Twin Arachnids Build

[ArachnidBrosMN]

Greetings to the Arachnid (maybe Ah-crap-nid) builders out there on DIY. In December, before discovering this website, my brother and I decided to make two matching go-karts. We decided on a project that would be be challenging for a couple of guys with a new MIG setup. Glad we found these forums. Here's where we are so far: got the welder dialed-in, shield gas: good idea. Welded both main frames and sub frames, discovered we needed a longer kart... we are 28, not 8yrs old. Added 10" to the front of the karts, and 10" to the rears. Bought 2 16hp clones. Used pillow mount greaseable bearings instead of cheaper ones called for on rear end. Using a forward, neutral and reverse transmission for each (comet) Also sing a Comet 40 CVT system. "Planning" on using a 10T sprocket off transmission to a 54T on our 1.25" live axel. With 25" tires on rear... top speed "should" be 48mph. Engines are de-governed. They were "cheap" at $299 apiece... so if we wear them out year 1, we'll have to get something nicer. We will try and post as we go. Our next major step is to create the front "box" with A-arms... scared

 

[ArachnidBrosMN]

A few more

Just a few more jpgs.

 

[souperman000]

Welcome to the forum!

Your builds are looking good

 

[landuse]

Welcome! Your karts are looking great so far. From all I have read about the plans provided for these karts, you might have a few problems. There have been quite a few members on here who have build them. Here are some really good threads to read. They will give you loads of ideas and help you with all the problems encountered on the plans

http://www.diygokarts.com/vb/showthread.php?t=8493&highlight=arachnid
http://www.diygokarts.com/vb/showthread.php?t=9463&highlight=arachnid
http://www.diygokarts.com/vb/showthread.php?t=8615&highlight=arachnid
http://www.diygokarts.com/vb/showthread.php?t=8537&highlight=arachnid

Post up as many pics of the build as you can. We like seeing what other members are doing

 

[qtband]

That is looking good! What kinds of transmission are you using?

 

[ArachnidBrosMN2]

Hey all,

Brother Number 2 here. Here are a couple of pics of the engines while removing the governors. Should make a nice added power bonus as long as our feet have throttle control

 

[ArachnidBrosMN]

Here are the transmissions:

NOTE: They are rated for "up to 16hp" (which is what we happen to be using).
We are putting the best gear oil we can find in them (synthetic)... then we will run the hell out of 'em!

http://www.bmikarts.com/item/Comet-Forward--Reverse-Gearbox-800350-3191

 

[B.M.800]

Looks like a good time! Nice builds.

 

[ArachnidBrosMN]

End of March Update

Ok... we're still alive here in MN. I "think" we just had a winter. Anyway... a couple of pics... making double of everything makes me think of Henry Ford and his "fun" assembly-line idea.

 

[B.M.800]

Ok... we're still alive here in MN.

Well thats good!

 

[chris_the_poser]

Well you guys got what looks to be a great start keep up the good work. My only concern so far is that the comet transmissions are rated for 3600 or so I thought. Will they work with your ungoverned engines? I'm really curious to find out if so I might consider buying one for an upcoming project

 

[r_chez_08]

Sweet builds guys!
Those comet gearboxes are up to 4000 rpm.
I wouldn't worry for 2 reasons:
1. The comet 40 tries to keep the load on the engine reasonably constant, and will probably keep the rpm under 4k most of the time
2. Comet under rate most of their products, and let's be honest, for $245 they should be able to take whatever a go kart can throw at them.

Just make sure the gears are kept lubed. With the governor removed you can probably get to 5000 -5500rpm with the right gearing.

 

[Bluethunder3320]

the torque converter is a gear ratio. so its not putting 1:1 into that gearbox, right? it will be turning less than the engine.

i wouldnt worry about it.

 

[ArachnidBrosMN]

Thanks for the reassurance on the transmissions. Honestly, I was a bit worried that we were pushing the limit on them!

WOW...5,000+rpms! I'm convinced now that we have the karts geared too high... we're probably going to need a 60T or bigger axel-sprocket... but there's only one way to find out!

ALSO: after much deliberation and scratching of heads today, we have decided to take the A-arm pieces to a machine shop and have THEM cut a 68 degree angle..sixteen times. As usual, my compound chop-saw only goes to 45 degrees. We considered cutting the angles with a reciprocating saw by hand... ha... riiiight.

My brother ordered two 40 drivers, and two 40 drivens last Friday! YEAH BABY.

Oh, and the converters do actually reach 1:1 and so the transmission WILL spin as fast as the engine shaft.

 

[r_chez_08]

5k+ is possible, however be careful! The connecting rod and flywheel seem to be the weak link in these engines.

 

[ArachnidBrosMN]

5k+ is possible, however be careful! The connecting rod and flywheel seem to be the weak link in these engines.

Hahaha!

"Marty, if my calculations are correct, when this baby hits 88 miles per hour... you're gonna see some SERIOUS "

 

[r_chez_08]

You may want to gear down a bit. You could get a 60t for the rear, and 9t from the gearbox.
40mph @3600rpm,
50mph @4500rpm

 

[chris_the_poser]

Sorry to cause concern I just didn't know how many rpm the gear box could take

 

[ArachnidBrosMN]

You may want to gear down a bit. You could get a 60t for the rear, and 9t from the gearbox.
40mph @3600rpm,
50mph @4500rpm

Thanks for the ideas... I looked at a nine-tooth, but the shaft coming out of the transmission is 3/4"dia (which is 19mm) The smallest sprocket I can find for a 3/4" shaft is 12 tooth.

We will most likely be getting a bigger back sprocket.... I'm going to return the 54t right away... I don't want to waste chain links.... I'll keep you posted.

 

[r_chez_08]

Yeah, bigger sprocket is a good idea.
I have that exact 9t sprocket, and drilled out the I/D to 3/4", and put a little key slot in it. I put the key slot in on a lathe, but if you do not have access to the correct tools, I doubt the machine shop would charge you much.
Or you could carefully weld it to a keyed hub or locking collar. It's certaintly an option if you want a lower gear ratio.