Decking a Speedwerx Billet Head

dirtjumper895

dirtjumper895

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How do you deck a head when you have interchangeable domes? I have a speedwerx billet, with 12:1 domes, and i am thinking it has a slight warp on the Mag side.

Ive read about lapping the head on some 220 on a sheet of glass, but do you do the cover and the domes together or seperate?

When decking the head, how much do i have to worry about oring depth and squish angles and compression ratios?

Or, should i just bring it to an automotive machine shop and they should know how to do it?
 
why do you think the head is warped? does it leak on mag cylinder? that head should have no trouble sealing to the o-rings w/the proper torque on the bolts. head shell is thin enough to contort a few tho while torqueing down, if needed.
 
Well, i have had the head on and off, made sure all surfaces are cleaned, however i had been reusing the orings (new ones are on the way). I have used a 2 stage torque pattern, 9 ft lbs, then 22 ft lbs. Cross pattern, starting with center first.

It leaks on the mag side, into the cyclinder only. Sled only runs on center and Pto then.

Piston Wash looks perfect on center and Pto, piston top is clean on mag side. Same jetting straight across. All carbs clean.

Im going to try it with the new orings when they come in... (Friday or saturday)

Torque values are with clean dry threads, from a trusted torque wrench.
 
i personally like to 3-stage torque head, cylinder, and crankcase bolts down. are you torquing to 21 ft-lbs? also, i'm a big fan of wet torquing. i would suggest waiting till your new gaskets come, as i'm sure its only o-ring issues. while the head is off tho, you can check to see if the mag dome's sealing surface, sticks out past the sealing surface of the head shell. if it don't, then maybe you have a faulty dome? the dome should stick out like .002" past the head shell surface.
 
So you suggest a 3 stage wet torque of 21 ft lbs? What Step Sizes should i use? Just use oil on the threads? OR shold i go out and buy the ARP Moly Lube?
 
i would suggest a wet final torque of 21ft lbs. put some engine oil on the threads of the bolts and on the washers underneath the heads of the bolts, so the friction between everything while the bolt is turning and threading in, is reduced to a minimum. you don't need to buy arp moly lube. your engine oil is fine enough.
 
yamaha srx 600/700 service manual section 9 ( specifications ) page 17 - clean dry threads @ room temperature.
bob
 
Okay. Thanks for the info. Ill wet torque them to 21 ft lbs, ill go 9 ft-lbs, 17 ft-lbs, 21 ft lbs.

Now if only my new orings would get here soon ill be golden..
 
The max you need to take off is only a couple thou and the O-ring up top should be able to seal for that. If you are worried, get a thicker diameter oring fromt he hardware store and change it out. I was cutting my own chambers for my heads and played around with that oring, but only because I had some issues with the old ring.
 
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