Kart Klinic 32 Hot Rod

[firemanjim]

If you look at pic #4 of my last post, you see that there is still flat body sticking out from both sides of this part of the frame. Both of these tunes will be capped by 2" x .100" flat bar, bent to the v shape of the nose. On the outside of that tube, you see a long stretch of a1" strip of body, then it gets wider as it curves to the front. That gets filled in by a piece of 3x1" tube, bent to fit. One end gets a tapered cut to follow the body contour at the base of the running boards. The other end gets the famous curled tip with the cross bar. I have my templates drawn and cut out already, like I did to make the welding jig for the above frame parts. I will definitely use this base to build a jig for a complete chassis. I'm gonna make more of these. I had a lot of fun with it today. One of my neighbors came over today, to return my lawn mower. I was working on this chassis. After a few minutes of small talk, he tells me, " you know, I look over here at you with your little cars, and think, that man lives to stay young"... He said he sees the spring in my step as I work on "my little cars". My wife, upon returning from grocery shopping, found me after putting the chassis into the body for the first time. And it fits just right..... She said I was OBVIOUSLY in a good mood....
Speaking of my neighbor..... He brought me some fiberglass mat to fix the ding in the rear. Told me he has plenty of resin too, when I'm ready... Also said he has brand new in the box shocks for me, for free! He bought an engine at an auction and ended up with a big lot of auto parts with it. I just met the guy Friday night. He also gave me a lead on a new product supposed to be better than gel coat. He showed me a sample and it's hard as a rock,smooth as glass, sandable, printable, competitive priced,and best of all, it's put on with a brush. No need to buy expensive spray guns. And the company is about 10 minutes from me. He says they are really cool, and will teach me how use their products correctly. Cool.....
Well, it's a small start, but it's a start. Whatcha think? O below is a pic of a frame detail just to show the curved tip.... In case you don't know what I'm talking about....

 

[Poboy kartman]

Nice....

 

[JMINDY]

Nice start Jim!

The black 32 you pictured, although nice looking, is not a good reference... First, that 32 has been channeled over the frame or the front half of the frame has been re-arched, or both as the grill shell does not go that much below the frame rails.

Second, 32's have a straight spreader bar. Not a V shape.

Last, the frame rails (front curve) do not show on a full fender 32. The splash pan below the radiator and the front fenders hide the curve portion of (frame horns). Only on a fender-less 32 would you see the front half of the frame.

Your body has the splash pan molded in below the grill shell. I would just build some support behind the fenders and make a nice spreader bar that shows.

 

[firemanjim]

JMINDY, no, you are correct. They came with a straight spreader, (i prefer that V look) and that body is channeled.... The curved tip I was referring to is the frame, not that bar. And yes, I know that the frame isn't really visible, but I'm making it as close to appearance as I can. The frame will stick out just a hair, enough to put the spreader bar in front of the apron and fenders. That's my only bumper.
I'm glad I got you to keep my build in line. If you see me screwing up, say something... Trying to make it look legit.....
EDIT ps NICE rides!!

 

[JMINDY]

I figured you knew... just thought I throw it out there so there wasn't an Oh--Really? moment later. LOL

I like cars customized anyways!

As for you screwing up... nah, you know what you are doing!!

Interested in seeing how you work in a functioning rear suspension with an engine AND get the trunk lid still on. It looks tight on space. I know nothing on kart suspensions, so it will be interesting to see how it works out.

With an enclosed body, are you concern about how to get air to the engine? And keep it cool? That was one of my concerns on enclosing my engine on my sprint kart build.

Also, any ideas on how you will do a windshield? Windshield is not necessary for a kart, but it is an important look for a 32 roaster. It would be a crazy amount to fab, but I've always liked the look of a Duvall on a deuce roaster... just a thought.

 

[firemanjim]

I was looking at the Duvall last night! An aluminum golf cart chassis custom built.... I've been searching images for months. It's how I get my ideas, mix and match what I like.... If I attempt the windshield for the build, it will be aluminum flat stock with 1/2" aluminum angle. That's how I framed out the windshield for the H3,then cut a piece of plexiglass..... It will be a chopped screen most likely. Idunno.....
Tight space? You bet your asterisk it is! The engine is 16"+ ... The body has an internal height of 18". I'm using 2" tube.... My math skills better sharpen up real quick or this might get hairy.... The engine will be ON the pivot for minimal movement. The swing arm will have a stopped to limited the upward travel to just before tire to body impact. I'm only wanting enough suspension to take out a sudden pot hole, just a couple inches. It should all fit, of course , I've been doing all my measuring upside down the whole time.....

