Pop goes the Motorized Bicycle.

[rcflier500]

So while riding today my air filter fell off and i did not notice until the bike started backfiring and then died. I took the bike back to my house and reattached the air filter.

Now i just spent the last 20 minutes pushing it along trying to get it started to no avail. All it will to when i pop the clutch is act like it wants to start for a second then die and backfire at me.

I rode it about 10 miles today before this issue with no problem.

Any ideas?

 

[rcflier500]

Re: Pop goes the MB.

PS. Just checked the plug and it was fouled. Before i took it out i changed the mixture to one click richer. Could this be the issue?

 

[Blakenstein]

Re: Pop goes the MB.

Does it work now?? Is your exhaust pipe and chamber clean??u know sometimes all it takes is just a little oil build up in ur exhaust to stall the motor under load. What made ur filter come off??? what was holding it on?? Is ur gass line clear? did u check ur gass/ air ratio??? was it really dusty when ur filter came out?? its either spark, intake or out take or all three... dust could have got into your carb and interfered with some very fine stuff....well hope u get it runnin, I,m sure u will.
Yesterday, I spent about 5 hours on mine, and today it's ruunin great. -Had a bad gass over flow-flood -carb problem, half a tank of gas was flowing into my cylinder and carb overnight- then, my return gas line,(my system has two gas lines) was rubbing up against the throttle cable housing ,and the housing ate right though it.
When I rectified the problem, I rectified everything at once--added two shut-off T needle valves along with new gass lines-I even mounted a new tank!! .......and today, I am dancing ....... to the movie sound track of the Lost Boys

 

[spit_fire]

Re: Pop goes the MB.

funny u say this i had the almost the same issue happen to me on monday not even 4 days ago, i whent on a long trim 40mph+ the bike ran great until i got about 3-4 mph away from my house i pulled up to the lights and it stalled and i could start it for the life of me, i brought it home pulled out the plug stuck a torch dont the spark plug whole to burn the engine clean and dried the pljus made my gap very small to ensure i have spark and it ran but like a bag of s hit and back fire like crayze flames coming out the pipe (sbp chmaber) turns out bad oil/gas mixture fouled the plug and filled the pipe up thats all it was, try airing out the motor(turning it over with no plug and no gas) make sure u got a spark put the plug and carb back on and it should go if it doesnt means the carb isint doin its thing

 

[rcflier500]

Re: Pop goes the MB.

So i let it sit over the weekend and after cleaning the plug and making sure there was a good area for spark i tried to fire it up and after pedaling and dropping the clutch for about 500 feet i stopped and checked the plug again to find it was fouled like no other. Could my crankcase just be filled with oil and gas and need to be drained?

 

[Blakenstein]

Re: Pop goes the MB.

First of all what u need is a stand like Willi moto has. That way u can turn the pedals with ur clutch engadged thus turning over ur motor with the bike standing still-get spark tester to see if magneto works- if so then see if ur plug works by touching the end of the plug to motor head with plug wire attatched while turning ur motor over. You have to be 100% sure that u have spark. Once this is done, then u can move on to another area.
The picture of Willis stand is second up from the bottom on page 11 in the picture and video section of this forum....u can make one easy, or find help to make one. It is something u all really need. It can also made out of wood 2x2s and 2x4s I,m gona make one myself.

 

[GearNut]

Re: Pop goes the MB.

Could my crankcase just be filled with oil and gas and need to be drained?

To put it simply, yes.

Drain the gas tank and carb, take out the sparkplug, lay the bike on it's side and start pedaling to work the engine. If you put the engine up-side-down the excess fuel will get trapped underneath the piston. if you lay it on it's side the excess fuel will pour out one of the transfer ports.
Or you could do what I did: while looking through the sparkplug hole, rotate the engine untill the piston is at the bottom of it's stroke. Now attach a piece of thin rubber hose (aquarium air hose is what I used) to an air gun and insert the hose into one of the transfer ports. blow the bottom end out for a few minuits and it should be cleared. This all is assuming you have an air compressor.

 

[bairdco]

Re: Pop goes the MB.

or... just pedal the bike really fast with the petcock closed, then let out the clutch and keep pedaling till you're tired. this should blow any extra fuel out, and you'll notice it. if nothing comes out of your exhaust, something else is wrong. also, keep your spark plug in. you want that compression to help blow it out. otherwise you're just pedaling while the fuel sits there.

before doing any of this, make sure your choke lever's still attached and tight, that nothing fell into your open carb after the filter fell out, and that there's no dirt chunks or anything that can get sucked into your intake.

 

[bairdco]

Re: Pop goes the MB.

i brought it home pulled out the plug stuck a torch dont the spark plug whole to burn the engine clean and dried...

