1st build wont work help:(

jordannichels

New Member
Jan 30, 2009
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australia
i made my first build on the weekend. i used a 25cc leaf blower motor. bought it brand new stripped the plastic body so i was left with a motor. i used a bmx peg i had lying around the house for the spindle and mounted it front wheel. oh and the pull start was on the same side as the spindle on the the plastic body so i was un able to use it and decided to drag start it.

i went for a test ride and it wasnt seeming to work
then i got it working and had it going for about 1 minute then it boged out. then when trying to start it again the spindle bolt fell off. :( i then replaced it again and i couldnt seem to start the engine again.

i tryed the next day and the bellish looking thing(sorry im very new to this) came loose and fell off i didnt find this out untill i removed the bmx peg.

im unsure whats wrong with it of if the motor will even work with out the bell looking thing. sorry i dont have pictures my camera is broken.

if some one could give me advise that be great because i bought this motor brand new and havnt semm to get it working yet:( and also this is drag start.:-||
 

deacon

minor bike philosopher
Jan 15, 2008
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First of all you will get more help on this in the DIY section thats were all the home builders hang out. That said, The bell looking thing confuses me. Is that the centrifugal clutch or the flywheel. The flywheel looks like a fan but it is at the motor end of the drive shaft not the fan used to blow leaves.

Not sure if there is a centrifugal clutch on the leaf blower but if there is then when it fell off there should be some parts held on with springs. Let me know which and I might can give you some idea.

How did you have the peg attached by the way.
 

jordanmichel1

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Jan 30, 2009
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sydney
hey thanx for the reply im useing a different account because my other one stuffed up.

ok it does look like a fan i think it is the fly wheel:(:(:(:(
that means its a uselss motor now right?

i attached the bmx peg on the spindle because it had a thread on it.
 

deacon

minor bike philosopher
Jan 15, 2008
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if you have the fly wheel try to see how it was held in place. There might have been a slot in the drive shaft and a key that held it in place. The again it might have been held in place by the thing you took off to put the peg on. In other words the peg might be what was holding it on. there should be a pin or key to line it up though. that might have been left out a the factory or it might have fallen out.

When it moved is why you couldnt start the engine. the fly wheel has a magnet in it that generates the spark as it pass the magneto coil. That has to happen at exactly the right time. Thats why there is usually a way to line it up.

Let us know what you find.
 

jordannichels

New Member
Jan 30, 2009
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australia
Ok the fly wheel is back on it sits in 2 grooves in the spindle. Its a rad loose so ill put some jbweld on the top of the flywheel were the spindle somes through it so it doesn't come loose.

Deacon have you got any tips on drag starting the bike. Because I don't really no how to do it. I just need to no the steps involved because it doesn't have a pull start.

Im very keen on riding this bike! Thanx for the help
 

deacon

minor bike philosopher
Jan 15, 2008
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You need to be able to raise the engine from the tire to start it best. Those small engine start like this.

1. full choke till it tires to fire.
2. `1/2 choke till it runs a little
3. no choke to ride it.

If you can raise the engine off the tire put it on full choke... wrap a rope around it. (the pull cord from the recoil starter will do fine.) Be sure to wrap it so that you turn the peg in the direction you want it to run. When it tries to start move the choke to half choke and pull it till it starts. Quickly move it to no choke. throttle it a bit to warm it up drop it to the tire and off you go.

Locktite on the threads of the spindle should keep it in place. Most of these small engines run backwards or counter clockwise. They will run clockwise but as mentioned it will loosen the peg. You may be trying to run it backwards. It should turn counter clockwise. Which will put your engine on the left side (as you sit on it) of the front wheel.

If you have your bike set so that the engine is on the left side where it belongs and it is tied down so that it can not be raised try this to drag start it by pedaling. Set the choke on full... pedal it till yo hear it try to start... then set it on half and pedal again.... then turn the choke off and ride it. You don't want to run it on half choke even though it is easy to forget to set it to open. It runs like crap and over heats.

