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Big Bore Kit for 2012 KXF250?

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any one put a big bore kit on their 2012 Kawasaki KXF250?

what was the result?

would you recommend it?

what brand?

what company did you buy from?

is it reliable?

any problems?

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check out last months Motocross Action Magazine. They build a 2012 KX250F with a Cylinder Works 269cc big bore kit. I had that kit on my 2011 KX250F, and it is a great kit that adds a couple of HP everywhere with no downside on the '11. On the '12, there is a slight loss in power over 11000 RPM, but everywhere else it is better. If you are the kind of rider who uses the over-rev a lot, you might notice it falls flat in that range with the big bore kit. Otherwise, there is no downside. The 269cc kit had more peak HP, it just occurs a bit lower in the RPM, and then the stock '12 passes it higher in the revs and does not flatten out. It is a good kit, mice price, will be even better with an exhaust system, and I also had stage 2 hot cams on my '11. They did the same thing on their 2012 big bore in MXA. The one hitch is they had to remap the 2012, as it is already a bit on the lean side stock and it will not correctly fuel the big bore. It needed more fuel. So you would have to remap. The '11 will run the kit well without a change to the stock map, but it is pretty rich stock so that is likely why.

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check out last months Motocross Action Magazine. They build a 2012 KX250F with a Cylinder Works 269cc big bore kit. I had that kit on my 2011 KX250F, and it is a great kit that adds a couple of HP everywhere with no downside on the '11. On the '12, there is a slight loss in power over 11000 RPM, but everywhere else it is better. If you are the kind of rider who uses the over-rev a lot, you might notice it falls flat in that range with the big bore kit. Otherwise, there is no downside. The 269cc kit had more peak HP, it just occurs a bit lower in the RPM, and then the stock '12 passes it higher in the revs and does not flatten out. It is a good kit, mice price, will be even better with an exhaust system, and I also had stage 2 hot cams on my '11. They did the same thing on their 2012 big bore in MXA. The one hitch is they had to remap the 2012, as it is already a bit on the lean side stock and it will not correctly fuel the big bore. It needed more fuel. So you would have to remap. The '11 will run the kit well without a change to the stock map, but it is pretty rich stock so that is likely why.

Thank you for the input, I just received my Big Bore kit in the mail from Cylinder Works today for my 2011 and now that I have it, am considering doing the Hot Cams at the same time but was worried about how it would run with the stock map. I read the article in MXA about how it worked flawlessly with the 2011 and your experience confirms that but with the addition of the cams did you need to re-map?

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I never ran the bike with the stock map after got the big bore and the stage 2 hot cams. I went to a Vortex X10 ECU that has 10 different maps you can choose with a switch and it also has trims to adjust lo mid and hi fuel. I used the fuel trims to add a bit of fuel and then I could use any of the 10 maps from the ECU to get different power character and for soft or hard terrain tracks. I have a '12 now and I am selling the X10 ECU if you are interested. It worked great with the mods I had, and it can also be programmed to an insane amount of detail but you have to buy a license and software or have Tokyo Mods do the programming. I did not need to as the 10 maps are very versatile for tuning the power. I had the ECU in the classifieds section here on T, but I do not know if has expired or what yet. PM me if you want to talk about it. I am tying to get $350 for it. It is $700+ new, and is in mint condition.

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That sounds like a good deal IF I require it. What I am trying to determine is, can I get away without doing anything in order to save money. I contacted the guys at HotCams and they said "In most cases the ECU should pick it up". But they also said that they use a Power Commander for all their testing along with Dyno-Jets maps.

Aside from the extra $350 I would have to spend, I also have no confidence that I would know what to do with it. I'm the kind of guy that likes to get my bike running well and then leave it alone. I have no desire to change characteristics from track to track.

On the other hand I'm thinking that I may need to do this in order to get the most out of the mods.

I never ran the bike with the stock map after got the big bore and the stage 2 hot cams. I went to a Vortex X10 ECU that has 10 different maps you can choose with a switch and it also has trims to adjust lo mid and hi fuel. I used the fuel trims to add a bit of fuel and then I could use any of the 10 maps from the ECU to get different power character and for soft or hard terrain tracks. I have a '12 now and I am selling the X10 ECU if you are interested. It worked great with the mods I had, and it can also be programmed to an insane amount of detail but you have to buy a license and software or have Tokyo Mods do the programming. I did not need to as the 10 maps are very versatile for tuning the power. I had the ECU in the classifieds section here on T, but I do not know if has expired or what yet. PM me if you want to talk about it. I am tying to get $350 for it. It is $700+ new, and is in mint condition.

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