Front engine 212 kart build - first real kart

[Kentucky Boy]

Is the exhaust going to pump directly into your lungs?

 

[TeamCheap]

Interesting project.
I think if you do the chain correctly it will work fine, I've seen hill climb dirt bikes with extended swing arms with long chains do just fine with massive horsepower.

Personally I'd go with the engine mounted dead center with the shaft facing the rear then clutch-chain-driven sprocket (covered with a safety shroud) to a drive shaft going back to a coupling then to a 1:1 right angle gearbox then do your final gear ratio to a live axle.
I'm thinking "mini AC cobra" style.

when you sit on a snowmobile your feet basically wrap around the engine so its a workable setup although you might need a couple of steering ujoints to go around the engine.

If your limited by funds or by just using what is in the shop then you'll have to get creative.

 

[TIGL]

I don't what your gear ratio is, but how are you going to fit the rear sprocket and clutch when they are bigger than the OD of the tube.
More so, there is going to be and excessive amount of wear of the "tensioning" blocks, at the point of contact in the tube as they do there job in the confined space, that's if there is enough to move to tension without touching the opposite running chain, I doubt you'll get far before it starts skipping teeth... from wear or stretch.

I'm planning on using a tensioning sprocket near the rear axle to keep the chain from clattering too much in the tube

exhaust will be piped out the sides and down and end up looking like an old hot rod hopefully

a shaft driven setup is tempting but i don't have the money to get a 90o gearbox right now

 

[Kentucky Boy]

It's an interesting project for sure. Good luck with it. I would mock up the motor and drive gear to see if it's gonna work before investing in anything else. That's a lot of chain to control and it's not going to be easy. A chain that long is gonna want to jump right off of your sprockets.

 

[Kartorbust]

Could do a couple 1:1 jackshafts to reduce overall chain length from front to back. Doc Sprocket's Diesel Weasel has a 40 series CVT and just one long chain going from the front to the rear. Long as there is a tensioner, should be fine.

 

[Kentucky Boy]

Is this build thread going to fizzle out? Any progress?

 

[TIGL]

Is this build thread going to fizzle out? Any progress?

Fortunately not. I made a bunch of progress this past weekend but getting home from the workshop at 11:30-midnight was starting to affect my job so I took a step back from it this week. I got engine, seat and rear axle mounted and the chain+tensioner largely sorted out so I'm happy with the progress. Work will resume again tomorrow after work when I'll start on the front steering spindles. I also got a whole mess of tires in and will be adjusting hubs to fit some of them and returning the ones I can't get to work

http://i.imgur.com/rFJbVRr.png/IMG]

[IMG]http://i.imgur.com/trEmhuO.png

 

[DaiSan76]

How are you planning to keep from burning your left leg?

 

[ironbutt]

Very cool build.

I do think you should consider turning the engine sideways and using a jackshaft. I'm doing the same thing with my 670cc engine on my 82 Honda motorcycle project. It's shaft drive and I have to have the PTO shaft of the engine pointed forward in order to match the forward spinning direction of the driven shaft.

BTW - Where can you find a 18" 5/8 jackshaft? Serious question, not joking even though it does seem unusual even to me.

 

[TeamCheap]

he's to deep into this setup to change it now....looks good although i'm wondering if you'll be using foot controls or hand controls for brake/throttle, feet look pretty well locked in.

Another cool thing is you'll be able to reach down and pull start it easy enough.

Will you be doing some triangulation of the frame to keep it from folding up?

 

[TIGL]

How are you planning to keep from burning your left leg?

It honestly hadn't occurred to me that it would be problem. most of the hot stuff is on the left side of the engine so at least I've got that going for me.

Very cool build.

I do think you should consider turning the engine sideways and using a jackshaft. I'm doing the same thing with my 670cc engine on my 82 Honda motorcycle project. It's shaft drive and I have to have the PTO shaft of the engine pointed forward in order to match the forward spinning direction of the driven shaft.

BTW - Where can you find a 18" 5/8 jackshaft? Serious question, not joking even though it does seem unusual even to me.

Thanks! I'm going to try and make it work with the one long chain, we'll see if its sucessful. if not, I'll look into shaft drives. I'd look on ebay to be honest.

he's too deep into this setup to change it now....looks good although i'm wondering if you'll be using foot controls or hand controls for brake/throttle, feet look pretty well locked in.

Another cool thing is you'll be able to reach down and pull start it easy enough.

