Predator 212 bogging/running rich

[six40]

Hello,

I am pretty new to small engines and carburetors in general, so I need a little bit of help. I have a 212cc engine I got used. It was fully stock when I got it, and it's still stock with the exception of a free flowing exhaust. The problem with it is, it keeps fouling plugs.

I grinded the tip of the plug down to a point and re-gapped it to .035, the gap was less than .025 which I thought was too tight. The air filter is clean, but to make sure that's not a problem I had it running without the filter and it still did the same thing.

Now to explain the problem, the engine will idle forever without a problem. I let it idle for about 15 minutes without a hiccup. The engine will also run at full throttle forever, without a hiccup. The problem comes when I try and rev the engine up from idle. If I roll on the throttle ever so gently, it will rev up no problem and it is smooth. But if I am aggressive with the throttle it will backfire really loud and sometimes even shoot a huge flame, sometimes it will clear out and rev up but the more times I do it the more the plug fouls, and eventually it just stalls out when I give it throttle. After, it won't start unless I pull the plug and clean it.

What would cause this issue? As stated before, the engine is all stock except for the exhaust.

 

[six40]

Here is a pic of the plug before I did anything to it. Also looking at it more today I realized it's just a clone 196cc engine, not a 212cc predator so I apologize

 

[Not so mini bike]

That 36 jet might be to be for the clone use a smaller jet. It might be a trial and error thing. And I would clean up the plug.

 

[six40]

Yep the plug is clean, I clean it every time it gets like that.

I took the carb apart and cleaned it as much as I could. Also cleaned the inside of the tank, the filters, etc and fully drained the old gas. There was a lot of debris in the tank, and some in the bowl. I was not able to get the jet out, the PO destroyed the jet trying to get it out and I had no luck either, it was stripped all the way around.

I did my best to clean everything with a lot of carb cleaner and compressed air. I am going to put it back together , and give it fresh gasoline and see if I got anywhere.

Should I use 87 or 91? I figured for stock 87 is plenty but it has ethanol. I can get 91 without ethanol.

 

[six40]

I put everything back together, all filters clean, new oil, clean plug, and fresh 91 octane fuel containing zero ethanol.

If anything, it's running worse. It won't idle for more than 2-3 minutes without bogging down and trying to stall. It doesn't want to rev out at WOT, or even get there. It's getting more fuel than before somehow I think.

When I cleaned the carburetor I couldn't get the jet or emulsion tube out, so I just sprayed them with carb cleaner and blew them with air the best I could. Everything else I cleaned and put back the way I found it.

I am lost as to what I should do. Maybe order a new carburetor? Could this have something to do with the valve lash?

 

[6.5hp Shinebox]

Ok, Look @ your plug.......it says I'm running too rich! It's bout fouled out. Rejet carb. You say You put a cold air intake on? Put an exhaust pipe on...& Rejet the carb

 

[OND]

If it were me...I would start with a brand new spark plug ! Throw that old one away.

 

[six40]

Ok, Look @ your plug.......it says I'm running too rich! It's bout fouled out. Rejet carb. You say You put a cold air intake on? Put an exhaust pipe on...& Rejet the carb

Yep I'm aware it's running pig rich, I could tell by the plug. Since I couldn't get the old jet out I just bought a new carb, as well as a couple different jets to play around with if needed. The previous owner kinda hacked the current carb. It does not have an intake, it's still on the factory air box. But it does have an exhaust.

I'm just confused as to why it ran well last year (I personally rode the hacked bike the engine was on before for a solid hour without any issues) but this year all of a sudden it's acting up. Hoping the new carb will help.

If it were me...I would start with a brand new spark plug ! Throw that old one away.

This plug is practically new. It just looks crappy because of all the carbon. But once it's cleaned up it looks pretty damn new and fires a really bright spark. However, I could try a new plug too. For what it's worth, it sure as hell won't hurt!

 

[trinik7597]

if your plug looks like that after only running it for a short time i hate to think what your head and valves look like !!! instead of jetting it down you could and probably should pull the stock air box and add an aftermarket filter and adapter. since you put a header on it opening up the air so it will flow better is the way to go . at that point you would probably be running lean and have to jet up to like a 36 or 37 :thumbsup:

 

[trinik7597]

oh yeah and what is that some kind of scooter you made ? very cool !! you must hit about 60 with that gear ratio hmy:

 

[six40]

You're right, I never actually though about the inside of the engine I will have to sea foam it or something once it's running right to clear out the insides a little bit! I was actually extremely close to ordering an aftermarket intake when I bought the carb and jets, my only concern is that I don't have the room for that filter sticking out it would stick out far past the scooter (engine already does) and would get smashed into stuff as I like riding through trails and tight spaces. Is there anything I can do to the stock intake to get it to breathe better?mor any other solution?

