48cc Grubee, tuned fine. Boost Bottle, some issues...

H

his196

New Member
48cc Grubee, on a Specialized Mt. Bike. Running fine.

Installed Boost Bottle and WOW, increase power on low/high end.

PROBLEM: Mid range.

This thing BOGS at about 15-20MPH and THEN kicks in to pulling just fine, up to about 30 MPH.

What's causing my bog at 1/3 throttle?

Clip at 2nd.

Air/Fuel at about 2.5 turns out.

Idle OK...It'll idle fine.

But man, at about 12-18 MPG, it's just BOGGING BAD!

Anyone?

Thanks.

~Chris B.brnot
 
There is no air fuel - the screws only adjust idle. That's it.

If I were you I would adjust the float and look for air leaks with carb cleaner.
 
Hey there DuctTaped Goat,

Yeah, I've adjusted the float, the clip, the muffler has one hole punched in it, took off the red air cleaner cap completely, removed the small black tube that connects to the rear of the air-cleaner and plugged hole with tape.

Running boost bottle, with 25:1 mix, on my 4th tank.

It's starting up right away, and idling fine, nice and low. I understand that there's the idle speed screw, and then right next to it, the air screw, which when I make minor adjustments there, it changes whether or not the bike will idle at all.

Finally, low rpm, good torque.
Mid rpm (like 10-18 mph), extreme bog.
Then finally, at WOT, it slowly gets real deep sounding, and pulls out of 18 mph, right on up to about 30 in no time, and won't go much faster.

Thanks for any thoughts you may have.

PS: All connections siliconed, and no leaks (that I can find).
 
Yeah, not expecting much more as far as speed.

Just trying to figure out why the mid-rpm bog, from 10-18 mph, VERY sluggish, then all of a sudden WAAAHHH, with nice, smooth pull and speed right on up to 30 ish.

Thanks!
 
I would guess you're getting too much fuel in that range, especially as how you say there's no leaks.

What I would do is remove the tank's filter, run an inline filter, and adjust the float to reduce fuel. That oughtta keep the flow high to keep up when climbing in rpm, but not overkill with fuel. That, and leaning out via rejetting.
 
Cool thank you much!

I do have an inline fuel filter.

I had previously adjusted the float by:

1. Spreading out it's 'wings' a bit;
2. Setting it parrallel with the seal-line.

Not quite sure what the above accomplished...opened it up to allow MORE fuel I believe, so if so, you're saying set the float a bit lower, to allow less fuel?

I'll get around to jetting one day, not quite there with the tools/experience.

Thanks again.

~Chris
 
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