I am new to karts, sorry for the noob question. I think my kart could use new parts as mine are pretty corroded and will therefor most likely eat up my new belt (even after sanding, they are pitted). I currently have a 7" driven, but have seen the 6" on sale, what difference would this make to the kart?
comet 30 7" vs 6"
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DCProductions
Cockney Ragamuffin
The kart would have less torque to the wheels and more speed. It would be equivalent to re-gearing the kart. I think the numbers are 1:2.7 for the 6" and 1:3.1 for the 7". If I'm not mistaken the 6" works better (has a larger ratio range) than the 7", but your kart will definitely act different if you go to the 6".
According to Dave at gopowersports "smaller driven pulley takes away a little on the low end and gives you a little more top speed", so you are in agreement, but in my mind that still seems backwards. Unless both pulleys change and not just the driven?
Either way, for a kart that my son and I drive for fun around a field, which do you guys recommend? The difference doesn't seem that big, and we have only small hills and bumpy land.
Either way, for a kart that my son and I drive for fun around a field, which do you guys recommend? The difference doesn't seem that big, and we have only small hills and bumpy land.
speedshopmike
New member
the larger driven will provide more pulling power/mechanical advantage.
the smaller will hurt acceleration but provide more top speed IF the motor has the power to pull the taller (numerically lower) gear.
you'll also need a shorter belt and/or slotting the motor plate to allow adding enough tension - you'll need to slide the motor ~3/4" away from the driven to use the same belt as now if you change to the 6".
the overall ratio range for the 6" is is 2.68:1 through .9:1 (10% overdriven).
the 7" gives 3.13:1 through 1.12:1 ratio spread (12% underdriven).
changing (accidentally; i stupidly didnt measure prior to ordering) from a 7 to a 6 on my cart notably reduced it's hill climbing ability and acceleration.
the smaller will hurt acceleration but provide more top speed IF the motor has the power to pull the taller (numerically lower) gear.
you'll also need a shorter belt and/or slotting the motor plate to allow adding enough tension - you'll need to slide the motor ~3/4" away from the driven to use the same belt as now if you change to the 6".
the overall ratio range for the 6" is is 2.68:1 through .9:1 (10% overdriven).
the 7" gives 3.13:1 through 1.12:1 ratio spread (12% underdriven).
changing (accidentally; i stupidly didnt measure prior to ordering) from a 7 to a 6 on my cart notably reduced it's hill climbing ability and acceleration.
I was asking as I found a kit on sale cheap, but it was 6" only.
So today I learned 2 things:
1) Stick with 7", thanks to lots of good information
2) Find a supplier that sells quality parts. After reading this forum and looking more closely, my great deal appears it might just be junk. Now to find a good 7" 30 somewhere...
So today I learned 2 things:
1) Stick with 7", thanks to lots of good information
2) Find a supplier that sells quality parts. After reading this forum and looking more closely, my great deal appears it might just be junk. Now to find a good 7" 30 somewhere...
genuine OEM Comet Dealer right here: http://www.mfgsupply.com/gomini/gom...iniclutchtorq30/gominiclutchtorq30driven.html
(they also sell belts by driven-size & center-distance)
(they also sell belts by driven-size & center-distance)
the only Comet "kit" would be the TAV2, or copycat, all come only with a 6" driven.
if you wanna stick with the 7" driven, the full solution is to pick out your parts and build your own kit...you prolly don't need everything, so how about you post a pic of your setup, and i bet someone can give advice on jackshafts and such.
if you want an easy way to retain your top-speed, just go with a TAV2 and get a smaller rear sprocket...i doubt you'll need all the low-end anyway...corrections encouraged.
if you wanna stick with the 7" driven, the full solution is to pick out your parts and build your own kit...you prolly don't need everything, so how about you post a pic of your setup, and i bet someone can give advice on jackshafts and such.
if you want an easy way to retain your top-speed, just go with a TAV2 and get a smaller rear sprocket...i doubt you'll need all the low-end anyway...corrections encouraged.
Either I missed half of your post or it got edited lol, so I will finish responding.
Everything runs and pulls fine, and I'm pretty sure it's all stock. I posted a pic in the noob thread of the kart itself, but when I take the thing apart again I will post pics of the guts and pulley faces. The faces are corroded and I'm worried that I won't be able to smooth them enough to keep from eating belts. How smooth do they need to be? The 'shoe driver assembly' actually looks a little beat up in one spot, maybe from the previous owner not lubricating? Other than that, after cleaning, lubing, replacing the belt (the one on it was less than 1/2" wide lol) and carb, it's a fun little ride!
