AGK's Stage 3 79cc Predator Build

[@pgp2880]

This video deserves way more love than it is actually getting because this is a proper video introducing a badass engine build✌

[@agkracing140]

Thanks!

[@mybikes1970]

That was the best sounding 4 stroke I have heard! I just bought one of those 79cc predator motors and I have a lot of work to do if I want it to run like that. Great job done👍

[@almostsapien]

What size are you using for pilot and main jets in the 19mm carb?

[@bigcconservativeguy2534]

I'd love 2 see one of these with dual carbs and a staged linkage. So you run a smaller primary carb and then a larger secondary that only starts to pump fuel at higher rpm/speed. Once the tuning was worked out it should be very efficient and hella boost to power in alll rpm ranges!

[@agkracing140]

A dual carb set up is something we've always wanted to try. A very long time ago we heard that Charles "Mini Drag Bike" did it. We never saw it or heard how it worked. Dual carbs would be fun to experiment with though.

[@raideryaga4889]

Or a pwk

[@fatbuddycat]

I was literally just wondering about how you did the big bore!

[@agkracing140]

There is a ton of work that goes into piecing something like this together when all the parts aren't readily available. We don't expect to sell very many of these because they are so expensive, it was more for our own curiosity and we wanted to share some of build with everyone.

[@fatbuddycat]

@@agkracing140 it's super cool. You guys are doing a great thing with the Predator 79cc. It's a lot of fun to work on and ride. It provides some serious joy after working on 212s all the time.

[@SB-fe4gt]

What connecting rod did you use...I did see where you turned the engine 7680 rpm. Didn't know whether the stock rod could handle that rpm :).

[@agkracing140]

There isn't an aftermarket rod available at this time. Fortunately the stock rods are durable. We haven't broken one yet.

[@MrJasenstewart97]

Would one of these motors work with a mikuni vm18 or would that carb just be too small?

[@agkracing140]

A vm18 would work.

[@firehawk3860]

Will anyone answer a question? What do you do with the tube coming out of the OHV part when putting on a different air filter?

[@agkracing140]

You can leave the tube open to the air. It's just a breather tube. Or we sell a breather filter you can put on it (p/n 18450)

[@alternatemusicaddict5226]

I hear you can go with about the same carb to intake valve size see what happens with a bigger carb

[@firehawk3860]

Plus any suggestions on a good but not the most expensive torgue converter?

[@agkracing140]

We don't recommend using a torque converter on the 79cc engines.

[@firehawk3860]

@@agkracing140 thanks but already planning on it and got one in cart waiting to order it. I do appreciate the suggestion and reply. Would you happen to know where I can find the red air filter for the OHC air

[@dylanschulz2404]

What piston did you you use? I built a long tail boat motor and used the 79cc engine to keep the weight down. Runs ok but more torque would be better. Don't really need the rpm just more power up to 3600 rpm would be nice! Thanks.

[@agkracing140]

Have you tried increasing the compression yet? We had a customer who needed more power from a pump that was on his boat. The pump used a 6.5hp engine. We used a high flow air filter, larger main jet, adjusted the governor to get a little more rpm and we milled the head for more compression (which is the biggest factor for the torque). The customer was thrilled to death with the outcome!

[@dylanschulz2404]

@@agkracing140 yep planning on milling the head and playing with jetting/timing.

[@chrishughes8504]

I run a 79 cc Longtail also milled the head ported jetted and advanced the timing does great. Might also look at a smaller prop. Helped mine alot

[@KB_Joys]

Im afraid to put one of those carbs on my 136cc. I need a charging flywheel for power. But ill probably just use a pz20, as i have a few of those and i can only mount my engine vertical because its the only way it will fit in my felt faker gas bicycle frame

[@dynomitetopieces]

why not a 24mm carb?

[@Leake8]

Do you know of a top plate for this motor to mount a fuel pump?

[@agkracing140]

We are not aware of a top plate for the 79cc engine. We've made them before without too much trouble using a piece of 16ga sheetmetal.

[@javankuusisto6614]

Where did you get the intake manifold from

[@agkracing140]

www.affordablegokarts.com

[@ThatGuyShuuby]

@AGK RACING does your big bore 49cc come with carb gaskets?

[@agkracing140]

This is a 79cc bored out to a 105cc. We don't include carb gaskets but we can.

[@LNRRidez]

Just subbed to your channel, great video!

