I have a 2001 yz 250 that i bought off a guy. His word was that it has brand new top and bottom end in it, but i keep fouling plugs and my buddy said i might need to do crankseals. Does that mean crankshaft seals and bearings or what? I dont know much ive only owned trail bikes until now so i havent had to tear down an engine. Im mixing 40:1 and it fouls plugs when im riding the bike just bogs out and the plug is really wet and black. I know its got a new jug on it and head gaskets but the rest is a mystery
Yz 250 Crank Seals?
- Thread starter smerch69
- Start date
that is a possiblity. It is also possible that the jetting is way off, the igntion is weak, the float level is too high. For the seals beibg out, have you noticed the gear box oil going low?
You aren't fouling plugs because of crank seals. If you were the smoke chasing you would be obvious.
Jetting is a good one and so is a worn top end. First clean that carb to eliminate any plugged jets and stuff.
Mix some gas at 32:1 and that will lean out your jetting a little bit. But if I had to guess I would say worn top end. Autozone will rent you a compression tester for free. Psi should be around 170ish.
Jetting is a good one and so is a worn top end. First clean that carb to eliminate any plugged jets and stuff.
Mix some gas at 32:1 and that will lean out your jetting a little bit. But if I had to guess I would say worn top end. Autozone will rent you a compression tester for free. Psi should be around 170ish.
No i havent. I dident even change oil yet. Bought the bike had it for 4 days. Spent more time pushing it then i have riding it
Try jetting, and 32:1 Yamalube premium pump gas. If the seals are done you will find oil on the ignition side, and it would run like crap. You can check the bearings for slight movement by pushing on the crank with a big screw driver or pry bar and looking at it off center to see if it moves. Kind of tricky to see, and don't leverage off anything fragile with the prying tool.
Read mike again and then go learn how to set the float. it is pretty much a standard tuneup procedure that pretty much gets "standardly neglected". if it is something you cant say has been done recently just do it and then do your jetting there. jetting without that can end up being a repetitive process. way better now than they were at one time, the float is a pretty mickey mouse set up when you think about what it does. check the needle for wear as well.