 

[JMINDY]

Have not seen much of the swing arm with pivot engine, the thread with the wheel hop issues is all that comes to mind.

Well, may I remove my foot from my mouth long enough to shove my other foot in...and threw this up for suggestion. This may have been done before (or common), my kart experience is very, very short live.

Have you seen how a Jag rear suspension works? I'm sure you have... what if you replaced the differential with a fix axle & sprocket? Something like this crude drawing...

Won't this work well in your kart? You have a live axle. Engine is in a fixed location. Brake can be mounted to the fixed axle. You would need 4 housed bearings and u-joints for the axles. Maybe bearings in the lower a-arm? Rest is made from square tubing. It can be simplified down to basics.

For a reference, here is a pic of the Jag suspension in my Cadillac...

 

[firemanjim]

How come we don't have a "you hit the nail on the head!" emoticon? That first image is how the big boy version is gonna be set up. It's the only way I can squeeze a crf450r into it and have a decent ride to handle the power. Was gonna use joints from surplus center....
For this, I'm gonna build a swing arm, and at the pivot end, the engine will sit in a cradle,on a perch OVER the pivot. That will do 2 things for me. Limits the amount the engine will move and gives me a "stopper" for my suspension travel. I'll put a rubber snubber under it, with a heavy coil between them to slow the blow.... Gonna work on that when I get there. I'm gonna focus on the front half (keeping the rear in mind) first. I need to be able to flip the body over on the frame so I can get better measurements and see what's gonna work best.
As far as cooling goes, it should get plenty of fresh air through the cockpit. When I get to the point that I put in an interior, I'll put fresh air ducts in and "blend" them in to the interior.... roflol: yeah, ok..... )

 

[firemanjim]

Engine needs 17"+ room from top to bottom. (internal measurement ) There is only 16 1/4" from the body to the BOTTOM of the frame. I forgot I used 2x1 so I lost an inch...mounting the engine in a cradle that is the swingarm is gonna drive me nuts....

 

[JMINDY]

mounting the engine in a cradle that is the swingarm is gonna drive me nuts....

I haven't really figured out exactly how your set up will be...

My theory on setting it up like a Jag rear was that the center section (center axle - sprocket - brakes) and the Engine with clutch would be hard mounted to the frame. (blue-center section, red-sprocket)

The only moving suspension parts are the outside axles (black line) - lower a-arms (green) - hubs/wheels(purple).

Perhaps this would give you more flexibility in placing the engine - forwards, backwards, high or low in relation of the center axle section, thus giving you more clearance for the body...

EDIT: I sent you a PM...

 

[firemanjim]

This is what's going through my head at the moment. Built from 1x2 and the OEM engine cradle,the swingarm will have 2 coil over shocks rated for 125# each. 2" stroke,that's perfect for my needs.....
OK ,back to work... I'm pulling the engine tonight so I can post pics of the frame/body right side up and with the engine so you get a better idea of how tight my workspace is.....

 

[itsid]

the swingarm will have not mut of a travel util the engine knocks on your seat

engine on the swingarm... for the benefit of an easier chain routing... IDK
this will be a great built as far as I can tell so far;
so I'd add a bit of comfort and take the jackshaft chain reroute to reduce the unsuspended mass.

but that's just me.

'sid

 

[firemanjim]

Sid, there is NO room in there.... The big boy version is getting a drive line like what jmindy drew up. It was easy to get that figured out. That kart too, will get the engine mounted in a lower than frame position like this build, but will be stationary.
For this kart, the engine has to be on the swing arm because of space. The engine will be REALLY close to the axle. And I only wanted about 2"-3" of travel. The engine should move that much being that it's on the short end of the arc of travel.
I just realized I need more than 250# of spring.... I'll sort that out shortly. Do you not think this will work well? Point out the flaws now, not after I put it together....

