Bt80 engine wiring help

[Whizz_the_motor_kid]

View attachment 78475
Yes the red switch is not hooked up. When you turn the power switch on near the starter switch, everything gets power.

You are going to love it. My engine is great, very smooth and has great power. So far I got it up to 37mph with a 40T sprocket and take off with no pedal.

YouTube Video

Where did you put your battery?

 

[Jam-D-Man..! AKA Jamie Mc]

Hi Dude. This is my second BT80 KIt And I can 100% Tell you that the Big red Switch (Yes I agree should have been the engine RUN / STOP ) IS Only half complete inside. The bare soldered connections are there but there is no wires connected to it inside from the throttle / switch assembly wiring loom, from stock. Although I did solder up a couple of wires to this switch properly when I checked the resistance through the switch using a standard multi meter it showed variations in resistance especially when the engine was running and vibration seemed to exasperate this. So I suspect that may be the reason they went with using what was originally planned to be a light switch, As the ignition ON / OFF switch. So for that reason if you did as I did And are planning on using the big red rocker switch on top of the Switch array / throttle assembly then I would for the sake of reliability Use the Red rocker switch or an after market switch for your lights or 12v accessories. And keep the originally incorporated switch to turn your ignition OFF / ON.

 

[Jam-D-Man..! AKA Jamie Mc]

Also regarding the green and orange wire that the manual says are reserved for Lights / Horn or whatever 12V accessorie (As long as you dont seriously over load the inline fuse from the battery (Can't remember fuse rating of top of my head is on side of fuse and in manual). When you turn your ignition switch on it causes these wires to become 12v + positive from battery well at least one of them does I originally assumed that the other was a 12v - negative for return but didn't seem to quite function right or had some weird affect on engine running smoothly if I remember, So I just used which ever wire it was that went 12 v + positive when ignition was turned on to power my lights through a switch to the positive of my lights and the negative of my lights I connected to engine earth you can attach it to the same place the green 12 v - negative wire that runs from the 12v - negative terminal of your battery and bolts to the bottom of engine, If you like. Make sure you use thick enough wires for the current that the wire is intended to carry for a couple of standard 12v lights it wouldn't have to be as thick as the Green wire running from 12v - negative battery to engine earth / casing for example.

 

[Jam-D-Man..! AKA Jamie Mc]

Regarding The black foam sponge type material that is used as an air filter inside the air filter cover. I have found this to be the culprit for seriously affecting the engines ability to breathe and as a 2 stroke is all about getting a finely tuned mix of petrol / 2 stroke oil and air flowing freely into engines combustion chamber and detonated efficiently & precisely timed so the exhaust gas can be expelled quick as possible to repeat the 2 cycle. Well I removed my air filter assembly including the oil soaked bit of sponge and ran the engine.
I could clearly see that at a certain point in the engines cycle instead of sucking in the vaporised liquid fuel just for a split second in the engine's cycle. It's clearly evident that pressure is blowing back out the wrong way of the carbs air intake and spraying what ever happens to be there with fuel / oil after a while the fuel evaporates and leaves mainly oil saturating your air filter & leaving the engine literally gasping for breath / air and so making your engine run rich (Which means the engine is getting slightly more fuel / oil mixture than air than it should be and makes what should be a nice reving engine seem very sluggish. Just to see if this is the case with you just for a quick ride to judge the difference in performance, As long as it's not excessively dusty running with out an air filter for a short while (unless you were extremely unlucky!) Shouldn't cause any contamination problems. I had been running mine for about 3 months with out an air filter only the black air filter housing with the 4 built in funny little air openings, Without any problems but if like me when you removed the soggy bit of oil soaked sponge that is supposed to pass for an air filter. Suddenly found ohh my god that's were all the power is in my engine the difference on both the BT80 kits I had was like night and day it just ran so much better & developed so much more power and higher engine speed was also a lot more responsive & better on fuel to boot. If you have tried this and the same happened to you pls let me know. As a suggestion for those who Don't want to risk sucking anything in passed the removed sponge air filter I really fine denier pair of tights makes a perfect replacement that offers protection without getting as choked up as easily as the stock black sponge.

 

[Jam-D-Man..! AKA Jamie Mc]

Im just gonna get straight to it..

I have a bt80 or bullet train engine.

Leftover green and orange wires, instruction manual says its for headlamps or horns.

How do i install a horn and headlamp with those wires?

Whats it the big red toggle switch on the throttle grip combo used for? I thought it was a kill switch but when used in any position, it does nothing.

If anyone here knows exactly what im talking about please help me out.

