Engine Trouble Not igniting every 2 stroke / brake problems

[Vikingimike01]

Hello forum!

I have a 66cc 2 stroke motorized bike. It's stock, well almost. Mods: Banana pipe, 60mm mesh air filter.
I was running rich before.

So what happens: the engine does not ignite every 2 strokes at low-mid RPM. I can use the choke, and put it to about 1/3 - 1/2. Then the bike runs OK in low range RPM. But it (Not sure wich) bogs or 4 strokes at mid-high range RPM, its a very loud thunder-like noise. It does not slow down, it just accelerates slower, and becomes louder as it goes faster.

But when I turn the choke to max, or more than halfway, it almost doesn't go and 4 strokes all the time.

I did notice the green wire that connects from the kill switch is 90 degrees bent. nothing else. White wire is not connected to anything, not touching anything, it has the plastic cap over the metal part.

Ideas?

 

[crassius]

when motor is running, choke should never be used - use the clip on the needle to fine tune the mixture once the motor has run in for 100 miles or so

 

[Vikingimike01]

Well..... I checked the needle..... It was on the highest (leanest position)
I dropped it down to default (One from the bottom, mine has 4 places)

Runs better than new! No joke. Torque is way better. Maybe its the banana pipe, maybe the oversized air filter... Maybe both.


THEN IT HIT ME. I had around 1/8 litres of fuel in the tank... In the morning, i put 65ml of oil in the tank... To get ready to get 1 litre of gas... Saw I had a flat (3rd time) then decided not to go to school with this thing (I did 3 times, its amazing! I'm standing in front of the main entrance on the street, idling the engine to get it warmed up. I have had good looks, even very nice compliments!)
And I forgot... I didn't go to the gas station... So I was going 16:1 before. I had 1/8 litres. Then plus the oil for a whole litre.....
What a waste of oil. Will the plug clean by itself? Should I wipe it??

I'm literally dying

 

[crassius]

you should drain tank and carb - from now on, always mix fuel in a can, never in the tank

 

[LewieBike]

Get to know intuitively your carb's controls. The choke on the NT is backwards to most Keihin style motorcycle carb's I'm familiar with.

If this engine is still breaking in, it's probably better to let it four stroke a bit in the mid and top range, I'd lower the needle circlip, *after* I made sure my fuel and oil mix ratios were correct. These are old school two strokes and they like to be kept a bit on the cool side of operation while breaking in.

 

[Vikingimike01]

Yeah, thanks guys. I had these (66 and 49cc) for over half a year, but still sometimes forgetting stuff. Then remembering!

I don't want to start a new thread again, just asking here: Are rim brakes superior to disc brakes? Or no? I'm looking for powerful braking power (I'm a big guy, so the bike doesn't exactly stop when I pull the brake in)

I have a 7-8 year old rim brake. It hasn't been used much, maybe half a year of 1 hour riding in side streets.
Also I only have a brake on my front wheel since the back wheel had to be offset because of the sprocket, as well as some of the screws had to be filed off. It's so offset that the rim brake would have to be re-positioned.
My front wheel is out of true- but just a bit. I know it'd help to true it for braking power, wich I'm gonna do in the morning.

Should I replace my front rim brakepads? Or just go for disc brakes?

 

[LewieBike]

Having both brakes working is best. An untrue wheel will not help your braking with rim brakes. How badly out of true is it? more than a few millimeters? Can you have someone who is adept at wheel repair true this wheel so it's safe to ride? You should also get your back brake reconnected.

Disc brakes are better than rim brakes, but you'll need new wheels, discs, calipers, and if the bike is older, some way to adapt the calipers to the frame and fork It starts getting more expensive than what your bike is probably worth. You wanted to motorize a less than optimum condition bike, this is not a good life choice.

Maybe best to save your money and put it into making this bike safe to ride while being pedaled. Having one questionably good rim brake system on a rim that wobbling, on bike that can easily exceed the speed you could get from pedaling alone is stacking the odds against your self in Darwin's Awards Casino.

I refuse to help you make more bad choices about this bike if you can't stop making stupid decisions.

 

[Vikingimike01]

Ugh I don't really get where you're going in the last sentence. I can't really get anyone to true it since the local bike mechanic shop refuses to even look at it, because it's motorized. They don't even want to sell me parts anymore, so I have to order them.

As I said I'll true my front wheel, if I have the money get a disc brake and a new wheel maybe.

I had the rim brakes disconnect 2 times when riding... This is why I was asking. It's not badly out of true (The front one) it's just barely noticable (1-1.5mm) but the back one is bad (2-3mm)
The bike is exactly 7 years old, it is an MTB with a strenghtened frame. It doesn't have the top bar part so I had to install a piece of wood for my fuel tank. Don't worry, tested it it's not comming off.

I also have fat tires and I pump to about 30 - 35 PSI (not good roads here sometimes)
You can look at my PFP and see the double bars on the frame (Under the engine)


I've also modded the thing with a banana pipe and a 60mm mesh air intake. Torque is better.

 

[JerboaJohn]

I think he means don't build it up (or ask help) until you have good wheels. some ppl are sticklers for safety, but you can true your wheels at least 2mm with a spoke wrench.
back wheel probably has a couple hits on it. replace...
craigslist is a good source for used bikes for parts.
be safe. have fun.

 

[Vikingimike01]

Thanks, I'm trying to be very safe, this is why I asked.

I'm not one of those hooligans that ride WOT all the time and yeah... In back streets you have to brake a lot!
(Not saying I don't like WOT

I don't have a spoke wrench.

Back wheel has 2-3 spokes ripped out from last crash, that was the first time I rode, long time ago, still not fixed, because of
1) lack of money
2) lack of equipment

But my question still hasn't been answered: Should I replace the front brake rim's pads (7-8yo sitting under the tree, used for half a year, weak braking)
Or just forget it and save up for the disc brakes?

Also is cleaning the rim + brake pads with very strong paint thinner a good idea (because of contamination)