Help with predator 224

[aust9002]

Now i need a bigger cam since its outta breath?

 

[aust9002]

 

[BrownStainRacing]

View attachment 142641

Nope.

IMHO, port the head 1st.

Cam ain't no good, without a good way to get the air/fuel mix in and exhaust out.

You Will be surprised what a turd motor stock cam will do with the right head to flow for it.

People give up WAY to fast on the stock cams. Dont even giv em a chance.
They are actually too BIG for 90% of the builds I see here.

Truth be told,.....they work much, much, better then what the "you tubes" are selling.

You wanna haul a$$, asap, on the cheap???

Buy carbs from carb BUILDERS
Buy cams from cam BUILDERS
Buy heads from....yea you guessed it, from head BUILDERS.

A big mega warehouse selling bs, cheap, useless parts on the you tube, won't get you there.

I got this Ducar 224 on my grandsons buggy today. Its done at 5500 rpm, bone stock, with a PVL flywheel with 26* timing.

Theres no more Hp to be made above that rpm. It's gonna take the CORRECT combo of CR, head, carb, and exhaust to push it farther.

Its a torq monster being stock, no need to kill it with high rpm.

Build it for low rpm torq, and you will be dropping gear to calm it down on the low side, then your mph will come up faster.

 

[aust9002]

Dang that things lookin good in that buggy, ok so I tried the 12 tooth tonight got me up to 51mph for a split second going down the big hill but my rpms dropped down to max about 5250, I think I might go back up to the 140 jet i dropped down to the 135 because I wanted it lean enough to seat the rings but it seemed to run just a hair better on the 140 maybe like 50-150rpms difference, Im going to order a couple different belts including a genuine comet to see if any last me better or not I might need a new belt after tonight i could see some wearing on this one already, I might take the head off and use my dremel and see if i can open up the intake and exhaust port at all they looked pretty clean and big from factory, ill check deck height and maybe put a smaller head gasket or something but i still think I can get more out of this setup before I swap cam, springs and rod

 

[aust9002]

Can I swap springs on a stock cam?

 

[BrownStainRacing]

Can I swap springs on a stock cam?

Yea.

You can go with 22# springs and 1.3:1 stamped steel rockers.

It'll make the cam feel bigger, and give you around .288" lift.

You got plenty of break in time on it, I say, start tuning it, .

I got .002"- .0025" piston to deck on this 1, so a .027" thick gasket will be perfect, make sure you measure the gasket. I checked a 3 shim 68mm and it was only .021", it should have been .027".

On the head, dont open the intake runner, it's too big as is, jus rough it up, and work the area around the valve guide, lay those steep drop offs down into nice slopes.

The exhaust won't take much work, its bigger then any 212 exhaust port. Jus take off the sharp edges, and smooth the rough areas.

Take those sharp gasket edges off the intake and exhaust, and gasket match those.

Smooth out the rough spots in the chamber, and take off the sharp edges.

Anytime you take a head off, go ahead and lap the valves to the seats, these lil engines have the worst valve seats.
I've probably see 5 or more that was leaking this year.

The jetting, head gasket change, head work, those 1.3:1 stamped steel rockers, and 22# springs, I'd bet that 12t sprocket will work for you then.

Here's the 1.3:1 stamped steel rockers. You might find a kit with springs.

I've broke these rockers with 26# springs, but 22# springs are no problem.

Mini Bike Predator NON-HEMI Clone ROCKER ARM 1.3:1 RATIO GAIN 30% Lift! USA | eBay

NON Hemi Heads and Clone Heads ONLY will not work with a Hemi Head. Predator NON HEMI Clone KART RACING ROCKER ARM 1.3:1 RATIO GAIN 30% Lift! THESE WILL NOT NOT work with the Hemi head engines! 30% more lift with ANY CAM!

www.ebay.com

 

[aust9002]

Ok perfect I already have some 22lb and 26lb springs, I wasnt sure about how ratio rockers worked but ill order those and see what we can make out of the head!

 

[aust9002]

Would these work?

 

[BrownStainRacing]

View attachment 142665
Would these work?

Yeap.

 

[BrownStainRacing]

@aust9002

Heres how rough you can be on the intake runner, DO NOT MAKE IT SMOOTH.

You can smooth and polish the exhaust and combustion chamber, but NOT THE INTAKE RUNNER.

