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big bore advice needed please

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well i just brought a 2004 wr250 with the motor in bits already ( was very cheap) and it needs a new cylinder , valves , maybe cams and a crank.

i was thinking about putting the athena 290 kit into it instead off buying the standard factory cylinder again . its only going to be a couple off hunderd differnt than staying at 250cc . are these kits ok and wots the reliablty like and that .

also wot mods should i look at doing wile the motor is down i was thinking a mild port job, maybe some after market cams ( wot are good cams to run in the wee wr ) since i have to replace the standard cams.

any advice would be cool to help make this thing a wee rocket

thanks

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What's your parts budget? Also, if it had a catastrophic engine failure, I'd be thinking about new crank/rods & bearings valves, springs to go along with that new cylinder.

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My "05YZ Athena 290 has been totally reliable through 60+hrs mx track. I recommend Hot Cams stage II to feed the increased displacement at higher RPM (make sure the air box is opened on a WR!!) Jet it lean (maybe start with165 main).

I replaced the crank as precaution after dropping a valve on my '02. If your engine experienced sudden stoppage it might be money well spent.

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zero problems on my 05 WR. Lost track of how many hours,riding EVERY weekend for well over a year

glenn

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cool thanks for the replys guys , no the engine was still running before they started pulling it down . it was just getting hard to start since the valves were tight . the standard cylinder has gone thro the crome just below the top off the clyinder in 2 wee spots .

i was gonig to do the cams because there was a wee bit off wear on the cam chains sprockets and the crank just to be safe . im looking at spending about $2000 on it and ill still come out pretty good on the deal considering the price i brought the bike for

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Hey all,

I have been looking into these big bore kits (specifically the athena 290), however I can't seem to find much info on what happens when you need new rings / a rebuild. Is there enough meat on the cylinder to hone out again or would the walling be too thin? What happens here? Are you up for the cost of a whole new kit?

If anyone also has advise on how often these would require a rebuild. Oh, and also what the cost difference is between rebuilding a 290 and a standard 250.

Any help would be greatly appreciated.

Thanks guys

Jared

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Hey all,

I have been looking into these big bore kits (specifically the athena 290), however I can't seem to find much info on what happens when you need new rings / a rebuild. Is there enough meat on the cylinder to hone out again or would the walling be too thin? What happens here? Are you up for the cost of a whole new kit?

If anyone also has advise on how often these would require a rebuild. Oh, and also what the cost difference is between rebuilding a 290 and a standard 250.

Any help would be greatly appreciated.

Thanks guys

Jared

You won't need to replace the cylinder. You can buy a piston replacement from rockymountainatv.com. $150 or so and comes with rings, wrist pin and circlips.

You can get cheap gaskets from cometic. Don't buy the Athena gasket. They are twice the price.

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