C

Colm

Guest
Hi I have a black 80cc engine that I got off eBay. It’s done a 1000km according to my speedometer at 750km I change the fuel mixture from 16:1 to 20:1 after I did that the engine started bogging I got rid of that by replacing the spark plug. But the engine still has a hard time accelerating compared to what it used to do. I also have to pedal a bit to make it start unlike before when I just let out the clutch and the engine took over just fine. I tied changing the little clip on the jet needle to make it leaner but that made a tiny difference. I can’t figure out what it is but I think it has something to do with the engine not getting enough air or fuel. Also a few days ago the engine refused to start. I got it going by taking of the carburetor, air filter and draining the fuel tank by the drain screw on the carburetor bowl. If anyone has any idea on what it would be i will greatly appreciate it.
 


FurryOnTheInside

Well-Known Member
Joined
Sep 23, 2013
Messages
3,997
(I would) first check for leaks, check head nuts are correctly torqued, clean carb (jet & needle valve particularly) with carb cleaner spray and air filter, improve or upgrade the air filter. Use less oil, full synthetic. Jet correctly.
 

rwaterman00

Member
Joined
Jul 7, 2018
Messages
71
you are probably running rich now is my guess and as furry states you may need to rejet carb. the oil dilutes the gasoline in a 16 to 1 mix more then it does in a 20 to 1 mix. therefore you are getting more gas in the mix and it is running rich as a result. I know it seems strange that you could be running rich with less oil but that is how it works in a 2 stroke. how rich you are running is from what I understand the ratio between the amount of air to the amount of gasoline and the oil is more about lubrication then combustion
 

crassius

Well-Known Member
Joined
Jul 23, 2012
Messages
4,568
it is unfortunate that sometimes one of the older model motors never gets really good - H2 motors were notorious for that many years ago

we don't see that much these days, so I'd try a 32:1 mix, a compression test, and then any tuning the carb might need
 

Detroitbradster313

New Member
Joined
Jul 6, 2018
Messages
17
If you have a NT Carb the purge push button thing will press down on your float and bends the floats brass prongs outta wack when full of gas id check that and take the foam out of the carb cover and take the baffle outta your exhaust let the motor breath better. Sounds like your a lil off tune with your mix but i would go rich two strokes get hot and poorly lubed when ran lean. Check your bowl float level also could be thirsty. I reset my float to 21mm and removed the foam from carb cover and drilled holes in the cover and removed the baffle from exhaust pipe. I run a ngk plug also. These motors come ball park tuned and heavily restricted. They need fine tuned after break in and allowed to breath better at the carb an exhaust.
 
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Detroitbradster313

New Member
Joined
Jul 6, 2018
Messages
17
On 2 strokes you have gas to oil ratio and fuel to air ratio.. One off sets the other and if the motor aint breathing or sparking good it will never run good no matter your mix. Poor spark appears to run rich to much oil appears rich not enough air flow appears rich..
 

ranchopower

New Member
Joined
Jun 30, 2018
Messages
3
been running 100:1 AMSOIL SABER break in period, commuting period and WOT periods. Everything else bad happens to the bike but the piston and the cylinder are still pumping air and making compression. never any smoke or spooge out the tail pipe. I must be doing it wrongo_O
 

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Detroitbradster313

New Member
Joined
Jul 6, 2018
Messages
17
Yea i run mine with no air filter or housing and took the guts outta the stock exhaust with a ngk plug. But you might wanna replace the stock magneto and cdi if its old.
 
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