Top end power/top speed not great

[Jaycee604]

So everything about my bike feels great, great throttle reaction and really jerky in a good way, but the top speed isnt as good as my other ones. I can just feel shes got more juice in er, like shes holding back power.

I have an 80cc (66cc) 2 stroke with a windowed piston with reed valve, slighty ported jug, aftermarket exhaust (viper), ngk spark plug and heavy duty 420 chain (on all 3 of my bikes), and a cone air filter. All my bikes have the 44 tooth.

I have one other bike that has the same setup but has better top speed. The brand on the faster one is YAECCC and this one is EXGIZMO, both from amazon. What is holding back this power? The way its ported? Jets? Head?

 

[DieselTech]

So everything about my bike feels great, great throttle reaction and really jerky in a good way, but the top speed isnt as good as my other ones. I can just feel shes got more juice in er, like shes holding back power.

I have an 80cc (66cc) 2 stroke with a windowed piston with reed valve, slighty ported jug, aftermarket exhaust (viper), ngk spark plug and heavy duty 420 chain (on all 3 of my bikes), and a cone air filter. All my bikes have the 44 tooth.

I have one other bike that has the same setup but has better top speed. The brand on the faster one is YAECCC and this one is EXGIZMO, both from amazon. What is holding back this power? The way its ported? Jets? Head?

Are all 3 bikes running the same carb & jetting? If it's all the same, I'm going to guess the porting is not as aggressive on that cylinder. I've had good luck with the ExGizmo engines, my buddy runs them & I build his bikes. It's got about 600 miles on it without a hitch.

 

[Jaycee604]

Are all 3 bikes running the same carb & jetting? If it's all the same, I'm going to guess the porting is not as aggressive on that cylinder. I've had good luck with the ExGizmo engines, my buddy runs them & I build his bikes. It's got about 600 miles on it without a hitch.

All three have the same old style nt carbs. I find the new style suck ass. All three are tuned rich, stock jets. I have went through three of the black painted ones and they all have power issues

 

[DieselTech]

Ok 1 thing I do know on the ExGizmo engines, every 1 of them I've had squish was set at 1.2-1.5mm, which is way too much. They all had .065" head gaskets in them, try switching to a thinner head gasket. All the exgizmo engines i have, have been doggy until I set squish to .7mm

 

[Karl Snarl]

So everything about my bike feels great, great throttle reaction and really jerky in a good way, but the top speed isnt as good as my other ones. I can just feel shes got more juice in er, like shes holding back power.

I have an 80cc (66cc) 2 stroke with a windowed piston with reed valve, slighty ported jug, aftermarket exhaust (viper), ngk spark plug and heavy duty 420 chain (on all 3 of my bikes), and a cone air filter. All my bikes have the 44 tooth.

I have one other bike that has the same setup but has better top speed. The brand on the faster one is YAECCC and this one is EXGIZMO, both from amazon. What is holding back this power? The way its ported? Jets? Head?

Check the squish, should be about .8-.7 mm. Then check the jetting after adjusting the squish. Should get ya up there if everything else is in order. Lots of these come with a huge to not there squish.

 

[Jaycee604]

Check the squish, should be about .8-.7 mm. Then check the jetting after adjusting the squish. Should get ya up there if everything else is in order. Lots of these come with a huge to not there squish.

Im pretty good with other stuff but how would i measure squish and how would i lessen it or make it bigger if needed

 

[DieselTech]

Im pretty good with other stuff but how would i measure squish and how would i lessen it or make it bigger if needed

The easy way, is to remove spark plug & use a piece of 1mm solder bent to fit in plug hole till it touches the cylinder wall. Then rotate engine over to squish solder. Measure the thinnest part of solder & that is your squish clearance. The other way, is to remove cylinder head & tape a piece of solder in cylinder the entire width of cylinder. Then install head & torque to specs, 12ft/lbs, then rotate engine over a couple times, then remove cylinder head & measure thinnest part of solder. That's your squish clearance.

 

[Karl Snarl]

The easy way, is to remove spark plug & use a piece of 1mm solder bent to fit in plug hole till it touches the cylinder wall. Then rotate engine over to squish solder. Measure the thinnest part of solder & that is your squish clearance. The other way, is to remove cylinder head & tape a piece of solder in cylinder the entire width of cylinder. Then install head & torque to specs, 12ft/lbs, then rotate engine over a couple times, then remove cylinder head & measure thinnest part of solder. That's your squish clearance.

The easy way, is to remove spark plug & use a piece of 1mm solder bent to fit in plug hole till it touches the cylinder wall. Then rotate engine over to squish solder. Measure the thinnest part of solder & that is your squish clearance. The other way, is to remove cylinder head & tape a piece of solder in cylinder the entire width of cylinder. Then install head & torque to specs, 12ft/lbs, then rotate engine over a couple times, then remove cylinder head & measure thinnest part of solder. That's your squish clearance.

I prefer method 2. To me it gives me a better reading.

 

[DieselTech]

I prefer method 2. To me it gives me a better reading.

I agree method 2 is the safer more accurate way.

 

[Chainlube]

To make the squish band thinner, either sand down the head or the jug, to make it thicker ad another or thicker gasket.
If the piston already comes to the deck height, then it has to be the head.