Superjet help

Bikerant83

Bikerant83

Location
Ocala florida
Im a newbi but whats the highest compresion i can run on pump gas and what cc domes make that pressure or how much to mill head to get that stock superjet factory dry pipe duel carbs
 
V

Vortex

Location
Southeast
You want a girdle head with a type 4 etc dry pipe. It uses studs to tie the cylinder and head to cases, reducing pressure on the base of cylinder. They are tricky to install right. Need to clean and tap case threads. Can be tedious.
 
Big Kahuna

Big Kahuna

Administrator
Location
Tuscaloosa, AL
Installed many a girdle kit, Never have I had to Tap the cases threads for the cylinder bolts. They come tapped from the factory...... Do you mean clean and chase?
 
V

Vortex

Location
Southeast
Yes. Edit: Don't use a tap, just chase the threads. Most of the grunt work is getting all the factory loctite residue out of there. (I also use 2washers to make sure there isn't any bottoming out)
 
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Big Kahuna

Big Kahuna

Administrator
Location
Tuscaloosa, AL
Bikerant83 said:
What does girdle head mean?
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The headshell has either studs that go into the cases to sandwich the head and cylinders tot he cases, or you have a bolt system that bolts the cylinders to the cases then has longer bolts that thread into the cylinder bolts to hold the head down. This puts all the support on the cases. When you run a dry pipe, that is alot of weight and force that gets transmitted to the cylinders. With the Girdles, this helps to keep the cylinders from cracking.
 
V

Vortex

Location
Southeast
Big Kahuna said:
So your saying the bolts that come from the factory do not have adequate enough thread engagement to hold down the cylinders?
Click to expand...

The studs have to be threaded down far enough into the cases so that you can torque the acorn girdle nuts properly. If not, it bottoms out on the inside of the acorn and you have effectively not torqued anything down.

It's right in Ada instructions. Do not bottom out the acorn nuts. Common sense isn't so common anymore...
 
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Big Kahuna

Big Kahuna

Administrator
Location
Tuscaloosa, AL
"4) Install studs into cases, make sure the studs go all of the way in. The studs should all be approxi- mately the same height when sticking out of the cases. It may be necessary to clean the lock-tite from the case holes applied by the factory. Do not bottom the 10mm acorn nut to install the studs! It is best to use a stud tool. The studs do not need to be torqued into the cases, they should just be tightened until they stop."

Actually it says nothing about drilling and or re-tapping. Yes you need to be sure to clean out threads so all of the threads engage. If you do this, there should be no issues.
 
V

Vortex

Location
Southeast
It took a lot more cleaning/chasing than I expected to get that even height with my 64u cases. Thanks for the clarifying posts though.
 
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V

Vortex

Location
Southeast
Sorry about that man, just get an Ada girdled head kit with 37cc domes and a set of metric thread chasers and you will be happy as a clam.

Alot of us long time riders prefer to torque the girdle nuts a little more than the 23 ft/lbs recommend by Ada. I put anti seize on the stud threads and torque the nuts to 28 lbs in two iterations.
 
V

Vortex

Location
Southeast
It's important to note that with a dry pipe, Ada recommends one size down for domes. So 37cc is what you want for pump gas. With 35cc you will need 100 Oct when a dry pipe is installed.

I also run a similar dry pipe to the type and 37s on my ported motor.

As far as girdle studs. I have used both the 2pc and the one PC style. The 2pc may offer a tad more strength and at the track ease of inspection via head shell removal, but it is quite possible for those lower halves of the stud to get very stuck in the case threads if they are tightened a bit too much . Not fun when it's time to disassemble.
 
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