Mario Kart Update (aka DuroPower)

[snowjob]

Oooh, I didn't consider the motor movement for chain tension as it is also applicable to our kart. If we do support the exhaust off the motor vs the frame, that problem takes care of itself.

BTW, your kart is krazy ;-). I may have to take a closer look.

 

[madprofessor]

I'll attach a few pics of the kart, can't describe all the krazy in that thing, not even in pics.
See your mounting ears for your gas tank that was there? What I see is a couple of long bolts with their heads tacked to the exhaust under there, sticking up thru those elongated mounting ear holes. Rubber isolations against vibration, nutted in place above and below. Moves in place with the motor, no other metal contact.
Note: Pics are old, entire front end now changed, flag paints done, flamethrower in place, dual pedal sets done, etc.

 

[snowjob]

Tacked on the straight sections before the rear cones and welded up the seems on the cones. Since I got my 1/16 electrode and filler rod, I played with amperage and pulse while welding the cones and was pretty satisfied with the results without using any filler rod. I am surprised how much harder it is to weld once you start adding the filler. Definitely NOT like soldering or even brazing, much more precise taking lots more skill on this thin material.



My son routed the longer fuel line, finished the new throttle linkage and rotated the pull start so it is straight up.

 

[snowjob]

Oh, and unfortunately running it at the nearby track is out. They say anything other than an actual race kart is just too easy to tip. That leaves us to find a good spot for testing.

 

[madprofessor]

So what's their miff, Biff? How do they decide what an "actual race kart" is? Is it because the center of gravity's too high, and there's a max measurement allowed between butt and pavement to prevent "tipping"?

 

[Denny]

Their playground their rules.

 

[snowjob]

Yes, they asked what the ground clearance was and decided it was too high. They also indicated race carts have bumpers, spec tubing, etc. He did offer I take it over for a tech inspection, but guessed it would not pass. The track is about an hour away, so I don't like the idea of running it down there on a trailer (no truck at the moment) only to be turned away.

 

[snowjob]

As always happens with our projects, this has gone off the rails.....again. Wife got a new job, we decided to move, put house on market and son broke off the exhaust bolt in the head. A couple attempts to weld a nut to it have not worked. I was hoping we would have a window between selling and moving to finish this project, but now I am not so sure. Broken studs, bolts in heads are the bane of my existence!

 

[Denny]

Take it to the new house with the 5 acre yard.

 

[snowjob]

Funny you say that, we have discussed it. The housing market is so crazy right now, I have no idea what we will end up with. Sadly, the most promising prospect today is a custom built home in a golf estate with an HOA......definitely less go-kart friendly than even our current neighborhood. Though there are a few tracks in the nearby vacation town, so perhaps we could at least get permission to run it there.

 

[Denny]

Stay away from the HOA! The yard NAZIs will drive you crazy.

 

[madprofessor]

I second that HOA notion! Hidden Hills community's HOA tried to outdo Hidden Hills Country Club's HOA on the other side of the street, made my life miserable. In the end I had to scare them so bad that they'd go inside their houses if they saw me coming, that's no real community.

 

[snowjob]

It has been long in the works, but nearly done now....and very loud. More details to follow.

 

[Denny]

Looks like it turned out very well. I’ll bet it is loud with the 4 megaphones on it now.

 

[snowjob]

We were slowed down by a move and lack of workspace, but he had a trimester worth of small engine class that gave him time to "finish" it. It's not quite to the level I would do it, but considering it was supposed to be his project, he is happy with it and just wants to be done and move onto a full size car. I still bought the pieces for a custom tank and I am pretty sure the engine needs some tuning, so we'll see where it goes from here.

 

[madprofessor]

Very creative exhaust, snowjob. Didn't realize it was going to be all separated out like that. Are all 4 megaphones functional, or just the 2 on the bottom? If all 4, that's a slick splice attachment job for the top 2.
BTW, is that just regular paint? Very high temp header paint in rattlecans costs less than half-again of regular paint. Used flat black VHT on mine.

 

[snowjob]

The exhaust was all his idea. All four cones are functional. The splice is pretty rough, but I let him take the lead to keep it moving forward. He got a quick lesson that fab is nowhere near as simple as he thought.

I think he used VHT, but I'm not sure. It likely has 20-30m of runtime and no discoloration yet. I would have gone polished, but he was fine with painted.

 

[Denny]

You gotta give it to the kid I think he did a good job pulling it off.

 

[madprofessor]

That throttle linkage that's not hooked up to the throttle shaft on the carb, is it like that because of nothing being there to keep it from popping up and out with vibration? I've considered some kind of tab over one of mine (just one screw securing it to easily remove it) just for the added security of it, haven't tried to invent one yet. Got any plans for that on yours? Scratch that, got any easy ideas I could use for mine?

 

[madprofessor]

Just looked closer at your exhaust header, great job fitting that pipe in between the stud nuts. Is that 1" EMT tubing there and throughout the exhaust system? I know that 3/4" is a little small per my performance guy, so I struggled with fitting my 1" EMT with its big rough stick welds in between the nuts, had to grind away some weld.
Very nice and symmetrical 90 degree bends in the system, are those store-bought sweeps from the electrical parts aisle like I've used in places, or do you have a pipe bender that good?