Any Go Kart Gurus here? I have a need for more speed but can't get more!

[cabmandone]

Went to a shorter/tighter belt... no improvement in top end but a definite improvement in throttle response. Installing a 10 tooth sprocket on the jackshaft with the driven pulley to change final ratio to 8:1 to see if I can pull more RPM out of it. Will let everyone know how that all pans out. Might not happen till Sunday though. With rain tonight I have to get out deer hunting sometime tomorrow!

[asphaltgambler]

Let us know
...

[cabmandone]

Got delayed today. Between hunting and customers coming in I didn't get a chance to work on the kart. I found the sprocket side of the reverse gearbox was a bit loose but for the life of me I can't figure out how it comes off. I'm hoping to get the reverse gearbox off tomorrow and tightened up and then on with the 10t sprocket and a test ride. Will let everyone know how it goes if/when I get it all back together.

[cabmandone]

I think that about sums up my experience for the day.

I didn't consider the size of the 10T sprocket vs the 12T sprocket. The 12T was larger than the diameter of the jackshaft housing. The 10T is slightly smaller which means I need to have a spacer to give the chain room between the jackshaft housing and the sprocket itself or the chain will hit the jackshaft housing! I should have changed the sprocket on the rear jackshaft!!! Oh well... live and learn.

[cabmandone]

Yes! one more angry face than the last time. I put a 10 tooth sprocket that is centered on the hub on the front jackshaft, moved the rear sprocket over to align with the front, moved the driver pulley to the left to give clearance for the chain being moved left, aligned the driven pulley, took it out and ran it... still no joy when running in a field. I did slightly build RPM but still didn't approach 4000 rpm.. In the words of Jeremy Clarkson... POWA!
I need more power. I think the engine just doesn't have the power and torque to build RPM when out in a field.

[flipper35]

Have you checked the torque cam to make sure it isn't loose?

[cabmandone]

Originally Posted by flipper35

Have you checked the torque cam to make sure it isn't loose?

Not sure I'm following you.

[flipper35]

The torque cam on the other pulley. It lets the pulley system go to "top gear" then there is no torque on the drivetrain but when you are hard on the gas it lets the system go to a lower overall ratio.

Again, I am assuming this is similar to a CVT in a snowmobile or other machine and not a simple centrifugal clutch like the cheap rental karts that lock up immediately when you get on the gas.

[cabmandone]

Originally Posted by flipper35

The torque cam on the other pulley. It lets the pulley system go to "top gear" then there is no torque on the drivetrain but when you are hard on the gas it lets the system go to a lower overall ratio.

Again, I am assuming this is similar to a CVT in a snowmobile or other machine and not a simple centrifugal clutch like the cheap rental karts that lock up immediately when you get on the gas.

I follow you and yes, I have checked to make sure both the drive and driven are working as they should. The only thing I'm debating is trying to stiffen the spring to see if I can delay the driven going into full open or "overdrive" until higher in the rpm range.

[cabmandone]

Just to update: I found a Lifan 420CC with electric start at Home Depot for $299 delivered. They practically made me buy it! There are loads of power adders for this engine if I want to go that route but for now I'm going to leave it stock until I have put a few tanks of gas through for break in. It should be interesting to see what the gearing change does with this engine. I'm hoping I don't have to go back to the 14T sprocket on the driven due to a lack of top end... we shall see!

[sammyg2]

Originally Posted by cabmando

What got me on this quest was getting my ass handed to me by my friend on his two seater Helix 150CC. He has a vehicle weight advantage of about 200 pounds but that gets reduce slightly when you consider he goes about 275 and I weigh in at around 175.

My friend said he was going to have to put a horn on his "buggy" to get me out of the way so the faster Kart could get by. I can't have that nonsense going on!

Weight affects acceleration but not top speed so much.
It could take you longer to get to top speed but you should still top out faster.

Have you done a compression check?

Remember, 90% of all induction problems are ignition-related




Or was that the other way around ....

[cabmandone]

Originally Posted by sammyg2

Weight affects acceleration but not top speed so much.
It could take you longer to get to top speed but you should still top out faster.

Have you done a compression check?

Remember, 90% of all induction problems are ignition-related




Or was that the other way around ....

I think it boils down to I was getting as much as I possibly could out of my 9 hp engine. I just don't think it had enough oomph to overcome the friction and weight of the Kart. I picked up the 420CC engine hoping the additional HP and Torque will get me over the hump figuratively and literally.

[sammyg2]

Kool, sounds like a blast.

[nota]

Originally Posted by cabmando

Just to update: I found a Lifan 420CC with electric start at Home Depot for $299 delivered. They practically made me buy it! There are loads of power adders for this engine if I want to go that route but for now I'm going to leave it stock until I have put a few tanks of gas through for break in. It should be interesting to see what the gearing change does with this engine. I'm hoping I don't have to go back to the 14T sprocket on the driven due to a lack of top end... we shall see!

aka a honda clone [china direct copy of the honda]
so lots of aftermarket parts like valve springs rods cams to get MORE POWER
but doNOT over rev it stock 4k is the limit before mods
you can get them to live at 6k and make a lot more power
but that requires the springs rods ect