Engine Trouble Bike wont go faster than 24mph with 36t sprocket

[BikePete]

It shoulded be caked because about 3 weeks ago i cleaned it with petrol

 

[6blueoval9]

Do you know what size jet is in your carburetor?

 

[FurryOnTheInside]

I did that mostly with a grinding wheel on the dremel. Then a quick polish. I opened the sides a little bit more than the top and bottom to give it a more oval shape but the main thing was just to round off the edge of the header pipe so there's a bit less turbulence. A little turbulence can effectively narrow such an already narrow header pipe.

 

[BikePete]

Okay Blue will do that. Like i said i bought this bike second hand and the guy said ot was a bit used so maybe the engine needs a bit more breaking in perhaps, i hope

 

[BikePete]

Thanks for all the help guys. Im going to go back up to a 44t to break in the engine, the reason for going back up with a 44t is because i dont want to stress my engine on low speeds

 

[FurryOnTheInside]

If you're taking the exhaust off I'd appreciate a good picture of the exhaust port so we can see what has been done to it. (Measurements are done with paper inside the cylinder so don't worry about that)

 

[BikePete]

Okay will take a pic when i get to it. Thanks

 

[FurryOnTheInside]

Thanks for all the help guys. Im going to go back up to a 44t to break in the engine, the reason for going back up with a 44t is because i dont want to stress my engine on low speeds

High load and lower RPM is better for break in. It keeps pressure on the rings throughout more of the down stroke. High RPM with little load is not good. Might be a good idea to keep the 36t on for break in if you're riding on level ground.

 

[6blueoval9]

What oil and gas mix are you using to break it in?

And the adjustments of the carburetor or jetting should be quite rich for break in and you wouldn't have very good speed from it.

The way you explained it before never indicated you're in the "break in" process.

For that slow is good.

 

[Street Ryderz]

Thanks for all the help guys. Im going to go back up to a 44t to break in the engine, the reason for going back up with a 44t is because i dont want to stress my engine on low speeds

Did you not say this was a 8 y/o engine from 2009 and run from the previous owner.And if so why would you be breaking it in?