Ordering T-66/80cc replacement Motor Tips?

[Philandra Chambliss]

hey so my motor tanked again, so ive decided to order a 66/80cc motor for 68 dollars my question is that these paticular motors can do 35-40 mph from what i hear,


What size rear sprocket would i need to die back the speed to 30mph dying back the speed is crucial to passing it as a 50cc engine.


a loss of top speed wouldnt bother me cause if i am correct if i up the sprocket size past 44t it returns that into low end torque which i would like to have.

 

[crassius]

I've never fitted one with more than 56 teeth cuts speed a lot and gets pretty close to frame as diameter is bigger - they make a standard mount 60 tooth, but I'd check the diameter to see if it would fit without hitting frame before ordering

 

[FurryOnTheInside]

So your plan for breaking in a brand new engine is to run it at high RPM with little load and reduced airflow?

I would rather stick with the 44t and use some self control lol. Less RPM for the road speed means less of that distinctive, cop magnet, 2-stroke noise.

30mph is 6500RPM on my bike with 32mm tyres and a 42t, equivalent to a 43t on your 38mm, and it's IMO a good compromise between torque and speed. I think raising the RPM needed to hit 30mph won't help the engine's reliability or stealth.

 

[Philandra Chambliss]

I've never fitted one with more than 56 teeth cuts speed a lot and gets pretty close to frame as diameter is bigger - they make a standard mount 60 tooth, but I'd check the diameter to see if it would fit without hitting frame before ordering

Thanks crassius,

In Regards to Torque,
how would the effects of the torque play out on the 66/80cc geared at 56t max vs the 50cc?

i can actually dash the attached screen shot below: uphill for a full 3.8 miles of my 18.1 mile trip one way under mild to intermediate assistance by pedaling at the height of the travel 20ft to 374 ft of those 3.8 miles with a 44t sprocket @ 25-30mph.


this is a demographic print of route which depicts the effort i go though starting near W meeker St fallowing up the side of kent des moines road which will turn left near Greenside Rec

i figure the low end torque would come in handy for that hill alone i don't really like to pedal too often on cheap bikes but i get some pedaling in when speed launching when necessary.

 

[Philandra Chambliss]

So your plan for breaking in a brand new engine is to run it at high RPM with little load and reduced airflow?

I would rather stick with the 44t and use some self control lol. Less RPM for the road speed means less of that distinctive, cop magnet, 2-stroke noise.

30mph is 6500RPM on my bike with 32mm tyres and a 42t, equivalent to a 43t on your 38mm, and it's IMO a good compromise between torque and speed. I think raising the RPM needed to hit 30mph won't help the engine's reliability or stealth.

standard break in no high rpm til power building second tank.


regardless the 80 and the 50 look alike bone stock for as much as anyone cares i could print the old engines paper work out at the end of the day the 66 shares the same bottom end, gaskets, and parts etc.
the only difference is the case studs and the piston to bore ratio.


other then that they both the same 48cc excluding the stoke length.,

 

[FurryOnTheInside]

69cc is 40mm stroke, 66cc is 38mm stroke. But no one can see that either. (65 was a typo, sorry)

Stick with the 44t IMHO because it provides more resistance, more load for the break in.
It takes 8000 RPM for me to hit 37mph with the 42t and I don't think you would want to be having to use such high RPM often if the idea is to be less noticeable to predatory cops.

 

[Philandra Chambliss]

69cc is 40mm stroke, 65cc is 38mm stroke. But no one can see that either.

Stick with the 44t IMHO because it provides more resistance, more load for the break in.
It takes 8000 RPM for me to hit 37mph with the 42t and I don't think you would want to be having to use such high RPM often if the idea is to be less noticeable to predatory cops.

thanks and by the way i am going for my endorsement on a rented moped as passing shall be easy on a 50cc and the steering on my bike is a bit more healthy then that of a moped.

i should pass with flying colors. then i can open my bike up with pride around police.

 

[crassius]

I'm a bit lost - if you get 25 to 30 uphill with 44T, isn't that fast enough?

 

[Philandra Chambliss]

I'm a bit lost - if you get 25 to 30 uphill with 44T, isn't that fast enough?

The objective is no assistance
But torque would help that is fast enough but adding more rpm would help as with no assist it's 15-20

 

[crassius]

unless you weigh about 300 pounds, it sounds like your motor isn't running properly