I am pretty sure he seized it, and then tried to tighten the sprocket thinking that would do something....then found that the nut would thread past the threads on the shaft and that entered (needlessly) into the equation.
PLEASE HELP, engage clutch, no rotation of sproket!
- Thread starter Chickenegg787
- Start date
Hey Al, sorry for not letting you guys know I was leaving yesterday. . . I was running late for something, anyways, I am going to go look at the bike now. I still am struggling to understand how to manually try to turn over the engine, as I am not a gear head in any respect!
So after I re read your instructions, and get out to the garage, I'll post what I find out. I do plan on taking off the head and looking at the cylinders as well. I hope it is just 'seized'... It took forever to get it going.
So after I re read your instructions, and get out to the garage, I'll post what I find out. I do plan on taking off the head and looking at the cylinders as well. I hope it is just 'seized'... It took forever to get it going.
http://i1088.photobucket.com/albums/i329/chickenegg787/P1050989.jpg
http://i1088.photobucket.com/albums/i329/chickenegg787/P1050990.jpg
http://i1088.photobucket.com/albums/i329/chickenegg787/P1050991.jpg
http://i1088.photobucket.com/albums/i329/chickenegg787/P1050995.jpg
Some pictures of the piston and such, I couldn't remove the head completely because there are items in the way, if necessary I have means of removing it, but that's only if needed. Also, it seemed to stick on the piston head because as you can see, I removed it almost all the way..
Top of piston is coal black...idk what that means...
Also, good news. I am able to engage the clutch now and have the entire system rotate as it did before, however, it is not the same... My momentum after i engage quickly diminishes as if there is some immense amount of tension that didn't exist before, and it also doesn't sound nearly the same...When it worked and I went to start it, there is the hum that's given off or "whirrrr" that people call it. That is there, but barely, it is very 'compressed' in sound and it defiantly doesn't sound right. Something is still messed up with the clutch i believe. . .
To fix the fact that nothing rotated when I engaged the clutch, i found that the Bevel Gear Bolt (#3) (http://www.bicycle-engines.com/2stroke-parts-crank-piston-c-4_8.html) was completely loose. After I screwed that back in, I got to the situation I am in now...
http://i1088.photobucket.com/albums/i329/chickenegg787/P1050990.jpg
http://i1088.photobucket.com/albums/i329/chickenegg787/P1050991.jpg
http://i1088.photobucket.com/albums/i329/chickenegg787/P1050995.jpg
Some pictures of the piston and such, I couldn't remove the head completely because there are items in the way, if necessary I have means of removing it, but that's only if needed. Also, it seemed to stick on the piston head because as you can see, I removed it almost all the way..
Top of piston is coal black...idk what that means...
Also, good news. I am able to engage the clutch now and have the entire system rotate as it did before, however, it is not the same... My momentum after i engage quickly diminishes as if there is some immense amount of tension that didn't exist before, and it also doesn't sound nearly the same...When it worked and I went to start it, there is the hum that's given off or "whirrrr" that people call it. That is there, but barely, it is very 'compressed' in sound and it defiantly doesn't sound right. Something is still messed up with the clutch i believe. . .
To fix the fact that nothing rotated when I engaged the clutch, i found that the Bevel Gear Bolt (#3) (http://www.bicycle-engines.com/2stroke-parts-crank-piston-c-4_8.html) was completely loose. After I screwed that back in, I got to the situation I am in now...
Thanks for letting us know. The piston looks like something ate it up around the outside edge, see there where the carbon (normal) is pitted?
Now, what happens if you push the cylinder back down, leave the head off, and rotate the engine with the 14mm nut on the mag side (left as you are sitting on the bike, behind the "front" cover)?
What you need to do is get that piston down, so you can look into the cylinder, and see if it's gouged up.
Keep us posted.
Now, what happens if you push the cylinder back down, leave the head off, and rotate the engine with the 14mm nut on the mag side (left as you are sitting on the bike, behind the "front" cover)?
What you need to do is get that piston down, so you can look into the cylinder, and see if it's gouged up.
Keep us posted.
