My first poke at your problem would be to ask if your carb is level, if not then you should adjust the float to allow less fuel in the bowl. On your CNS carb doing the float adjustment would have stopped the overflow problem you had, and would be the first step toward getting it tuned properly. With the NT carb I would guess you should adjust the float as well, since the carb angle is gonna be the same for both carbs, but I cant offer any more advise since I dont own an NT carb....
Please help - Grubee GT5 80/66cc will not accelerate running rich
- Thread starter nexgen91
- Start date
""This one only gets up to 20mph....turn off the petcock...wait a little (with throttle pinned) then it speeds up to 28mph...then turn the petcock back on before it starves...and it stays at 28mph..""
That was sorta like what I am getting. I though at first the engine was not getting ENOUGH fuel, because my tank was low and it's a gravity feed on these things...but then I realized it had been getting too MUCH fuel - by, as you said, turning off the fuelcock, and within a few seconds I could really fly! In fact, this is the only time I can twist full throttle without it "bogging" down.
Of course eventually you creat a vacuum and the engine is starved of fuel
so I would turn the fuel cock on for a few seconds and repeat the process.
I was actually content with this for a few days - experimenting with just the right "sweet spot" on the fuelcock. This works great for 5-10 minutes, but eventually it either starves for fuel (you turn the cock fully ON and it runs), or it would bogdown with a possible flooding condition (turn the cock OFF and after a few seconds, it takes off again!)
But today, it was getting worse, flooding more and more, and for the first time, I noticed gas pouring out the air intake when the bike is off. That's a definite over-fill of the carb bowl.
So I found this thread, amonst many, looking for "flooding" threads - there aren't any specific ones I could find. But I found one saying to cheack the float and perhaps 'adjust' it by bending the tines...
Well, lol...I took the bowl off and my plastic donut ring float is about half filled with gas.
I found reference to this on one or two other threads. Like the other threads - I can see no leak, so I assume t only let the gas in when it was hot, and slowly over the past weeks. (I have about 35 hours on the bike).
So that is defeintely what's causing the |"bogging down", and I discovered it like Gear Head said, by shutting the fuelcock off while running.
Now the problem is how do I fix this float. I am considering drilling a tiny hole (or two) to get the gas out, and encasulating the whole piece in gas-OK sealant. But the guy that was doing this a few days ago hasn't updated!
I know I can order a new float, even way up here in the frozen north, but I am even considering making one from cork (fisherman's bouy)...hmm
It`s very weird how the gas won`t leak back out!
bMf
KEY WORDS flooding, flooded, float filled with gas, carb float, donut ring
That was sorta like what I am getting. I though at first the engine was not getting ENOUGH fuel, because my tank was low and it's a gravity feed on these things...but then I realized it had been getting too MUCH fuel - by, as you said, turning off the fuelcock, and within a few seconds I could really fly! In fact, this is the only time I can twist full throttle without it "bogging" down.
Of course eventually you creat a vacuum and the engine is starved of fuel
so I would turn the fuel cock on for a few seconds and repeat the process.
I was actually content with this for a few days - experimenting with just the right "sweet spot" on the fuelcock. This works great for 5-10 minutes, but eventually it either starves for fuel (you turn the cock fully ON and it runs), or it would bogdown with a possible flooding condition (turn the cock OFF and after a few seconds, it takes off again!)
But today, it was getting worse, flooding more and more, and for the first time, I noticed gas pouring out the air intake when the bike is off. That's a definite over-fill of the carb bowl.
So I found this thread, amonst many, looking for "flooding" threads - there aren't any specific ones I could find. But I found one saying to cheack the float and perhaps 'adjust' it by bending the tines...
Well, lol...I took the bowl off and my plastic donut ring float is about half filled with gas.
I found reference to this on one or two other threads. Like the other threads - I can see no leak, so I assume t only let the gas in when it was hot, and slowly over the past weeks. (I have about 35 hours on the bike).
So that is defeintely what's causing the |"bogging down", and I discovered it like Gear Head said, by shutting the fuelcock off while running.
Now the problem is how do I fix this float. I am considering drilling a tiny hole (or two) to get the gas out, and encasulating the whole piece in gas-OK sealant. But the guy that was doing this a few days ago hasn't updated!
I know I can order a new float, even way up here in the frozen north, but I am even considering making one from cork (fisherman's bouy)...hmm
It`s very weird how the gas won`t leak back out!
bMf
KEY WORDS flooding, flooded, float filled with gas, carb float, donut ring
Hey, you don't adjust the fuel delivery with the fuel valve petcock! If you're bike runs better a little bit after the fuel valve is turned off then you need to adjust your float for sure, to lower the fuel level in the bowl. Briefly reading your post I see you may or may not have done that, need to if you haven't.
Not sure what carb you have, but a rebuild kit is cheap and they include a new float, if you have damaged yours and not gotten it fixed check out a carb rebuild kit. (The spare parts are always nice too, second set of jets so you can compare sizes, air filter you can alter the flow and compare etc Having parts to swap is a great way to learn)
I posted a thread about tuning my CNS carb, including info on adjusting the float, specifically when you have the condition above (bike runs better when fuel valve is off). If you have a CNS carb I would suggest you check this thread out, http://motorbicycling.com/f4/cns-carb-working-great-32736.html?highlight=cns+carb+working+great . Even if you have another carb you might be able to find something usefull in that thread, specially if you have a flooding condition due to bad float adjustment...
Yes...my float was half-filled with gasoline.
Given the large number of occurences of this, I am surprised they continue to use the same little hollow donut...
Cheers
Given the large number of occurences of this, I am surprised they continue to use the same little hollow donut...
Cheers
I have seen pictures of what looked like an all brass float, but I have only seen the plastic ones in real life.... Both Grubee 2010 SkyHawk 66cc kits came with plastic float as well as the rebuild kit. I haven't had one leak yet though...
i re jetted the main to .065 adjusted the float to 21mm off the gasket seat and replaced the throttle cable. brakes are not scrubbing, and im a little guy (145 lbs) turning off the petcock does nothingare your brakes scrubbing?
do you weigh alot?
what method of deduction did you use to make whatever (plz outline) changes you made to get it running better?
Let us know.
This one only gets up to 20mph....turn off the petcock...wait a little (with throttle pinned) then it speeds up to 28mph...then turn the petcock back on before it starves...and it stays at 28mph..
just trying to help you man.
I'll mess with the carb more when i get it finished....
in the mean time...it runs great at low throttle and i don't need to blast around anyhow. and when i do...i know how to get it to go...
Maybe when to previous owner said it was broke in, he did not mean all the way. Thanks for your help