2000 Yamaha Big Bear 400 No Spark

[EugenM]

Is the electrical installation accessible now? or do you have to fit other parts to gain access? did you see on my grizzly post I found somewhere under the tank 4 cables that were broken.....(I have never had a Big Bear before and I don't know how different it is from a grizzly) you can search...or are there more the possibility of a main contact being oxidized...and when you measure with a multimeter you have continuity and power, but when you check with a light bulb it doesn't light up because of oxide

[Gwbarm]

All electrical is accessible, everything  is off including the tank, except console area with key switch neutral light, I will take a look in that area and see what I can see.

[Mech]

Yeah I'd be checking the key.. you will have turned that turning it off..

Did you pull start it this morning or use the starter ? 

[Mech]

Another place that catches people out is the starter and earth cables can get bad connections between the wire and the terminal..  Because they get a big load they can be fine one start, then sort of blow the contact and be dead as....  I've seen it on cars trucks and bikes..

Good news about the spark.. 

[Gwbarm]

I only turned on key no green light which I always see no start with button pull starter is still off till I get new gasket

[Gwbarm]

Well I found the problem I had a flawed wiring connection in my high tech testing facility.

See the red wire that's supposed to be hooked to the negative battery post, it goes down to a little short black wire hooked to the frame, the connection point that is now covered in black tape was the problem.

[Gwbarm]

Still waiting on parts to get the big bear going, decided to take 5 minutes to pull the carb and check it out, it is an aftermarket, choke plunger was stuck an hr later after PB Blaster for corrosion and Berryman Chemtool for varnish I  finally got it out.

 

Carb was dirty but not as bad as I expected

[Gwbarm]

I got my parts in today opened the box and the gasket was broken, the joys of mail-order, still had to clean the tank and petcock out so started on that: not bad:

Tank was in. good shape, petcock not so much, but I cleaned it up, lots of corrosion under the gasket probably was leaking, if it leaks I will replace it, boring stuff but I thought I would share, I like to see photos of revival projects.

[Jim Denton]

On 3/11/2023 at 9:52 PM, Gwbarm said:

Thats a good thought, i may do that just for fun, no telling what they would charge to do that, but nobody around here brings this old stuff to a dealer, they charge more to fix them than the bike is worth, that's why you see so many junked ones. Example: I have a 2003 Cadillac it was my mothers car, pristene condition 45,000 miles on it,  took it to the dealer, they did not even want to work on it , said the car is older than most of their mechanics, this certainly isn't the world I grew up in ,changing daily. 

Scarily so.

[Gwbarm]

Went out today thought it might be a good idea to check the valve clearances while the tank was off, too bad I didn't think of that before I put the tank back on, so I took the tank back off, I could tell these bolts had never been removed from factory, intake was .003 perfect, range .002-.004 exhaust was .006 range.006-.008 I usually try to go middle of range but was good so didn't touch it. Pull starter needs attention, this bike was so neglected.

Really rusty no gasket, have to make one.

Cleaned up fairly well with the cheek poker.

[Mech]

I'm not sure a gasket is a good idea Gw.. Water gets down the pull handle anyway..I think some even  have a small dimple bent into the metal to leave a drain hole..

[Gwbarm]

Thanks for the info, wasn't sure, it does show one in the parts diagram but it may just be a spacer.

[Gwbarm]

My new gasket is supposed to be in tomorrow started cleaning up the mounting surfaces:

Found another obstacle I knew there were bolts missing, but not really expecting this, broken stud, not surprising the shape this thing was in, but its coming around.

Got it out with a little patience ,PB Blaster and hammer and chisel, I only use ease outs as a last resort, the small ones always break then you really have a problem.

[p5200]

Looking good! 👍

[Gwbarm]

Thanks guys I really appreciate the support!

[Mech]

I'd seen that broken bolt earlier..  Good work.

I always use a tiny chisel (made of an old pin punch), to get broken bolts out too..  Whenever possible.

