I know this is old but I can tell you have your governor removed. I’m assuming you did the billet rod, flywheel, etc. Do you think the stock rod and flywheel could handle not constant high rpm but only sometimes?
The stock rod can handle 3500rpm all day long, but when you go higher than that your pushing it past its design limits. Stock rods look pretty fragile to me, and if one brakes I hope you got the warrantee because its a disaster.
Your top speed will be determined by your gear ratio, and wind drag. You can experiment with different size sprockets to find what's right for you. The taller the ratio the slower it accelerates. Choose a tire suitable to the terrain you will be driving on. If driving on street it would be a smaller tire. If driving on dirt it will be a larger tire. A larger tire weighs more, and has more wind drag which will slow down acceleration and reduce top speed.
14 tooth Noram Star clutch, 67 tooth drive sprocket with 15" wheels. I don't run torque converters because they use more hp to operate. Centrifugal clutches are more efficient. The less teeth you have on the clutch sprocket the faster the teeth wear out, and when teeth wear it robs hp. You wouldn't think a slightly worn sprocket would make a difference, but it does. An efficient clutch sprocket would have 19 teeth. Anything less and the drive shaft won't be round. It would be like an octagon shape which robs hp. The down side on a go kart is when you add teeth to the clutch you have to add more teeth to the axle sprocket to keep the same top speed which makes it closer to the ground and rocks. Tried to keep it short, but there's a lot to it..
Thank you very much for the information I'll be running a 10 tooth to 60 tooth which means I'll be a 6 to 1 ratio I think is what I figured out with a 420cc as well took the governor out upgrades valve springs and did a stage 1 Performance Kit looks like you are running this thing at a higher altitude I'm in Colorado so I will be going to higher altitude as well do you find issues with it at high altitude. I will be doing a lot of trail riding solo torque is good for me I'm not looking for a high-speed but if I need a higher speed I will up the teeth on the sprocket
@@mtnpeeksgokartfreeks7503 The higher the altitude the more you will have to lean out the mixture in the carb since there is less oxygen. I recommend using a motorcycle carb they flow way better which equals more hp. I'm running a 40mm Dellorto carb. Something easy to do that will gain hp is build a proper length exhaust pipe thats about 33" long. You can get 90* degree bent tubing from eBay for cheep.
I haven't put one on a dyno just yet. Nrracing has some charts of a fairly mildly tuned one at 37hp. Im assembling a 390 right now that's on the extreme side of performance, and I do have a dyno to put it on. I was thinking about starting a thread over at DIYGoKarts to show all the pictures Ive collected of this build.
Right now its geared to 55 mph at 6500 rpm and it gets there quick. If I geared it up it has enough hp to easily do 90 and possibly over 100. I consider this engine to be a mid range build. I have another one that should produce quite a bit more hp when its done.
Mammoth its not gonna do 90/100 this motor makes like 13hp and carsandcameras had a 20hp+ motor on a race cart and only got to 75 and u riding a yard cart
That's the best 420cc setup I've seen good job Cantor wait to see more of your content
You can never get bored of this one dang
This guy is keeping his cool going around corners fast as hell how? I would be shitting myself to be hinest
This is fun what you mean
@@2strokesRuleeee it is fun but scary 😟 I’d love to do
Incredibly fast , You got balls,
This is a proper send it.
Sick setup and vid
That's like some LeMans racing,.,.Or something Slick like it!,,
Maby put a Little Turbo on one of your builds,,And Make Mowa PawaAa BaByy;)
That thing is quick!!
Thats awesome! Are you running the clutch or torque converter??
Torque converter i blew 3 clutch in 30 sec on my 420
I know this is old but I can tell you have your governor removed. I’m assuming you did the billet rod, flywheel, etc. Do you think the stock rod and flywheel could handle not constant high rpm but only sometimes?
The stock rod can handle 3500rpm all day long, but when you go higher than that your pushing it past its design limits. Stock rods look pretty fragile to me, and if one brakes I hope you got the warrantee because its a disaster.
720 pm hi I have a yard ovary putting a 16 hp 420 cc motor on it how fast will it go and do I need to put bigger tires on it
Your top speed will be determined by your gear ratio, and wind drag. You can experiment with different size sprockets to find what's right for you. The taller the ratio the slower it accelerates. Choose a tire suitable to the terrain you will be driving on. If driving on street it would be a smaller tire. If driving on dirt it will be a larger tire. A larger tire weighs more, and has more wind drag which will slow down acceleration and reduce top speed.
Stock 420?
Tht thing jhi dangerous 🤘😂😈😭😭😭💪😩😩
I was curious what is your gear ratio running from Main sprocket to your clutch or torque converter?
14 tooth Noram Star clutch, 67 tooth drive sprocket with 15" wheels.
I don't run torque converters because they use more hp to operate. Centrifugal clutches are more efficient.
The less teeth you have on the clutch sprocket the faster the teeth wear out, and when teeth wear it robs hp. You wouldn't think a slightly worn sprocket would make a difference, but it does.
An efficient clutch sprocket would have 19 teeth. Anything less and the drive shaft won't be round. It would be like an octagon shape which robs hp.
The down side on a go kart is when you add teeth to the clutch you have to add more teeth to the axle sprocket to keep the same top speed which makes it closer to the ground and rocks.
Tried to keep it short, but there's a lot to it..
Thank you very much for the information I'll be running a 10 tooth to 60 tooth which means I'll be a 6 to 1 ratio I think is what I figured out with a 420cc as well took the governor out upgrades valve springs and did a stage 1 Performance Kit looks like you are running this thing at a higher altitude I'm in Colorado so I will be going to higher altitude as well do you find issues with it at high altitude. I will be doing a lot of trail riding solo torque is good for me I'm not looking for a high-speed but if I need a higher speed I will up the teeth on the sprocket
@@mtnpeeksgokartfreeks7503 The higher the altitude the more you will have to lean out the mixture in the carb since there is less oxygen.
I recommend using a motorcycle carb they flow way better which equals more hp. I'm running a 40mm Dellorto carb.
Something easy to do that will gain hp is build a proper length exhaust pipe thats about 33" long. You can get 90* degree bent tubing from eBay for cheep.
Was this video speeded up or are you really a daredevil?
Its not... even scarier
That's a badass kart man. How much power can you build these 420cc engines to? How much is yours pushing you think?
I haven't put one on a dyno just yet. Nrracing has some charts of a fairly mildly tuned one at 37hp. Im assembling a 390 right now that's on the extreme side of performance, and I do have a dyno to put it on. I was thinking about starting a thread over at DIYGoKarts to show all the pictures Ive collected of this build.
@@Mammoth1632 Definitely post it. I'm on diygokarts as well, so I'd be interested in seeing it.
@@BunkerBlog Here you go. www.diygokarts.com/community/threads/gx390-build.42856/
have you tested top speed on that thing yet
Right now its geared to 55 mph at 6500 rpm and it gets there quick. If I geared it up it has enough hp to easily do 90 and possibly over 100.
I consider this engine to be a mid range build.
I have another one that should produce quite a bit more hp when its done.
@@Mammoth1632 Jesus Christ
Mammoth its not gonna do 90/100 this motor makes like 13hp and carsandcameras had a 20hp+ motor on a race cart and only got to 75 and u riding a yard cart
@@jamesdellaquila1939 This engine is far from the stock 13hp. How fast do you think this kart would go if it had say 35hp?
@@Mammoth1632 also there is f**cking way you are making 35 hp lmao
dangerous