Safe rpm to run for my motor? And my TC is smoking? Plus other questions

Kaden02

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Close to the end of building my version of the spidercarts tarantula. I have the full chassis done (no body panels or floor yet) and all the mechanical is also done. At the point where I am driving it to make sure it all works good and like I want. Just finished with my final upgrade and that is a juggernaut on my basically brand new TC despite one or two run hours. The first time I used the whole stock TC and it worked fairly well just did not let the predator 212 rev past 4K so I put a juggernaut on to help that issue and also put a new green spring in instead of the stock red spring in the TC also. Took it out for a spin and does not go as fast as the stock TC did. Why is this? Gets to about 5500rpm on flat ground so it revs like I want it to. For reference I was hitting 45mph before now about 38mph using the same app.
Also noticed that when I whip the kart around and do a donut every now and then the engine will all the sudden loose all load and rev out and the tires will stop spinning. When I look back the TQ where I put the new spring in is smoking, what is causing this?
One more issue I have is oil coming out of the valve cover breather. I think this is my fault as I filled it about 20 ounces and not the recommended 16 ounces. Am I correct? I’m planning on just running it until it hopefully stops as it gets back down to the correct level.

The last question I have is what is a safe rpm for me to rev to considering the connecting rod is stock? s of now I’m keeping it under 5500 as I have a digital tac to help me keep track.

Predator 212 mods-
• Governor removed
• Low oil sensor and sensor inside engine removed
• Performance air intake
• Bigger carb jet
• Custom exhaust, no restriction
• Arc Billet flywheel
• 22lb valve springs
• 30 series TQ with Juggernaut and Green Spring

Go Kart-
60 feet of 1/8 wall 1x1 tube so far
18x10 in rear, 18x6.5 in front
6:1 ratio
I weigh 160 I’m guessing kart weighs 200 as it sits
Yes the engine is at a pretty large tilt but it somewhat flattens when I sit in itDF770FE6-033C-4B2A-A42F-BA57003A5EB6.jpeg7478858A-DF4F-4D9D-AB95-AA61FAFF4730.jpeg605A5686-AA47-4E55-AD99-648A58D08340.jpeg8F677FE1-E20A-43FC-A181-3BE24D476694.jpeg
 

madprofessor

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Loss of traction spinning a good donut relieves load on the TC, lets the front close up, the rear open up. Reapplying traction suddenly reverses that and snaps the belt tight again. Not sure what the clutch smoking is about, but this can certainly get a belt smoking.
Your extra oil is a good idea since the deleted the oil sensor leaves more space in the case. If the breather tube on the valve cover is dripping oil, you can do several things:
Track racers believe in the oil catch can, a kit you can find in various places online.
You can do the gravity return thing with a longer breather tube, and a simple inline adapter to make tube diameter larger. You have to strap it or brace it to breathe upright for a few inches, with a small filter at the end. Larger diameter reduces velocity of engine pulse, upright lets gravity drizzle it back down. NOTE: Some will decry that method for the fact that the breather fitting is on the outlet side of the flutter valve built into the valve cover. (Pulse for fuel pumps must come from other side.) If that's the case.....................
You can plug off the valve cover fitting, and install a breather fitting elsewhere on the engine. Do the catch can thing from there, or the gravity thing. Just be sure new fitting is high on the engine, and not in rod splash territory.
 

Snaker

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It seems like an awful lot of belt side gap at the drive pulley.

I searched the belt Yameige 669, not conclusive, but looks to be asymmetrical.
The drive pulley is, the rear has to be also.
Is that a 30 series?

I keep going to the drive chain in the first photo, some look like excessive gap between the roller and link?
Inspect the links close to be sure pins aren't pulling out.
 

madprofessor

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Rpm's with that billet flywheel and 22# springs can spin a billet rod to over 7K rpm's. Flywheel is safe there, stock cast iron flywheel could easily (and they have) be exploded by then, chunks thru the casing, and thru people.
It's the stock rod that's scary. I wouldn't even spin one past 5K rpm's. The little splash arm likes to break off, and then you lunch the motor. Billet rods come with a bearing set, stock doesn't have one. The ARC billet's splash arm is ground to a "scoop" instead of a "splash", and drilled thru to the rod bearing, keeping it always lubed. NOTE: Better oil "scoop" slings more oil around, including up into valve cover. A good thing, not bad one.
I don't ever do this myself, but another breather tube idea is to drill your intake adapter for a fitting, and connect your drippy breather tube right back into the intake the way the engine originally came.
 