Everything runs and pulls fine, and I'm pretty sure it's all stock. I posted a pic in the noob thread of the kart itself, but when I take the thing apart again I will post pics of the guts and pulley faces. The faces are corroded and I'm worried that I won't be able to smooth them enough to keep from eating belts. How smooth do they need to be? The 'shoe driver assembly' actually looks a little beat up in one spot, maybe from the previous owner not lubricating? Other than that, after cleaning, lubing, replacing the belt (the one on it was less than 1/2" wide lol) and carb, it's a fun little ride!
i was editing, i do that a lot...
well, the inner faces of the pulleys should ideally be smooth as the proverbial baby-bottom...as you say, you can go thru things step by step. mfgsupply also sells every individual part you might need to get your existing pulleys back in order.
well, the inner faces of the pulleys should ideally be smooth as the proverbial baby-bottom...as you say, you can go thru things step by step. mfgsupply also sells every individual part you might need to get your existing pulleys back in order.
speedshopmike
New member
i'm enormously pro-Buy American personally.
however, sometimes an import deal is too hard to pass up when money is tight.
pursuant to that, my new 6", which i bought from bmi karting, is presumably chinese, as it was only 30ish bucks.
i'm outta work so i took the gamble.
after setting up for correct belt tension, i have to admit it works exactly like it should and seems to made of better quality steel then my oem comet is made of (the inner sheave of my comet driven is quite soft/weak).
the china hub casting is nice, spring is quite stiff, cam ramps look good, etc.
in case yours is fubar and you're short on $, bmi sells their 7" for just over 60 bucks; cheapest one i've found and at least some of the money stays in america.
however, sometimes an import deal is too hard to pass up when money is tight.
pursuant to that, my new 6", which i bought from bmi karting, is presumably chinese, as it was only 30ish bucks.
i'm outta work so i took the gamble.
after setting up for correct belt tension, i have to admit it works exactly like it should and seems to made of better quality steel then my oem comet is made of (the inner sheave of my comet driven is quite soft/weak).
the china hub casting is nice, spring is quite stiff, cam ramps look good, etc.
in case yours is fubar and you're short on $, bmi sells their 7" for just over 60 bucks; cheapest one i've found and at least some of the money stays in america.
Ok, here are some pictures. Any comments/ advice appreciated! I am going to try to do some more sanding. As I feared the belt has frayed a bit just from a couple of laps around the yard.
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good post. you say it works correctly, and it seems to be coming apart ok for you...so beyond the rust/pitting, i don't see a problem.
i do, however, see a lot of "sanding" in your future...and i dunno if you'll be able to rejuvenate those surfaces or not. use emery cloth for your best results. someone more experienced will be able to say for sure if they can be saved.
you could buy only the replacement sheaves/faces, it'll cost $60-70 per pulley, plus your time...
i've recently bought (not TC parts) from BMI, fast & friendly service...and at least they're not being misleading about the pulleys being imported clones.
without having tried it myself, i don't think i'd recommend trying to mix genuine and clone parts...imo it's either completely repair those old ones with the proper parts, or snag complete new ones, either genuine or clone.
i do, however, see a lot of "sanding" in your future...and i dunno if you'll be able to rejuvenate those surfaces or not. use emery cloth for your best results. someone more experienced will be able to say for sure if they can be saved.
you could buy only the replacement sheaves/faces, it'll cost $60-70 per pulley, plus your time...
i've recently bought (not TC parts) from BMI, fast & friendly service...and at least they're not being misleading about the pulleys being imported clones.
without having tried it myself, i don't think i'd recommend trying to mix genuine and clone parts...imo it's either completely repair those old ones with the proper parts, or snag complete new ones, either genuine or clone.
I have the driving pulley (terminology...) pretty darn smooth. I sure wish I had a wheel for my air compressor at this point. How does one remove the driven pulley to get to the surfaces?
edit: I found the article on here that covers driven clutch maintenance. I will try spreading it apart to provide access as recommended.
edit: I found the article on here that covers driven clutch maintenance. I will try spreading it apart to provide access as recommended.
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speedshopmike
New member
the driven's held together by a snapring found under the retention bolt.
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