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250sxf bigbore

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Alright so I've been looking for quite a long time to put a bigbore kit on my 250sxf. I was thinking about a cylinder works bigbore but on their website they state that the compression ratio is increased from 12.8:1 to 13.3:1 with that said, am I still going to be able tu run 93 octane gas with that much compression? 

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We installed on on our 08 250sxf. Ran it on pump gas without detonation. Extra load on the crank though so make sure its fresh!

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We installed on on our 08 250sxf. Ran it on pump gas without detonation. Extra load on the crank though so make sure its fresh!

How do you like it? Do you loose a lot of overrev with it?

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We did loose a little over rev but low and mid range were unreal. Top end was similar to stock. Great out of the corners!

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5 hours ago, Zien19 said:

We did loose a little over rev but low and mid range were unreal. Top end was similar to stock. Great out of the corners!

Excellent how many hours do you have on it right now? Do you have any idea of how many hours you will put on the conrod before tearing apart and replace it? Oh and also I've heard that with a big bore the sxf tend to overheat but I don't let my bike idling for a long time but I'm curious about it.

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We have 40hrs on it now. MX use and I did the crank at the same time for peace of mind. Engine ice with no heat issues. The odd weekend in the bush as well.

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My 16 250sxf comes 14:1 compression stock and I can run non ethanol pump gas. Idk what year yours is but I bought an aftermarket waterpump kit for $80 on ebay that should help with any possible overheating. I don't really like the stock setup either i think it's a poor design

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13 hours ago, Modded ktm said:

My 16 250sxf comes 14:1 compression stock and I can run non ethanol pump gas. Idk what year yours is but I bought an aftermarket waterpump kit for $80 on ebay that should help with any possible overheating. I don't really like the stock setup either i think it's a poor design

If so, at 13.3:1 there should be no problem 

Edited by jackstrap

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19 hours ago, Zien19 said:

We have 40hrs on it now. MX use and I did the crank at the same time for peace of mind. Engine ice with no heat issues. The odd weekend in the bush as well.

Looks like you're actually doing what I will use the bike for thank you for your review that's exactly what I was looking for:) 

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10 hours ago, smv ryder said:

http://thumperracing.net/index.php?route=product/product&path=37_39_284_346&product_id=362

I went with there 290kit on my '11 250SXF and was so impressed! Lost a little over rev but the bike was a blast! No problems after 3 seasons either.

I don't think I will use that one, I will probably go with the cylinderworks 276cc kit as it seems to be the best all around bbk available if you do MX/wood

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On 11/18/2017 at 6:32 AM, jackstrap said:

I don't think I will use that one, I will probably go with the cylinderworks 276cc kit as it seems to be the best all around bbk available if you do MX/wood

good luck my man! TR 290 is no joke

Edited by smv ryder

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