Bogging, Cutout, Electrical power problem need help?



I have a kings motorbike engine.

Here is my situation. When the bike is going up a hill, It is fine. But when I am on a level surface or going down a hill, the engine acts like it wants to cut out at high rpm. If I dont turn the throttle way down it bogs down but yet it almost seems electrical to me. It bogs for a little bit then jumps right back in.

Ive checked for air leakage and checked the wiring 3 times. Even changed the spark plug.

This bike now has about 1000 miles on it and I am just frustrated. This just started last week.

It works great at low to mid rpm, but I cant open it up. It acts like It wants to bog out. But like I said it sounds and feels electrical to me.
have you tried changing slots on carb needle ?
you could also see if float is sticking and you are using fuel faster than the bowl can fill
mixture comes to mind, & have you searched here for "bogging" before? because i see some "similar threads" at the bottom of this page that look mighty relevant.

one more thing...are you still in break-in?

btw-i was looking thru "introduce yourself"...have we met? ;)
Yep we have met. Gonna take apart the carb tonight.

I just got done with a specialized bike and posted pictures.

I am going to take apart the carb tonight and see whats going on in there. Have not taken it apart, probably would not hurt with some miles put on it now.

Will let everyone know how it goes.

One more thing, I really appreciate all the help here on

I had a bogging problem with my 4-stroke that I fixed by disassembling, cleaning, and reassembling the carburetor. There's some gunk that gets put on the parts during assembly that screws up fuel flow through the carb.

(You said you already have about 1000 miles on it...still, it might not be a bad idea to go through the carb. Mine started acting up after only 30-40 miles.)
It must be air. Gonna seal the dang thing up.

I should also mention I am getting a little worried that my trailer hauling has affected the motor. The only thing I can figure is I have an air leak.

I have cleaned the carb checked the float and adjusted the side screw to have the same problem. Under load I have no problem like up a hill.

It has to be an air leak. I will try using an o-ring on the engine intake tube to see if that works. The motor sounds and runs like a top but when it warms up and runs down hill or level surface at high throttle or rpm it acts like it cuts out. Low rpm or throttle it works like a champ. There isn't a real "bogging" sound. It almost seems electrical like power loss. When I took the spark plug out it was almost solid black. That tells me rich, but I dont know for sure. When I run it out of fuel on purpose, it just runs out of fuel. It doesn't speed up or anything. Just stops.

All I can figure is it is a very small air leak. I will keep you all informed. I really do appreciate all the help and suggestions.

If this dont work I guess it will be off to DACS for a new motor, holy cow he has great prices there. Either that or I will be commuting at low speed.
Try ......

Try Checking for leaks before replacing gaskets. Spray some carb cleaner around areas that you feel may be leaking. Do this while the engine is idling. If there is a leak..You will know...Enjoy the ride...
high power bogging

I once had a 250 cc 2 cycle that had been bored out to 300 cc. No change had been made to the carb and it would act just as you describe. It would cut out at high speed due to lack of enough gas. I might pay to check out the carb and try a little cleaning to open up the gas flow. Good luck.
If your plug is black you could try moving the e-clip up a notch on the carb needle, then run it for awhile and check your plug again. I think you want to see a nice brown color indicating not too lean, not too rich. Also, have you checked for good flow from the tank/filter? Good luck!!
I'm bumping this thread because I had the exact same problem develop before I put it away for the winter. I'd like to have it resolved before spring.

It's definitely a high RPM problem, it doesn't happen under load like uphill because it never gets to absolute max rpm going uphill. My motor would run wide open for 5-10 seconds and then pull back hard dropping about 8MPH within 2 seconds and slowly start to pick back up and cycle all over. I got to the point where I could anticipate just before it bogs and if I release the throttle a bit and drop just a few MPH and I could prevent it from happening.

I'm thinking it's either starving for gas, possible test may be to run without bowl float and valve to see it it can sustain top RPM longer. Not sure if that's even possible? Any input?

If it is electrical, possibly magneto or CDI can not sustain sufficient output at top RPM. The only test would be to replace and I don't really want to buy parts I may not need.

If anyone has resolved this particular problem please post what you did.