need crf450 big bore advise

[trx/lt500r]

I am not an expert at these crf450s,
I am rebuilding at terd of an engine that i picked up. I was assured that it was a good runner, however it was in no condition to run anywhere.
I have rebuilt the bottom end and looking into the top end now.
So need advise on a big bore kit.
Are they any good? Reliable? worth it?

1) I need a new piston and cylinder cleanup any way? Should i just buy a "Works Performance" Big bore kit for 380$ and call it a day? No dealer involded, no labor, no machineing, no
matchning piston to cylinder, etc.

2)Also need advice on compresion ratios. I run mostly xc but need the feel of performance as well. I have access to 105 octane gas for a fair price and will run this gas no mater what. Head is ported, crank in good shape.

Thanks

[strick9racing]

I have an Athena 480 big bore that I run and I like it, I would stick with Athena over anything else but that's just my opinion. Cheap price usually means cheap parts.

[trx/lt500r]

Thanks for the reply....

The "Works" kits use "Vertex" pistons. I have never heard anything bad about them.

Anyone have experience with these Works kits?

Or just some feedback on weather to (pay someone to bore my stock cylinder and match a piston that they are gong to mark up at dealer price) or (just go spend the money on a bigbore kit).

Not going to go with Athena as i have already dumped enough time and money on this engine's bottom end.

Just lookng for advice on a brand of kit that is reasonably priced as well as what compression ratio piston to go with.

Thanks

[2-330s]

Look around for a used cylinder that has good plating. Check some of the flattrack forums. AMA dosent run the 505 class anymore so someone probably has a good cylinder sitting on a shelf. If you are gioing to run race gas go with a 13.5:1 piston. I'd use cp first Wiseco is my second choice. I would also look into a cam to go with your big bore.

[koh0001]

I have a JSR 101mm with a CP 14:1 piston, stage 3 cam pretty strong but... .. I still feel after all the money I spent on this build.. It was faster with my stock bore 14:1, 208 Web cam. Just my 2 cents.

[shadd_27]

here is the kit on ebay im going to put in my crf hybrid over winter going with cp 14:1 instead of the vertex i figure for complete motor overhaul thats a good price and it comes with everything

http://www.ebay.com/itm/350484161791?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

i agree with 2-330s completely cp #1 then wiseco ive tried many kinds and those seem to last longest with best increases, web cams are my ideal choice but for price of kit ill go with hot cams
myself i would get new big bore cylinder with piston (13:1+ compression) as a kit and bolt it up

http://www.ebay.com/itm/CRF450R-CRF-450R-Cylinder-Works-4mm-488cc-Big-Bore-Kit-/250604726624?pt=Motors_ATV_Parts_Accessories&hash=item3a5934a960&vxp=mtr
email the seller and see cost of upgrade to cp piston and go rip up the dirt :)

they say timing is everything on these motors to get the power they can have thats possible why your stock bore build felt faster ^^ Koh0001; could be the web cam in general though they make some great power across the board