Kaden02

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Loss of traction spinning a good donut relieves load on the TC, lets the front close up, the rear open up. Reapplying traction suddenly reverses that and snaps the belt tight again. Not sure what the clutch smoking is about, but this can certainly get a belt smoking.
Your extra oil is a good idea since the deleted the oil sensor leaves more space in the case. If the breather tube on the valve cover is dripping oil, you can do several things:
Track racers believe in the oil catch can, a kit you can find in various places online.
You can do the gravity return thing with a longer breather tube, and a simple inline adapter to make tube diameter larger. You have to strap it or brace it to breathe upright for a few inches, with a small filter at the end. Larger diameter reduces velocity of engine pulse, upright lets gravity drizzle it back down. NOTE: Some will decry that method for the fact that the breather fitting is on the outlet side of the flutter valve built into the valve cover. (Pulse for fuel pumps must come from other side.) If that's the case.....................
You can plug off the valve cover fitting, and install a breather fitting elsewhere on the engine. Do the catch can thing from there, or the gravity thing. Just be sure new fitting is high on the engine, and not in rod splash territory.
I figured traction may be the case as we have got some snow and I haven’t had it out before in the slick. It sounds from reading and looking that I would want to do an oil catch can. My question is when the oil goes in the catch can does it stay in there or keep filling up to where you have to drain it or put it back in the engine? I have never had any experience with catch cans.
 

Kaden02

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It seems like an awful lot of belt side gap at the drive pulley.

I searched the belt Yameige 669, not conclusive, but looks to be asymmetrical.
The drive pulley is, the rear has to be also.
Is that a 30 series?

I keep going to the drive chain in the first photo, some look like excessive gap between the roller and link?
Inspect the links close to be sure pins aren't pulling out.
The chain drive looks all good in person, the chain and sprocket and all is brand new and I haven’t had a problem with it yet.
Yes, it is a 30 series TQ. It has a 30 series pulley with the green spring and a go power sports juggernaut driver. The belt is slanted on one side and flag on the other and I have it positioned the correct way. I read somewhere that you should use a bigger belt with the juggernaut driver. How could I use a bigger belt though because the stock looks like it is tight on the pulley? And if I did what belt would I use?
 

Kaden02

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Rpm's with that billet flywheel and 22# springs can spin a billet rod to over 7K rpm's. Flywheel is safe there, stock cast iron flywheel could easily (and they have) be exploded by then, chunks thru the casing, and thru people.
It's the stock rod that's scary. I wouldn't even spin one past 5K rpm's. The little splash arm likes to break off, and then you lunch the motor. Billet rods come with a bearing set, stock doesn't have one. The ARC billet's splash arm is ground to a "scoop" instead of a "splash", and drilled thru to the rod bearing, keeping it always lubed. NOTE: Better oil "scoop" slings more oil around, including up into valve cover. A good thing, not bad one.
I don't ever do this myself, but another breather tube idea is to drill your intake adapter for a fitting, and connect your drippy breather tube right back into the intake the way the engine originally came.
I had in mind to get a billet connecting rod from arc in a little bit I just wanted to finish the kart all the way and drive it before I decided to up the rpm. I have a tach and it flashes red when I go above 5500 rpm with how I have the settings.
 

madprofessor

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Glad your chain drive looks good to you so far. Just want to harp on a subject again that's always bothered me.............
I utterly despise seeing an axle sprocket slid up inside a TC like that, and not just for the clearance/hitting issues. Yes that's a generally bad idea even on the surface. Barely clearing contact now means grinding things to death later when it goes into sand or debris. But mainly...........
That little output sprocket on the TC is likely a 12-tooth, at your 6:1 ratio is spinning a 72-tooth. Or a 10 spinning a 60, no matter. That extreme chain angle due to sprockets proximity means you're barely getting enough teeth on that 12 (or 10) to engage the chain to make it roll.
Sketch yourself a 6:1 picture with the circles as scale close together as your sprockets, and draw a line over the sprockets' edges like your chain. Divide the small circle into 12 (or 10) spikes. Sketch another just like that with a scale foot between sprockets, and count how many teeth are engaging on each.
When your chain eventually does skip, it'll be around the small sprocket. Don't need a sketch to see how fast only 12 or 10 teeth will wear down, and/or fold over, and/or etc.
Hmmmmm. You sure that chain didn't skip during one of those sudden loss of traction situations?
Before anybody chastises me about proper chain tension to avoid skipping, think about how tight you have to keep it with only 3-4 teeth biting. Chains too tight have destroyed more bearings than I can picture, that picture's making my head hurt.
 

