Kart newb has questions

[95s52]

Hello gearheads. I come to you for your advise and wisdom.

This weekend I purchased what I think was a decent deal for a go cart that I thought I'd fit in relatively well. The kart is callled Murray Kilowatt. Pictures below is the exact Kart that I have, although that's not my picture.

The motor has a ripped pull cord and I didn't try to trouble shoot it on the spot. I am looking to do some frame modifications to it so I can move the seat back a little for better fitment.

I am also looking to replace the motor with something from HF. I was looking at their 8 and 13 hp motors. Ideally I would want this thing to get up to about 50mph.

Please forgive my ignorance and general lack of knowledge. I am requesting information on gears, clutches and whether the 8hp HF predator will get me up to about 45-50 or will I need to go with the 13 hp monster?

Thanks in advance!

 

[KartFab]

I really like how this kart looks. The white/red/black really sets it apart from most. You can get to 50 mph even with the engine that's on it right now, looks like an old Tecumseh. A direct replacement (if you don't want to fix, which I think you should at least try). Would be the hf 212cc, expect about 28-33 mph with this engine size(assuming you want to be able to climb hills too, the higher you gear it the faster it will go, but it will have no bottom end/torque on start up. It will also take a long time to reach 50 mph. Starts will cause a lot of excess wear on the belt. Think of it like a stick shift car. Like trying to get going from stop in third gear..... it's possible, but lots of friction/slipping on the belt will be choppy starts.

If you go to 8-13 hp they typically have a 1" shaft and loads more torque, and would require a 40 series torque converter. You could expect a reasonable top speed of 40 mph with this setup.

Itsid can do some math for you, I'm just going off the top of my head on what works for low end torque and speed for engine size (with no modifications). How big are the tires? 18"? How many teeth does the axle sprocket have? Jackshaft sprocket?

Also another thing to consider if you really want to have a big engine is:
1)will it fit?
2) can I weld or pay someone to fabricate a new motor mount and weld it on there w/new Jackshaft assembly?

 

[95s52]

Thanks for the reply gran_pann!

I will tare into this thing over the week to see what I'm working with. I believe it's just as simple clutch with a gear that shares a chain with another gear. No torque converter in this set up. Harbor Freight is currently running a special on their 6.5hp motors for $99+tax, I will see what i can pick up the 8hp unit for. What clutch/gear and axle gear would I need to run to have the kart top out at ~50mph?

 

[2SlickNick]

Thanks for the reply gran_pann!

I will tare into this thing over the week to see what I'm working with. I believe it's just as simple clutch with a gear that shares a chain with another gear. No torque converter in this set up. Harbor Freight is currently running a special on their 6.5hp motors for $99+tax, I will see what i can pick up the 8hp unit for. What clutch/gear and axle gear would I need to run to have the kart top out at ~50mph?

Welcome!!
No torque converter? Weird....

 

[95s52]

Welcome!!
No torque converter? Weird....

I may be wrong!

Like I said, I'm a total rookie to carbonated anything and have never owned a kart, mower or anything of the like. I will take this thing apart over the week and look at what I'm dealing with. I'll post pics up as I go. I'm really tempted to pick up that HF $99 6.5hp special.

What mods can I do it to it pull an extra pony or two out of it?

Thanks fellas!

 

[Scout]

If you go into the engine and clutches forum there is a sticky on the 212 predator. Ive got one on my kart with no governor, and new intake and exhaust. It'll go 34 mph. For me to hit 40 I need to spin the motor over 6000rpm, and that means a rod and flywheel. So for about $500 I'll have about a ten hp motor.

 

[Poboy kartman]

Chain guard smells of aTC....Jest saying......

Welcome to the forum.....you won't be a rookie long...if you know how to ask questions. ...answer questions. ...and listen.......

It's that simple. ....although some never get it......

And knowing where you are and beigng able to look at pictures of the problem will seal the deal! !!!!

Edit!!!! OOPS...Yeah....thats just a chain guard.....no a TC....Kimmesabe....me get plenty confused for just a littlem bit!

Me try better....in the future....see...me know big white man words....like future.....by not know ...to say "I" instead of me....plenty big conumdrum for Tonto....Me may wind up with pyscololigical damage!!!

