Off Road Kart Build - Lots of Questions

[mpepin48]

I am fairly new to karting, but have decided I want to build my own off road kart. It will be a one-seater, made from 1" steel tubing which I will weld myself. I plan on making this kart a bit on the large size, and I live in the country and would mostly be on gravel/dirt roads and hilly terrain. Because of this I wanted an engine bigger the a standard 212cc. I have it narrowed down to the Predator 346cc from harbor freight, (http://www.harborfreight.com/346cc-ohv-horizontal-shaft-gas-engine-epa-69735.html) or the Lifan 270cc engine (http://www.homedepot.com/p/LIFAN-9-...Shaft-Engine-LF177F-BQ/203277135#.UaTh5Zx3XkV).
I am not much of a gear head, and would prefer to leave the engine mostly stock. I plan on using a 1003 GTC TC2 Torque Converter. Also, it will have a live axle.

Sooo now for the questions:

1. Does anyone know where I can get free plans for the frame of the kart?

2. What do you think about these engines?

3. Is the Predator engine a clone? Are there parts available for both of them?

4. Will the torque converter fit on these engines?

5. This is more of a general question. I understand that the torque converter attaches to the engine, but from there, how do I attach it to the sprocket on the axle?

6. What gear ratio would you recommend? I would be happy with a top speed around 35-40mph.

7. Tire size? I was thinking 18" rears.

Any help or input would be appreciated.

 

[turkeyfellow91]

Yes the torque converter will fit on those engines
I would use the gtc tc2 1004 (it uses a #41 chain and 10 tooth drive spocket
I would use 20" tires better for offroad
A torque converter drives a jackshaft, which has a drive sprocket that drives a sprocket attached to the axle
If you get the tc2 1004 and 20" tires you would need a 60 tooth axle sprocket to go the max speed of 39.65 mph (with plenty of power for hills)
I recommend the predator engine, known to have more torque than lifan

 

[Cole Tallerman]

check this out. This is the same price as the HF and is more powerfull: http://www.homedepot.com/p/LIFAN-15...Shaft-Engine-LF190F-BQ/203277165#.UaUqqWTwKv0

 

[mpepin48]

So the torque converter would drive the jackshaft, which would have another sprocket on it, which then would drive the rear axle?

If that is correct, what would you think about a 10 tooth sprocket on the jackshaft, attached to a 60 tooth on on the axle? I figure since it has a torque converter and a larger engine it would still take hills well while increasing top speed.

 

[mpepin48]

Towards Cole, I had looked at that engine but it would require me to use the 40 series torque converter which is quite a bit more

 

[turkeyfellow91]

Yes that is correct, the more teeth the axle sprocket has the more torque it has but less top speed, so less teeth = more top speed
So like I said a 60 tooth sprocket has plenty power for hills and 40mph max max speed

 

[OzFab]

Are you building a kart or a buggy?

 

[landuse]

I would go for more than 60T if you have 20" tyres. A TC is good, but not that good. I am not too sure what that TC you talked about is rated to in HP, but if it is comparable to the Comet 30 series, then it won't work with the engine you have posted. You will need a comet 40 series

Edit: I just read up on that TC, and it is a knock off of the comet 30 series, so anything larger than 8HP is not going to work. You might get away with the Lifan (which is rated at 9HP) but you will burn through belts quite fast. The Predator is just out of the question without a Comet 40 series

 

[turkeyfellow91]

According to the company who makes it, it is rated for 13hp

 

[landuse]

According to the company who makes it, it is rated for 13hp

If you look at the manufacturers webpage for that TC, you will see that it "Replaces *Comet 218354A *TAV2 30-100 Torq-A-Verter". That Comet is only rated for 8HP. There is no way that a knock off is going to handle more HP. Don't be fooled by advertising propaganda.

Have a look at this pic. It shows you what a Comet 30 series is rated at. Do NOT believe GTC!