Ok so i got a new stator for the 90 big bear 350 after falling in love with my 88 big bear.good news it runs like a charm after new stator.bad news is it had a bad rattle that my 88 does not have.so shut it off changed all fluids in the bike as it sat for a few years and readjusted the valve lash wasnt out by much but needed done and greased everything and replaced the oil filter,new brakes all around new rear brake cable and added a winch as well,plus new spark plug and coil.HERES my problem after all this i ran the bike for about 2 minutes and opened the bleed screw on the head to make sure i was getting oil to the top end and NOTHING is coming out.Does ANYONE know what can cause this?what should i look for im lost and want this bike for the wife and dont want it to sieze up cause any damage ect or leave her standed in the woods somewhere.ANYONE PLEASE HELP ME.

 

well i went back to the shop to test a few things and these were the results....disconected the oil cooler line at oil cooler and started the bike no oil maybe a bit came out when it was running.blew the cooler out and the hoses no blockage was noticed.no oil coming out bleeder in head after cleaning out the lines .I am now thinking the oil pump is done or a broken oil pump gear.seems the bikes are not know for this issue as there is very little written up about this.What is your opinions and how hard are they to fix or replace?thx guys im am now discouraged. maybe its not that big of a fix but hoping for good news from this point forward.thx again. ps its a 1990 big bear 350.

 

Not a Yamaha guy,but looking at the parts breakdown does show the oil pump drive gear has a woodruff key. If the key has split/broken may not be turning the oil pump gear? Item #29. Dirt Cheap Yamaha, Honda, Arctic Cat & Polaris OEM Parts & Accessories – Cycle Parts Warehouse

 

wow looks like it might be a job for the dealer then.looks a little out of my league dangit.

 

OK so heres the update.I figured i could handle replacing the oil pump myself as i have mechanical expierence and would save a 500-600 dollar cost at yamaha for this job.turns out i know why i love Yamaha as they keep things real simple.lol. As i removed the cover on the engine and kept an eye open for broken parts ect i found nothing and was as clean inside as the day it was built.HMMM.good to see but still knew there had to be an issue with the pump as i was getting no oil to my head ,valves ect.I then continued to remove the clutchs ect to gain access to the oil pump.After getting access to it i pulled the 3 screws from the pump and pulled it off.I inspected the pump gears ect to see no cracks or issues.then looked at where the pump bolted on to find a big chunk of blue silicone plugged in the lower oil galley.I am now going to reasemble the oil pump and engine without replacing the pump as I think I have found the culprit.I also blew out all the passages to make sure there was no more junk including removing the oil line beside the pump and blew it out as well just to make sure.WISH ME LUCK but i am 99% sure this was the fault.just a heads up to everyone if they have problems like this.I have no clue as to where the silicone came.maybe from assembley as the engine has never been apart before.will keep you posted if it solves the problem.

 

Update # 2 bike is back together and running like new again opened bleed screw on head and had oil squirting out across the shop.wow amazing how such a small thing can cause a person to blow up a machine.well all said and done i saved my yammy and am off to take it on a run.it sounds better than the dry rockers now theres oil on them lol.so never suspect the worse until you investigate everything.my wife will love me now she can ride with me.thx .

 

You must be living right! Glad you found the problem without having to take it to a shop.