Kaden02

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It is a 10 tooth with a 60 tooth sprocket like I stated at first. I have counted and it has 5 teeth grabbing with good contact and the chain is not overly tight at all and not to loose. I would love to move the engine back and trust me I’ve tried but with the gas tank still on there it is I can not move it more than a 1/2” back and then I can’t get the chain to line up properly. To the debri issue, I will be putting side panels and a floor on the front and rear section of the go kart so the likely hood of anything really grinding in there is very very little as it has a 1/4-3/8” gap on both side of the chain. I can assure you so far I have had to chain slipping because before I messed with the TC it was perfect and never lost grip even when I was spinning around. And I think there is no coincidence that I messed with the TC and now it is doing this. I am wondering what is happening there and I’m leaning towards what was said about the belt slipping and smoking. When I got and installed the new driver I thought that it looked like to much spacing but still ran it. I am trying to get in contact with GPS to see what they recommend but their offices are closed because they are blocked by snow🙄
 

Kaden02

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Looks like I did not state but yes it is a 10t 60t, also I meant “had no chain slipping” not “had to chain slipping”
 

madprofessor

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Surprised to read there's 5 teeth grabbing. Was referring more to how many have the rollers seated in the bottom of the valleys, as the partial engagements at beginning and end of rotation are the ones that fold teeth. Still, surprised a little.
Really smart to floor out the rear section of the kart, everything in that vein is a good thing. Floored 2/3 of my current kart's rear, but still struggling with how to floor out some of the center drive section, or maybe to just put an iron brace directly below chain. Kudos for you doing that.
A little envious of your ground clearance, we're both running 60-tooth rear, but mine's on tires only 12" tall.
 

Kaden02

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Went back out and actually got under the kart, looks to be 4 rollers solidly seated and two about halfway-three quarter way in. But if it becomes a problem and I do shred my chain and bearings I’ll have to throw the current gas tank out and mount a different one somewhere so I can move the engine way forward. I’m trying to floor and panel as much of my kart I can since it will be 90% in dirt, tall prairie grass, puddles etc...

Wow, how much clearance do you have between your sprocket and the ground? I have 4” but that still worries me and I’m trying to think of a way to make a guard so I don’t have to worry about slamming the sprocket into a rock. But other than the sprocket height I love this designs width and height at the front and middle. It sits 50” wide front and rear (I widened the whole cart frame 4” however) and 9” clearance in front frame to 12” in middle. Very good design I’d recommend it
 

madprofessor

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So far mine only has basic 4.10/3.50 x 6 tires on 6" split rims all the way around, with frame space built in for larger sizes. Don't know the 60-tooth sprocket clearance because of never measuring. Always planned on a 9" dual-sided guard (4-piece) on a hub. That's for the possibility of finding that I want to change from the 60 to a 72, and would still want it protected.
Just doing the math on 12" tall tires and a 9" guard says there's only 1.5" clearance for the guard at this time. Will likely swap all 4 out to use on next build (bare bones wheelie machine), get bigger stuff for this kart.
Note: The decision to use a hub was easy. That means a 2-piece split sprocket of any size can be swapped out in just minutes, 3 bolts per half. No sliding off wheels, bearings, anything to change. And the 4-piece guard changes the same way using the same bolts, for a pair of 2-piece sides. That effectively makes it also a chain guide. And strong enough to take some degree of a hit without folding, I just want more.
 

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Here's some various-stages pics of the small tires setup before final paint, beefier tierods, linkages, and such.
 

