I finally got the starter on my breeze 125 sorted out (had been turning the wrong direction)
But I get nothing from the motor, not even a pop. I already cleaned the carb out. But Im not seeing fuel on the plug.


Even if I pour fuel through the spark plug hole, I still don't even get a Pop.


I have a compression tester, but not a small enough adapter for it.


There is compression, you can feel it sucking at the carb.


But, should I be able to turn the motor over by turning the starter shaft by hand? It isn't very hard to turn the motor over...I would expect it to get really hard to turn over at TDC. You can feel when it hits TDC but it doesn't take much effort to keep turning it.


Im wondering if there isn't proper compression, or if the valves are not opening/closing at the right time. I don't know how to check the latter.


I thought I was golden after figuring out the starter issue...I figured it was way the bike had been sold. The starter's rotor can wiggle around some and hits the case causing a terrible grinding noise. I think someone took it apart to inspect it, then put it back together with the case rotated 180 degrees...thus making the starter turn in the wrong direction.

 

If you're able to turn the motor through the compression stroke easily by hand you definitely have a compression problem. Air is getting out instead of compressing.

 

Is it possible to install the cam or set the cam timing so that it moves the valves on all 4 strokes?
I am turning the motor by hand while watching the valves and cam gear...and either I am really tired or there is no point at which the piston makes a compression stroke...meaning I cant see a stroke where a valve doesn't open!


Can some one confirm which direction this motor turns? And any links to how to set cam timing would be helpful as well.

 

If you're facing the left side of the crank shaft,counter clockwise on the crank shaft. On the right,you turn the crank shaft clock wise. Place a straw in the plug hole. On the compression stroke the intake valve(s) will begin to close as the piston(straw) moves upward. At tdc both the intake and exhaust valves should be closed. At this point you check valve clearance if you haven't already.If valves are too tight against specs,could be part of the problem.Plus check if the cam chain is tight or loose.

 

I was able to figure it out.
I turned the crank by hand while having my other hand over the carb boot.
Right after the intake valve closes, I could feel air being pushed out.
The intake valve was not fully closing.


I adjusted it and got the bike to start. Now Im trying to figure out why it wont run when I close the choke.

 

Hopefully you checked the exhaust valve clearance also.A compression test is best,you can "rent" these testers at any auto store if you don't want to buy one. If compression is at least 115-120psi or so,then problem may just be carb related. A simple carb cleaning and a new kit may be all that's needed. http://www.ebay.com/itm/YAMAHA-YFM125-YFA-1-BREEZE-CARBURETOR-REBUILD-KIT-89-06-CARB-REPAIR-KIT-/251018492237?hash=item3a71de394d&vxp=mtr

 

I have a compression gauge...but not an adaptor for the small plug hole on this motor. I see what you are saying tho, if I could test it then Id have a better idea if both valves were properly set.
Later today I plan to look up the proper way to set valve clearance. What I did was get the piston at TDC on compression stroke and set both valves so that the rocker only has a tiny bit of play. Not exactly the right way to do it im sure, but this method did get the intake valve so that it wasn't letting air/gas get pushed back out of the cylinder.

 

You just need a 10mm adapter for your kit for the CR7HS plug or a simple cheap tester can usually do pretty good if you have room.