First tank, poor MPG!!!

relaxxx

Member
Joined
May 2, 2008
Messages
96
I'm sure I didn't even get 30 miles out of my first tank!!?? I figure about 50MPG rate right now. Also having hard starts. runs fine after start but a lot of playing around with choke and pedaling. I also noticed my spark plug is now completely black inside! I'm wondering If I might have something not set right? 80CC HT
 


spad4me

Member
Joined
Jan 6, 2008
Messages
570
Congrats on your first tankfull of gas oil mix.
Break in the engine first, then you will like the mileage.
Did you glue the carb to the leaky intake manifold with red rtv, or use a washer to seal the carb to the intake manifold.
My engine was a bear to start the first time when it was new.
It got a-lot easier after 5 or so tankfuls.
What ratio of gas to oil are you using.
20 to 1 is for break-in then 25 to 1 or what ever you feel comfortable with.
 

relaxxx

Member
Joined
May 2, 2008
Messages
96
No, I didn't seal the carb yet. When I was finished putting it together I had a red washer left over, I think it was supposed to be for the gas tank shutoff but I had used teflon tape instead. I did seal the electrical output with high temp silicone.

Instructions tell me 16:1 for first 500Km then 20:1. Keeping at 15MPH is extremely difficult. especially since the motor runs smoother at higher speeds.
Oh yeah, I think gas is spitting on my legs from somewhere.
 
B

BSA

Guest
Are you sure you haven't got a leak from the tap or the tank?

BSA
 

relaxxx

Member
Joined
May 2, 2008
Messages
96
I think it's from the spark plug. It's burnt gas/oil, black spots on both pantlegs and there's black oil all over the top around the plug. Carb is clean as a whistle.
I'm thinking of putting some sealant around the plug but I don't want to insulate it and have it not spark.
 

relaxxx

Member
Joined
May 2, 2008
Messages
96
I went ahead and sealed around the spark plug and carb with high temp silicone sealant. I noticed it was harder to turn over, popped clutch and acted like a break! So I had to go a little faster than usual but it fired up better and it's not spitting anything on me yet. Hopefully this will boost my MPG's as well.
 
M

motoschwinn

Guest
At this time, be easy on the first tank. I would run no more than 20 minutes, let it fully cool down and checked everything! Leaks, things vibrate loose. etc during the break in. Just be patient. Check abd then double check everything. I've gotten over 3000 miles on my bike now and I rarely have to adjust anything... Patience is the key and baby it.
 

relaxxx

Member
Joined
May 2, 2008
Messages
96
Ugh! Now it looks like I've blown my exhaust gasket, spitting burnt oil from there now. And the gasket itself was sandwiched in metal? I'll have to take it apart tomorrow and see what it looks like. I hope this will be the last thing to fall apart on me. I suppose the extra compression that used to blow out my spark plug found it's way out the exhaust gasket. I'm almost scared to fix it. Is there such a thing as too much compression?
 
J

JosephGarcia

Guest
Ugh! Now it looks like I've blown my exhaust gasket, spitting burnt oil from there now. And the gasket itself was sandwiched in metal? I'll have to take it apart tomorrow and see what it looks like. I hope this will be the last thing to fall apart on me. I suppose the extra compression that used to blow out my spark plug found it's way out the exhaust gasket. I'm almost scared to fix it. Is there such a thing as too much compression?

looks like you got a bad engine.

its running too rich and has a compression leak at the plug, and now that compression blew your gasket.

just remake new gaskets for everything and tighten the head bolts nice and good, but in a cross pattern so they tighten evenly. also make sure you plug is in there well, you want it to seal the chamber.
 

relaxxx

Member
Joined
May 2, 2008
Messages
96
Just to revisit my issue;
Eveything's sealed good now, no leaks or blowouts.
My gas mileage is still a dismal 50MPG.
Kind of lost count but I'm sure I've gone through 5 tanks.
My top speed is 25MPH.
Mixing a little better than 20:1

Is there any hope in seeing 100MPG ever?
 
Top