2005 Yamaha Big Bear 400 wheel bearings and ....?

[mga]

I just brought home a used 2005 Yamaha Big Bear 400 4x4. It needs front wheel bearings, and a new choke cable. I think i can handle those two items. However, when i went to look at it, it ran good, shifted good, brakes all workds great, but at home when i started it, it would idle nice, but when i gave it gas it seemed like it was flooding out and would die. If i just gave it a little throttle it built up RPMs but any more throttle it began dying out again.

any suggestions why it's doing that? 

I'm looking for a service manual, but forum rules say i have to make 10 posts..lol

 

oops...i just realized i posted in the wrong section of the forum!!

Edited January 8, 2023 by mga

[Mech]

Spark plug cable got knocked half off.. 

If you're saying it's got this problem on the trip home on the truck then it must be something simple surely.

Are you sure you got the tap in the right position ? Plenty of gas? No rags stuffed up the exhaust ? (hey I don't know.. but humans do stuff like that ). Hasn't got a tap on the fuel tank breather ? Check anywhere wires might have got pinched by tie-downs.

[mga]

44 minutes ago, Mech said:

Spark plug cable got knocked half off.. 

If you're saying it's got this problem on the trip home on the truck then it must be something simple surely.

Are you sure you got the tap in the right position ? Plenty of gas? No rags stuffed up the exhaust ? (hey I don't know.. but humans do stuff like that ). Hasn't got a tap on the fuel tank breather ? Check anywhere wires might have got pinched by tie-downs.

thanks!  i'll check it out in the morning. it has gass in the tank, but i'll drain it and add fresh fuel.

[Shadow1]

You should consider a carburetor clean and some fresh new gaz

[M4ATVfun]

I believe you have a carburetor issue, my guess is the primary carburetor jet is clogged. I would remove the carburetor bowl and remove the larger jet and clean the tiny hole that runs through the center of this jet as well as the tiny holes on the jets sides. You can buy the professional jet cleansing brushes or to save money find a piece of stranded wire and remove one strand and use that to clean the jet. This clogged jet can be difficult to clean and sometimes you need to buy a new jet, the size of the jet is marked on it (you'll need a magnifying glass to read it). 

[mga]

I noticed today theres a cover misssing on the throttle side of the carb. And, it appears the carb is new. Of all dumb things to be missing...ARGH!! I think i put a picture up of the missing cover

[Shadow1]

You can make the cover for no cost from a piece of plastic and screw it to protect the throttle from dirt! 

[mga]

12 minutes ago, Shadow1 said:

You can make the cover for no cost from a piece of plastic and screw it to protect the throttle from dirt! 

ha...never thought of that. thanks

here i was ready to buy a new carb!

[Mech]

Did you ride it when you went to look at it ? If it was going fine, and you went for a ride at the point of sale, then surely it's something simple, and the carb doesn't need stripping..

If you bought it untested then that new carby is probably the problem, but it's not likely to be as simple as needing a clean.. it probably needs retuning for the bike. I'd contact the old owner and ask if they still had the original carb and could you get it please. It's easier to clean an original carb and get it running right again that retune a new after market carb that might need new jets.

About the only simple adjustments are the idle mixture and speed, and the slide needle height. Your symptoms sound like it could be the slide needle, and the easy test is to take the top cover off and move the slide needle's circlip down one notch and see if that improves things.

Before pulling anything off the bike though you should check the fuel tap and filter's aren't blocked by undoing the drain screw on the bottom of the carby and making sure fuel runs out freely. That checks the tap, filters and that fuel is getting into the carb fast enough. If that's good, try adjusting the slide needle.

Oh.. and that side cover will be availiabe from the dealer. They have a rubber seal and will be much better than a home made one of plastic.

[mga]

1 hour ago, Mech said:

Did you ride it when you went to look at it ? If it was going fine, and you went for a ride at the point of sale, then surely it's something simple, and the carb doesn't need stripping..

If you bought it untested then that new carby is probably the problem, but it's not likely to be as simple as needing a clean.. it probably needs retuning for the bike. I'd contact the old owner and ask if they still had the original carb and could you get it please. It's easier to clean an original carb and get it running right again that retune a new after market carb that might need new jets.

