Giving me a hard way to roll

[Gypsybikes]

what's the problem? I am new to the moto-bike world. However I have a considerable amount of experience in the mechanical world. After following the break-in process I find that I am plagued with problems starting this motor. Then I look at the bike and see oil residue on the cylinder outside.. this can't be a good thing as I know that the oil is mixed in the gas. So I ask you for an opinion on the problem. I think that maybe it needs a re-torque on the head bolts. This is an 80cc motor kit and only has about 100 miles on it.

 

[wrench]

what's the problem? I am new to the moto-bike world. However I have a considerable amount of experience in the mechanical world. After following the break-in process I find that I am plagued with problems starting this motor. Then I look at the bike and see oil residue on the cylinder outside.. this can't be a good thing as I know that the oil is mixed in the gas. So I ask you for an opinion on the problem. I think that maybe it needs a re-torque on the head bolts. This is an 80cc motor kit and only has about 100 miles on it.

You guessed correct, re torque the head bolts
It's normal to re torque the head bolts after the first 100 miles

 

[Gypsybikes]

Thanks for confirming my theory

 

[Mossy]

Make sure the mating surfaces are flat and smooth... A file and sandpaper working from 220-800 on a 3/4" 18x18" piece of glass and a head gasket made from dead soft copper... Same deal for the intake and exhaust but use some square stock as a sanding block and some felpro gasket material... An '09 Toyota Tacoma oxygen sensor gasket for the exaust... Ultra grey gasket maker for gasoline or Yama bond 5 as an insurance policy... 2stroke china motors need constant retorque... The cylinders are made from soft aluminum and over time and heat cycling compress under the bolts... its a good idea to check the squish with a piece of solder in the spark plug hole in a few places between the piston and head along the edges... .070 thousandths will get you good compression the heads have a ring so if you can remove that to make it flat and use the whole gasket it's really going to seal and use 91-98 ethanol free gas... Read up on the threads on 2 stroke stuff and welcome to the forum...

 

[Gypsybikes]

What a difference toyrquing the head made. I have way more power. When I re-torqued the head the motor caught right off and the bike popped a wheel stand. Wasn't expecting that to happen. So yes constant re-torque is warranted. Now I have to replace my torque wrench because of the thief I had working for me.

 

[Venice Motor Bikes]

What a difference toyrquing the head made. I have way more power. When I re-torqued the head the motor caught right off and the bike popped a wheel stand. Wasn't expecting that to happen. So yes constant re-torque is warranted. Now I have to replace my torque wrench because of the thief I had working for me.

Be careful to only torque the head to 12 ft/lbs!!! (Otherwise you'll end up warping the head & having low compression again).

 

[Gypsybikes]

Does hot torque make a difference when torqueing the head

 

[Mossy]

Does hot torque make a difference when torqueing the head

As the engine heats up it expands so 12lbs cold could be 14 hot in theory anyway... So torqued hot would be under spec when cold... On another note theres wet and dry torque specs for engines like on rod end caps and head bolts... but it's really overthinking it on a china motor... If Maserati made a 66/80cc then maybe

 

[Mossy]

Does hot torque make a difference when torqueing the head

As the engine heats up it expands so 12lbs cold could be 14 hot in theory anyway... So torqued hot would be under spec when cold... On another note theres wet and dry torque specs for engines like on rod end caps and head bolts... but it's really overthinking it on a china motor... If Maserati made a 66/80cc then maybe

 

[wrench]

Does hot torque make a difference when torqueing the head

Do not torque the bolts when your engines hot
That's the easiest way to strip the threads.

Always torque engine bolts (especially the head) when the engine is COLD

 

[Mossy]

Something to have on hand or use as a preventative measure