[@exotic_gamer2308]

If you could can I please have a link to the carb and the carb manifold I would really appreciate it thank you

[@agkracing140]

affordablegokarts.com/collections/79cc-performance-parts

[@larrytemen4789]

How much? I just don’t want to chop up my phatmoto frame but want all the speed

[@Sauron_Green]

When are we gonna see a billet connecting rod or billet piston for the 79cc engines?

[@agkracing140]

The chances of seeing a billet rod are pretty slim. This engine doesn't get a ton of attention from the aftermarket community. In karting, the 79cc Predator is considered an entry level "kids class" engine where they only allow a couple modifications. Once those kids get some experience and step up in class, they'll go to a 212cc Predator. So the mainstream aftermarket isn't trying to build a killer 79cc Predator that produces big power. The other thing to note is the stock connecting rod in these 79cc Predators has proven to be very durable. We use the stock rod in our Stage 3, big valve, big bore (105cc) version and the stock rod has not been an issue. So far we've turned that engine to 7680 rpm and it's probably making about 10hp.

[@houseoffire72]

Badass⭐️⭐️⭐️⭐️⭐️

[@Jameson-jk2qt]

I got the 19mm carb for the 79cc predator and everything for it I got it together and it before with the stock carb I would go about 40 got it all together with the new carb and now it goes about 28 and just sputters and back fires at at top speed at 28 I kinda sounds like it’s not getting barely any fuel can y’all help me

[@agkracing140]

Does sound like a fuel issue. Check the spark plug. If the plug is white you need to go bigger on the main jet. If the plug is black you need a smaller main jet.

[@sw1ft2U]

what carburator is this?

[@agkracing140]

We use two different carbs on this engine depending on what our goals are. The 19mm and 22mm slide carbs are what we prefer.

[@motorizedbicyclenation53cu90]

Where can I get the 2 speed javkshaft?

[@agkracing140]

As far as we know they stopped making 2 speed jackshafts many many years ago. We had to make our own.

[@SpACeCruizeR2o3]

can u send me the link to this kit i have the 80cc motovox motor mini bike

[@agkracing140]

affordablegokarts.com/collections/79cc-performance-parts/products/105cc-big-bore-build-stage-3

[@josephsaucedo8691]

The back ground looks like you in a water pump yard it's what I do for a living ever have a problem I can tell you what it is that for sure my company goes as far as sb. I just had to ask how's the 190cc going. I ended up buying a ohvale Daytona engine after all there lots of upgrades in parts on them you can mod them to be a 212 4v beast. I'll drop a email soon have a great one till the next one 👍👌✌️💯🏍️🥂

[@agkracing140]

Can't go wrong with the Ohvale Daytona engine. That thing is a little beast!

[@roccobarca4558]

Hello, it is possibile to install a large sleeve and large piston in the new Honda gx50 engine(it is new engine, very different to Honda gxh50)? The displacement is 47,9 cc and it has 2 horsepower.

[@agkracing140]

There is a lot of research that needs to be done to determine what's possible. Just like with the 79cc engine we had to make sure the larger sleeve wasn't going to interfere with oil passages and the block had enough meat to hold the bigger sleeve. The hardest part is finding a suitable piston with a compression height that will work and wrist pin combination that will work with the stock rod. If you find the right compression height, chances are the wrist pin will be the wrong size, so then you need to figure out if making a new connecting rod is feasible so you can set it up with a wrist pin bore that will work with the new piston. The obstacles go on and on when doing a big bore like this.

[@roccobarca4558]

@@agkracing140 Ok thanks for the answer, very detailed and clear. Will you prepare the new Honda gx50 engine in the future with performance parts? It would be perfect for small karts because it is also very light, it is very compact and weighs only 4.1kg.This new version compared to the old version (gxh50) has an OHC system that supports high rpm such as 10000-12000rpm and in my opinion with a flat top piston, a serious porting of the intake a exhaust, performances cams, timing advanced, free flow muffler and a 15 mm carb, it is possible to reach 4-5 hp, what do you think? The original Honda gx50 engine without modifications reaches 9500-10000rpm. If the Honda gx50 engine would pass into your hands, I am sure you will create a little monster with a lot of horsepower.

[@roccobarca4558]

Here there is a video of the new Honda Gx50 engine, so you can see how the engine is made. At the minute 2:40 you can see the bore of Honda gx50. Thanks. Best regards kzbin.info/www/bejne/nquplZt8nZd-a8U.

[@edelmejia]

cool man, how you make the 2 speed shift, can you tell me please you awesome

[@agkracing140]

The 2 speed shifts automatically based on centrifugal force and the spring/weight combination we put in the two clutches.

[@OneGritMinis]

Does one clutch have a free wheel or are they both normal?