So, you are asking yourself what the hell is a Terranex? It is an off-road go-kart that comes stock with a single cylinder 250cc engine based on the Honda CN250 engine. Since getting the kart, I have loved every aspect except for the 250 and the lackluster performance. I chalk that up the gear-head in me. I have quite a bit of mechanical experience and thought to myself "why not simply drop in a cycle engine"? My only problem with planning this project is a lack of knowledge with motorcycle engines and system and thus why I am posting this here. I will need help on identifying things and thus will often be asking questions ... please excuse the noodness of some of these questions.

Fast forward 2 years and here I am with a 98 600F3 engine that I picked up from eBay. The previous owner says it is a 636 (with a stroker kit???), but the stock numbers compared to the existing 250 will do just fine. Anything beyond the stock numbers on this engine is just icing on the cake!

Noob question 1) do these transmissions have reverse? If you could explain the trans operation is great detail, that would be awesome and greatly appreciated.

The reason for asking is that the kart comes with a F/N/R selector for the CVT trans that will need to be retained if the 600F3 trans does not have reverse. I will then have to simply add a trans selector in addtion to the differential unit F/N/R selector and a clutch pedal. Below are pics showing the 600F3's new home and the trans reversing housing.

Now for some pictures

 

I always liked those off road go carts... that thing is going to RIPPPP when you get the f3 engine in there... now to the questions.
1. Not sure what a stock kit is, but the f3 motor is 600cc not 636cc unless he put a big bore kit on there
2. there is no reverse on the transmition

Not very mechanically inclined so i cant help on the technical aspect but hope i helped a little

 

Thanks, I reread my post after posting and corrected it too late ... I meant stroker, not stock

Thanks for your help ... now I know that I'm going to retain the LSD/reversing unit and will have two shifters ... kinda like an older manual 4x4 truck

 

thats gona be a bad little build! Have you figured out what you are going to do about getting the power to the wheels yet, seeing as how the cart is IRS with CVDs? as far as the trans goes, there is no reverse. just 1-6 forward. If I where you I would set up a paddle type shifter like a shifter cart would have, you could possibly use shifter cart parts for quite a bit of your build. I will definitly be watching this.

 

the price for any advice you get on here is to make a video of it when its all done

 

Consider it done! I suspect a wheelie is required

I was thinking of something much simpler (i.e. cheap), but if you have any parts sources URLs that you would like to share, I would be most greatful!

I plan on retaining the existing reversing mechanism, which has an LSD diff in it. The input shaft will need to be machined to accept a sprocket, which will be chain driven from the F3 output sprocket. Come to think of it, since I will have a seperate reversing mechanism, I will have 6 gears in each direction ... this would get real fun real quick! I will no doubt snap this thing in no time since it was designed to be mated to a ~18hp 250 ... my backup plan is a Quaife unit if I can find one used ... brand new they run $3,500!!!

 

Money!!!

http://www.rpmgearboxes.com/

From this link, a poster stated that they cost about $2K ... OK, there is my backup plan ... no pun intended

 

I was going to build a cart with a friend using a f2 motor. Anyhow, that lsd probably won't last a second with x7 the hp running through it. Consider running without one, sport atvs do it all the time and turn great. The f3 carbs will need a fuel pump, fyi. As for reverse, how about a line lock for one of the front brakes. I know it is barbaric but that thing should have no problem spinning the tires to get around.

 

You would think, but the only thing I think I have to worry about is "shock loading" the reversing box. As long as I feather the gas and slip the clutch, this thing should be just fine.

Noob question 2) How much horsepower/tq is this engine rated in stock form (98 F3)?

Thanks!

 

I pondered this for awhile. If I where doing this build Here is how I would go about doing it. I would do away with the stock rear suspension. I would shorten up a swing arm from a quad. I would then get ahold of a trans from a late 80s honda 250x( or any sport quad with reverse.). They had reverse. You then could mate that trans up with the f3 engine, have your shortened quad swing arm and chain drive and not have to worry about trashing some random transmission. just my own oppinion.