Okay, so I finally understand now 
I was able to rotate the 14mm nut and manually drive the crank arm and pulled the piston down. It was interesting. At first, the nut wouldn't rotate because it appeared that the )_( shaped piece that is directly after the nut that rotates in a circle with the crank arm and the piston and etc. was stuck in the position that I first found it in. ( I believe that the ")_(" shaped piece i'm referring to is the magneto magnet) However, then it eventually rotated all the way around, moving the arm, moving the piston 360 degrees until I got back to that same postition and it would hit some friction and it would snag a little on something and then continue to rotate around cyclically in this fashion. As far as the cylinder being gouged, when I rotated the entire mechanism, the piston didn't go down any further than when I originally had the head removed and I pulled the cylinder up. So from what I can see, the were no gouges, but if none of this makes sense, I can get a picture later tonight up of it. Also, I put everything back together once I freed that 14mm nut and everything else, went to pedal and everytime it hits that once spot, it snags a little and it is very noticeable. It cuts all momentum and the 'whirrrr' from the engine still doesn't sound as it did before. any ideas? thanks in advance. I appreciate all of this input and sorry for prolonging this. there's only so much time in the day
I was able to rotate the 14mm nut and manually drive the crank arm and pulled the piston down. It was interesting. At first, the nut wouldn't rotate because it appeared that the )_( shaped piece that is directly after the nut that rotates in a circle with the crank arm and the piston and etc. was stuck in the position that I first found it in. ( I believe that the ")_(" shaped piece i'm referring to is the magneto magnet) However, then it eventually rotated all the way around, moving the arm, moving the piston 360 degrees until I got back to that same postition and it would hit some friction and it would snag a little on something and then continue to rotate around cyclically in this fashion. As far as the cylinder being gouged, when I rotated the entire mechanism, the piston didn't go down any further than when I originally had the head removed and I pulled the cylinder up. So from what I can see, the were no gouges, but if none of this makes sense, I can get a picture later tonight up of it. Also, I put everything back together once I freed that 14mm nut and everything else, went to pedal and everytime it hits that once spot, it snags a little and it is very noticeable. It cuts all momentum and the 'whirrrr' from the engine still doesn't sound as it did before. any ideas? thanks in advance. I appreciate all of this input and sorry for prolonging this. there's only so much time in the day
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I think there is a serious problem in the crankcase. Does the piston or rod have any up and down slack in them?
By the look of the piston with all those dings around it's edge, there's obviously some metal particles been loose in your engine. First thing I would suspect is the wrist pin or rod needle bearing failure.
There's still metal loose in there somewhere and that's what is giving you the cyclic resistance to turning the crankshaft.
By the look of the piston with all those dings around it's edge, there's obviously some metal particles been loose in your engine. First thing I would suspect is the wrist pin or rod needle bearing failure.
There's still metal loose in there somewhere and that's what is giving you the cyclic resistance to turning the crankshaft.
Would it be more efficient to try and locate this lose metal or to just replace specific parts? I am willing to do which ever to get her running again.
I have been watching this thread and decided to jump in, it sounds like a bearing failure. The thread below will guide you through the tear down, if you don't know much about these engines you will learn alot by this thread.
http://motorbicycling.com/showthread.php?t=391
http://motorbicycling.com/showthread.php?t=391
You will have to dissassemble it first to see what is damaged, post pics and someone will tell you. Alot of members build these everyday so help is here.
Hi first timer here and extremely green grease monkey speaking.
I suspect engine seizure ???
Bike and engine only just run in btw.
I noticed that prior to this, the chain tensioner, where you adjust the wheel bit up or down, the nut was slightly loosened. Rather than tighten it up, I let it be. Then last week I rode my bike and felt the chain slipping one night.
Almost immediately, the chain unhitched off the rear wheel sprocket and the bike came to a complete stop on it's own, skidding to a stop.
At first I thought it was the chain that needed to be put back on, tensioner fixed and all will be ok.
Not quite, when the clutch was pulled in, to free the wheel and roll the bike for free wheel pedaling, I was not able to free wheel albeit clutch in or not.
I ended up dumping my bike behind the bush, going home to get the tray back vehicle and carted the bike home in shame. Lol...
I'm ****ting myself a little and hoping that I haven't done major damage and that it's repairable.
I appreciate all advice and will attempt to be online very frequently a few times a day, till I fix this issue. I'm currently unemployed so have the time to fix this.
Cheers and thanks in advance.
xo
I suspect engine seizure ???
Bike and engine only just run in btw.
I noticed that prior to this, the chain tensioner, where you adjust the wheel bit up or down, the nut was slightly loosened. Rather than tighten it up, I let it be. Then last week I rode my bike and felt the chain slipping one night.
Almost immediately, the chain unhitched off the rear wheel sprocket and the bike came to a complete stop on it's own, skidding to a stop.
At first I thought it was the chain that needed to be put back on, tensioner fixed and all will be ok.
Not quite, when the clutch was pulled in, to free the wheel and roll the bike for free wheel pedaling, I was not able to free wheel albeit clutch in or not.
I ended up dumping my bike behind the bush, going home to get the tray back vehicle and carted the bike home in shame. Lol...
I'm ****ting myself a little and hoping that I haven't done major damage and that it's repairable.
I appreciate all advice and will attempt to be online very frequently a few times a day, till I fix this issue. I'm currently unemployed so have the time to fix this.
Cheers and thanks in advance.
xo
