Yerf dog engine install

[craigp602]

I just picked up the yerf dog go Kart that I believe it had a 150cc engine originally. I don't have the original engine but I am curious if anyone has done a engine swap in this make of Yerf dog because the sprocket is on the right hand side.
They were trying to use a predator engine with it mounted up on top of the frame and that doesn't work. I'm going to cut the mounts they made but I don't know what would be a good engine to get for this build.

Any information about this would be greatly appreciated
Thanks

 

[mckutzy]

Hello and welcome
Probably a better candidate for a big block clone... But what ever you can afford...
As pictured itll be fine as a basice setup.. probably needs reinforcement to properly hold the motor...
Biggest thing will be to replace the sprocket, And most likely youll need a jackshaft to make a good gearing and save some ground clearance...

 

[craigp602]

Thank you for the information.
I just found out that its a Yerf Dog Little Fox, series 40000 that originally had a 90cc two stroke engine.

So my only options are to use a GY6 type engine or swap the sprocket to the other side some how but I have been trying to remove the axle most of today without much luck I think its rusted in.

 

[mckutzy]

If you find out what the chain type is, you could use that with a jackshaft just have to account for that when you calculate the gearing... And just get a regular predator or a big block clone, runs on that side anyways..

 

[Karttekk]

Now you know why it was in the dumpster in the first place.

 

[Brianator]

Now you know why it was in the dumpster in the first place.

That was uncalled for...

---------- Post added at 09:39 PM ---------- Previous post was at 09:27 PM ----------

Dont listen to him Craig, not sure what his issue is but it shows a complete lack of character to bash someone then sign out. Lots of members here have and love their YerfDogs

 

[Budget GoKart]

Love my big block yerfdog I run a gx390 it's awesome!

 

[craigp602]

I really do appreciate all of the options and ideas from everyone, I just wanted to now all of my options before I started down a path.
Thanks

 

[Karttekk]

Sorry if I came across the wrong way. What I meant was if you're new at this or don't have a lot of experience, I think it's best to start with something that's nearly complete so it doesn't become overwhelming and frustrating. Once you learn your way around then start fabricating and modifying as much as you need to. Again, my apologies for the unnecessary comment. Good luck with your project.

 

[Smerft85]

If you can remove the axle via the bearing hangers and flip it over it would put the sprocket on the left side of the kart, I'll snap a picture of the factory engine plate location on the yerfdog we cut up for another project and post it, engine plate on ours sits in the middle on the parallel bars with the axle sprocket just to the left (looking at it from the rear) I'm not sure if yours was originally like ours or not, but it's a good setup.

 

[craigp602]

Yeah, this project is definitely turning into a lot more than I was originally thinking. I thought it just needed a new motor mount and throttle cable. I will probably put it back together and put it aside until I can find a engine I can afford that can use the sprocket that is on it and in the location it's currently at.
Thanks for all of the information before I dumped a lot more money into this.

---------- Post added at 09:49 AM ---------- Previous post was at 09:44 AM ----------

I am curious if anyone has put a GY6 engine into this kart before, it looks like it should work well but I would like more information before buying one.

 

[Karttekk]

"Yeah, this project is definitely turning into a lot more than I was originally thinking."

This is what I was getting at. It's great you're interested in learning about karts, these are things you run into when first starting out. Don't get discouraged, keep plugging away. I wouldn't go the GY6 route with it but that's just my view.

 

[craigp602]

I think I should be able to flip this rear axle if so I can use the engine set-up I currently have. I would just need to buy a new chain and 61 tooth rear sprocket, what website is good to get parts like this at?
Thanks

 

[craigp602]

Success!
I was able to flip the axle with no problem. Now I will be able to use the engine setup that came with the Kart once I make a mount for it in the center of the engine compartment. I just need to order my rear sprocket before I can finish installing the axle.
Any recommendations for a rear sprocket on this setup?

 

[Brianator]

Glad to see you pushing through! A few things to take into consideration when choosing a rear sprocket are : kart weight (with driver), outer diameter of tire (as measured not read), tooth count on torque converter sprocket (and what size of chain its for) approximate power and rpms of motor and what kind of terrain you plan on tearing up with it! Lol. We can't make bricks without clay, fill in the blanks and we'll move forward.

 

[Smerft85]

I usually get most my stuff from Amazon. What size chain are you going to need? I may be wrong but throwing a guess out saying you probably have a 9t sprocket on the t/c mounted to that Subaru and its front #40 chain, by the way, that Subaru engine is much better than a gy6, love the 4hp Subaru running my kid's kart. If I'm right about my guess then a 54 tooth would be the highest I'd go in ratio, or amazon has an 84t? which would make it torquey, a 60t would possibly be a bit high for your ratios maybe burning up belts. Somewhere around 70t on the axle would be fast enough to be fun, with enough torque to break the wheels loose in the dirt, or maybe lift the front end off the ground a little bit. Would you like that picture of our engine plate on our yerfdog?

 

[craigp602]

Yes, any pointers and ideas are greatly appreciated. This forum has been a big help for my first Kart project. I have done a lot of motorcycle and car projects but this is my first go kart.

 

[Smerft85]

It's not a yerfdog anymore, but we left it alone just enough to help out a bit, hope it helps.

 

[craigp602]

That's how I have my mount mocked up, I'm just waiting to get the sprocket so I know exactly the location it needs to be at. You did some nice work on that!

 

[craigp602]

I finished all of the fabrication and the Kart is up and running! I moved the sprocket to the left side, installed the engine mount, put the engine in and put on a new chain and a throttle cable.
The kids had a blast on it all weekend now I need to tighten the chain back up because it stretched.

I am curious how you are setting up the throttle cable to the engine because I'm not getting full throttle and it sticks sometimes.
Thanks