need some tips!!

2575 Views 20 Replies 4 Participants Last post by CAM2, Jan 29, 2013

angrychild1997

Discussion Starter · Jan 16, 2013

so guys i have a 49cc engine that am going to use for an experiment but i was wondering if there is a certain torque that i need to apply to the head bolts when i put the head back together?? i know that in cars u need to tight them down to a certain torque but idk if it applys to cags? also i make take some pics and post them up for all the newbies so they can see a chinese quality product

1 - 20 of 21 Posts

EPR

· #2 · Jan 16, 2013 (Edited)

I believe it's 15 ft lbs., mine are more like 30 or 35 ft. lbs. I crank them down pretty good on a criss-cross pattern, alittle at a time, with SS split lockwashers under the bolt head.

angrychild1997

Discussion Starter · #3 · Jan 21, 2013

oooh thanks man, i was looking all over the place for this piece of information and also do you have any idea how to make boost ports on a piston? is there an specific place ?

EPR

· #4 · Jan 21, 2013

When I make my own ported piston I drill a 1/2" hole over each upper intake ports, so 2 ports 2 holes. I like mine .150" below the bottom ring.
My 47cc ( 43cc ) 40mm bore Boosted306 Canted modded head stock w/ 3 port has no boost hole in the piston and it works real good.

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angrychild1997

Discussion Starter · #5 · Jan 22, 2013

ooooh. but i saw the pistons they sell with boost ports and they have an oval shape hole? its that any different than just making hole in the side of the piston? i mean am trying to make the biggest hole possible so i can make the piston the lightest i can and also have you ever drilled holes in your crankshaft??? i was wondering if i could do that but am scared that the piston might start rotating in the wrong direction? What you think? and real nice bike,i like that exhaust

EPR

· #6 · Jan 23, 2013

I just bought a lightened Cag Flywheel from Hugh at SDscooters, minus 45grams he has 35g also, don't know if it will work, going in my Z1 one ring piston Cag engine. It is hard steel don't know if you can drill it. I am drilling holes in my rod in the middle, and will mod the piston but have not got there yet.

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angrychild1997

Discussion Starter · #7 · Jan 23, 2013

Yea i see what he did with that,.but i really dont have the right tools for that

but I can.do.something.similar.and about the.piston would you.mind showing me a.picture?

EPR

· #8 · Jan 23, 2013 (Edited)

Don't have a photo of a ported piston, lost alot of photos last year when my Laptop died. The oval port is one size fits all 1, 2 or 3 ports. The three ports now have 2 triangle shaped holes.

angrychild1997

Discussion Starter · #9 · Jan 23, 2013

Ooooh got it thxs for the explanation and wow that really sucks ,my pc died not to long ago and i lost all my family and vacation pictures,really sucked

CAM2

· #10 · Jan 23, 2013

angrychild1997 said:
oooh thanks man, i was looking all over the place for this piece of information and also do you have any idea how to make boost ports on a piston? is there an specific place ?

I match my main hole to the boost channel and face the other 4 towards the transfer ports................

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EPR

· #11 · Jan 24, 2013

I did mine with a center punch and hand drill.

TheDog

· #12 · Jan 26, 2013

A boost window is only necessary when your are not case pulsed. I prefer to case pulse and not use the window cause it increases crank case pressure which is good for top end. Here is a pic of a cag motor I cut 3 boost ports in. It sold on ebay about a month ago.

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angrychild1997

Discussion Starter · #13 · Jan 27, 2013

Whats the point of having so many boost ports in the side.of the cylinder head, and also whats a transfer port? Am kidding lost when it comes to this 2 stroke modding? I know a few things but most of them i dont , so if u could explain what that those i be very happy

because idk what to do ,.1,2-or 3 lines

EPR

· #14 · Jan 28, 2013

It's better to have one wide 9/16" to 3/4" upper port, I have a 5 port, not much cylinder for the piston to ride on.

angrychild1997

Discussion Starter · #15 · Jan 28, 2013

So your saying that its better to have one or two big.ports than having 4 or 5 big.ports? And whats the point of this ports? To get.more fuel into the mix?

EPR

· #16 · Jan 28, 2013

I have stock 2 main transfer cylds in 40mm and 44mm, 43 & 49cc. Have 47 & 49cc 2 pcs ported cylds from Boosted306 that have one wide 1/2" or 9/16" intake channel port, and 2 & 3 upper port kit cylds. The 5 port w/ FC crank a good carb & exhaust has better low and mid range, not sure about the top speed, think a 3 port would work better, but I have no tests. Boosted, Sam, and CAM2, will tell you the same thing.

CAM2

· #17 · Jan 28, 2013 (Edited)

angrychild1997 said:
So your saying that its better to have one or two big.ports than having 4 or 5 big.ports? And whats the point of this ports? To get.more fuel into the mix?

The best bang for your buck without diminishing engine life substantially is the 3 port engine........

5 port cylinders deliver nice lowend power but they last the least...This is because the diminished cylinder face the piston rides on aswell as the ring splits interfere with the two outter ports which is succeptable to ring and cylinder damage as the rings wear down and get more flexible........

When I built my 5 port 1pc engine on my 2011 cag I grinded-in the two outter ports to be with-in ring splits........but my 5 port I bought however I wasnt so lucky....The rings are imbedded into the piston on the lefthand side

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EPR

· #18 · Jan 28, 2013 (Edited)

I was not happy with the pin placement for the rings either on my 5 port, either in or real close to the outer port edges. The older 44mm piston with one Oval port is a better start for modding cause it pins are spaced farther apart and ride all the way up & down the cylinder walls.

angrychild1997

Discussion Starter · #19 · Jan 29, 2013

Yea thats my goal so far to port an oval into the piston and go with 2 or 3 ports on the cylinder head , also whats the two little holes on the side of the piston for? The one right next to the piston guide thing , sorry forgot the name

EPR

· #20 · Jan 29, 2013

I believe that mod is for the piston port engine only w/ the carb mounted to the cyld head. Can't remember if you do it to the reed port piston.

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