Good luck Also if it will not start you might have the flywheel on out of adjustment so check that the first time. the spark from the magneto has to be delivered at the right time. It the flywheel is on 180 degrees out of alignment which it sounds like it could be then it will not try to fire at all.

About those groves... If there is a grove in the drive shaft and a grove in the flywheel then there should be a key that slips between them and holds it in place.... If there is a grove in one and a nipple on the other then you are good to go... If you need a key any lawnmower repair shop should have one.
 
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jordannichels

New Member
Jan 30, 2009
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australia
ok the motor is fully starped down and is on the left side.
so if i ride it on full choke untill it sounds like its starting then on half then turn choke to open.
what do i do with the throttle so i justpull the throttle the whole time or do i rev it or somthing?
and do you think it will work being drag started with the engine bolted down??
thanx
 

jordannichels

New Member
Jan 30, 2009
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australia
oh and deacon the flywheel did no sit in the grooves. but i lined it up with the grooves. taped it down so it wouldnt move. and i jb welded orund the spindle were it comes throw the flywheel. im waiting for it to dry but i really need to nnno how to drag start it because it is bolted down on the bike. thanx again
 

toytime

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Mar 20, 2008
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Ontario
If you use a rope, get a pal to lift the bike off the ground for you so that the wheel can spin. If you want to start it by pushing, same thing, get a pal to push you and start it as you would any motor. Give it choke until it fires up, play with the throttle and let off on the choke when it sounds like it will stay running.
i have the feeling , as mentioned above, that the nut comes loose because of the direction the motor is turning. You MAY want to hammer the shaft to mushroom it out so that that nut will never come off again or if there is room , put another nut on and tighten them up on each other. If it's a bolt, forget my last suggestion.
 

deacon

minor bike philosopher
Jan 15, 2008
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I believe that you need a key to hold that flywheel in place.

It will start fine that way but let me caution you do NOT run out of gas. I had my first weedwhacker set up like that on the rear and when it ran out of gas I was on a hill and didn't realize that I was pulling an engine with no oil. Your only lubricant is in the gasoline. If you do run out stop immediately and cut the engine loose from its mount so that it won't turn as you roll the bike. Even if you push th ebike home if you turn the drive spindle you are running the motor with no oil it wont take long to seize.

Check with an engine repair show about that key for the fly wheel It might have been left out at the factory or you might have sheered it off. All kinds of things can happen. I had one do that but mine broke when it hit the pavement. If I still had my weed whacker collection I would try to find you a key but alas they have gone to the trash.

You are going to need that key to make the engine run.... Some of the guys here have used a dremel and a piece of scrap to make keys.


If you look around you might find it where the spindle came off if it was in the shop. If not try to buy or make one.

Sorry I can't put you riding today.
 
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deacon

minor bike philosopher
Jan 15, 2008
8,117
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north carolina
I believe that you need a key to hold that flywheel in place.

It will start fine that way but let me caution you do NOT run out of gas. I had my first weedwhacker set up like that on the rear and when it ran out of gas I was on a hill and didn't realize that I was pulling an engine with no oil. Your only lubricant is in the gasoline. If you do run out stop immediately and cut the engine loose from its mount so that it won't turn as you roll the bike. Even if you push th ebike home if you turn the drive spindle you are running the motor with no oil it wont take long to seize.

Check with an engine repair show about that key for the fly wheel It might have been left out at the factory or you might have sheered it off. All kinds of things can happen. I had one do that but mine broke when it hit the pavement. If I still had my weed whacker collection I would try to find you a key but alas they have gone to the trash.

You are going to need that key to make the engine run.... Some of the guys here have used a dremel and a piece of scrap to make keys.
 

deacon

minor bike philosopher
Jan 15, 2008
8,117
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north carolina
I wouldn't even try a rope unless I could lift the motor. You might try blocking it up to get the wheel off the ground and pedal it to start while sitting in the shop. that would be easier than riding down the road but both are doable set up as you are.
 

Friction

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Nov 25, 2008
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make sure you put on the bmx peg on good with a welder or an oxyacetaline torch and just weld them on or braze them on either way make sure they dont fall of again it could cause some accidents
.bld.