yz 125 problems

[nslick125]

i recently put a new crank shaft into my yz along with new bearing and seals. i was riding it around and after a while its would bog down on me. i checked the spark plug and it was oily and had no spark. i replaced the plug and started to have the same problem. is there any way i could tell that its the seal leaking or maybe from the case. i did put gasket sealer on the case befroe i put it back together.

 

[96speed]

Did you replace the crank seal when you had the case apart? If not, I would replace the crank seal now to narrow down the culprit. Its a cheap fix, but it will take a little elbow grease to remove the clutch basket and get down to the seal.

edit: So the seals were replaced with the new bottom end?

What kind of mix are you running? Is your jetting stock? I would start with the jetting if the crank seal was installed properly.

Ryan

 

[nslick125]

the seals where new but the only reason i thought it was leakin was bc the oil in my case was low. i havent touched the jetting since i got the bike but i got it with the hot rods crank in it allready so i dont know if it was chnaged .

 

[nslick125]

i am running yamalube with a 32:1 ratio. has worked fine with me in the past.

 

[_JOE_]

Are you certain the seal is in correctly? There is a specific side that needs to be facing the oil. Usually the side with the lip.

 

[nslick125]

almost certian, in the manual it says the side with the manufactures words faces out.

 

[nor_cal7]

hye you should probaly run 50:1 i think it runs better when you do that and it saves you oil

 

[atkkid250]

no way

50:1 is way to little oil, 32:1 is what the manual calls for. stick with that.

 

[twpgummi1]

what kind of trans oil are you using

 

[nslick125]

i use 10W-30 which is what the manual calls for.

 

[Ron2stroke1]

its probly just jetting try leaning it out and see if that fixes it.

 

[nslick125]

well im getting the athena high compression kit for the bike so ima put that in it and i cleaned the air filter got a new plug new gas and ill see what happens when i get it all back together.

 

[whenfoxforks-ruled]

You put a used top end on a new bottom end? A leak down kit is price less. Before you go figuring, you need to check that your bottom end job is sealing properly. There is a chance that your plug fouling is the worn top end, but the oil loss is another story. You need the bottom end checked before you try the athena thing.

 

[NO HAND]

hye you should probaly run 50:1 i think it runs better when you do that and it saves you oil

Even top pros used to run 32:1, Why would anyone want to brutalise the engine more than we have to! Plug fouling and spooge is almost always a jetting issue and not a mixing ratio issue.

 

[wake_rider]

hye you should probaly run 50:1 i think it runs better when you do that and it saves you oil

No way... On smaller cc bikes it is more imperative that you run higher oil to fuel ratios because you keep smaller cc bikes in high rpms. Don't let anyone tell you that spooge or fouling plugs is because of wrong oil/gas mixtures. Look at jetting first...

 

[SBC383STROKER]

You might have installed the ignition side seal backwards therefore letting air into your air-fuel mixture which will then cause your motor to run lean causing the "bog".
Now, the oily sparkplug could be caused by 2 things:
1. rich jetting
2. blown clutch side crank seal which will let extra oil go in the engine.

 

[nslick125]

i know that the seals are in correctly like the which way it faces whether or not i put the right one in correctly is another story but ill def try that leak down kit. the reason y i got another cylinder is bc i think nickle coating in the cylinder was starting to go it looked like it was starting to chip off and was scartching my piston up. now i know that could and most likey y the plug was oily but the low oil in the case made me have second thoughts. and the top end was almost brand new. all put it together and try the leak down kit on it and see wat happeneds.

 

[nslick125]

ooo, and once i get the leak down kit hooked up how much pressure should i be lookin at or puttin in?

 

[whenfoxforks-ruled]

The kit comes with recommended pressure and time to leak out.