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315 big bore, any reviews?

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I'm interested in a big bore for the 250F, any reviews for it.

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Yes... I put a puny 262 (stock compression) RPM kit in mine and I love it. Its the best mod I've done yet. Next time I'll go for the 270 kit!

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Thanks Float, anyone else? I'm a big guy but the 450 I had would just kick my butt after a couple of laps. Sold it and am considering something else. Thanks for any info.

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By any chance do you know what the HP & Torque gain is with your mod? Maybe a dyno reading?

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If you are refering to my 262 Kit... No! But, my seat of the pants dyno says it is a bigger improvement than the size increase might lead you to believe. I can now use 3rd gear coming out of some corners that I previously had to use 2nd.

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Thanks for the reply's. I'm looking at an all around bike, I ride mostly MX but will playride also. I'm 42, 200lbs and stay in fairly good shape(not race shape). The 450 just wore me out to quick, and I think the 315 would be perfect, lighter, good power and trail rideable too. So any info is great, thanks fella's. Wally.

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i weigh 205 and it pulls me around fine stock.

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I allways suggest getting head work done before a big bore.

The RMZ can make good power with mild head work. Especially when the correct cam is added.

I feel there is a need for big bores but the main reason for their popularity is that they are a no brainer for the people who sell them. They bore and replate your cylinder, sell you a piston,suggest jetting specs then there isnt any way you can complain.

Because bigger is allways better correct?? A big bore alone on most bikes turn them into a torque slug. You may get a mad hit off of them bottom and into the mid range but the top fades quick. Yes it may make more power all over(bigger is better).

But a big bore along with headwork make the entire package work. Then you can make mad power all over. A knowledgeable engine builder can custom tune the set up and make the power where you need it.

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Thanks RC for the info and you are correct, but I'm looking to do a big bore kit and then I might do other mods. This might be my last bike(42 with a 2 year old and maybe more on the way!) and I might as well get what I want. I'm Int Vet/Old timer speed, dont race much anymore but practice a lot and I'm going to take up TRAILRIDING more. So for all around I think the 315 would work great for me. Thanks again for the reply and I'm interested in the product on your website also.

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Thanks for the interest.

The point I was trying to make about the big bore is that you can make as much power with the other mods if they are done by the right person.

I just feel it makes for a much better motor to do the headwork over the big bore. I personally would the headwork,pipe and maybe cam, first.

AS I have posted in the past I am fairly certain we had the first big bore stroker RMZ on the planet. This motor has extensive headwork. The exhaust port was welded and smaller in diameter than stock and flowed more.

To my amazement this was the funnest and easiest bike I had ever ridden and would have made a good woods bike also. I cannot ride it to its full potential that ny son does though.

So I am not against big bores I just see so many people going what I feel is the wrong route.

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My son rides RPM's 315 and it kicks, but it is definately a race bike. Not a good comparison since he only weighs 150# soaking wet. I know this is a 4S site, but have you considered the KTM EXC 300? I know what you mean about the 450, but there are some that are a bit tame, so maybe hold out for the CRX and get teh suspension set up right. BD

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also the big fact that a big bore in the 125 class is ILLEGAL.

so make sure you aren't entering in any of those classes :naughty:

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Thanks for the link on the Athena kit, I've been looking all over for that. Wally.

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For anybody that is interested in the big bore kits, they are doing a test of a KX280F in the July Dirt Rider.

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I was watching a new TV show last night called 2XTREEM and they installed a RPM 315 ICE Cube kit on a YZ250F(sorry about mentioning the YZ in a RMZ forum) anyway, it was pretty cool and informative. Randy Hawkins was on the show helping them build it then they put it on the dyno and it had like 41.5 HP. Awesome show has anyone else seen it? It's cool to have a show that is dedicated to Two Wheels and shows lots of technical stuff. Now I have to choose between American Chopper and 2XTREEM guess i will have to get TIVO now.

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I was watching a new TV show last night called 2XTREEM and they installed a RPM 315 ICE Cube kit on a YZ250F(sorry about mentioning the YZ in a RMZ forum) anyway, it was pretty cool and informative. Randy Hawkins was on the show helping them build it then they put it on the dyno and it had like 41.5 HP. Awesome show has anyone else seen it? It's cool to have a show that is dedicated to Two Wheels and shows lots of technical stuff. Now I have to choose between American Chopper and 2XTREEM guess i will have to get TIVO now.

What channel and time?

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You can get it on Direct TV all over in the country, channel 632. It's on a southeast cable networks as the Sunsine network or Sunsports (same thing)

Good luck finding it in your area, I think you will like it, I thought it was pretty cool. :)

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