As for the scooter, yeah it is pretty quick even with the engine governed. The scooter has a short wheel base and it is really light, much lighter than say a doodlebug. That's the reason I'm not going to go heavy on the mods, it's plenty for what I need

It started life as a 33cc Chinese turd that looked something like this

I stripped it as soon as I got it home so it was just the frame and engine

And then decided to go crazy and rebuilt 90% of it. The only thing that remains original is the front end.

 

[trinik7597]

that is real creative !!! i like it :thumbsup: if you were only riding on the street i would say just get the adapter and not the filter and run it wide open . but some one posted recently where they used a piece of lexan and a velocity stack on the bottom part of the stock air box . but other than making something i am at a loss maybe someone else knows though

 

[six40]

Thank you the idea came out of nowhere I swear. One day it just crossed my mind. As for the intake, you are right. Perhaps I should get it.. I ran it with and without the filter today (chain is off so just revving it without moving) and it runs much better without the restriction. I should call OldMiniBikes warehouse and see if they shipped my stuff yet, if not maybe add the intake. I was looking around the garage and realized the spark plugs out of my turbocharged Elantra (ngk bkr6es) will work on the clone. So I tossed one in, I think I had them gapped to .028 so they don't blow out the spark under boost. But I just tossed one in, and go figure.... It ran great.

I feel stupid now that I trusted the 'old' plug (despite looking brand new when cleaned). I know now that most of the problem was just an improper spark plug. However, after running the engine for 45 minutes to an hour, mostly idling but I kept going and cracking the throttle, I pulled the plug out and it's still covered in carbon. The engine is still a bit rich, although it never stalled or cut out, it was a little boggy and it still did shoot flames out the exhaust when going wot from idle sounding like a shotgun going off. But it ran pretty consistent and never tried to stall.

With a brand new proper plug and the carb with the proper jet (happy I bought a few sizes... Stock 28 in the carb, I also bought a 32 and a 36) it should run well.

Here is the ngk after I pulled it, you can see it's still black but it ran much better.

 

[six40]

Hey guys

Well I got the brand new carburetor in the mail, with the stock 28 jet, and installed it on the engine. Unfortunately, it is still having the same problem. It will idle fine for the most part and run WOT fine (sorry for the surging, I think I hooked up the throttle a bit wrong) but it still tries stalling out when going WOT from idle. What else can it be? I don't think it is the carb, nor do I think it's the plug as this point as I have tried a few. The fuel and all the filters are new and clean.

Here is a video. Watch the throttle lever to see what input I was giving it. At the end, that stalled out by itself. Also note the loud crackles as throttle is applied.

196cc clone problems - YouTube

Please help me, I am completely lost at this point.

 

[gumpit]

Go to Harbor Freight and get a new engine $99

 

[six40]

Go to Harbor Freight and get a new engine $99

We don't have HF up here nor can I find them for $99. I would like to get my currently running engine running better. It's not like I put a hole in the block....

 

[OND]

Are you sure you have all the carb and intake gaskets on it correctly ? There is air bleed holes at each end of the carb ...and they don't need to be restricted.

 

[six40]

Are you sure you have all the carb and intake gaskets on it correctly ? There is air bleed holes at each end of the carb ...and they don't need to be restricted.

Yep they are absolutely correct. I read up about the air bleed holes and made sure (even double checked) that the gaskets are all on the right way.

 

[mckutzy]

Checked to see the Carb Insulator isn't cracked aswell?
The princess just had a sale on 212 motors(princes auto brand unfortunately), I picked mine up for $139 +tax. They still are half decent motors.

 

[OND]

I had a problem recently with my DB that has a 212 engine on it..thing started out running ok for a few minutes..then would die, but crank back up. Progressivly got worst got worst on shorter runs....then died and wouldn't start back. So I went to work checking and changing the coil coil gap, kill switch, plug wire , resistor and never thought about the spark plug....as a last resort I stuck a new stock spark plug in it and it run great again. Plug looked good but like yours it was black. Just a thought !