love2ride1111
Scoot Enthusiast
Posts: 222
Location: Indian Rocks Beach Florida
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Post by love2ride1111 on Oct 28, 2020 13:30:32 GMT -5
Ok , so there is more to this whole story but just some quick questions. I noticed this phenomenon last year. Quickly revs , no lag , alot more torque and power and speed....because of the leak at the exhaust gasket. Yes I know of all the negatives of this. Moving on to my question. Is this because of alot more air getting inside or some other reason ? when it is tightened for a short time till it untightens it lags and has less power. I have a 19mm Arrchiee carb on 73cc kit. If I ever get the exhaust to not leak would a much larger carb provide the same explosive power ? As it was before this I would slowly get to about 8k lag some and move up. Now it just jumps really strong. Ive owned this for more then a decade and although its fast , it became really fast when the exhaust( old and new ) would not seal ( and this thread is not to discuss that issue ).
Thanks .
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Post by aeroxbud on Oct 28, 2020 14:00:37 GMT -5
It's because the engine was running lean. That's when it makes most power. Right up until the moment it seized.
It's a similar thing to when you have a crank seal start to leak. That's why it will hold onto revs.
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love2ride1111
Scoot Enthusiast
Posts: 222
Location: Indian Rocks Beach Florida
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Post by love2ride1111 on Oct 28, 2020 14:28:54 GMT -5
So yes I am aware of that , but that was not my question.
What do you mean " hold on to revs " ?
My question is about carb size
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Post by aeroxbud on Oct 28, 2020 14:30:32 GMT -5
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Post by aeroxbud on Oct 28, 2020 14:47:19 GMT -5
Ok Moving on to my question. Is this because of alot more air getting inside or some other reason ? Yes because it's running lean. |
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Post by Zino on Oct 28, 2020 17:18:40 GMT -5
When I used to race snowmobiles as a kid we would lean them out and they would just scream across the ice on radar runs .
We would either come home winners or drag it home with a hole in the piston .
So you will feel extra power until she goes boom with a exhaust leak.
You might be okish for now but leaks get bigger over time and if its a cool night you will run closer to the holing a piston or if your lucky just a soft seize .
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love2ride1111
Scoot Enthusiast
Posts: 222
Location: Indian Rocks Beach Florida
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Post by love2ride1111 on Oct 28, 2020 20:30:33 GMT -5
Like I said there is a whole lot more to this "thing " just curious if a larger carb ( more air ) would do the same performance enhancement as the exhaust leak or it doesn't work that way because the fuel allotment will go up as well .
Thankyou.
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Post by Zino on Oct 28, 2020 21:13:01 GMT -5
A larger carb with a sealed up nice exhaust would add power
17.5 to 19 mm is all you would need
Bigger than that is not better .
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Post by aeroxbud on Oct 29, 2020 5:40:46 GMT -5
Like I said there is a whole lot more to this "thing " just curious if a larger carb ( more air ) would do the same performance enhancement as the exhaust leak or it doesn't work that way because the fuel allotment will go up as well . Thankyou. If you look at the link I posted. The 19mm carb actually had less performance than the 17.5. The 70cc kit just couldn't take advantage of the extra fuel. And the lower flow rate of the bigger carb performs worse. |
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