Air/exhaust leak?

Zoom555

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Sep 27, 2021
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Hey guys! I picked this MB from Facebook for $60. The guy fired it up for a second. When I got home I started it and the rmps are extremely high and dies when I give it gas. I also noticed the exhaust had no gasket. I ordered O2 sensor gasket- per advice by @DAMIEN1307 from another thread- and material to make intake gasket. Any other ideas as to why the rpm’s are so high?

D1348767-C6E4-4E1D-B089-056B1FC7DE65.jpeg
 
Any other ideas as to why the rpm’s are so high?
Yes I do...lol.

It is running too lean because that carburetor is not exactly level, it's angled at an almost 45 degree angle.

I bet the builder put on a straight intake tube on it rather than the standard angled ones that come with the motor kits so the carburetor could be angled correctly.

This means the float level will not operate correctly at all.

I magnified that pic to view things as best I could because that pic taken at a distance and not close up to the motor is almost useless in spotting anything else except for the fact the fuel filter is on upside down as well.

The more narrow end is supposed to face the gas tank...You will see a little round magnet in that narrower end which is supposed to aim towards the tank in order to pic up any fine metal and or rust particulates resulting from lousy Chinese quality control.

Definitely get the gasket on there that you ordered because that is an obvious problem along with that extreme angle of the carburetor and change that intake to one like the stock ones in the kit which will give you the angle needed to feed the fuel to the motor correctly along with a new intake gasket.

The guy who built it didn't have a clue as to how to build one of these...That is why he sold it so cheap...lol...His loss, your gain if your careful to look for anything that could be found due to his faulty building proceedures...lol.
 
Yes I do...lol.

It is running too lean because that carburetor is not exactly level, it's angled at an almost 45 degree angle.

I bet the builder put on a straight intake tube on it rather than the standard angled ones that come with the motor kits so the carburetor could be angled correctly.

This means the float level will not operate correctly at all.

I magnified that pic to view things as best I could because that pic taken at a distance and not close up to the motor is almost useless in spotting anything else except for the fact the fuel filter is on upside down as well.

The more narrow end is supposed to face the gas tank...You will see a little round magnet in that narrower end which is supposed to aim towards the tank in order to pic up any fine metal and or rust particulates resulting from lousy Chinese quality control.

Definitely get the gasket on there that you ordered because that is an obvious problem along with that extreme angle of the carburetor and change that intake to one like the stock ones in the kit which will give you the angle needed to feed the fuel to the motor correctly along with a new intake gasket.

The guy who built it didn't have a clue as to how to build one of these...That is why he sold it so cheap...lol...His loss, your gain if you’re careful to look for anything that could be found due to his faulty building proceedures...lol.
Thank you! I did notice the carb was angled pretty good. Looks like the guy who built it has it upside down so it can fit. I have an offset intake I’ll try out. I didn’t notice the fuel filter but I only spent 20-30 min playing around.

Yeah I’m sure he didn’t know what he was doing. The axles on the front and rear wheel are uneven and many bolts were loose- especially the axle nuts. The coaster brake is all torn up as well.

At least it has a sprocket hub adaptor and a spring chain tensioner. I’ll post pictures in the morning. Figured I can’t go wrong for only $60!
 
Yeah I’m sure he didn’t know what he was doing. The axles on the front and rear wheel are uneven and many bolts were loose- especially the axle nuts. The coaster brake is all torn up as well.
In other words, a Dr. Jack Kevorkian do it yourself suicide machine, death trap, until YOU go over the entire bike and motor and make everything right that he didn't...lol...lol.
 
Hey guys! I picked this MB from Facebook for $60. The guy fired it up for a second. When I got home I started it and the rmps are extremely high and dies when I give it gas. I also noticed the exhaust had no gasket. I ordered O2 sensor gasket- per advice by @DAMIEN1307 from another thread- and material to make intake gasket. Any other ideas as to why the rpm’s are so high?

View attachment 190766
Good deal! The frame and fork is worth that much.
 
Hey guys. I have some better pics. New gaskets and fixing some mistakes from the original builder and it should be good to go.

Let me know what you guys think
 

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Good deal! The frame and fork is worth that much.
That’s what I was thinking. Plus it has a hub adaptor. My original plan was to put this engine on my stretch build but I kinda like it the way it is. So who knows what I’m going to with it yet.
 
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