Projects (PROJECT) old skool twin-engine Rupp kart build...with a twist!

Thanks guys. I appreciate the encouragement.

I've been working on the exhaust while the work on the mounts was farmed out. Here's what I started with. A couple of U-bends, a couple of flanges, and the KX60 pipes. Thanks to George for making my 1st set of flanges. However, they were too thin and I burnt thru 'em. Sorry bro. But I am going to use them for shims behind the plate.



Wheeled off the coating and cut off the entry and exit pipes.



Checking clearance with my back. With my jacket hanging over the back of the seat, I don't have much room.



Started with the larger pipe right out of the motor.



To transition from the 1.5" pipe to the expansion chamber, I clamped a chunk of heavy-wall 1.5 tube into the bench vise and used a body hammer to massage the end of the chamber.



The more I monkeyed with it the better it got. More or less a perfect fit after a while.



Here's where it gets tricky. I don't have much more room off the back of the expansion chamber without hanging off the back of the kart too far.






I really want the silencers pointing straight back. I tried a couple of bends off the back of the chamber but it stuck out too far. What about the silencers right off the chamber? Look ok?

 

Thanks Rfaze. I thought about that. Probably won't be tuning while riding. Not really going to compete with this kart. However, I could always get a pair of those remote needle adjusters kart racers use.

 

just found this dang this is cool
if you were a kid in the 50's and 60's you got started 1 of 2 ways either with a kart like he is doing here
or with a soapbox car like I play with
if you need a axel fabbed up for this get a hold of my buddy Derek at
www.zero-error.com he is a fab shop for karts, derby cars, bob sleds,jr dragsters,
bar stools,and a whole bunch of other cool shit

 

Beautiful job, especially on the motor mounts /chain guard. About the exhaust... I know your not worried about optimum performance and the pipes aren't exactly matched to your engines but if you want to keep the length of the stingers on the end you can run them inside the chambers with just enough of a nubbin sticking out to mount your silencers to. According to Gordon Jennings book (2stroke tuners handbook) this inverted stinger didn't have any adverse effects on performance but had the side effect of substantially reducing the noise output. We did this on a Yamaha rd350 ice racer back in the day and it worked. Also your joint between the head pipe and the chamber should be a butt weld if you can manage it, so there is no part of the header pipe sticking in the chamber and the transisition is smooth as possible. Just a couple easy tips that should help make a little more power cause we all know "Horsepower is King! Paul

 

It's been so long since an update that I was afraid something might have happened. Welcome back.

 

Thanks bro. Just using a standard Azusa Flexpruf axle. But I checked out his website...I need his help on a rotor hub issue I have.

Thanks FF. That internal stinger idea makes sense. I have a removable silencer on the end, maybe I could insert a pipe inside from the end. I could then adjust it to the correct length. That headpipe goes into the chamber maybe an eighth of an inch. That closeup pic makes it seem big.

Sorry Wfo. Glad to be back in the garage tho!

 

Mine are 12X6.00-6 Chen Shing tube slicks. GKS doesn't list that size anymore. They have a tubeless one but I'm not sure if they're different.

BTW-Im running staggered sizes-5" fronts and 6" rears.

 

Need some help here. I bought this brake setup on eBay for the kart. It's a nice billet aluminum kit with two pistons, braided stainless line, and a cross-drilled rotor. However they were only available for 1 1/4" axles. The kits were a good deal, so I bought one thinking I could replace the hub with a 1" hub. However, they don't make 1" hubs with the 3-bolt pattern I need.



Can anyone suggest maybe a machined spacer or shim thats 1.25 OD and 1.00 ID? I've looked all over. Lemme know!



Thanks.

 

Watch how many RPMs you spin them . The rod will be the weak link and will fail when over reved .. Very nice fab work I really like the mounts .

Brian

 

hi,
even though to me you've hacked up a nice original vintage kart your build is well thought out and pretty neat.
had to say that i'm a moderator on a vintage racing kart site.

like brian said the motors you picked aren't really high rpm as the c-rod is weak.
regardless you should be able to get er going pretty good.

on your brake issue two ways to fix.
one just buy a different rotor with the correct 1" diameter that's the same size rotor.

two will be more up your alley.
go to this url

http://www.forum-auto.com/sport-auto/karting/sujet380714-175.htm

this is a french auto site with a vintage kart rebuild.
i don't read french but the pix tell the story.
about near the bottom there's a mod he does to fit a 1" axle into a 1 1/4 set of bearings.
basically he slotted a threaded pipe and fit it over the axle.
the same mod should work on your brake with a little thinking.
dave

 

What's the one inch hub look like, can you just re drill the rotor.

 

Thanks B. Let's hope they don't. If they do self-destruct, it'll be time for plan B. Twin Huskvarna concrete saw motors.

Thanks Dave. After sandblasting I discovered the frame was stretched 3" between the steering hoop and the front axle. It's subtle, but rules out any restoration value. Actually, it gives you just a little more legroom without looking out of place.

Checked out that French build-thanks! I see the pipe fitting but I also saw something that could work even better. He was using an Azusa Vari-hub. Remember the collar that goes over the axle?



I have one of those somewhere! I'm gonna see if that OD would work.

 

It's a 4 bolt hub. Not sure if I could re-drill the rotor...there's no meat in that area. Good idea tho.

 

Do you have room laterally? Can you machine an adaptor from four to three?

 

Yeah I do. In fact the axle has a split keyway...meaning the keyway runs halfway down the axle, then switches 180 degrees to the other side. Its at that switch where I need to place the rotor hub. An adapter would probably offset it just enough.

 

This is one of the coolest builds I have seen here! ....makes me want to build one with the kids

Sent from MrModelT's DROID device using the TJJ mobile app

 

Great thread! I'm just starting to tear into my '60 Simplex Challenger Mark II and it has some of the same issues.

I hope you can bring your kart out to the White Knuckle Scramble on June 29 and Sept. 14!

 

Awesome!

 

Your twin is cool but can it beat this quad motor laydown cart?

 

This thing has a great exhaust!

 

What a great project. Good work!

 

Thanks again for the encouragement! Time to make some progress.

Making a bracket to support the silencer. Wanna use the old tank support bracket cast into the block for support. Here's a template I made-any suggestions? Look goofy?





Of course I`d nip off the corner of that tank support. Lemme know what you'd do.

 

Silencer... as in an exhaust muffler, or intake silencer for a 2-stroke? I'd love to know what you're doing to quiet the intake.

 

Exhaust silencer (muffler). Just using an open element air filter.

 

Glad to see you back at it. I love this thing! Pauly

 

What happened to this thread? Any update?

 

Lost interest for a while. Still have everything. Thinking of getting back to it.

 

Sorry to hear.. I'll keep an eye on this thread so in the event you pick it back up I'll be glad to read along.