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Need Help! - CR250 Engine Dilemna

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Going over my '02 this winter and found that the piston was shot and the cylinder was oversize .0015" due to sucking in some sand/grit this year. Am happy with the bike (SST/Vforce/Shorty/JD jetkit/Exhaust spacer/Power now) but need some honest help/opinions on how to repair the bike up keeping in mind getting the most bang for the dollar:

1) Having USChrome replate cyliner ($170) plus piston ($100) total $280.

2) Rechrome/Eric Gorr porting ($295) plus piston ($100) total $395.

3) 265 big bore ($225) plus piston/gaskets ($140) total $365

4) New '03 cylinder ($280) plus '05 head ($80) total ($360) , I have access to some single ring '05 pistons but will have to buy a new head as the new pistons are domed. Not sure if this will work, will have to check clearances before assy.

5) '03 cyinder ($280) plus piston ($100) total $380, will have a spare head to rechrome/port later. Not sure if I will have to buy new powervalves with the new cylinder, will have to check.

The 256 Eric Gorr w/porting would be great but is outside of my budget.

Thanks in advance with your help guys.

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Uh...no offense here......but are you sure about that measurement....

0.015" over?? Typical thickness on the stock nikasil coating is only like in the range of 0.002-0.004". So if you are 0.015" over, then you shuold be right thru the nikasil coating. ????

Now if you are talking .0015" difference, you might be able to take care of that with a different piston. Vertex pistons come in like three different sizes.... 66.35, 66.36, 66.37

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I would do the 265cc kit, no porting necessary.

This route adds more value for not that much more than normal rebuild. Also, w/a 265 kit, you'll be riding on lower rpm, thus top end rebuild will last longer too.

IMO, there's far more power output w/ +15cc than using the '05 top end.

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Uh...no offense here......but are you sure about that measurement....

0.015" over?? Typical thickness on the stock nikasil coating is only like in the range of 0.002-0.004". So if you are 0.015" over, then you shuold be right thru the nikasil coating. ????

Now if you are talking .0015" difference, you might be able to take care of that with a different piston. Vertex pistons come in like three different sizes.... 66.35, 66.36, 66.37

Yes Charlie, that's .0015, typo, my bad. The bore is worn to a point that some of the coating has worn off below the exhaust bridge so a replate is in order.

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I would do the 265cc kit, no porting necessary.

This route adds more value for not that much more than normal rebuild. Also, w/a 265 kit, you'll be riding on lower rpm, thus top end rebuild will last longer too.

IMO, there's far more power output w/ +15cc than using the '05 top end.

Mini do you have firsthand experience with this - other tuners suggest that porting offers more gains, porting + bore gives the most.

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It would depend to me upon what tp of riding you do and where you want the power. Big bore *generalllY* make more power, but down lower. Porting...you can get it ported to where you want the power. Personally, I'd be more tempted to get it replated and ported. Of course, doing both would get you the most, but also cost the most.

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