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Kaden02

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Here's some various-stages pics of the small tires setup before final paint, beefier tierods, linkages, and such.
I wish I would have done a two piece sprocket but I didn’t, hind sight 20/20... man those tires do look real small for your cart size, I would at least look into a 16” tall and at least 6.5” wide. Also, is that a purpose built design? Just wondering about the rear suspension, looks fairly complicated
 

madprofessor

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Short answer is yes, it's purpose built, my purpose. Works this way.............
I sit down and think long and hard about what I would have if I could just magically have anything at all I wanted.
Then I figure out how to build it.
This one's main purpose was to have everything I could dream up all at once on the same machine at the same time. Everything. And for it to be the only one in the world like it.
That means a frame that transforms from 12" frame clearance offroader to 3" clearance flattracker. Left drive steering for two-seater transforms to single-center drive. Race harnesses that convert from dual to center along with the steering, and dual gas and brake pedals to match. Dashboard full of everything, like Blaupunkt AM-FM, remote, w/bluetooth stereo, six red, white, and blue separate lighted toggles and five pushbuttons for it and head, tail, and brake lights, dual tone 105 db horns, a siren, charging system, dash main, etc., and a scared-passenger E-stop slapswitch. And 12 volt Cuervo Gold and O.J. dispensers to boot. Not to mention a padlocked steel cover for those two pushbuttons, for the open container law.
212 Predator 6.5 hp. hotrodded up to be a 7,200 rpm., 15+ hp. screaming demon-jizz pump.
Oh yeah, suspension...........Besides the Monroe 27" air shocks in the front, that rear is a............... cantilevered-coilover-nitrogen-filled-diminishing-resistance-design custom swingarm rear suspension. Whew!!! Mouthful. Would allow almost two feet of travel at rear bumper. I'll add a couple more early pics (been over a year, not done yet).
BTW: With your axle sprocket jammed up inside your TC like that, you've got at least a partial guard ten times stronger than mine.
 

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Kaden02

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Sounds like you have a street cruiser, track racer, off-roader, and yard kart all in one. That took a lot of thinking and time to design. Personally if I had it I would get a set of street tires and a set of big knobby off-road tires, and maybe beef up the tie rods a little up front. I used heim joints and dom tube for mine. I’m more of a purpose built person, as a kart does one thing great then everything decent. As mine is just to beat around, hopefully my next will be like a barracuda mk2. But I respect it that took a lot of time. I do have a question, how come you did not go with a bigger block such as a 301 or 420 for a bigger two seater kart? Also, i never thought about removing the stock tank and remounting it. I might have to do that so I can get the engine slid back more.
 

madprofessor

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Tank relocation: You can't tell it, but there's soft rubber cushions on all 3 of the factory mounting points where I built that angle iron bracing for it, don't want any fuel bouncing.
Stronger tierods: After snapping one of the 3/8" tierods before getting the whole kart off the patio, they're now made of 5/8" allthread slid inside of 1/2" EMT thinwall conduit, with a 5/8" rod coupling in the middle of each for adjustment. I know the math looks funny, but the 5/8" rod really does slide inside of the 1/2" EMT, perfect fit. Paul Bunyan strong.
Bigger block: Predator 212 hemi, Harbor Freight sale coupon, $99.95 plus tax. Even wasted another $50 for a full year warranty I didn't need. Wasted because you don't warranty exchange a motor that you have to remove your ARC rod and diyperformance cam and valve springs and top plate master kit and carb intake and jets and flywheel and hi-perf coil from, put originals back in, put the fuel tank back on, etc. for a hundred bucks worth of new stock motor. And that ARC rod is now mated to the crank of the bad motor, needs new bearings to be used again.
Bigger block is 3-4 times the purchase money, and the last 212 hemi I built into a an equally custom minibike death machine turned out so much scarier than even I had intended to make it (though only 12 hp.) that I got hooked on hotrodding. Hooked, addicted, possessed, junkie.
BTW: A junkyard piece of any vehicle with the vin on the piece, and the title it got junked with, the piece mounted onto kart frame anywhere, and I can street legalize the beast. Hmmm, have to make a license plate mount for it though...................
 

madprofessor

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Question: As I've never bought any drawn-over-mandrel tubing before, how much was the stuff you got, for what size and wall thickness?
Also, how much was that good looking gravity rain flapper on the exhaust?
Lastly, how did you get such a clean, almost nonexistent weld of that exhaust header to the flange, still having room to run the nuts?
 
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