v - twin Briggs engine

[xxmiaja]

Do anybody have knowledge of the Briggs v - twin engine 20 hp engine on a gokart.i want to swap out my predator 420cc engine for this engine can my frame handle it how fast can it go what mods will I have to go through

 

[gman3850]

How fast it will go is a relative term. Speed is based on gearing. What that motor will give you is a far beetle torque and power curve. You will gain some top speed but not that much. The motor weight twice the weight and has twice the rotating mass.

Plus the gov should still kick in around the 3600 range I belive.

 

[xxmiaja]

Thanks for your reply..so this means I will have to change engine mount again to fit this engine yes the rpm is still at 3600.i am debating if it is even worth all the money I will spend to convert it..keep in mind the engine alone is 1,200

 

[mckutzy]

I would think of the clutching first when looking at these motors. They(afaik) have a 1 1/4" shaft.
I would think your looking at snow machine territory, and then it still won't be cheap.

I'd say unless you have a ton of cash for a cool toy, go for it.

 

[gman3850]

For me I sold my 24 v twin and went down to a gx390. I got it for cheap and intend to upgrade it a little. If you already have the 420cc IDE say use the extra funds and do a little motor work

 

[rv8riveter]

These guys have a good rep and get 20 hp out of a clone.
http://www.vegascarts.com/product-p/vrx46-a.htm

Same footprint and less $$.
Thought about for mine, but didn't see the point for now.

 

[gman3850]

That deffinetly is a good deal even adding every option your still under 1k. And can run ungoverned. So top hp you'd bee sitting probly around that 20-25hp range. IDE go with the torque cam

 

[landuse]

With the larger engine and unchanged gear ratio, you are only going to get to your top speed faster, but the top speed will still be the same.

What kart do you have. I am not sure if you mentioned that. A small yard kart will not handle that much torque

 

[xxmiaja]

My gokart is a streaker dd9.this was the high powered one with a 9 hp tech.engine funny thing is this engine had the same foot print of a 6 hp and the output shaft was a 3/4. I moved up to the 420cc.i really would like to beef it up to 20 hp but this means the life of the engine will suffer and I will dump 4 or 500 bucks into it for 5 more mph..

 

[xxmiaja]

My kart is a streaker dd9 high output it came with a 9 hp tech.i changed that with the 420.cc

 

[gman3850]

Gotta remember beading up your engine to 20hp is not gonna grab you that much in top speed. But will get u extra power and reliability. You could always do a bilit rod and flywheel, a cam, valves and valve springs and remove the gov. Should put you around the 400 range. Now what this does is allow you to change your gearing to help you get that extra mph without feeling to loss of torque.

 

[gman3850]

I guess my last post got delete because of the server rash, so ill write it again to make sure you can read it.

There is a difference between building a engine stupid power and building a engine for reliable power. Take either my truck or vw bug. Both of them have forged cranks, rods and pistons. Both engines run better, more efficient and more reliable than stock. Truck 375 vs 290, vw bug 128 vs 56. With better parts and proper maintenance of course they'll run longer.

Now your Predator 420cc 13hp is an under carbed utility motor. With a aftermarket carb or proper jetting, intake and a header with that motor youll easily gain 2-4 hp. Next add a cam and net 1-2 hp. That right there leaves you with an almost stock 16-19hp motor. Now unhook the governor and reach the higher rpm that will gain you that last pony. That is were the bilit rod and flywheel come in place. Now i only would recommend these if you plan to have the motor at full blast for long periods of time, No the stock ones probably wont blow up on you, but like you you know higher rpm = shorter motor life.

for you i think you'll be fine with leaving the gov on, maybe adjust so you hit the 4k range.

here is what i am going to probably get for my honda gx390. Im going for more torque than hp. thow i should be sitting in the 16-18hp range
Gx390
mikuni 28mm or bore 390 carb- $56-$75
jets- $4
custom intake $3 in materials
custom header $3 in materials
280 Marine Grind cam $119

so ill be less than 200$ into my engine and be right were i want to be

 

[OzFab]

No one has mentioned gearing; if you still have the stock gearing, you can afford to bring it up a bit due to the increased torque of the larger engine.

If you've already changed it, forget I spoke