let me first start off by saying hi. this is my 1st post here. hoping i can find lots of advice from you folks.

i just bought an 87 big bear from a neighbor of a friend. this is my 1st atv. it sounds good and starts up fairly easy. of course i haven't changed the gas, oil or spark plug. just needs a little TLC. its going to need new plastic all around. front suspension needs a little attention.

my biggest issue though is brakes. the only brake that works is the foot brake. neither handlebar brakes work. i'm pretty sure it will be the lever and cable for the rear but not sure what might be the problem with the hydraulic brake. i can find most of the parts online but i can't find brake drums. everywhere i read it says discontinued. if it comes down to the drums does anyone know where i can find them? thanks

also, if you know of some good sites to find parts please share.

 

Welcome to the site. Those old Big Bears are tough machines, and run forever.

Do you get any pressure with the front brakes? Or when you pull the lever, does it go all the way to the grip with no resistance?

If the parts are discontinued, ebay is a good place to look. You may not find new parts, but you can usually get used ones that are in good shape there, and for cheap.

Another place to check is your local powersports shops, the shop I go to has all kinds of hook-ups and can find just about any part ever made if you give them a few days to look around for it.

 

Thanks for the quick reply. the hydraulic brake pulls all the way to the grip. actually both hand brakes do that. any suggestions?

i'll be sure to check out ebay for any parts i need. i'll probably stop at the local shop tomorrow, if not the next day. a friend also told me to pick up a clymer book so i'll order one of those.

 

Since your foot brake works, you probably just need to adjust the cable or get a new one to get your rear handbrake working again.

For the front brakes, i'd start out by bleeding the system with some new dot 4 fluid, and see if that builds your pressure back up. That may be all it takes to get them working again. If it doesn't seem to be pumping any fluid out of the reservoir into the system, you may need a new master cylinder, which you can probably grab up on ebay for 30 bucks. If you cross reference part numbers, you may find that your master cylinder is the same as other yamahas like the warrior and raptor, and if that's the case, you'll have even more options for getting a cheap replacement. Another cause for the problem would be a cracked or otherwise leaking brake line in the front, obviously if you have brake fluid coming out anywhere, then you found the leak and know which line needs to be replaced.

Good luck, let me know what you find out.

 

Pull the front wheels and drums off and see what ya got. I'll bet the shoes are completely shot and are not making contact with the drum. I worked on a buddy's Big Bear of the same vintage...spent a lot of time freeing everything up and adjusting everything, had good front brakes...for about 8hrs of riding, then nothing again. Another buddy with a Big Bear was asking about his brakes and I just told him to give it up. Solid machine the Big Bear but DRUM BRAKES SUCK!!!

 

well i had to drill out the screws for the master cylinder cover plate. a screw extractor didn't work. this atv must have just sat outside in the rain. or its just 19 years of accumulating rust on the screws. i opened it up and it was completely empty of fluid. the diaphram is completely dried up and brittle.

so i will need atleast a new body, but i would much rather have a complete assembly.

searching through ebay, i see lots of yamaha master cylinders. trying to match part numbers off the parts list and i get only a 1996 wolverine match when googling the part number.

is there an easier way to cross reference these without contacting yamaha. are there any known cross references out there?

i found this to be the closest non match:
2GU-25870-00-00 for a 2000 wolverine
my part # is 2GU-25850-00-00

does this mean this part number definately won't work? any help would be great. thanks

 

I'll take a look around and see what I can find out for you.

 

From what i'm seeing, the part numbers don't mean much. I can't see any reason why the master cylinder for a raptor, banshee, or warrior wouldn't work, and those should all be abundant on ebay. It may not be an exact copy of your master, but the brake lines are all the same size. There may just be some differences in the color, lever, and cap, nothing that really affects the function.

 

Well I checked Riva Yamaha out for ya and the parts are still available, the whole master cylinder assem. is $95, and the rebuild is like $27. Good luck with the machine, I like fixxing old bikes.

 

ok, ordered a new parking brake cable and all new hardware from the handlebar to the back. i found a master cylinder on ebay, just waiting for money to get into my paypal account.

worked on the front suspension today. the guy had ordered a new lower a arm for it but after looking at it today i didn't really see where it needed it. nothing was cracked or bent. the bushings weren't coming out anyway. i tried for half the day. i just figured why not replace it. but it didn't happen that way. he said it was too low on one side but after a little tweaking of the "low"a arm it's back to level and looks fine and seems to be working fine. it's like someone loosened the one side and tightened it back up without raising it so there was no bounce in it. seems fine. i'll keep an eye on it.