bunch of Grubee GT5 questions
- Thread starter andy b.
- Start date
I know. That's what makes me so mad. I've rebuilt multi-cam engines, antique engines, racing engines, heck, even a 1962 Harley XLH with four cams in it. How the heck can I not get this stupid Chinese 2-cycle running. It doesn't even have reed valves in it!!!!
Maybe it is a float issue. If I hold the primer button in, it takes about four seconds for the fuel to start flowing out around it. Does that sound correct?
andy b.
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Ah Ha!
I can hold my primer in for an hour and gas never flows out anywhere. No wonder you are rich. Your float isn't turning off the gas flow. Holding in the primer only allows the carb to fill faster as you are letting air out of the bowl so gas can flow in. Thanks to Gear Nut we know how to adjust the float. And if that doesn't work, your float valve isn't seating. Make sure you check the valve and seat and blow it out good. That may not cure everything, but it is a problem you need to cure.
Rod S
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GearNut
Active Member
Sorry man, but the primer button does not let any air out of the float bowl. The float bowl is constantly vented to the atmosphere through an internal port between the air cleaner mounting face and the ceiling of the float/ fuel chamber.
The primer button presses down on the float which will open the fuel inlet valve and if it is held down long enough, it will force the carburetor to flood.
This is also known as a "tickler button", a term that alot of the old timers here will recognize.
4 seconds to flood sounds about right.
The primer button presses down on the float which will open the fuel inlet valve and if it is held down long enough, it will force the carburetor to flood.
This is also known as a "tickler button", a term that alot of the old timers here will recognize.
4 seconds to flood sounds about right.
Flight Risk
Member
hey so im kind of a noob 2 motors/ motor bikes, does it matter whether the clutch is installed because my clutch does not have any affect, is there a video on how to install it? thanx
Evan R
What motors do you have? The China Girl motors come with the clutch installed. and Yes, the clutch will have no affect if it isn't installed. Or do do you mean engage the clutch?. It takes tremendous pressure to release the clutch. When I first set up my bike I couldn't get the clutch to disengage until it ran for awhile and got the clutch to slip. I think the pads may have swelled up or something.
RS
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Dang, You're right. I just tried it, and dagnabit, it had fuel coming out. So that'll give it a rich prime eh?
RS
GearNut
Active Member
Yes, a very rich prime.
The old fashioned Amal and Bing carburetors used this system, as well as a few others I cannot recall right now.
By today's modern motorcycle carburetor standards, it is in the stone age.
Some larger displacement European motorcycles just would not start up with out being flooded a little, even with a choke being used as well.
The old fashioned Amal and Bing carburetors used this system, as well as a few others I cannot recall right now.
By today's modern motorcycle carburetor standards, it is in the stone age.
Some larger displacement European motorcycles just would not start up with out being flooded a little, even with a choke being used as well.
Well the Grub has REALLY been p!$$ing me off!!!!! I still can't figure out what may be wrong with my setup.
The darn thing still wouldn't run and I was getting fed up, so I tried a few other mods the past few days. I finally got most of them finished up today, and amazingly, the thing now fires right up!!!!
What really impressed the h3ll out of me was the effect just adding a few Italian parts has. AMAZING!!!
Yeah, I cheated.
But I WILL conquer that Grubee yet!!!! It will just end up being a winter project. Even if I have to take the entire engine apart to see what the problem is.
andy b.
The darn thing still wouldn't run and I was getting fed up, so I tried a few other mods the past few days. I finally got most of them finished up today, and amazingly, the thing now fires right up!!!!
What really impressed the h3ll out of me was the effect just adding a few Italian parts has. AMAZING!!!
Yeah, I cheated.
But I WILL conquer that Grubee yet!!!! It will just end up being a winter project. Even if I have to take the entire engine apart to see what the problem is.andy b.
Andy,
I just saw those pics and notice the spark plug, you should try replacing stock parts 1 by1 while trying to start after exchanging 1
(I.e use stock sparkplug instead and try to start, fail to start then put the new one back in and replace another part etc etc
Evan
Believe me, I tried every method and part I could think of (spark plugs, fuel mix ratios, air cleaner on or off, exhaust on or off, angle of the engine and carb, choke in every position I could think of, speed when engaging the clutch, etc.). And here's the thing, the Morini engine fired up on the second kick right out of the box, so I haven't lost all mechanical aptitude. Also, I left the choke on for longer than I should have, and the Morini started acting EXACTLY like the Grub acts all the time. As soon as I gave a full twist of the throttle (that is how you kick the choke off on the Morini), it settled down to a perfect idle and revs right up the instant you hit the throttle. It really leads me to believe the Grub is just getting way too much fuel. I will probably have to fool around with the jet orifice and see what effect that has on the Grub.
For now though I should have this baby fully operational by the end of the weekend and be riding it around. That was my goal in this entire project, not to spend two months fiddling with it.
andy b.
I have a GT2B 48cc motorbike that i recently built. So far it has been problem after problem. First the clutch wouldnt work but then i fixed it. Then the throttle had some problems, finally fixed that. My worst problem was that the float in the carb had a small crack in it so it would flood. I got a new float and now it works better. My problem with it now is that if i am going, it will get up to speed at about 25 to 27 mph (full throttle) then it starts to bogg down to about 15 16mph. Once it does this it slowly works its way back up to speed at 27 mph then it boggs down again. I dont know what to do to fix it. It is still during break in period. I have ran about a tank and a half through it so far. could it just be still breaking in?? Anybody Know what to do???????????????
We first need to know how you define "bogging". The two possible extremes are - it slows down while you have the throttle full but sounds like it is running smooth just no power. The other extreme would be you had the throttle full and the engine started to sound like it was running rough and missing as you slowed down. As you are slowing down what does changing the throttle setting do? One way it is too rich the other way too lean.
Jim
Jim
Flight Risk
Member
My Grubee 48 used to lose power on hot days during a long ride, when I was still breaking it in. It's cooler now and I haven't had the problem lately, so don't know if it is just tight parts breaking in or a heat thing.
Rod S
Rod S
well first what i mean by bogging down i mean it will be going then it just starts to slow down. next i am running a 24:1 ratio for the gas. When i change the throttle setting on it when it slows down it usually starts to go the speed of the throttle. Like its only when i get to around 27mph then it starts to stall out.