08 head

4 replies to this topic
  • Yamahajoe292

Posted July 12, 2016 - 01:24 PM


Looking to get a little more power out of my 08 450. Having a hard time keeping up with these FI bikes and was thinking about getting the head ported...and good recommendations or thoughts? Thanks

  • stevethe

Posted July 12, 2016 - 03:04 PM


Ahh the new bikes are awfully fast. If you have a 08 I would make sure you don't have the stock muffler with all the baffles. Pro Moto billet end cap with all the stock baffles removed works pretty well. I would send the carb to Zipty Racing and get all the mods done. If you send the head out make sure it is someone that knows the five valve heads or you could loose power.

By the way even a pretty well built 08 will be down by less than five hp on the top.

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  • grayracer513

Posted July 12, 2016 - 03:38 PM


The most (that I know of) that top YZF flat track engine builder Ron Hamp ever got out of a 450cc 5 valve YZF was ~62-63 HP, it took him years to get there, and a lot more than the head went into that.  The '15 got delivered with a fer real 57 RWHP, and it's mostly because of the head.  The '10 and later cylinder head basic layout is pure Moto GP stuff, and by contrast, a 5 valve layout is a limiting factor in producing fat top end numbers.  As Steve pointed out, it's ridiculously easy to make the intake ports work worse than they did when you started out.  Whoever you have do the job really needs to know what's up.


One alternative is to see if you can still buy the GYT-R head for the quad 450 that they were selling a couple of years back.  Used to be about $2500 completely assembled and ready to drop on.

  • stevethe

Posted July 12, 2016 - 04:01 PM


Geoff at MMAD racing can get you big hp if your willing to part with some dough $$$. He's the best and well known at porting and knowing the Yamaha five valve head. He specializes in them. Also good cams. http://www.ford-y-bl...com/atvkits.htm

By the way certainly nothing wrong with the GYTR heads. Especially if you get a deal on one with everything new included. However if your head is in extremely good condition the MMAD porting might cost less and he can port your head to match his cam.

Edited by stevethe, July 12, 2016 - 04:06 PM.

  • coastlinecascott

Posted July 15, 2016 - 08:32 AM


Pro 1 heads in az. Got mine done by them and made a difference. New seats and guides with porting. 600 bucks

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