Clutch erratic engagement? 420 with Series 40

[atholon]

Hi everyone,
I recently purchased a gokart from someone and it seemed to drive alright when I test drove it. I wasn't able to drive it for a bit after purchasing it and tried to move it by driving on some grass all of the sudden the belt started smoking. The Gokart is an old Crossfire150 with a PowerLand PD420E

I changed the belt and cleaned the pullies (including inside the sheaves) like I saw here and read the troubleshooting guide here but I'm getting erratic/jerky engagement. I've tried adjusting the yellow reverse wound spring position and it didn't do anything. I'm assuming I have to use the yellow reverse wound because of the driven placement. The pulley looks pretty aligned to me but may be a little off.

I'm seeing belt fragments mostly on the driven and wear on the left side of the belt (alignment problem?)

I would love any help I can get troubleshooting. I'm out of ideas. I purchased a cheap new driver (the troubleshooting guide seems to indicate erratic shifting is likely a bad driver) and driven and those should get here Monday. If that fixes it I'll get the nicer comet parts.

 

[Whitetrashrocker]

That 40 series need to have the fixed sides of bothe driver and driven on the same side. You need to flip one around and figure out how to realign it with spacers.
Other than that it looks nice and clean to me.
Perhaps someone else will see something I don't.

 

[atholon]

I'm a bit confused by your comment about one of the pullies being flipped. I'm seeing a similar configuration in the series 40 instructions (except both of mine are flipped).


This video shows the same configuration as mine but it uses a red spring.

I'm struggling to understand what the reverse wound yellow spring is for. I know it is supposed to give you more torque but it isn't clear what also has to change with the rest of your configuration. For example, when using the reverse wound spring do I also need to flip the pulley(s) horizontally?

I tried throwing the red spring in the driven pulley in the current configuration and it immediately locked the driven open.

 

[panchothedog]

The reverse wound spring is to keep the points of the cam on the front side of the plastic stops on the driven pully. Yours looks perfect. I have a 40 on one of my karts and my driver is turned around just like yours is. I feel funny saying this, but from a visual standpoint your setup looks spot on. You might try turning the driver around, can't hurt. Your could also install light weight rollers and heavier springs in the driver. That will raise the engagement rpm and drastically change the way the kart performs. You have to delete or bypass the governor though, because otherwise the engine won't spin fast enough to get the driven to open up and shift into the higher gear ratio. You said you have some new parts coming, hope that helps you out. Are you sure you have the right belt. Almost looks tight in the one picture ( hard to tell) . It should be somewhat loose and relaxed when the kart is not running.

 

[Whitetrashrocker]

Thay video is wrong. See how the belt moves sideways?
The moving sides should be on the same side of the belt.

The red and yellow springs are wound opposite of each other.
If you turn the driven around it will need the other spring to make it work correctly. It has to do with the direction of spin. It also will slide on the other side of the ramps.

Keep you driven the same and flip your driver. Then align the stationary sheaves.

Can you move the sprocket on the axle that will also help with alignment.

 

[atholon]

The only thing the spring affects is performance and where the cam sits? I wonder why the red locked open then. I had it sitting on the opposite side next to the button to the right

I'm not sure what weight rollers I have but I know the driver had red springs in it.

The belt measurement is a bit off... from what I was seeing the distance between centers of the pullies was 8 3/8" instead of the 8 3/16" or 8 5/8" listed in the chart for the belts. Not sure how I'd fix that except for by getting a new mounting plate. Looks like I have the 203785 for the 8 3/16" distance.

I can try flipping the driver and see what that does too...

 

[Whitetrashrocker]

Give a tooth count on your sprockets too. 6:1 is a target ratio. Too far off and it might be your problem with smoking the belt.
Also does everything spin freely? Don't have rusted axle bearing or something like that?

 

[atholon]

Flipping the driver outs it too close to the mount. Don't think I can move the sprocket much on the axel. On one side I'm limited by the brake rotor on the other side I'm limited by the engine mount.

From what I counted it looks like 38 tooth and 10 tooth in the sprockets.

I haven't been able to get it up in the air (don't have anything to lift it right now). Wheels seem to turn fine on a slight incline with it off.

 

[Denny]

WTR. His clutch alignment is perfect. 40 series are different than 30. From what I can see his gear ratio is way off. Can you give us a tooth count on your sprockets?

 

[atholon]

From what I can tell it is 38 and 10.

 

[Denny]

3.8:1 will fry belts in a hurry! It needs to be 6:1 which is a 60 tooth axle sprocket and a 10 tooth drive sprocket.

 

[Denny]

Now you know your problem. You need a 60 tooth axle sprocket! Also Use Only Genuine Comet Belts!

 

[atholon]

Looks like the chain size is 530. Not seeing many sprockets with that number of teeth. Do you usually just order from Azusa? They seem like the only place that has something for a 530.

Noticed the chain isn't sitting great on the sprocket too

 

[Denny]

I’ll bet your drive sprocket and chain is #40 and your axle sprocket is #530. That means you will need to replace your drive sprocket, chain and axle sprocket. What happens in a mismatch situation as yours is the chain gets chewed up by the wrong sprocket and wears funny the good sprocket. That chain doesn’t look real healthy to begin with so replacing it is a good idea anyways. And before you ask yes, #40 chain and sprockets or #420 is plenty strong and will work together.

 

[atholon]

Thanks. That's very helpful. I'll start looking for 40 or 420 sprockets. I was seeing a lot of stuff for 35 but that was for smaller 212 sized engines.

 

[Denny]

Glad I could help! I hate seeing people fail.

 

[panchothedog]

Denny nailed it. You have two different types ( pitches ) of sprockets. You have probably damaged the 10 tooth as well. Get a 60 for the axle, a new 10 for the drive, and a new chain, all in 420 pitch. Leave your clutches exactly like in your first post, and you will be ready to go. That picture of the chain on your sprocket in post #13 is absolutely HORRIBLE. No wonder it wasn't taking off smoothly.

 

[atholon]

Thanks. Just confirmed that the new driver didn't make a difference (figured I'd give it a shot before disassembling the axle).

Looks like a 60 tooth is going to put me really close the frame. It is 5 inches from the center of the axle and it looks like the sprocket is 9 3/4" so it would be 4.875" and then I've got the chain on top of that.

 

[panchothedog]

You could probably get by with a 56 tooth. With those 22" tall tires I don't think I would go any smaller. If that doesn't give you enough clearance, it might be time to get out the hacksaw and and do some modifications.

 

[atholon]

I'll try the 60 tooth tomorrow like you all suggested and see if it works. If not I'll go with a 57.

Thanks again!