 

[itsid]

well unsuspended mass is best as close to the pivot as possible, that much is true

I'm not a fan of the 90° angles too much, it's just my guts though.. stress points pushing the lower and pulling the upper angle apart unnecessarily
So personally I'd sy a straight swingarm pivoted UNDER the main frame might end up being the stiffer option.. (again just my guts talking here )

still you can lower a frame-fixed motormount to the very same position as it would be ON the swingarm, but appart from the swingarm, which would basically end up being nothing but two individual swingarms that are connected at the rear end
although I must admit.. that'd be tricky to route the chain properly.
*shrugs*

I think I need to take a nap prior final judgement

'sid

 

[firemanjim]

Dam Germans....... You just gave me an idea. You're real good for that, among other things...
Don't think about it to hard. Wait till tomorrow when I post up pics of the kart with the engine...... For a visual..... Besides.....

 

[JMINDY]

Ok I see where you are going... It is different than what I mocked up. Your engine is mounted on the swing arm, although never changing in relation to the rear axle, it will be in constent flux as the suspension travels. That may work, IDK. Some things I would be concern about is A) I think it would be hard, even at a non-moving setting position, to get the resting position of the swing arm, and thus the engine, to be at a level position. Plus, the engine will also change levels as the swing arm travels up and down while the kart is in motion. Will these non parallel levels affect the performance of the engine? ie. oil & fuel,etc.? And B) With the engine on the swing arm, you have to accommodate for space inside the body for the engine to move, ie back of seat, top & sides of body. Which is already a tight space. And C) any issues with limiting travel and stress of the swing arm.

What I mocked up, like Sid mention above, is two swing arms mounted to a fix rear end, or in this case a short fixed axle and sprocket. The engine is mounted to a fixed position and does not travel with the suspension. So after it is mounted you will not have additional space issues, nor any potential performance issues.

I'm not saying your design won't work, it may work really well (and I don't mind being proven wrong). I just think a "Jag Style" seems less troublesome with your kart body, although more fab work and probably a little more expense.

 

[firemanjim]

J, I already have that type set up designed for the big boy version of this kart. Vw style training arms, tapered bearings on 2 sides of a cnc'ed custom hub, 20hp joints from surplus center, and a home built "spool".....
I actually WANT a swing arm on this one. I plan to build more "kiddie" versions so want to get this right. Tonight, when I get home, I'm gonna put the kart up on my table,with it sitting at expected height. This way, I can get a better idea how much room I really have. I decided on a solid engine mount, with it being set at 4" of it sitting below the frame. The swing arm pivots will be in line with the output shaft, hopefully eliminating any chain tension issues... (chain should never encounter any slack) I'm still using a short swingarm. I only want/need a couple inches of suspension travel, so it's not so rough a ride. With 2" travel shocks, placed correctly, I can get 3" of travel. More than plenty. I'm pretty sure I got it sorted out now, and can push forward. I pulled the engine last night, and tested the starter.... . Being able to get in and start my kart at the press of a button is gonna be sweet!!
More pics , tonight.....

 

[firemanjim]

Not sure if the pics are working....
OK yep they're working.... The engine is hung,on 2 of the 4 mounts I'm gonna use. Nice fit.... I should have taken pics of the upper mounts before welding,because it would show you how I cut them to ensure they were even when welded.... O well,next time.
If you notice,the frame is upside down.... DOHHH!! Its OK, that bar has to come out and gets pushed back 4".... I'll flip it then, I just wanted to hang the engine..... Its a littltle progress. Don't worry,it will be done.

 

[firemanjim]

Tonight, the plan is to take that tube out and trim the ends so it will fit 4" further forward. (and flip it...) While the tube is out, I'm going to cut 2 short pieces of tube to make the sides of the "engine bay". The rear engine mount will attach to these tunes. The top mount will tie into the chassis hoop behind the drivers area. The hoop will go up from one side,and follow the body line between trunk and cockpit,back to the other side. That will get braces running around the cockpit,and tie into the front of the chassis,up near the front.
Once I get the sides done, and tack the tube back into the chassis, it will get braced as well,laterally. Actually, I take that back. The sides will get tacked into place. I'll take my measurements for the pivot location, then I'll remove the to drill the holes for the round tube that the rod ends will bolt up to. I'm going to drill the holes at work, using the mill,so I know everything lines up perfect....
More later.... Feel free to comment or ask questions,I'm at work and kinda bored.....

 

[itsid]

Nice.. frame fixed engine.. less unsprung mass

'sid