What you think Kimmesabe. ????

 

[95s52]

Thanks for the replies guys, I got a 6.5HP HF special getting shipped to my door, but in meanwhile, I decided to tear into this motor a bit. I removed the chain cover to find a dirty mess underneath.

Assuming the HF motor will bolt on to the existing mounts, what do I need to get for the HF motor to get the kart moving?

What are you guys using for clutches?

I'm thinking about tearing the new motor apart and upgrading it while it's dry. I found a website that sells mods for the motors. Is there a more popular go to site that most get their parts from? Is there a member vendor that's more convenient?

This is the parts website:

http://www.nrracing.com/category-s/1819.htm


take a screenshot

 

[OzFab]

Ok, you started off talking about 8-13hp engines & now you say you have a 6.5hp on the way; personally, I think you made a bad choice...

For starters, not once have you mentioned what engine is currently on the beast; if it's larger than a 6.5hp then you're going backwards...

What you have there is compound gearing; I could be wrong but, I'm almost positive that's not standard; IIRC, they came standard with a torque converter...

If you really want that thing to do 50mph, you'll need:
-a big block Predator (as you mentioned earlier)
-a series 40 torque converter
-mild engine mods

NR Racing is a popular site, not only for info but, for performance parts. there's just one exception to their upgrade list, heavy valve springs go in LAST, after the billet rod & flywheel! They also "mention" that

STOCK FLYWHEELS ARE UNSAFE!!!!
ANY MOTOR WITH GOVERNOR REMOVED SHOULD USE AN ALUMINUM FLYWHEEL.

which is not exactly true; the stock flywheel only becomes "unsafe" if you upgrade the valve springs. Left stock, the valve springs become the new governor, creating valve bounce at around 5000rpm but, in reality, the conrod will let go a long time before the flywheel does...

 

[landuse]

Just looking at your pic you posted, I would say that ypu have an engine larger than 6.5HP. Is there a reason you want to downgrade?

 

[Half-breeder]

I am requesting information on gears, clutches and whether the 8hp HF predator will get me up to about 45-50 or will I need to go with the 13 hp monster?

You can mod a 'clone'(HF212) to have 9-10hp for less than 100$... and if you do run a clone w/ a 3/4" shaft parts a 'can' be alil cheaper as far as clutches. I also recommend a TC/CVT to attain your desired 45~50mph.

Mine does 50mph w/ a modded GX200(clone originator), 16" wheels and a 5:1 gearing ratio on my TAV2.

 

[OzFab]

Uh, Tihm, that thing probably has 16s on the front; it's twice the size & probably twice the weight of your kart

 

[Half-breeder]

Uh, Tihm, that thing probably has 16s on the front; it's twice the size & probably twice the weight of your kart

hmm... mine is 61" from front axle to rear axle n a 40" axle.... not to sure bout twice the size,,, however w/ that roll cage and other stuff.... 'maybe' alil heavier than mine... i gotta do all the final measurements b4 i blab out bullogna.

and those look like 13s on the front and 15s on the rear.... just from my perspective...

 

[95s52]

Thanks for the insightful information gentlemen. I will take more pictures of my set up later today and update over the weekend.

The current motor on the kart says that it's a 6.5hp. It looks tired (thus the new motor) and has a ripped pull cord. I think the previous owner mentioned that it "might" get up to ~25mph.. I will still try to get it up and running, but won't be heartbroken if it doesn't turn over.

Is the gear compounding set up something I should ditch for a torque converter or I should stick with it hoping the higher reving predator will get me up to my desired speed goal.

Also, that brake set up does not look too efficient. Is anyone else running a similar friction type brake?

Thanks again for the comments,

I will keep this thing updated as I tare into the motor some.

 

[KartFab]

Torque converter will provide a much much bigger jump in performance/speed than pimping out your engine.

Also, the compound gearing looks legit/original to the kart.

So do want to hear some good/bad news?

Good: if you just slap on a TAV2 (bolt on style torque converter) your going to be going super fast

Bad: you won't have low end torque


Here's why. Your compound gearing has allowed the kart to have a smaller tooth count axle axle sprocket. If you keep that axle sprocket on there and just change out to a tav2, is already geared for speed because you won't be using the compound gearing, just the smaller axle sprocket. The smaller your axle sprocket, the faster you go, but you sacrifice acceleration/torque.