DON'T DO THIS!!!


unless you want to make a bomb out of your bike. if you have a large puddle of fuel basically sealed up in your engine and exhaust, you could die when this thing shrapnels on you. or worse, you won't die...

 

[rcflier500]

Re: Pop goes the MB.

or... just pedal the bike really fast with the petcock closed, then let out the clutch and keep pedaling till you're tired. this should blow any extra fuel out, and you'll notice it. if nothing comes out of your exhaust, something else is wrong. also, keep your spark plug in. you want that compression to help blow it out. otherwise you're just pedaling while the fuel sits there.

before doing any of this, make sure your choke lever's still attached and tight, that nothing fell into your open carb after the filter fell out, and that there's no dirt chunks or anything that can get sucked into your intake.

How will i know when it is cleaned out.

 

[GearNut]

Re: Pop goes the MB.

KABOOM!

[INSERT]19161[/INSERT]
Please heed bairdco's warning. He ain't joking.

 

[bairdco]

Re: Pop goes the MB.

How will i know when it is cleaned out.

when it starts.

on my bike the float went bad and filled up my crankcase and exhaust with fuel. after i put in a new float, i just kept pedalling it until it went dry. then turned the fuel on, and after a few tries it started up.

 

[spit_fire]

Re: Pop goes the MB.

WOW!!! i know I sound stupid right about now but you do make a good point i remember being at a boat show and they blew up an old boat with a empty gas can with just vapours in it so i understand why it is you say its dangerous, a guy that did small engine repairs showed me this trick when i flodded the crap out of my weed wacker and ive been doing it ever since ive never gotten more the a flame shoot out threw the sparkplug whole, like i said ive done it LOOOOOOOOTTTTTTSSSSSSSS of times but i guess i just got lucky it didint blow up, just out of curiousity have you personally herd of or seen any accident happen by doing this it is a great method has worked great for me ever since???

 

[bairdco]

Re: Pop goes the MB.

never heard of it happening, but even if it's a one in a million chance, i don't want anyone here to be that "one."

plus, people look funny with no eyebrows.

 

[spit_fire]

Re: Pop goes the MB.

im not argueing any facts just curiouse as to why you believe it would grenade isint the motor designed to handle internal combustion? and also you would need to achive somwhere around 14.7/1 fuel/air ration for it to blow otherwise it will just burn such as if you put a lighter to a can full of gas it wont blow it will just burn it doesnt have the vapours and the required air mixed into it for it to explode?

 

[bairdco]

Re: Pop goes the MB.

i'm not gonna argue, i'm just saying "ya never know."

if your exhaust pipe was filled with fuel, and your piston was at BDC, or even just a little bit below the port, allowing fumes to build up in an enclosed area, it's possible they could ignite. it may or may not explode, but i wouldn't take the chance, and i definitely wouldn't recommend that method to anyone else.

the fact is, i have no way of measuring the fuel to air ratio in a gas can, a flooded engine, or anywhere else, but i would never use an open flame to find out.

the least that could happen is nothing, and it works. or, it could make a small flame, which could easily turn into a bigger flame, if there was a lot of fuel present, dripping out. this might just burn up your bike, or your house.

i have actually seen an episode of "COPs" once, where a guy went to check for spark on a VW by laying the plug on the block and cranking it over. this ignited the fuel, burnt up the bug, a couple other cars, and a barn. it was actually a pretty funny episode. the guy was tweekin' hard and screaming at the firemen...

 

[GearNut]

Re: Pop goes the MB.

I have to admit that I have not heard of anyone blowing up themselves either, but I can tell you that I have done some really hairbrained things in my youth. Things involving gas and confined spaces, and I have come very close to meeting my maker. I cannot sit idly by and see someone do that. I did not intend to belittle you, spitfire. I am sorry if my comment made you feel that way.

 

[spit_fire]

Re: Pop goes the MB.

you know what im glad you corrected me it never struck my mind as this being dangerous but when most accident happen most people will tell you they never though of it happening or they did it all the time and it was fine, i told my story to another guy and i just went back and corrected myself and worned him about the home made grenade

 

[spit_fire]

Re: Pop goes the MB.

its why i like this forum some great advice from some experienced people im 21 and have pikced up some good and bad habits and tips along the way to being a mechainc ( 2nd year apprentice), everbody i meet that teaches me does things a diffrent way and tells me the other way is wrong i learned to pick up what i need from diffrent people and i never ignore advice that is towards being safe its very easy to pull a stupid and hurt yourself im starting to realize this but i must admit it feels great being young and invincible

 

[GearNut]

Re: Pop goes the MB.

We all were there at one time!