 5/5 Performance 5/5 Power 5/5 Style 5/5
Great torque

This kit + stage 2 hot cam + head porting = awsome

DrWoj
Manistee,Mi
Excellant Kit

I own a motorsports repair shop,customer brought a TRX-450 in that needed a crankshaft and top-end. Thanks to Motosport we were able to rebuild the motor with better parts than stock and save some money at the same time. We have a test track here and before the customer picks up his machine we like to have him or her take a few laps. When they get off their machine and there is a smile from ear to ear you know they are pretty happy.This particular unit the customer was realy impressed. The big bore kit realy woke up the TRX. Thanks Motosport

hwy2hll
north jersey
Durability 5/5 Ease of Installation 5/5 Performance 5/5 Power 5/5 Style 5/5
Perfect fit

works great easy installation everything was there

PWR70
whidbey island WA
Durability 1/5 Ease of Installation 4/5 Performance 2/5 Power 4/5 Style 4/5
Problem purchase

Purchased this kit for my 2006 YZ 250F and it took two tries to get a piston and ring combination that fit (rings would not fit in the grooves) finally sent me a piston that worked but it did not have the moly coating. Excellent power gains unfortunately it is on its 4th head gasket due to a poor alingment with the cylinder head allowing the gasket to hang over the combustion chamber. this was possibly the worst purchase I ever made and nobody is willing to stand behind the product, better off buying a Athena kit.

yzbigbore Top 1000 Contributor
Rigby, Id
Ease of Installation 5/5 Performance 5/5 Power 5/5 Style 5/5

I installed this on my 06 yz450f it looks just like the OEM cylinder i did not install the piston instead i ordered a high compression piston. This bike runs like i added another 10 HP. I have been riding it for 3 months with no problems. hill climbing you can't run out of power. power is strong all the way through i would recommend this product.

hayder Top 250 Contributor
Phoenix, AZ
Durability 1/5 Ease of Installation 5/5 Performance 5/5 Power 4/5 Style 2/5
It's your call

Had some prblms with it.. to start off i have built over 15 yfz motors with no prblms so it wasn't me.. but back to the product. First problem I had was the piston pin clip came out and put a gouge in the cylinder so i went and got another cylinder and rings and clips and maybe had 10 hours on it and I broke a valve which went through my piston and as i tore it all apart again I also noticed that the inside of the cylinder had a crack in it. It could have been from the valve but i dont think so because the valve went through the piston and ive read about the cylinders cracking on other people too. so just thought I'd say if you wanna risk it go for it had lots of power but if you want something that will last i would go OEM. thats where I'm headed now.

Cylinder Works Big Bore Kit
Cylinder Works Big Bore Kit
jwells147
aberdeen, nc
Durability 5/5 Ease of Installation 3/5 Performance 5/5 Power 5/5 Style 4/5
Very nice

Quality construction, made a huge difference in power. probably the most cost effective way to mod a 250f. I did have to rejet with a JD jet kit after i installed this; before it really ran to its potential. Was popping on decel and throttle response was not as crisp. after the bike was rejetted it is a monster.

29 Questions
Answered:   29
Not Yet:   0
Mitch
Q: Will this fit a 2004 KTM 250 EXC?
1 month 9 days ago
MotoSportExpert
MotoSport Staff Expert
1 month 9 days ago
A: No sorry this Cylinder Works Big Bore Kit will not fit your 2004 KTM 250 EXC.
Macon
Q: Will this fit my 2005 Yamaha ttr 230?
2 months ago
MotoSportExpert
Expert MotoSport Staff
2 months ago
A: No sorry this kit would not fit your 2005 Yamaha TTR230. If one is available through one of our suppliers, we would be happy to order it for you. Please call one of our sales professionals to inquire about special orders and availability.
Dirt Bike: 1-888-676-8853
Nathan
Location: Tyler, tx
Q: Does this fit a 2003 Yamaha yz250?
2 months 19 days ago
I have a 2 stroke 2003 yz250, will this fit? And will I need a new head cover? Also can the stock piston rod fit with it?
MotoSportExpert
MotoSport Staff Expert
2 months 5 days ago
A: Yes the Cylinder Works Big Bore Kit will fit your 2003 Yamaha YZ250. 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. Will work with your stock head and crank. Also, feel free to give us a call at 888-676-8853 and we would be happy to help you out with your order.
Nathan
Location: Tyler, tx
Q: Is this available for 2 strokes? I have a 2003 yz250. and will I need a different sized cylinder head?
2 months 19 days ago
MotoSportExpert
Expert MotoSport Staff
2 months 5 days ago
A: Yes, 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. This kit will work with the stock head. Also, feel free to give us a call at 888-676-8853 and we would be happy to help you out with your order.
ryan
Location: Kentville, NS, Canada
Q: Does 2004 crf250r need case mods to get big bore kit?
Over 8 months ago
what jets are best when putting big bore kit.
MotoSportExpert
MotoSport Staff Expert
Over 8 months ago
A: On the 2004-2009 Honda CRF250R the 256CC kit would not require any modifications. However the 269cc +3mm kit would require slight case modifications.
Carter
Location: Queensland Australia
Q: High compression kit?
Over 10 months ago
Can you buy a high compression kit to go into this big-bore kit so that I could have a 270cc high compression piston?
MotoSportExpert
Expert MotoSport Staff
Over 10 months ago
A: Unfortunately Cylinder Works only offers big bore cylinder kits with standard compression, they do this to help retain reliability.
ab714
Q: 2006 CRF250R case modifications?
1 year ago
Are there any case modifications needed for the 269cc kit to fit a 2006 CRF250R?
MotoSportExpert
MotoSport Staff Expert
1 year ago
A: Yes for your 2006 Honda CRF250R this Cylinder Works Big Bore Kit (11001-K01) Requires case machining.
CPruett57
Q: Is there more to know about how long this would last?
1 year 1 month ago
Is there an estimated time that this would last you? Or is that more dependent on how you ride the bike?
MotoSportExpert
Expert MotoSport Staff
1 year 1 month ago
A: There are too many variables to say how long it would last. That would be determined on how the bike was ridden, maintained and serviced as well as riding conditions.
jchampion
Location: Hanover, MI, USA
Q: Do the valves need to be replaced with big bore kit?
1 year 7 months ago
Im thinking about purchasing this for my 06 Yz450f and i am wondering if i will have to replace my valves? Is there anything else besides rejetting that needs to be done or is this a bolt on rejet and have a blast kind of kit?
MotoSportExpert
Top 1 Contributor
1 year 7 months ago
A: Unfortunately we at Motosport.com are not able to give you repair advice. We highly suggest that you purchase an OEM service manual for your machine and refer to it to answer your repair questions. If you need more assistance, please consult a local repair shop to further assist you in your repairs. If you need parts to assist in your repairs, we are happy to assist you with your parts order.
garrettcibak
Top 500 Contributor Top 1000 Contributor
Q: 2012 CRF250R durability?
1 year 8 months ago
How much stress will the 270 kit put on the rest of my motor? I know it will add a bit more,but will I have to worry about engine parts wearing out soon?
MotoSportExpert
Expert MotoSport Staff
1 year 8 months ago
A: That is hard to say since there are so many other variables that go into engine wear and life. Generally High Performance Big Bore motors do wear faster and are less reliable.
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