About the only simple adjustments are the idle mixture and speed, and the slide needle height. Your symptoms sound like it could be the slide needle, and the easy test is to take the top cover off and move the slide needle's circlip down one notch and see if that improves things.

Before pulling anything off the bike though you should check the fuel tap and filter's aren't blocked by undoing the drain screw on the bottom of the carby and making sure fuel runs out freely. That checks the tap, filters and that fuel is getting into the carb fast enough. If that's good, try adjusting the slide needle.

Oh.. and that side cover will be availiabe from the dealer. They have a rubber seal and will be much better than a home made one of plastic.

yep, i drove it, shifted the gears, etc and i ran nice. However, i never lifted the seat until today and noticed there was no air filter. so, i did order one. I'm not going to try messing with the carb until i put the air filter on. Someone micky moused a throttle spring (You can see it in the picture) and i'm not sure why unless there's an original return spring missing someplace. I'm going to get a service manual and go thru this.

 

As for the cover, i'll see is some one has one. thanks.

[Mech]

Oh yeah get the filter on there.. That might cure it. They might have warmed the bike up before you arrived to cover up a few small faults..

The carb should have a strong return spring inside that cover.. Perhaps the throttle cable is old and wasn't returning properly.. You should check the kill switch works !!

[Gwbarm]

You definitely should clean the carb if for no other reason peace of mind, you might try turning your petcock to prime and running it ,sometimes the vacuum petcocks go bad and you can't tell if its getting gas without the engine running.

[mga]

unfortunately, my wife wants me to finish putting down the hardwood flooring before i play around with this. 

i appreciate the feedback and when i get into it, i'll let you guys know what i find.

 

thanks again!!

[Mech]

That's a fair deal...  I'd get it in writing...

[Gwbarm]

Yeah my BigBear is on hold also, thought when I got the granite countertops in I would be in the clear, but honey doos never end. Floor is next.

[Mech]

Lol..  Life's good.

[Krominator]

Yeah my wife was probably not thrilled that I have been working on the Kodiak instead of the kitchen but if we get that snow today, she might forgive me........Its really funny that the Honey Do List just keeps growing no matter how many items you knock off of it.......That is how God gave women the power to keep us boys out of trouble..

[Mech]

Hey. My wife died and left me with two very young sons and a house to finish and land to tend and a workshop to run..

If I ever thought she kept me to it (which I didn't), I soon learn just what an asset a good wife is..  Be thankful.

[mga]

ok...back in business!  I replaced the left front wheel bearings. What a pain that was. The drive shaft was rusted to them and i had to use a torch and plenty of penetraating oil to get it out. I ordered new ball joints too. 

I ordered that choke/starter cable from amazon (after market) and it was the wrong size. Sent it back and just ordered the OEM part from Yamaha. Plus that throttle spring. I guess someone was too lazy to remove the broken one and just put that mickey mouse set up i posted above. makes you wonder about people's mechanical abilities. So, that will be here in a day or two. Hopefully with the new "choke" cable it'll start better. And i removed all the old gas.

The carburetor look to be brand new, but i'm not sure if it's an after market or an OEM. in my spare time i'm checking wiring thru out to make sure every this is OK. The cooling fan works but it's noisy...a lot. But, to get it off looks like a big project, so that'll be for another time.

When i get the new ball joints, i'll do the right side bearings as well.

If i change the oil filter, will all the oil drain out from there, or should i just open the drain plug?

And the hardwood floors are done and i also laid hardwood on the staair cases as well. She's happy...happy wife, happy life....or, so they say.

 

[Mech]

Some of the fan's have a water drain hose, I've filed them up with wd40 through that hose before to shut them up.

Most service manuals tell you exactly what model carb the bike should have.. It will be in a table of specs about the jet sizes and settings.

You should use the drain bung I'd think.. though I don't know yammies.

I think to get the new carb spring in you will have to take the butterfly shaft out.. it's got screws holding it that are splayed out at their ends so they can't come loose. If you try and wind them out it will bugger the threads in the shaft. Try to grind/file the ends back or pinch them into shape before removing, and it's best to have new screws to go back in.. and do re-munt the ends after they are in..

