85YZRacer

Member
Aug 7, 2006
46
0
whats up vintage riders. i just finished my restoration on my 85 YZ125. I tried to start it today and it was a no go.the engine is getting gas. I checked my timing and spark plug gap , there good. im getting a good spark. every 5 to 6 kicks, the bike will let out a puff of air out the exhaust.Its a brand new top end and new filter. help me out here, am i missing something here. im tired of kick starting the hell out of it.
 

originaldirt

Member
Apr 25, 2000
103
0
Hmmmnnm,

Sort of sounds like the crank seals are bad. Pull off the l.h. side cover and grab the mag flywheel with your hand and try to detect any movement up/down, left right, in/out by feeling for a "slight click". While you are there look at the area around the mag flywheel , especially below it for any signs of moisture. Any signs of wetness indicates bad crank seals and any "click movement" felt in a non-rotation movement indicates bad crank bearings. Both will make it hard to start and on a short fuse to destruction.

Otherwise, make sure you are using the choke and not turning the throttle. The choke on those models is a fuel bleed circuit that is eliminated when the carb slide is raised by the throttle. Also, make sure the carb slide is completely bottoming out. I have seen many that were put in the carb body backwards and many that had the cable adjusted too tight to let the carb slide bottom out.

AND make sure you are using a NEW spark plug.

OriginalDirt
 

85YZRacer

Member
Aug 7, 2006
46
0
there is some up/down play when you move the flywheel. BUT, the bike was running before i did the restoration. This thing should at least start. I did some things while restoring it like, aftermarket boyeseen reeds,moose ignition, DG exhaust system. When i'm kicking my bike over and over and over, there is gas leaking out from the connection from where the pipe meets the cylinder. and when i pulled the plug out, it was covered in gas too.
 

85YZRacer

Member
Aug 7, 2006
46
0
By donut do you mean gasket? then yes, there is one. I am totaly stumped people, this bike is not starting and almost everything is fairly new. I think the engine might be flooded with gas. What should i do?
 

IndyMX

Crash Test Dummy
~SPONSOR~
Jul 18, 2006
5,548
2
Amo, IN
Sounds to me like your floats are set way to high, causing it to flood out...

You shouldn't have that much gas in the cylinder.
 

85YZRacer

Member
Aug 7, 2006
46
0
Ok, i checked the floats and they were out of adjustment. They were set too high. So i set it to factory specs. Now, i called a guy from a local moto repair shop and he said that since both crank seals are worn that maybe the reason my bike isn't starting up is because i have too much of an air leak. But the weird thing is that the bike should at least start , shouldn't it?
 

84cr125

Member
Apr 8, 2007
292
0
make sure that the slide is not stuck fully open. then, run hop on the bike and put it in gear. Honestly if you want to see if your bike will start this is the easiest way, and i bet your not going to listen to me.
 

muski250

Member
Jul 4, 2007
11
0
well now you have rebuilt the top its got a lot of compression making more pressure in the crankcase sounds like you need new crank seals and while your in there replace crank bearings too
 
Top Bottom