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Head work (valves, springs, porting, cam)

Yamaha Raptor 350 & Warrior Forum

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xbigxredx

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Winter break is just around the corner!!! I plan on rebuilding the head on my Warrior while Im out of school. I want to install performance springs, valves, cam and port the head and maybe even shave the bottom for more compression (milling I think its called?). Does anybody know the best combination of these parts? For example, a Hotcams cam with Duncan Racing springs, Im not sure, Im just throwing out name off the top of my head. I also need to get e new sleeve for the cylinder. Ive already got a .040 over Wisco and dont want to go any bigger so I want an aftermarket sleeve with a stock sized high comp piston from JE. Any advice or leads would be great.
Thanks, RIDE HARD!
 

DeadLastRacing

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Why waste the bore? Why not a high comp JE and keep the big bore. Make the quad a 366. No need to mill the head either if you go with the thin cometic gasket kit. It sets the deck just perfect.

If you got the money and are going to do the valves and springs, I'd look into a better cam (megacycles, web cam or poweroll) Thinking of getting an over-valve too?
 

xbigxredx

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All this advice is great! Thanks guys! I still cant get over how awesome this website is. The reason I want a new sleeve is to try and keep my bike cool and reliable. Ive heard having a thinner cylinder wall promotes heat build up and thats an issue im already having problems with. If Im wrong or there is a way to compensate (Ive already got correct jetting and an external oil cooler) please correct me.
Over valve?? Are you talking about over sized valves?
 

DeadLastRacing

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yeah, the external cooler will help. Air cooled engine just run hot. I got a .40 bore on mine and the oil cooler but it still gets wicked hot. Not more then the cooler you can do. Scoops help a little, direct the air to the head better.

Over-valve would be +1mm over on the intake.
 

87warrior917

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thats what i got on my intake valve (+1). does that make a diff.? maybe try keeping the head, cylinder and motor super clean of mud and dirt everytime you wash it. after mine drys i take wd-40 and drench it haha. it doesnt let the mud stick as good. helps on the inside of your fenders too.
 
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