Ok so I have the bullet train 2 stroke centrifugal clutch kit on a huffy nel lusso.
Out of the box the motor was super powerful. Nt carby with 56 tooth sprocket because where I live there are tons of hills. Bike was going 32 mph at open throttle and barely slowed up hills. After about 200 miles I drained the 4 stroke oil and filled back up with about 120ml of fresh oil. Its hard to tell just about how much i put in it was about 120ml. Now I max at 25mph and losing power up hills. Put in a new plug also. What could be the problem? Tried hp carb but the throttle cable that it came with was to long and could barley move past 20. Put nt carb back on no vaccuum leaks. Where did my power go? Also i noticed a small pool of gas on motor under carb but may have just been spilled while filling. Will keep an eye on and update if i notice it again. Thanks for any help. I will check to see if head is tightened down but waiting for the allen tool to arrive from Amazon.
Hi there Kman123, My name is Jamie McCaffer hailing from the UK I also bought the BT80 about 2-3 weeks ago & had exact same problem I tried a HP carb also BT80 didn't like that at all wouldn't even idle! Also tried the Speed carb worked better than the HP carb but Worse than the NT I got with BT80 kit. (Bought mine from Petrol scooter.co.uk as I live in the UK) Only improvement from the other 2 carbs I tried was that the pool of petrol which you describe has also afflicted me. I t initially thought that it was maybe a bit of spillage from refueling or may be i had accidently hit the primer button a few times and it had over flowed into the air filter then out onto the top of the engine completely filling the 2 toughs that run transversely across the top of the engine underneath the carb as you described. I am pleased to tell you after much frustration and also a lot of petrol spilt from the carb, I finally fingered the culprit. Well for me anyway could be that this is the fix you were looking for...worth a try.
Well believe it or not, The petrol actually leaks out from the underneath the primer button along the metal shaft that the gold coloured button is attached to there is no seal what so ever to stop the petrol as it sloshes around or even with the engine of and just leaning it over far enough for the fuel level inside the carbs float bowl to simply travel unimpeded up the hole in the carb that the primer button shaft uses to push the float down manually,. In so doing pouring down the side of your carb and making a mini swimming pool on top of the BT80 engine. It made me & where ever my bike was stink of petrol fumes to the point of nausea!
That's not to mention the risk of turning your beloved bike engine + 1's self into a blazing ball of fire!
I solved the problem up to now that is By simply either sealing around the bottom of the primer button with some kind of sealing compound that will resist petrol simply eating it's way through it or turning blue-tak to goo-tak! I mean come on how often do you use your primer button anyway?
Me personally have.
1. Never had to use my choke to start it even from 5 degrees C !
2. Never had to use my Primer button it started on the second short press of the starter button after just being assembled and fuel just poured into the fuel tank!
So if you don't for see a vacum lock in your fuel delivery system that you can't circumnavigate without a primer button? Might in extremely rare cases mean that, At the worst you'd have to blow down a fuel hose, Or even worse have to Suck it!
Seems easier to just lift your full fuel filter a few inches higher up, That usually does the trick if it's a bit of a stubborn air lock.
I used a cut to shape piece of thin rubber inner tube (originally on the inside of carb so as to allow the primer button return spring to make a tight air / fuel seal with the carb housing but failed after rubber swelled to twice it's size! and sank to the bottom of the float chamber. Lol
So retro fitted the same to outside of carb using a piece of plastic to act as a buffer to the rubber and blue tak hybrid seal hasn't spilt a drop up to now but only completed this a week ago.
If this eventually fails again I think I will either remove the primer altogether and use petrol proof sealant or something to block up the hole solder maybe max operating carb temp and fuel contamination issues permitting.
Maybe a bit more expensive than a generic sealant would be to obtain a good quality petrol tank sealing compound. This would be the best quick & reliable route to go down, Me thinks or even drill it or not, To a Slightly wider diameter so as to use a small nut & bolt to compress a material sympathetic to the tasks constraints but appropriate to the cost & time invested into this critical repair if these were official transport vehicles say a modern aircraft for example the entire fleet would be grounded and heads would surly roll for such a potentialy fatal total oversight of something so apparent I mean do they actually put one of these together themselves before they properly test them and mass produce to sell to the end consumer (That's us by the way, Lol). Not to mention how simply & cheaply this could be fixed that's 2 so far .
Anyone else who has had the same issue with this type of carb design outing please let me know as I would like to put such a serious issue to this carbs manufacturer to see what their reply would be.
I know if I was incinerated by one of these carbs that has the potential to turn quite easily into a 30+ mph 3 litre petrol bomb on wheels!
For sure, My family & friends not rest & would be wanting to string the carbs quality controller & designer up by their little ends!
