high tooth gear for Size 40 chain clutch

KMART014

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Are there gears with more teeth for the size 40 chain clutch? Im currently running 10t clutch and 54t axel sprocket. but i would like 14t clutch sprocket to go faster. Can I get a size 40 chain clutch with more than 10t? or buy a gear with more t?
 

Brianator

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Depending on several factors (weight of kart plus driver, rear tires outer diameter as measured and what engine your running) you may not want to go below the 5.4:1 ratio you have right now... a torque converter might be a better option for you to keep your low end torque but gain top end speed at the same time.

Please post pics and give us some background to best help you.
 

landuse

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Are there gears with more teeth for the size 40 chain clutch? Im currently running 10t clutch and 54t axel sprocket. but i would like 14t clutch sprocket to go faster. Can I get a size 40 chain clutch with more than 10t? or buy a gear with more t?

I'm sorry, but this is just a bad idea, no matter how small your tyres are.

You are already running 5.4:1 and now you want to go down to a 4.5:1 or 3.8:1?? Never going to happen without damaging your clutch. It will be like taking off in 3rd or fourth gear in a manual car. You will be incredibly sluggish and the clutch will slip and wear out real fast. You might eventually start going faster, but it will be at the expense of your clutch

Please post some more info and pics of your kart. It will be a lot easier for us to give you advice. With the information you gave us, we don't even know if it is a centrifugal clutch or a torque converter. Post the height of the tyres, weight of kart and rider, and maybe what terrain you are going to be riding on.

How fast are you going now?
 

KMART014

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I will post pics of my kart when I get home and explain a little more. However Im running a stage 1 212, I weigh about 243 and the frame was made specifically for me as a kid. I dont know exact weight however im guessing about 120 to 150 with engine and seat. my wheels/tires are about 7 to 8 inches top to bottom. and the kart tops out at 33/34 mph. its a street kart. I had a chinese torque converter on it but they didnt send the correct size bolt for the shaft. it ended up stripping the inside of the jack shaft. The TC kept flying off mid ride. I went back to clutch cause a TC wont bolt properly to the engine anymore. The kart runs good. I just want more top speed. I was thinkin about switching to a 420
 

itsid

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my wheels/tires are about 7 to 8 inches top to bottom. and the kart tops out at 33/34 mph. its a street kart.

yeah I call BS on that I'm afraid :(

here's why:

Are there gears with more teeth for the size 40 chain clutch? Im currently running 10t clutch and 54t axel sprocket.

a 54T #40 sprocket is 8.64" in diameter.. so bigger than your claimed wheels (and that is w/o the chain wrapped around)

and to go 33mph that wheels at that gear ratio would require
about 7.5k rpms (nope.. you don't ;))

Sooo a more realistic wheelsize is 12"

that would make the sprocket fit and require roughly 5k rpms (which is at least doable for your stage 1)

and with 400 lbs, that setup would want roundabout an 8:1 gear ratio
for the average yard kart clutch in order to not glaze over and burn in a matter of days.

So race clutch it will be I hope (Noram GE at least I'd say)

more likely IMHO.. even bigger wheels and less 'useable' rpms
which to me means in order to go faster you need a LOWER gear ratio instead
(yes that does help; if the engine struggles to reach more rpms, lower gearing means more torque AND speed at times)

a 14T clutch and 54T axle sprocket will surely not move at all
not with some massive improvement of your engines output power
and say a "GE Ultimate" or "Noram premier stinger" to prevent a burned clutch on day one.
(with a gear ratio that bad even those might kick you on day three though ;))

'sid

PS Sorry I need to ask.. are you younger than 17?
 

KMART014

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Im 32 but sheesh i just realized idk how to post pix. Im new to forums. How do i Post pix?
 

KMART014

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here she is
 

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mckutzy

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You are kinda at the limit of the capabilities of the machine... you might be able to make a 60t fit... But you mostlikely will have almost zero clearance.
At this point, youll need a jackshaft, or bigger tires to really change the ratio.

Off hand, did you totally remove the gov(inside and out) or just directly hook up the throttle to the gov arm???...
Also I see you have disabled the low oil sensor, but I dont see any kill switch. You can use the relay to make a kill by wiring inline to ground a momentary push button switch to ground, place anywhere convenient like on the wheel. easy one wire, kills instantly.