I dont bother smoothing the exhaust runner, jus clean up the left over casting flash and call it good.

I use 1oz of seafoam to 1 gallon of gas to help keep the carbon build up, down.

PAULS KARTS RACING 🇺🇸

www.paulskarts.com

 

[BrownStainRacing]

Ole4 from the oldminibike forum does some very impressive head work.

He makes molds of the runners, vacuum test and flow bench test them. Whatever springs and valve size you need, that's a really good prices for what you get.

Check him out, he knows his stuff about these heads.

Reconditioned big valve head for sale

This came off my kart engine that I am upgrading. It is a 32 x 25 head and was a 22cc chamber. It has been milled and is 17.5 CC's now. It has a backcut intake and both seats were touched up with a 45 stone by hand and relapped and vacuum tested. Head Flows a max of 86 CFM and I can provide...

oldminibikes.com

 

[aust9002]

Do I need this too?

 

[ezcome-ezgo]

 

[aust9002]

Lol is that supposed to be an elephant?

 

[BrownStainRacing]

Do I need this too?View attachment 142666

You shouldn't need it, if you use the stock push rods. Grap it if you want to. You never know what you might change later.

You should have that GOOD long slot guide plate in the Ducar 224, mine did.
I hate those square slot ones, they usally too wide and not long enough.........uhm, reminds me of an old gal back in the day, we called Push-Rod,.....ahh maybe not, she was more round then square,

 

[aust9002]

You shouldn't need it, if you use the stock push rods. Grap it if you want to. You never know what you might change later.

You should have that GOOD long slot guide plate in the Ducar 224, mine did.
I hate those square slot ones, they usally too wide and not long enough.........uhm, reminds me of an old gal back in the day, we called Push-Rod,.....ahh maybe not, she was more round then square,

Hah this guy... alright so I ordered some 1.3:1 ratio rockers, new belts and a green spring, some magnetic drain plugs, hopefully mon or tues I can pull it apart and change those out and see what damage I can do to the head

 

[BrownStainRacing]

Hah this guy... alright so I ordered some 1.3:1 ratio rockers, new belts and a green spring, some magnetic drain plugs, hopefully mon or tues I can pull it apart and change those out and see what damage I can do to the head

You can practice on the old predator 224 head.

I got this Ducar 224 hitting 35mph in about 280ft. It definitely needs less gear. 6.66:1 with 7" driven now.

Moved the red driven spring to the farthest clockwise hole (least resistant), mph or distance didn't change, but the mph incase from 100ft-200ft is very noticeable, it really gets going around 3800-5000 rpm, that's right in the power.

I changed the stock .028" main jet to a .031" main, and turned the low speed mix about a 1/2 turn out and it hits much harder outta the hole.

"Old fat papaw" can put the rubber down now with this 224,

 

[aust9002]

You can practice on the old predator 224 head.

I got this Ducar 224 hitting 35mph in about 280ft. It definitely needs less gear. 6.66:1 with 7" driven now.

Moved the red driven spring to the farthest clockwise hole (least resistant), mph or distance didn't change, but the mph incase from 100ft-200ft is very noticeable, it really gets going around 3800-5000 rpm, that's right in the power.

I changed the stock .028" main jet to a .031" main, and turned the low speed mix about a 1/2 turn out and it hits much harder outta the hole.

"Old fat papaw" can put the rubber down now with this 224,

View attachment 142679

Damn! That things been getting it!

 

[BrownStainRacing]

Damn! That things been getting it!

Yea, I'm really impressed with this outta the box engine.

It'll run all over that stock predator 224.

I got 3 more coming, 1 is sold and I'm gonna hold 1 for my buddy, I know he's gonna want 1.

I had this one sold when it was on the work bench tore apart, but that guy came by today and said it was way to much for his 12 and 14 yr old boys on their hammerhead kart.

I let him borrow that 196 I jus put new piston and rings in, with a lil CR bump, more main jet, and timing it's still gov'ed with an aluminum flywheel.

It hits 4600 rpm, but I showed him how to move the gov spring over, if it was too much.

Let me know when or if you change that rod, I didn't get a chance to measure the stock wrist pin diameter.

 

[aust9002]

Im just gonna put the 9 tooth and the 7 inch driven on mine so I can just burn em down lol