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So my valves have no more adjustment and need to be redone. I was wondering what you guys think is the best brand, my goal is to make it just as reliable if not more so and add power while I’m at it. I’ve heard of kibblewhite but don’t know much about them. Also I was thinking while the shop has the motor off doing the valves I could throw in some upgrades. I don’t know what all goes into a big bore kit and if it’s just as reliable as before but I know I want the power. High comp pistons, mild cam, port polish head. But what else goes into doing a big bore kit? Thanks!
 

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Truck Yea
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guy i use for valve jobs always puts in steel ferrera valves, multiple people i know have him do our heads and we have had no issues. typically you need to do the valve guides by this point too, due to wear.

as far as big bore kits go - i had an athena 490 kit that was decent, it made a lot of torque but imho the cylinder walls and water jacket get to thin when you go that large. i prefer a 470 kit for the 06+ bikes. high revving and plenty of power when built right. i currently run a 12.5:1 470 kit, web cam, bored carb and a ported and polished head with +1 valves all around. we never dyno'd it but its probably about 60hp compared to other such builds.
 
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Yes as CJM said, the Stainless Steel Ferrea are best to my knowledge as well. Exhaust Valve Guides usually are bad at wearing on the TRX&CRF heads that have a lot of hourse (but sometimes you can get away with the old ones as long as there is no side to side play on the valves).

It may not sound like a big deal but if the guides ARE worn out they will wear out your valve stems and you valve will wobble more and more over time and prematurly wear out the valve seats as well due to the Valve moving "side to side" as it closes and spins at high RPM's.

Just a Suggestion from me... I would get the intakes cut for a +1mm Ferrea Valves and and some Ferea Exhaust Valves. As for guides (if you spend the money on some Fearrea Valves you might as well get some Bronze KPMI Guides while you're at it) They should be $65.00 bucks or so for 4 Guides (Depending on where you buy them and what shop has them).

As for Valve Springs I suggest staying away from the dual springs that are KPMI springs (KW) I see the intake springs break so often it's crazy and somany shops still use them.... IF you do use them just Check the valve clearences periodicully you will kow when a Spring breaks because the valves will be "tight" as if they need adjustment.

If you're looking for Power get the head ported as well by someone who knows what They're doing.

Head porting even with the Stock bore & Stock Compression of the 06+ TRX450's +1 intake valves alone wakes these bikes up A LOT. (Assuming it has a good breathing Exhaust)

Also Yes i agree once again with CJM Go with a 478 Big Bore kit (AKA the 480 big Bore) is more then enough and a Stage 3 Cam would work great too.
 
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