Decking Height checking the head?

So, I have almost 0 free time anymore since I started a businesss. I would like to get my quad done though, I have all the parts, but need to re-install the head.

Can I buy a gasket kit and just torque it all down and call it a day, OR would I be loosing out by not testing my deck height? Is it a long and hard process? (Valve clearance check and worrying about proper numbers)

I havent bought any gasket kit yet, any suggestions. I ran the EST cometic kit before, should I go that route again?

Just looking for some words of wisdom.

Need to get my head back on and hooked up, my yfz450 shocks on it and put my rebuilt shocks back on and call it good to go. Minor mantiance then its just wheeling all spring sumer and fall! Time to ride, not work!

Are you wanting to calculate true compression ratio (as compared to estimated ratio), check for flat gasket surface, valve clearance or just CC the head?

Looking at your sig, if you haven't done anything out of the ordinary like omit the base gasket, etc. you should be OK with a standard gasket set. I'd just check for gasket surface flatness with the 'ol sandpaper on glass plate trick. It doesn't really qualify as "decking", more just to verify "square". Factory milling sometimes leaves a lot to be desired. Mine wasn't horrible, took about a half hour or so starting with 150 to 600 grit.

I'm just a backyard tool monkey.
Hi tech stuff should be directed to Midway, aka The Head Man. :iagree:

Idk just order what you got last time

Considering the lift of the cam you had before compared to your new one, I think you will be just fine. I would not leave out the base gasket or you may have problems. I think the bent exhaust valve came from other issues and not piston to valve clearance being too close.

I think most all the replacement gaskets are the same thickness so people don't have timing chain issues. My co-worker ordered a Moose upper end set for his Wolverine. I will measure it compared to his stock one and see if they are close.

I just had my friend port and polish my extra head and had it decked .015" to raise compression some and to rid it of warpage. I also have a stage 1 hotcam and adjusted the valves to .004" and have no clearence issues. I wouldn't go more than .020" decking. I found that, at the least, the top end was rebuilt once before with a .020 over Yamaha piston and bike runs just fine. Am putting a .040 over 10.25to1 Wiseco in it this weekend, providing it and the gaskets get here tomorrow. I got the engine used and although it runs awesome it had some good wear on the thrust faces I wasn't expecting. So i'm doing the piston mainly for peace of mind. I'm not concerned about clearence. If there are guys out there running 10.50to1, or more, and using the biggest web cam available and they have no issues than I should be good. I'm also using cometic est gaskets.

Might be a dumb question, but can I reuse the EST head gasket I took off it? It is Extreme Sealing Technology after all, right? Looks the same as the day I put it on, well, I sure its lost some of its regitity. New EST kit is $71. Wonder if they will just sell me the head gasket?

I was going to reuse my head gasket when I install that wiseco, because I've only put about 3 hours on it since i swapped heads, did the oil cooler, and the direct shifter. But I just can't bring myself to do it. Because I know whats gunna happen; it'll look good and will work fine untill May when I go to Hatfield for the first time and it blows out on the trail. Sucks cause I still have the base gasket and base o-ring from the last kit, all is needed is the h/g. I got another kit coming from an ebay seller, $55 free shipping. I may have left over gaskets, but will probably use em down the line on a stock type rebuild for a customer. Will just get the factory Yamaha head gasket. Unless someone on here would like all the left over cometic gaskets + o-rings.

Just remembered; I reused a factory head gasket on a friends/customers warrior. It had a broken exhaust stud and I couldn't get the damn thing out with the head on. He wanted it done on the cheap. Bike is still going strong to this day. And that was 4 years ago!

I just put mine together, made sure valves didnt hit piston WITHOUT head gasket, reinstalled with head gasket and ran the snot out of it.

87warrior917 said:

I just put mine together, made sure valves didnt hit piston WITHOUT head gasket, reinstalled with head gasket and ran the snot out of it.

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How did you check that? Have to hook the cam up to it and bolt it all back together?

DeadLastRacing said:

How did you check that? Have to hook the cam up to it and bolt it all back together?

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Yupp, place some clay on the piston for the valves to leave an indent, put the entire top end together without the cam chain, snug the head bolts, makes sure the piston is at TDC, roll the cam over each lobe SLOWLY. Take all apart and check the clay. Cut the clay in half where the valves left and indent and measure that. That'll tell you how much Valve to Piston clearance you have, then add in the thickness of the headgasket and you'll have your total. You want a certain amount of clearance with out the head gasket, cant remember what that number was.... hmm someone help me out here haha

.40. But isn't that the number you want total, all gaskets included. Cant you do that same test with all the gaskets to get the exact number? You turn the cam over with a wrench and using the cam bolt? But woulden't you have to take it back off again to get the cam sprocket and cam chain back on. Those bolts are designed to be used one time.

87warrior917 said:

Yupp, place some clay on the piston for the valves to leave an indent, put the entire top end together without the cam chain, snug the head bolts, makes sure the piston is at TDC, roll the cam over each lobe SLOWLY. Take all apart and check the clay. Cut the clay in half where the valves left and indent and measure that. That'll tell you how much Valve to Piston clearance you have, then add in the thickness of the headgasket and you'll have your total. You want a certain amount of clearance with out the head gasket, cant remember what that number was.... hmm someone help me out here haha

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Exact same thing I said in a pm earlier. You can also put really light weight springs on and set the valve lash and check by putting feeler gages between the rocker and valve tip. Just keep adding feeler gages till its tight at the closest spot and measure that. We do all our race engines that way because they are usually close and the clay isn't as accurate when things are tight. The minimum amount is on Web Cams site: .050 intake and .080 exhaust.

DeadLastRacing said:

.40. But isn't that the number you want total, all gaskets included. Cant you do that same test with all the gaskets to get the exact number? You turn the cam over with a wrench and using the cam bolt? But woulden't you have to take it back off again to get the cam sprocket and cam chain back on. Those bolts are designed to be used one time.

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You can do it without torquing the bolt. Just tight enough to hold things in place. You have to do it with the chain hooked up and timed because duration is more what causes piston to valve issues than lift. It all has to do with when the valve is opening in relation to the piston traveling up or down. The exhaust is more critical because the piston is coming up as the valve is opening. Intake can have more because it is following the piston down.

If your running JE they are deck height corrected if I remember right.
a wiseco.040 with no jug gasket with OEM valves and head cc gives 11.022:1 if my math is correct, a stock warrior has about .065 deck mine has .039

Kewl, I think I can handle this. What type of clay should I get? Modeling clay from a hobby shop work well?

I'm gunna pull the whole engine just to make my life easier.

Modeling clay is what we use. Remember like I said and smear a little oil on the surface of the clay so it won't stick to the valves and pull away. It will definitely be easier out of the frame and on a bench. I actually made a cradle assembly to put mine on to assemble it and do all this to it.

yeah, I made a wood engine cradle a long time ago. I think its still around where somewhere.

Cool cool. hopefully I can get the beast back together here soon and give er a good ripppp. BBBBBRRRAAAAPPPPHHHH

Well, something is way off here guys, whats my issue?

Measurements with a micrometer.

4.66mm or .1835" Whaaaaa? WTF is the issue here?

What is it we are looking at, dead?

If that is the thickness of the clay after turning the engine over then you are good. The numbers I posted are minimums. If you have more clearance than the minimum that just means you have room for a bigger cam if you decide you need one.