Make sense?

If I were you, I would focus on trying to remove the clutch while you wait for your new engine. When your new engine arrives, bolt it on and try it out and have fun the way the kart was meant to be with the compound gearing.

.... If you get bored... Adding a torque converter will run you $150-$220 and you may need to change the axle sprocket.... Which judging by the pic, may be a problem. A larger axle sprocket could hit the frame, or make the chain hit the frame.

 

[95s52]

Another kick a$$ reply!

I appreciate you taking the time to drop some knowledge on me. Why do you think I should take off this clutch? To install it on my new motor? How much does a clutch cost? I was budgeting on purchasing a new one for the preditor.

I will try to see if I can get this thing to run over the weekend. If not, I will remove the motor to prepare the chassis for the new one. Does anything other than the brake needs to be address while I'm in there?

Torque converter will provide a much much bigger jump in performance/speed than pimping out your engine.

Also, the compound gearing looks legit/original to the kart.

So do want to hear some good/bad news?

Good: if you just slap on a TAV2 (bolt on style torque converter) your going to be going super fast

Bad: you won't have low end torque


Here's why. Your compound gearing has allowed the kart to have a smaller tooth count axle axle sprocket. If you keep that axle sprocket on there and just change out to a tav2, is already geared for speed because you won't be using the compound gearing, just the smaller axle sprocket. The smaller your axle sprocket, the faster you go, but you sacrifice acceleration/torque.

Make sense?

If I were you, I would focus on trying to remove the clutch while you wait for your new engine. When your new engine arrives, bolt it on and try it out and have fun the way the kart was meant to be with the compound gearing.

.... If you get bored... Adding a torque converter will run you $150-$220 and you may need to change the axle sprocket.... Which judging by the pic, may be a problem. A larger axle sprocket could hit the frame, or make the chain hit the frame.

 

[95s52]

A little progress yesterday.


Took the roll bars off. Makes for easier entry as I'm a bit too big for the kart. I'n the future I will end up removing one of the cross bars to move the seat further back.






Here is my current dilemma. I have these compound gears. I want to get the current motor running just to mess around with it, but I have a 212 predator on standby (see boxed pic) to go it. What should I do about these gears? My speed goals at ~45mph. I also want decent acceleration/torque. So the questions is: do I stay with these gears or go to a torque converter? Please keep in mind that this is a budget build and I want a most simple and reliable set up.



I want a new clutch, clutch sprocket (sp) and chains. Any recommendations on where I should go to get those?




Here is the main culprit of why this motor is not starting. The pull rope ripped. Is there a kit that sold separate? I want to see if I can spend a few bucks to get this motor running before I throw the 212 in there.



Lastly, here is the throttle set up that's on the current motor, will I need to swap this over the the 212 or is there another set up that's typical that everyone uses on their HF motors?


Thanks in advance!

 

[Half-breeder]

IMO... Your gonna need a TC in order to get the frame up to 45mph. Depending on rear wheel size will determine what gear to get w/for the TC.

 

[OzFab]

Is the gear compounding set up something I should ditch for a torque converter or I should stick with it hoping the higher reving predator will get me up to my desired speed goal.

Here's the thing, the predator won't rev any higher than the existing engine (not without a few hundred dollars worth of parts thrown at it anyway), they're both governed @3600rpm...

Fixed gearing gives you one ratio; a TC is variable, starting at around 2.7:1 & topping out at 0.9:1 so, you get the best of both worlds &, as half-breeder stated, you can shorten the sprocket gears to get more top speed...

 

[95s52]

Here's the thing, the predator won't rev any higher than the existing engine (not without a few hundred dollars worth of parts thrown at it anyway), they're both governed @3600rpm...

Fixed gearing gives you one ratio; a TC is variable, starting at around 2.7:1 & topping out at 0.9:1 so, you get the best of both worlds &, as half-breeder stated, you can shorten the sprocket gears to get more top speed...

I plan on removing that pesky governer off the predator. That will make it rev to ~5500rpm(?)

What's a good torque converter under $150? I might have to use one after all..