[Gwbarm]

I didn't notice it I guess was looking at other stuff, good eye!

[Gwbarm]

Got the new gasket installed on Saturday, aftermarket didn't quite fit only missed it by 5mm, I made it work but don't feels real secure, if it leaks I will get an OEM one, hadn't got it all back together yet but I torqued the bolts and had to know, shot a couple of shots of carb cleaner in the intake, fired right up first rotation, didn't run very long but it did run. When I get everything back together with gas I can tell more about it.

 

 

 

[Mech]

Big paper gaskets often shrink or expand. If they are too big when you go to fit them you dry  them out in the sun or in front of a heater. If they are too small when you go to fit them you steam them a little over a kettle.

[Gwbarm]

That could have been the problem with the gasket, but it was not a material that im used to seeing a gasket made out of, it was not like gasket material, was like paper but plastic coated or something, but not rubber. In fact its exactly like the one that came off of it that green color. 

I was surprised it started so easily after sitting so long and stuck engine. Its certainly come a long way, the oil is starting to look milky again so their was still water in the engine that didn't come out when I drained it, I v got to add a couple of quarts run it a little and then change it again, its looking promising if it will move, hadn't tried. that yet.

[Gwbarm]

Th gasket seems to be holding for now, but I did have a small oil leak at the oil cooler connection, I knew it was a potential problem area when I installed the new filter housingI didn't replace the copper gaskets thought they would reseal and they may have if I would have had a 23mm socket to get them tight enough. Got them out, reinstalled using Honda Bond #4 on the threads, I couldn't find my Yamabond. Scrounged around and found a 23mm box end, worked perfectly. The bottom one was so close to the frame rail couldn't use much else. Should have put them on before I installed the housing , but thought I could get them tighter one it was installed. Not high tech stuff, but might help someone that has to do this.

[Jim Denton]

Wow this has been a journey.  Looks like you're doing great though.  I'm with you on the ez outs. The buggers promise the world and then treat you like crap. Always hiding in the tool box, calling my name. 😀 

[p5200]

Looks like you'll be ready for a test ride soon!

[kp3004x4]

Looks good. I make most of my gaskets or use grey silicone that is made for small engines never had a problem yet. I get it in the tube that fits in caulk gun and it's fairly cheap compared to small tubes you can get at auto parts stores ect and in my opinion it works best in some cases ,when you go into an engine that was taken apart before and messed the matting surface up so much that a gasket won't seal,but you got it going good,be running in no time  ..

[unirambler]

Interesting thread. I think the quad I have is going to need a lot of the same diagnosis so really enjoying seeing how to figure it all out. Now I can't wait to see yours running and dreaming of when ours is running as well! 😀

[Gwbarm]

Its been interesting, not something I had planned on fixing, got it really cheap I needed the tires for my eiger, but after looking it over I liked it, so decided to try and revive it. Like the old saying, if you are not having fun, you are doing it wrong. I found this site shortly after and it really helps keep you motivated, a lot of good friendly people willing to help.

[Gwbarm]

Got it running on gas yesterday.

 

Not without its minor problems, petcock leaking, aftermarket carb leaking out a hole in the bottom, thought drain screw was loose but it wasn't maybe wrong screw who knows, maybe o ring missing. I expected these things, but it runs pretty good for stuck engine and sitting so long, idle was high but that's carb.

[p5200]

Glad to hear it's up and running your getting closer to to riding. I'm suppose to go pick the Polaris up this evening when the grandson gets off work. I guess I'll slowly find out what else wants to go south from sitting for 2 years. LOL!

[Gwbarm]

Thanks! That great you getting the Polaris, hope it works out good . Taking your grandson along and getting him involved is perfect, things like that kids never forget.

[Mech]

Yup..  good to get the kids or grandkids involved. Teach them skills and self reliance..  and how to keep out of the clutches of thieving mechancs !!