Other than that, it is a cool looking machine...
 

KMART014

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Man I was thinking of getting some larger rear tires.. I didnt disable to the oil sensor. I wired and put a kill switch in front of the kart. You cant see it from the pix. Right now my top end is 33/34 but I need more speed. Will a 420 make it faster? and what will a Jack Shaft do? AND Governor is still in the engine.
 

bob58o

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Bigger engines do not alone make anything faster. Bigger engines make more torque. More torque allows bigger tires and/or higher gears.

Small tires = more torque
Large tires = more speed
Short Gears = Low Gears = Higher Number Ratio (7.2 :1) = more torque
Tall Gears = High Gears = Lower Number Ratio (4.2 :1) = more speed
Higher engine RPM = more speed (regardless of tire size or gear ratio)

So if you slap a big engine on there with twice the HP, but don't change tire size or gear ratio, it is likely that you will go slower. The larger engine will probably turn less RPMs out of the box, so without changes you will go slower.

To go faster without changing tire size or gear ratio, you need more engine rpms.
To go faster without more engine rpms, you need taller tires or taller gears.
 

mckutzy

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First before you grenade the engine.... reset the throttle system the way it is stock or totally remove the gov inside and out... That way of bypassing the gov, will throw a rod soon enough.... Potentially through your head.... not good at all....

A jackshaft can be used to allow a different ratio by compounding ratio of a different set of sprockets to reduce the ratio to a lower number. say a 7,8,9,10:1 ect.... Change out what you need to accommodate the ratio, with out increasing the OD of the rear sprocket.

A big block wont necessarily make it faster, cause most of this is determined by the gear ratio...
Also a big block is a much physically larger engine, and doesnt fit in the small block footprint, Typically it will have a 1" shaft and clutches are really expensive compaired to the typical 3/4" bored verities.
 

KMART014

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Bigger engines do not alone make anything faster. Bigger engines make more torque. More torque allows bigger tires and/or higher gears.

Small tires = more torque
Large tires = more speed
Short Gears = Low Gears = Higher Number Ratio (7.2 :1) = more torque
Tall Gears = High Gears = Lower Number Ratio (4.2 :1) = more speed
Higher engine RPM = more speed (regardless of tire size or gear ratio)

So if you slap a big engine on there with twice the HP, but don't change tire size or gear ratio, it is likely that you will go slower. The larger engine will probably turn less RPMs out of the box, so without changes you will go slower.

To go faster without changing tire size or gear ratio, you need more engine rpms.
To go faster without more engine rpms, you need taller tires or taller gears.


Ok so my next steps are going to be getting some taller tires and removing the governor.
 

bob58o

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Don't go too large on the tires with 5.4 :1, nothing bigger than 15". Even with 15's, cheap clutches might not last long if you do a lot of low speed cruising (less than 15 mph) or stop and go often.

If the governor is not removed, do that first. See if top speed increases.

Putting larger tires on will only increase top speed if the engine has power left but is being limited by rpms. RPMs can be limited by the governor or by the valve springs. If you remove the governor and rpms increase from 3800 to 4200, then putting larger tires on will not further increase your max speed by much because the engine and gear ratio aren't putting enough torque to the street.

Now if you remove the governor and the max rpms (of the engine in the kart under load) increase from 3800 to 5200, I'd think about the larger tires. At around 5200 rpms, valve float becomes an issue. And if you are floating the valves, then the engine has more power to give - so increasing the tire size might help give you a higher top mph (even if the rpms are still limited by the valve springs).

5200 RPM
5.4 :1 Gear Ratio
15" Tires
=
43 MPH


5200 RPM
5.4 :1
13" Tires
=
37 mph


EDIT: ADDED:
Did we ever 100% verify the tire size (diameter) and the sprocket teeth counts?
4.10 x 3.5 - 6"? So like 12 - 13" right?

Assuming 12.5" Tires and 5.4 :1 gear ratio...
4900 RPM is around 33.7 mph.

So to start the Go Fast upgrades I'd first find out if...

1.) The governor is set to this RPM (4900ish)???
or
2.) The governor is non-functional and valve springs are worn to the point where valve float is occuring at 4900 RPM???
or
3.) The governor is non functional, the springs are good, but the engine isn't making enough power to push past 34 mph and 4900 rpm?
 
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