starting problem

[yz125j]

I have a 2001 yz125 that runs great. The problem is, is when i try to start it. Some times when i go to cold start it, it will start but some times it wont. If it doesn't it will start but in 5 seconds bog right out. Ill take the plug out and it is soaked. When i go to start it after its bin off for around 10-20 mins it does the same thing. The plug is always soaked. Please help thanks alot.

 

[Backslayer]

Sounds like your jetting is way off you probably need to lean your setting do a search on jetting this will solve your problem once you get your jetting right

 

[yz125j]

i just got my manual in today and look at the plug conditions. It says its oil fouled. I dont know how it could be jetting if it runs great once it stays running.

 

[yz125j]

does any1 have anyideas on this problem? My dad is yelling at me sayin "eveybody always says its the jetting", yatta yatta yatta so i cant jet it yet. i just bought an 8 sparkplug to try. Any other ideas?

 

[chiro972]

The only other likely choice is that the right side crankshaft seal is letting oil into the crankcase. That is what I am currently awaiting parts to fix on my bike. Similar symptoms.

 

[yz125j]

how could i go about checking that?

 

[whenfoxforks-ruled]

A leak down test. You will need a gauge and an air pump. Check out motion pro.

 

[DLHamblin]

I have a 2001 yz125 that runs great. The problem is, is when i try to start it. Some times when i go to cold start it, it will start but some times it wont. If it doesn't it will start but in 5 seconds bog right out. Ill take the plug out and it is soaked. When i go to start it after its bin off for around 10-20 mins it does the same thing. The plug is always soaked. Please help thanks alot.

The crank seal mentioned is one possibility (as is jetting, but you said the bike runs great so its likely not far off it is).

If not being ridden hard, going to a BR8EG or BR8ES (from the stock BR9EG) can help keep the plug hot enough to self clean and resist fouling better.

How long is the bike sitting between rides? If left for a good while the fuel (gas) can evaporate leaving an over rich oil condition on the next start (if my bike won't be ridden for a week or more I drain the float bowl).

Another thing that can cause this is an overly oiled airfilter. Besides causing a rich condition, filter oil can be sucked out of the filter and cause a foul when first started.

From what you have said, if the crank seal is OK I would try the BR8ES and see how it works for you.

 

[yz125j]

well its bin 2 days since i rode. before that it was everyday. Should i clean my air filter?