Mounting a Slant Head?

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Sparks66

New Member
Nov 4, 2009
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San Jose, Ca
So I was riding my motor bike home from work and saw another guy going the opposite direction.
He turned around and caught up to me. His bike had all the cool stuff like a custom expansion chamber and custom gas tank. My bike is generic. He said I should get a slant head to get more power. Well, I ordered one for 12 bucks. Seems like a small investment to me. I am a newbie so I have a few questions. What do I have to do to change heads? Do I need a new gasket? Is there a gasket? Can I make a gasket if I need one. Can I reuse the original gasket? Will it fit without any problems? Was it stupid for me to order the slant head being clueless and all? Any help would be highly appreciated.
 
skjjoe

skjjoe

Member
Mar 9, 2009
393
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Boerne Texas
depends on where you got the motor from.they dont all mix and match.you should be ok if you got the motor and head from the same dealer
 
Pablo

Pablo

Master Bike Builder & Forum Sponsor
Dec 28, 2007
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Duvall, WA PNW
www.sickbikeparts.com
Sparks66 said:
What do I have to do to change heads?
Do I need a new gasket?
Is there a gasket?
Can I make a gasket if I need one.
Can I reuse the original gasket?
Will it fit without any problems?
Was it stupid for me to order the slant head being clueless and all?
Click to expand...
1) Four nuts off, four nuts on. Proper torque. New HG. Retorque 2-3 times (ride cool torque, repeat). Torque depends on stud and engine size and thread count. Get rid of the acorn nuts and use real nuts.

2) I say yes because the mating surfaces will now be different. I have reused HG's with the same head but not changing heads.

3) Yes.

4) You can make one if you are handy, but they aren't expensive.

5) See #2.

6) It should fit. The biggest problem is that the mating surface will not be flat. You might need to lap sand it on wet dry paper on a piece of glass. Mine was VERY unflat. More tightening will not help.

7) No, smart actually. You can learn and do the change and have fun. Relax!! Your engine will come to life if you match the intake and exhaust and get an expansion chamber.
 
R

Riding Rich

New Member
Aug 14, 2009
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Anyway the PK studs are 8mm but i have heard of some 60cc not 66cc having 6mm studs.
I really don't know about the Grubee slant or the 48cc.
I think all the 48cc are 6mm.

Someone help us out here.
 
skjjoe

skjjoe

Member
Mar 9, 2009
393
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Boerne Texas
ok pulled the head again, the dax motor i have has a slightly larger bolt pattern and the studs are slightly larger .i cant find my caliper right now but now im wondering if the 48cc that i got is really a 48cc. will report

Ok the slant head i got from Zoom has the 6mm studs holes. And my dax engine has 8mm studs
Does any one know what the bore size should be for the 48cc?
 
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K.i.p

K.i.p

New Member
Nov 8, 2009
339
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CNY
I too would like to resolve the true identity of a slant I bought from Zoom. Please if anybody knows the bore diameters please post. I would be greatful!
 

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Riding Rich

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Aug 14, 2009
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Hard to tell about that one.
I have a PK80-J it's 68.8cc.

The bore diameter is 47mm.

I believe the 48cc has a 40mm bore.

If you pull the head off and measure the bore you will know what you have.

It is a Power King.
 
skjjoe

skjjoe

Member
Mar 9, 2009
393
1
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Boerne Texas
ok who makes the f50 that dax has 50cc 8mm studs. And where can i get a slant head that fits. i just want to try it. Ive already got a pk 50 engine but i just want to compare
 
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FileStyle

FileStyle

New Member
May 27, 2008
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Decatur,IL
I had to add another gasket to mine as the piston was hitting head, doubled the gasket, even made one from a soda can (didnt really help.0002) retorqed head bolts by hand and feel, went for ride,got it hot,retorqed,let cool, then repeat once more and have not had a problem! mine also was the $12.00 slant head. I have 6mm head studs and the head had the larger stud holes for the 8mm, centered head up and tightened down!
 
Z

z2400969

New Member
Sep 10, 2009
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San Jose
Hey Sparks, I was the guy that chased you down. I had saw a thread about the slant head and bought it without knowing anything about compatibility issues. I guess I lucked out because it worked just fine. I didn't change the head gasket either, then again I didn't have many miles on my engine either. But from bone stock to the new head and expansion chamber, wow it was like day and night. I have no clue about the origins of my motor. I bought it off some guy on craigslist new in the box.

Let's get together with the others locally and plan a ride.
 
K.i.p

K.i.p

New Member
Nov 8, 2009
339
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CNY
Thank you for bore specs Riding Rich. I will be pleased to finally have proof positive one way or the other with regards to displacement. (I am the dude that has the flat piston)
 
R

Riding Rich

New Member
Aug 14, 2009
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Hey Kip.

When you have the head off rotate the motor to Top Dead Canter.
Put the head back on.
Leave the spark plug out.
Get a medicine dropper graduated in ML.
Take 2 cycle oil and fill the top of the motor through the spark plug hole till the oil just reaches the sparkplug threads.
Remember to keep track of how much oil u put in.
The dropper will prolly be 5 or 6 ML total.

Then we will know the volume of the Combustion chamber.
And we can calculate your compression.

1ML = 1CC isn't that cool. "metric system dose have it's advantages"

When your all done dump the oil out.
Take the head off and clean up the mess.

Have fun.
 
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