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270 or 280 I can't decide

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I've been searching threads for days trying to decide on the TR 270 kit or the Athena 280. I like the idea of having 10 extra cc's and the larger coolant area, but I'm a little worried about the thickness of the cylinder. I know early crf's had some trouble with them breaking. Has anyone had any problems with either kit? Thanks

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Well I have had mine for about a year now and it has a about 8 GNCC races and a few DZ of harscrambles and it is going strong. When I installed mine I also replaced my head to a 06 R Head with new valves. Very easy to install without any case modification.

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Thats good to know. Everything I've found on the TR 270 has been favorable. I guess the Athena is still too new to get any feedback on it. My plans are to switch to the 06 R head myself. I'll probally run the 04 X head for awhile so I can compare the two.

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The displacements are:

borexstroke - cc

78.00x52.2 - 249.4 - Stock

81.00x52.2 - 269.0 - Thumper 270 kit

82.00x52.2 - 275.7 - Athena 280 kit

Athena is 6.7cc larger :thumbsup:

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If I were building a 276, I'd go with the IceCube over the Athena this year. The Athena kit has to have a seriously thin skirt to fit the stock cases, so I would let somebody else be the beta tester. There's no doubt that the thin skirt will be fine in the short term, but how long before it goes out of round?

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Well, I went with the Thumper Racing 270. Should be in by the end of the week. I got my 07 R head today. The porting will be done by next week. Already have the 04 R cam, Dr. D pipe and the closed circuit mod has been done. I'm expecting it to run pretty good.

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If I were building a 276, I'd go with the IceCube over the Athena this year. The Athena kit has to have a seriously thin skirt to fit the stock cases, so I would let somebody else be the beta tester. There's no doubt that the thin skirt will be fine in the short term, but how long before it goes out of round?

The Athena Kit is a tad more cheater as it looks stock. The one I saw required the cases to be cut/bored.

The Ice cube is a good design, it doesnot look stock but adds some bling.

We have run a 262 from Forward Motion that most have said will not last but it has done very very good. We choose that displace for the reason that our stock cylinder was about worn away and we wanted some nice power in the mid range and not loose the top over rev. RHC has done this with his cam and porting. I think he has reached the same torque without a bigbore..

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There's a whole thread on the 280 kit I'm sure you've seen.

He just deburred the skirt and it went on. My kit is still in the box. Maybe I'll install it this weekend :thumbsup:

I like the extra cylinder idea. Then I can do whatever I want with the old one!!!

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No cutting/boring just touchup and by the way it's a steel liner. I have been abusing oops riding the piss out of it for 3 weeks now and it rips. Too soon to know if it will be as reliable as the TR270, but absolutely would recommend the kit.

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We have a new kit with cam and valvesprings , sleeved OEM cylinder for stronger walls and stock look , spl . 81 mm 13.5 race piston from CP to our specs and japanese rings for best oil control and sealing....it's the highest compression kit out with a cam and springs to get up to 40 hp and 21 ftlbs! with a stock head , no porting.

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we use 94 or higher octane , i race with U4 and practice on 110 sunoco because it's cheaper...the 50 / 50 mix of 110 sunoco and 92 pump isn't too bad and keeps it cooler....you won't believe the low end throttle snap our 270 mammoth kit has....the extra compression and race camshaft are the deciding factor of why our kit make 21 ftlbs of torque from 6900 to 8700 rpm and it keeps a very flat torque curve up to 12000.... i think it does it all...major low to mid power with brutal top end ! what else would a 250 guy want ? and look stock still...even with stock pipes we hit great #'s on the dyno and it feels awesome on the track or trail.....fun fun bike

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