Sno-Kart 440 build...

[sno-kart]

Thanks Mysteryboy. We may do something like what you suggested, but since this is a race kart with no suspension, we want it to have some flex, which is why it has the hourglass shape to begin with. What we did for the butt welds is we reinforced it with 1/8" plate on top and bottom to add some strength there. We will test it out soon enough and if we see it bowing excessively, we'll definitely take your advice and put in some more tubing.

 

[sno-kart]

Exhaust

Today, we spent the entire day (almost 10 hours) designing and building our exhaust system. The snowmobile the engine came from had two separate exhaust pipes so we needed to build a 2-into-1 header. For that, we got a 1.75" J-pipe from Summit Racing and cut it to make two 90 degree bends. then we welded extensions onto that, removed the tubing from the existing flanges, and built our custom header. We are extremely happy with it considering it was our first attempt at something like this. Then, we took the fittings from the old exhaust and welded them in between our header and one of the two snowmobile expansion chambers. This required an exhaust adapter as well. Lots of cutting and welding today, but it all paid off. It fits great, and by using the fittings from the old exhaust (it's almost like a ball and socket joint), we will have flex in our exhaust system (the tabs are where the springs will go).

Now we just need to build some brackets/mounts to hold the exhaust in place, while still ensuring it can flex. Any suggestions for how to do this based on the pictures? I often see springs around an expansion chamber/muffler. What is the purpose of that? Thanks for looking!

 

[gixxerkart]

The silencer? It might have had a super trapp muffler. Those use bolts and springs to silence the noise. Not needed at all lol.

 

[gixxerkart]

Btw, great job on that exhaust. Looks amazing for uncharted waters.

 

[mysteryboy28]

yes, very pretty!

 

[landuse]

I like your welds. Nice job

 

[sno-kart]

Thanks guys! We will be doing some more work on the kart later this week so I'll post updates then. 2 row Mini Cooper radiator is on the way so that will be a project (hopefully it'll be enough cooling). Also need to hook up throttle/brake controls and do all the wiring. It's getting there.

Also, thanks to the exhaust set up we have, in case the kart steers like a cruise liner, we can always take about 8" out of the frame and shorten the wheelbase

 

[Doc Sprocket]

That header looks dynamite!

 

[sno-kart]

Thanks! will look even better once its polished and the rest of the exhaust (which is hideous right now) is painted.

 

[mysteryboy28]

make a header for me? lol.

 

[exenos]

You know, something like that wouldn't be half bad for the rotax mysteryboy as long as it met in the middle before heading off to the side. The extra length would even help make up a bit for that chunk you cut out of the pipe.

 

[sno-kart]

Update: almost there...

It has felt like we are almost done for too long now! All the little things at the end take longer than ya think.

We got a few more things knocked out:

- exhaust
- ignition panel
- brake linkage
- throttle pedal and stopper
- front subframe extension (bumper)
- radiator and fan
- gauge cluster

Now we are trying to decide if we need a chain tensioner or if we can get away without one and then we will really just need to make a battery bracket, wire the thing up, align and bolt everything down, and take her for a spin =)

 

[exenos]

Looking good!

 

[Doc Sprocket]

Lovin' the engine. If I squint a bit- it's a classic flathead Ford with an Offenhauser head, and a bad@$$ open header hangin' out over the front wheels... *drool*

 

[rwd4evr]

very nice work. should be a scary fast ride. the one issue i see in the front end geometry is yo have no kingpin inclination(KPI). you want the axle stubs level with the ground but the kingpins leaning in towards each other. i cant see if you have any castor either.

and the springs you see around expansion chambers are usually the hold downs. the pipe sits in a cradle under it and the springs hold it in.

 

[sno-kart]

rwd4evr - you're absolutely right about the front end geometry. My friend had a set of those spindles and brackets so we mounted them just like that but are pretty concerned about handling. You think with the geometry as it is (all right angles), it will steer like a boat?

 

[rwd4evr]

i'm not sure, but it may want to oscillate without caster. castor makes a big difference in high speed stability. i would really look into some race kart spindles with brakes if possible. that thing is gonna moooove and rear brakes only do so much. hope you got a nice smooth open space (or track) to rip on.

 

[rwd4evr]

so hows the steering working?

 

[sno-kart]

I wish we knew, but we unfortunately haven't tested it just yet. Haven't had much time to work on it and been sick as a dog lately with a cold/allergies/bronchitis... so annoying. We plan to fire up the engine in the chassis later this week and ensure that the drivetrain is working properly. Problem there is that we are only seeing about 90 psi of compression on each cylinder after doing the top end rebuild (including new pistons/rings). We haven't started the motor since the rebuild so some of it is due to that, but 90 psi is really quite low considering this motor should have around 130 psi. We'll see... updates to come soon.

 

[mysteryboy28]

did you hone the cylinder walls? did you go with bigger pistons? curious why you replaced the pistons.