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2000 Yamaha Big Bear 400


Gwbarm
Go to solution Solved by Mech,

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Iv been checking voltages and resistance throughout the harness, haven't found any real problems, everything seems to be getting to the CDI like it should. Have 12.1 volts going to the CDI  red/white , good ground at the CDI black wire , pickup coil resistance 528 at cdi, ani kickback coil .1 at CDI, and continuity from coil to CDI orange wire, start stop switch works as it should. It may still be the coil it is a brand new aftermarket, the secondary readings of 275 seem low, may have to go OEM.

Thank you for all the work you have put into helping me , I really appreciate your time.

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That's no trouble Gw...  I don't like mysteries.

That link above does actually seem to be the right one..  I must have got confused from looking at too many. The one above has the starter isolation relay and the fan control unit..  I think it's all right..

Yeah Gw, all the secondary windings are always in the Kohm range..  Primary windings always less than one.

The book(the right one) says the secondary should be 6.32- 9.48KOhm.

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That manual by the way, if you download it, arrives named "2000-01_big_bear_400_service".  That's where I got confused..  haha. I was looking at one but the quadcrazy manual page listed it as something else.. 

It's got the fan controller, the start isolation relay, the reverse relay (without a built in diode), and the carby warmer..

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Feeling a little more secure about the wiring so I thought I would change the oil, been sitting a long time and milky looking not real bad but I didn't like the looks of it, one adventure after another with this thing, figured it would take 5 minutes and change the oil, 2 hrs later  I haven't got the nut out yet, previous owner stripped the drain plug head off, probably used a 19 when it takes an 18, generally I get those off with a pipe wrench when stripped, but yamaha in their wisdom put this nut down in a hole so I can't get a pipe wrench on it, I had a set of nut extractors that I tried, didn't work. Any of you guys had this problem, ideas would be greatly appreciated.

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Single hex socket ?  Single hex socket that's been held against the grinder so the working end is ground off flat and sharp edged, without the usual rounded/tapered lead in into the socket. They go right down on the bolt, and the sharp ends get more bite and don't try to slip. Try to tap the plugs head first. That has two effects, it loosens the threads slightly, and if done the right way can slightly flare/spread the end of the plug so the socket gets a bit better grip.. Since it's in alloy which you wouldn't want to crack, you'd need to use the ball end of the hammer and go around tapping right on the edges of the plugs head to spread the metal without having to hit too hard..  If the hole it's in allows that of course. If it's accessible, and has a flange, use a small blunt cold chisel to try and tap/force the flange around. A few taps on one side then the other..

Drill right through it and use an easyout.. Smallish hole and easyout might work if it's not too tight. If it's tight it would need a big drill so you could use a big easyout.

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I ended up getting it out with hammer and cold chisel it was not a bolt at all, it was a casting, same soft metal as the cases about 2 inch diameter, I know you yamaha guys are laughing at me now but this is my first Yamaha ATV, this is what I got out off the crankcase, ugly, the only good thing is no metal chunks. This is a 6 qt container, right now I have the crankcase filled with used mobil 1 5w20, just to give it some lubrication, that's what I had, it's been deprived for a while, im thinking about draining this out and filling with Marvel Mystery oil and letting it soak for a while, quite boring but maybe a little entertaining. Lower photo shows the color a little better.

IMG_3499.thumb.jpeg.7a9c32288e68e9bfc94ef190bdca2e2a.jpegIMG_3502.thumb.jpeg.b660dbc6fa6dee1e84d7d362fd7b7e69.jpeg

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Well, that was fun, it seems like every simple thing I go to do on this Yamaha turns into an adventure, went to change the oil filter, which by the way is more trouble than it should be, housing came off in two pieces, that explains the massive oil leak, that's OK I wanted to flush out the oil cooler anyway.I think I will temporarily put it back together with JB weld while im waiting on the new part.

IMG_3520.thumb.JPG.0324e323b4d9278cd206ade7921436b9.JPG 

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Yes not even sure how that got broke unless they over torqued it , it was the top hole, I didn't really expect JB weld to work, and it didn't , I was very careful too, I put the bottom two bolts in first got them hand tight and then put the broken one in, tightened it slightly then backed off, torqued down the other two and then just tightened the repaired one hand tight, it should have worked. Went to check the compression and didn't have the right adapter for my gauge , threads appear smaller than standard.

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Kind of jumping back and forth here, but I am still not getting spark. I have checked all the systems that would keep spark from happening numerous times, does anyone know of an aftermarket CDI for a 2000 big bear, I find them for the 350,Warrior, and Kodiak, but haven't been able to find one for the 2000 400. Not really sure why, I thought the kodiak might be the same but it looks different. I don't mind paying the big money if its bad, im not sure, I still could be missing something. Pick up coil resistance is within specs but I haven't figured out how to check that it is actually putting out voltage. 

IMG_3524.thumb.jpg.8b37267dec9f24e2f93fa2661cf8c30a.jpg

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The book I've been working from latterly, the one which seems to be the best for your bike(as far as I can tell), says the pick up coil should be measured at the engine connector and it should have 459-561Ohms, but I'd check that figure at  the cdi to check the wiring as well.

Not all pick up/trigger coils put out voltage, some just change resistance as the flywheel tag goes past.. If it's one of those sort it should have some very small voltage and current coming out of the cdi..

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