extreme speed when almost out of gas

ex-28

New Member
i have had this happen to me 3 x times my bike averge speed is about 40 km/h but when i'm just about out of gas (have enough to ride about 2 min) my bike fly's at wot and does 49.3 km/h it literlly flys and runs just as smooth as if i had a full tank !

i was thinking maybe a richer mix in the verry last drops of the tank , or maybe its sucking more air , but if i try to adjust my air/fuel setting , no way can i make it run this smooth or as fast. it's really weird , i am on my 4th tank now for breakin running 32:1 and the ngk BP6HS plug with regular gas not high octane. 80cc engine from zoom and the cns carb.

so last night i went out for a ride , and shut off my gas sure enough boom 1 min later it kicked in my gps and bike spedo climbed to 65.8 km/h and was still climbing , but i backed off .

also anywhere else that sells a jackshaft at a descent price ? 200 at sick seems a bit high. i thought zoom was going to start selling them but cant seem to find on there site.
 
it's leaning out, that's what happens when it's using up the gas in your float bowl. so basically your bike's running rich.

try moving your needle clip up a notch, and keep an eye on your plug.
 
the notches on the clip , i have moved it up 1 notch from stock , on the bar there is 6 notches , stock it was in middle on the 3rd , i moved it up 1 notch so i am on 2nd from the top now and plug is still perfect , it good to go up 1 more yet ? , will it use more gas by moving the clip around ?
 
it won't use any more gas, or if it did, it wouldn't be noticeable.

if you move it to the top, make sure you start with a clean plug (doesn't have to be new, just clean,) and check it after a good ride. you don't wanna go too lean and burn up your motor.
 
his bike's already rich. lowering the clip would make it richer. if he started on the 3rd notch, then went up to the second and the plug is good, going up is the only way to go.
 
will move the clip up 1 more notch from current 2 from top to 1 from top and see how it is , with new plug , right now at 2nd from top plug is good no oil on bottom of exaust cap , bu if i pull off the racing cargbs filter , i do have a little oil always sittin in there , running 32:1
 
Just as a word of caution, don't run the engine completely out of gas when you do the valve shut-off lean scream. In doing so you are essentially siezing your engine with the lack of lubrication. Like I said...a word of caution.
 
yes, i was scard of that to running out of gas is not a good thing :) thanks for your input it will help others that read this thread as well :)
 
yes, i was scard of that to running out of gas is not a good thing :) thanks for your input it will help others that read this thread as well :)

No worries, a siezed motor is an unhappy motor...don't run too lean! That's all folks...cheers!
 
oil on the filter is normal. it's blow-back. take it off now and then, wrap it in a rag and squeeze all the oil out.

another word of caution, running at the top notch is usually too lean. not always, your bike might work better with it. just keep a close eye on the plug. better to be too rich than too lean.
 
yes but i have the racing carb from zoom , so theres no real sponge filter like in the stock carb , but i will keep an eye out on it , thanks
 
I would change the main jet. SBP sells dellorto style jets, that work perfectly with the nt new style carb. I wouldnt muck about with soldering them and redrilling. If you can get the mixture dialed in, she'll scream all the time.
 
Guys, he said he has the racing carb from Zoom, which I understand to be the same as the CNS carb. If that's the case then you can make all of you're mixture adjustments with the mixture screw.
 
I would change the main jet. SBP sells dellorto style jets, that work perfectly with the nt new style carb. I wouldnt muck about with soldering them and redrilling. If you can get the mixture dialed in, she'll scream all the time.


What does te NT new style carb look like?
 
Back
Top