predator gx160 head

[minigonzabel]

Hey everyone I'm needing some help cuz I'm confused. The predator motor out the box with a header would spin the tires on my kart. I put a gx160 head that has been ported and gx160 flywheel on it today with same header and stock filter. On the ground the motor rips but when I stuck it back on my kart the tires would not even attempt to spin. It gradually picks up speed. I set both valve lash at .003 ngk spark plug 87 gas and governor spring mod.

 

[Oldschool]

What does the plug look like?

If possible, buy a new plug and run this thing.
Don't let it idle....

Drive it as hard as you can and turn it off.
Let me see the plug.

I suspect you are running lean.

Also I would be running 91 octane.

 

[basselete]

do you know of a thread that would tell how to replace preditor head with a gx160 head?

 

[Oldschool]

do you know of a thread that would tell how to replace preditor head with a gx160 head?

No.
There is no thread I am aware of.

I told you what to do.
Do you want to fix this or not?

Because this will become the thread you are looking for.

 

[graygoose420]

do you know of a thread that would tell how to replace preditor head with a gx160 head?

Bolt pattern for the gx160 head is different then the predator head . It would need welding and machine work.

 

[basselete]

No.
There is no thread I am aware of.

I told you what to do.
Do you want to fix this or not?

Because this will become the thread you are looking for.

sorry just was wondering if there was another way (thanks for the advice)

 

[Oldschool]

Bolt pattern for the gx160 head is different then the predator head . It would need welding and machine work.

This fellow at any rate apears to have one ON his Loncin 212 so I would assume the modifications are slight.

 

[Oldschool]

sorry just was wondering if there was another way (thanks for the advice)

I want to see it work too.

Gasoline is your first step.
Get that 87 out and get some 91 or better in it and see how it runs
Don't let it idle and colour the plug do some runs and shut it down.
Coast to a stop.

And loose the stock filter, get something better on there.

 

[minigonzabel]

Well I did some inspecting and the head gasket was leaking so there went that (blue clone head gasket). So I used the stock predator gasket which is like the stock gx160 gasket and still the same results on the power loss. Seems that the motor does rev alot higher but has loss bottom end power. Plug reading was almost tan but you could see a white tint. I have no funds for a filter or can find drill bits locally to resize jets. Ill have to buy another thin head gasket because predator gasket started leaking oil from the bottom of the head. And bolt patterns are the same just the dowel pins are different sizes. Oh yeah this head has also been milled some and not sure how much has been taken off though. Will take some pics tomorrow of gx160 head.

 

[minigonzabel]

 

[Oldschool]

I would think for now you are better off with the preditor head gasket, at least untill you figuere out a few things.

Where did you get this head?
Are you sure its flat and the deck is square?

Try a hoby shop for some drill bits.

You did try some premium in it for thelast test right?

I think your compression and timing might be too much for Premium but we don;t actualy know what your compression ratio is.
I figuere with a 14 you should be around 11:1 at least ( just a guess ).

Also if your lean this will make the octane issues worse.

 

[minigonzabel]

im sure its not because the guy i got it from milled it with a sanding block.

ive looked at hobby lobby

no i havent tested it out with premium. got to get some.

im thinking the compresion is to high. the predator gasket is leaking oil so cant run it till i get a new gasket.

check list
head gasket
premium gas
find somewhere local that will check the head make sure its flat and deck is square
find drill bits
snag air filter off uncles atv that not being used. brand new.
homemade air filter adapter

also thinking about going to hf to replace my predator just to start fresh

 

[Oldschool]

So are there other issues with this engine I shoudl know about?

How old is it?
How old are you?
I am old......

I think you might have a warped head my friend.
And that porting job looks excessive for you needs.
It does not apear the valves have been unshrouded.

 

[Big Jim]

I worked in a machine shop that NEVER used sandpaper to mill somthing.
Sanding it is NOT good enough!! Hope you didn't pay more than $.50 for it that it's scrap weight which is what you have.
Put the stock head on it save your $$ and get a head from a "reputable" seller and leave the machine work to the professionals.
Good Luck!
Drill set,
20 Twist Drill Bits Spiral Drill and Swivel Pin Vise | eBay

 

[minigonzabel]

Head was free probably even going to give it back to my buddy. And Tex my blue clone head back. Yeah he ported it cuz he was going to build his gx160 up but never got around to it. The motor probably a month and half old. Nothing else is wrong with it that I know of. I'm 18. Still young and trying to learn as much as I can.

Thanks for the link.

 

[Big Jim]

I doubt you did any damage to the block by putting that head on it.
Good to hear that you are willing to try things and not getting cocky when you make mistakes :thumbsup:

 

[Oldschool]

Gte a piece of mirrow.

Put some valve grinding compound on it and rub the head.
This will show you exactly where or if there are high spots or a warp.

Use some spray adhesive to glue some 120 sand paper on that same gmirrow after and with even presure on a flat surface you maye be able to true if if required.

 

[minigonzabel]

I put everything back to original. The dowel pins are different sizes so any gasket I put in ended up not sealing right. When I get another gx160 head or my blue clone head milled I'm try figure how to make the bigger dowel pins from the predator fit in other heads and get alot of predator head gaskets. Yeah its not a big deal to me if I make any mistakes. I like trying different things.

 

[Oldschool]

I put everything back to original. The dowel pins are different sizes so any gasket I put in ended up not sealing right. When I get another gx160 head or my blue clone head milled I'm try figure how to make the bigger dowel pins from the predator fit in other heads and get alot of predator head gaskets. Yeah its not a big deal to me if I make any mistakes. I like trying different things.

I don't understand.

You lost the correct dowl pins?

No matter with or without the head should seal.

You should be using a Preditor head gasket from the start.
Preditor pins or non at all and that head should seal if its flat.
Sometimes I have issues with sealing and use a spray on head gasket sealer with the steel rings.

Alternately there are aftermarket head gaskets that will seal.

If you go back to Bob's 4 cycle send a PM to " SNEAKS ".
He has all kinds of copper head gaskets.
95% sure he already has something for this motor combination and if your real nice he might have some pointers for you.
Tell him Oldschool sugested you ask him for advice.

 

[minigonzabel]

Predator dowl pins are to big for the other heads and I had only one cuz the other was damaged trying to pull it out the block.

Alright ill try to get around to pm sneak
thanks oldschool.