Will you be doing some triangulation of the frame to keep it from folding up?

I'm planning on eventually doing standard pedals, maybe located low so they're operated using my heels. We'll see, That's honestly pretty far down the line. I'll probably do hand controls for testing purposes.

I wasn't planning on beefing it up further. I threw the frame around a bit and bounced on it a bunch and it seems pretty solid, and the bearing seats in the bottom rear add some extra stiffness. Any failure modes you think it's particularly prone to?


Thanks for all your input, I'm really excited about this build. The plan is to get some steering spindles cranked out tonight. Hopefully have the steering done by the end of the weekend. Also test firing the motor to check the chain system.

 

[Flyinhillbilly]

The frame being doube rail like it is I think it'll be fine.

 

[Whitetrashrocker]

I agree with FHB. It should be fine but I would add a diagonal brace. It would help with bounce.

 

[Tom Knight]

this is cool, way to go TGIL...are you still at it ?

 

[TIGL]

More pictures

More pictures. I didn't get a ton done this weekend, mostly just made and attached the front axles. Heres how it sits now.

I was struggling to figure out how to attach the the spindles and the correct angle and symmetrically so I decided to use a intermediate piece that was easier to get square with the U channel I am using for the spindle brackets. I milled out 1.25" slot a slot in a length of rectangular tubing

and slipped it over the bottom bar at the front of the frame where the green box is.

This is really nice because the tab-in-slot format is much stronger than just welding something on the face or trying to attach flat U channels to round tube. It also puts the wheels further out so they line up with the back wheels giving me more stability without adding more width.

I agree with FHB. It should be fine but I would add a diagonal brace. It would help with bounce.

So like where the red lines are in the image? (yellow is the plate on which the engine is mounted)


Thanks for all the input, keep it coming! my next move will be putting in the steering column by attaching it to bar B where I have decided that my feet will rest since that gives me much more movement than straight out on A plus it leaves space for proper pedals which will be nice.

 

[Kartorbust]

I'm curious to know if C-channel would be stronger than cutting and welding your own C-channel for spindles? I mean the metal is already bent in the shape and hopefully sized long for the tube or whatever you use to put a large and strong enough bolt through.

Hey any progress is great progress. Rather move 1 step forward than 3 steps back.

 

[Whitetrashrocker]

You have the right idea on the diagonal brace, but I don't think it's needs to be that long. Take a look at long framed race buggies or dragsters.

Making a triangle greatly stiffens things up.

 

[Kartorbust]

You have the right idea on the diagonal brace, but I don't think it's needs to be that long. Take a look at long framed race buggies or dragsters.

Making a triangle greatly stiffens things up.

Uhhhh have a closer look. That's the exhaust going from the engine all the way back. I too thought it was a brace, but then look at the opposite side, unless he only did one at a time for pics, it isn't symmetrical. Plus the exhaust seems to only be held in place by just the bolts on the engine block, of course there could be some hangers on the frame that we're not seeing.

But if the exhaust is only being held by the manifold studs on the engine block, put in a hanger or a few on there so it doesn't flex so much and damage itself or the threads in the block. When hitting bumps down the road, the vibrations could elongate the holes and make them oval.

---------- Post added at 11:13 AM ---------- Previous post was at 11:11 AM ----------

Woops never mind. Didn't notice the 3 wire coat hanger size hangers near the rear. Not sure if those 1/8" pieces will hold, but they are probably stronger in person than it looks by a picture. Carry on, my mistake.

 

[Whitetrashrocker]

Hey kartorbust! You look harder see? Lol.

TIGL any reason for the exhaust to go all the way back?
Why not make some fake zoomies around the one real exhaust. I think that would look sweet on that design.

 

[TIGL]

I may put a triangle brace in the front if other parts I put in don't make it rigid enough. The channel is pretty beefy so I'm not too worried about it. Def stronger and better dimensionally than I could weld up myself. I got it out of the maintenance department's scrap bin at work.


The rods holding the exhaust in place are actually stick welding electrodes with the flux knocked off since we have a bunch laying around, I also used one to stabilize the back of the chain guard. I will probably make a better bracket once the thing is more fleshed out but until then I just wanted to take some of the weight off the studs (as you mentioned). The route it takes now is just to get the noise and fumes back and out of my face. Hotrod pipes would definitely fit the look i'm going for so maybe I'll look more into that. thanks for the suggestion!