 

[Jam-D-Man..! AKA Jamie Mc]

Yes these engines do seem to collect a bit of fluid just below the carb on top of the engine. I have had two BT 80 engine kits and they both did this it took me months to finger the culprit. I know Frankenstein said he believes in gravity but there is a gearbox / clutch breather in the form of a straight headed screw with a 1-2 mm dia hole in the centre which can spit up a bit of 4 stroke oil which should be what you topped up the wet/oil auto clutch up with about 120ml of oil. (Probably better to fill up the engine with 4 stroke oil which is what the auto clutch uses for lubrication before mounting is a bit less tricky.
Also the carbs that come with these engines are notorious for leaking usually leaks out of where the primer button goes into the carb as the fit of the push rod of the primer is not a great fit in the hole that it goes through in the top of the carbs body that simply pushes down the float, Even if the float bowl is full it will allow fuel to "overflow" out of the carb.
I put a small bit of cloth rag and trapped it in between the gap underneath the carb and top of engine casing this soaks up the few drops that spill out into this gap and usually safely evaporates. (which points more towards petrol leak than oil).
But it is good practice to all ways shut of the petrol shut off cock attached to fuel tank when you have finished riding for the day as this will limit the amount of fuel that could leak out over night to just the small amount that the carb can hold.
Just don't forget to turn it back on when you go out to ride your motorised bicycle the next time as your engine will cut out after about 30 secs to a min.

 

[Jam-D-Man..! AKA Jamie Mc]

View attachment 78475
Yes the red switch is not hooked up. When you turn the power switch on near the starter switch, everything gets power.

You are going to love it. My engine is great, very smooth and has great power. So far I got it up to 37mph with a 40T sprocket and take off with no pedal.

YouTube Video

Yes you do need to wire the the big red switch your self there are some switching contacts inside the switch but they have no wires coming from them!
If you know what your doing you could solder on to the big red rocker switch's contacts and wire it up to run a set of lights or even add a third party or any switch that is capable of handling a 12 volt + what ever current your light draws. Best place for cheap switches would be to utilise car or motorbike switches. At a breakers yard for example would cost pennies.
Also the 2 wires you mentioned orange + green I think are switched through the bikes ignition switch. Which means when you slide the ignition switch to the left which is the ON position then +12 volt is supplyed to these via the ignition. So to use these to supply a horn or lights would mean that your circuit would start from one of these wires and go to one side of your horn or lights + power in and the other side from your lights or horn would connect up to the negative - 12 volt after running in and out of a suitable switch.
I used a car cigarette lighter socket usb adapter's circuits to knock the 12volts from my bike engine and battery's power supply down to 5 volts which is what usb powered/ charged equipment uses. I can now charge my lights or even mobile phone from my bike!

 

[Jam-D-Man..! AKA Jamie Mc]

View attachment 78475
Yes the red switch is not hooked up. When you turn the power switch on near the starter switch, everything gets power.

You are going to love it. My engine is great, very smooth and has great power. So far I got it up to 37mph with a 40T sprocket and take off with no pedal.

YouTube Video

Could you show me a better picture of your rear wheel mouted sproket and brake disk attachment. Nice that you have been able to use both a left hand side mounted sprocket and left hand side mounted brake disc together!
I get a max speed of 42.5 mph with a 36 tooth rear sprocket. But my wheels are 29 inch. Reached 46.9 mph down slight hill.
I Have tried the china doll engine with a 32 tooth it was ported with expansion exhaust, Hp carb, 1mm planed of cylinder head. Pulling away from stand still with the manual clutch that the china doll uses was a bit much of an ask and would have undoubtly destroyed itself in next to no time.
So needed to pedal off not just to start the china doll but to help get it rolling from standing start which after a while woiuld pick up speed.
It's like if you said to a car driver your in the middle of no where and your gear selection goes you have to choose just one gear to be able to get you home.... What gear would you choose? I reckon if not to many stop starts to get home I would probably go with 3rd maybe. Well the set up I had on the china doll with a 32 tooth rear sprocket would probably equate to a car driver choosing 5th or 4 th! From this you can probably imagine what in a car this would mean ie ridiculously poor acceleration and around a good chunk of your clutch's life expectancy!
I'd personally say if the rider is over 12 stone using stock powered engine with hills to go up don't go below 40 tooth rear sprocket.

 

[Guest-793307]

Im just gonna get straight to it..

I have a bt80 or bullet train engine.

Leftover green and orange wires, instruction manual says its for headlamps or horns.

How do i install a horn and headlamp with those wires?

Whats it the big red toggle switch on the throttle grip combo used for? I thought it was a kill switch but when used in any position, it does nothing.

If anyone here knows exactly what im talking about please help me out.

The red switch is a blank it as no wire coming out of it another Chinese mistake

 

[Guest-465184]

Im just gonna get straight to it..

I have a bt80 or bullet train engine.

Leftover green and orange wires, instruction manual says its for headlamps or horns.

How do i install a horn and headlamp with those wires?

Whats it the big red toggle switch on the throttle grip combo used for? I thought it was a kill switch but when used in any position, it does nothing.

If anyone here knows exactly what im talking about please help me out.

Red switch is headlights and yes the two wire are for the horn and lights YouTube has multiple videos on the lights and horn setup