[Gwbarm]

OEM carb should say Mikuni on it aftermarket no writing at all , some oil may come out from the filter but always drain oil from drain plug on bottom of engine, choke plunger should just pull out of the carb if the threads on the plastic piece are stripped if not unscrew it mine are always stripped. Good job on hardwood floors. Thats next on my agenda. Oh, good job on the bearings ,they can be a bear sometimes.

[mga]

On 1/8/2023 at 7:15 PM, Mech said:

Oh yeah get the filter on there.. That might cure it. They might have warmed the bike up before you arrived to cover up a few small faults..

The carb should have a strong return spring inside that cover.. Perhaps the throttle cable is old and wasn't returning properly.. You should check the kill switch works !!

the reason the cover was missing is because the return spring on the throttle lever box(?) on the handle bar was broke. So, someone rigged up a spring into the carb and wire tied the end to the frame to make it act as a return spring. i emailed the guy and he's supposed to send me the cover via mail. I ordered a new return spring to replace the broken one that's in the throttle box on the handle bar (if that's what it's called)

just a lot of neglect and laziness on this atv. next will be all new oils. 

again, i really appreciate everyone's help here. i downloaded some service manuals i found on line, and they kinda help.

[mga]

When it rains, it pours....i just noticed today that my lower A arm is BENT!!  ARGH! i was trying to figure ouit why one wheel didn't look like the other when sitting there and i saw why.  Apparently someone drove into a rock or tree and bent the thing. Unfortunately for me, they no longer make this part, (5FU-F357A-00-00) so i looked around ebay and found one for $145 used. I'll check out the pictures and maybe i'll buy it. This thing is nickle and diming me.......

[Gwbarm]

Ive noticed that also, the things have been abused so many years with little to no maintenance and just pieced back together when things don't work right. It will take a little patience to get it back right nickel and diming here and there but once you get it back right you will be proud and know it right. Then you can take care of it the way it should have been done from new. I don't know how bad you are bent but you may be able to take it out and. bend it back with heat. One of mine does not sit square either still trying to figure out why, it doesn't seem to be bent and does not cause any problems, but I don't like it, its like it needs an alignment.

[mga]

24 minutes ago, Gwbarm said:

Ive noticed that also, the things have been abused so many years with little to no maintenance and just pieced back together when things don't work right. It will take a little patience to get it back right nickel and diming here and there but once you get it back right you will be proud and know it right. Then you can take care of it the way it should have been done from new. I don't know how bad you are bent but you may be able to take it out and. bend it back with heat. One of mine does not sit square either still trying to figure out why, it doesn't seem to be bent and does not cause any problems, but I don't like it, its like it needs an alignment.

it's bad, cross member has a slight crack in it. I bought the one from ebay so i won't have to mess around. I'm waaiting for new ball joints to arrive, so i'll do everything at once when i get that arm. wife is getting ready to kill me....lol

see picture.....

Edited January 27, 2023 by mga

[Krominator]

Ahh its time to get the hammer out.......Save yourself a few bucks.........Well if you got the bike for a good price than it is worth sinking some money into ......Have you seen the prices on these new machines today?........I could have remodeled my house with that kind of money back when I purchased my machine.........It is beyond insane........Why would people go in debt for one of these things today........Well to each their own.........Hey if you got it flaunt it.........If you dont, put it on the credit card......lol

[Gwbarm]

With the crack that's good that you are replacing it would be hard to bend back exact.

[mga]

ha...price out a quart of oil...i used to buy a 5 quart jug for the price of one quart today.

i was going to try to bang it out, but like i said before, there;s a crack in the weld of the cross member and i don't have a welder and it's hard to find a good one around here. everyone like to use those damn sticks.

i spent a couple of hours looking for one. "no longer available from the manufaacture", so the only used one was on ebay. he wanted 145, but i got it for 125. free ship. that's going to be my last big investment in this thing. if there's aany thing else that's big bucks i'll sell it and get my money back (hopefully) with all the extra parts i'm buying i'm up to almost 1200 in it.

[Mech]

I don't know whether it applies to yamahas but some makes and models have different suspension arms in different years, some are longer to make the bike wider.  It's something to watch out for if buying second hand parts.

[Mech]

Also Mga, it's always worth looikng up the parts online, then seeing what other models they fit, because often the other model uses a different part number, and sometimes that other part number is available. They change the numbers if it's a superseded part, or got a different colored paint or any number of trivial things..