gearing using a 11tooth driver on 6.5hp clone engine 1/3 mile dirt track

RACERMIKE69$

New member
i need help with gearing we have to run 11 tooth driver on 1/3 mile track RR tires are 58" and LR 55.5" WE have tried 80, 73, 69 teeth on rear this is using a 6.5hp honda clone engine no governor and built for racing our karts weigh minimum of 500lbs we are new to this have little knowledge i have read the formulas for calculating this but do not understand also note while running the 80 tooth we were lapped twice because of being so slow using the 69 tooth it took all way to middle of the turn to hit the power band so we are just lost if anyone can help we would greatly appreciate it. thank you MIKE
 

RACERMIKE69$

New member
i need help with gearing we have to run 11 tooth driver on 1/3 mile track RR tires are 58" and LR 55.5" WE have tried 80, 73, 69 teeth on rear this is using a 6.5hp honda clone engine no governor and built for racing our karts weigh minimum of 500lbs we are new to this have little knowledge i have read the formulas for calculating this but do not understand also note while running the 80 tooth we were lapped twice because of being so slow using the 69 tooth it took all way to middle of the turn to hit the power band so we are just lost if anyone can help we would greatly appreciate it. thank you MIKE
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flattop1

Dawg 89
If you have too run the 11 tooth driver the 69 was too tall the 80 too steep .
Put the 73 on and tune from there , that big of a machine keeping the speed up would be a big factor .
Are the engines able to be modified ?
74 75 or 76 may be the ticket but the 73 should get it going .
 

RACERMIKE69$

New member
If you have too run the 11 tooth driver the 69 was too tall the 80 too steep .
Put the 73 on and tune from there , that big of a machine keeping the speed up would be a big factor .
Are the engines able to be modified ?
74 75 or 76 may be the ticket but the 73 should get it going .
Currently running race engines from dover power
 

flattop1

Dawg 89
Thats good but are there any rules pertaining to the engine because there is alot more that can be done .
I would run the 73 and try gears around that during the race or race nights however it works best .
Then maximize driving lines and driver improvement .
 

RACERMIKE69$

New member
Currently running race engines from dover power
Thats good but are there any rules pertaining to the engine because there is alot more that can be done .
I would run the 73 and try gears around that during the race or race nights however it works best .
Then maximize driving lines and driver improvement .
yes there are motor rules same as wka/nka. On gear is it possible with the two clone engines i need two different gears because of weight. First night we ran 80 on one kart and 78 on the other got lapped twice karts would not go very fast. 2nd week we ran a 69 on one kart and 71 this when both karts basically hit the power band halfway through the corner would take a lap to get up to speed i dont know enough experience to say the 80 and the 78 were to much gear im judging off sound of the engines. Is there any mathematical equation i can use to get the correct gear. Thank you for your help i do appreciate any. Mike
 
What information would you need i posted pics of both karts we are running having the same issues on both
When I ask there were no pictures, I see them now so everyone has to run an 11 front driver ? How many others are racing ?
Have you looked at there rear gear and compared gear to where teeth fill up the gear guard ? Is the clone per akra rule or stock ?
 

RACERMIKE69$

New member
When I ask there were no pictures, I see them now so everyone has to run an 11 front driver ? How many others are racing ?
Have you looked at there rear gear and compared gear to where teeth fill up the gear guard ? Is the clone per akra rule or stock ?
YES AKRA RULES THERE ARE ABOUT 4 OTHER RACERS i have been told the run 78 to 80 rear gear which we have tried with no luck.
 
I have NO idea the difference with that big of tires the effect it would have, Gearing just seems WAY off to me because I do know for a track that size with a Regular Kart chassis at 450 lb Super Heavy 17 / 65 gearing would turn that motor 6600 + RPM all day long, Yes I realize gearing will be different BUT an 11 / 73 AVG is far cry from that 17 / 65.
Are you positive there running 11 tooth sprocket ?
 

Bob Evans

Grumpy Old Admin
Staff member
With a 58" rollout on the right rear and an 11 tooth driver with a 69 tooth rear, 7000 rpm should give you around 60 mph.
IMO, that might be a stretch at 500 lb total weight, and I'd have to wonder if the motor could even turn 7000 at that weight.
On a 1/3 mile track, I'd imagine you would be after max mph since you should be wide open all the time, unless the turns are very tight paperclip style.
I would also expect slow acceleration at the start because of the speed that a 1/3 mile track would allow.
Just thinking out loud.
 

RACERMIKE69$

New member
I have NO idea the difference with that big of tires the effect it would have, Gearing just seems WAY off to me because I do know for a track that size with a Regular Kart chassis at 450 lb Super Heavy 17 / 65 gearing would turn that motor 6600 + RPM all day long, Yes I realize gearing will be different BUT an 11 / 73 AVG is far cry from that 17 / 65.
Are you positive there running 11 tooth sprocket ?
YES THE RULES there require an 11 tooth everyone else is well they have said are running 11 tooth with a 78 to 80 big gear but neither gear has worked for our karts they just walk off and leave us i just cant find the happy medium to atleast run on the same lap with our champ kart same engine half the weight we ran 16 driver and 69 big gear it only took us a couple weeks to figure gearing to run out front these other karts are just being a bear..
 
If indeed the others are that close on gearing and there motors are built to same specs, sounds like you have something bound up really bad hindering rolling resistance, or could be a clutch issue.
 

flattop1

Dawg 89
Initially you ran 80-73-69 .
Put a 77 on one and 78 on the other .
Then check your alignment and as stated the clucth may be slipping .
 
I think your just wasting track time focusing on just gearing If you got lapped TWICE on the 80 high 70's gearing is NOT going to make that much difference, you've already proved lower 70's is not the answer that tells me you have other issues you need to find, the only way it's Totally a gearing issue would be If the front driver is way off and you've confirmed that's not the case.
 

paulkish

Premium User
Put close to what ever gearing you figure the rest are using on each kart, a little bigger axle gear and "FORGET" for now about gearing.

You have two issues. The first is your clutches are not locking up and adjusted to engage properly and are probably by now both junk and in need of rebuilding. The second is both karts are setup so bad all your tires are fighting each other and the track for which way to make your kart go.

You also said nothing about having a tach on either kart. At this point throw on the gearing I mentioned, forget about gearing, buy a tach and change stuff driving and adjustments per what ever gives you the highest reading on your tack. Your at the beginners point which everyone on here has experienced. Don't even think about gearing until your maxing out on rpm from fixing everything else including gaining experience driving. Then when you see your rpm up take some gear off. The FIRST time you experience my rpm's are up, I took gear off and it's still up you will feel total satisfaction because the only result of what just happened IS YOU HAD TO BE GOING FASTER after taking gear off and obtaining the same rpm. After that it's an on going process. Fix stuff, get better and take gear off. Until then just THROW gear at it and make that number on the tach go up. ... :)
 
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