2000 Yamaha Big Bear 400 No Spark Mikuni Carburetor Install (Continuation of No Spark)

[Mech]

Good work.  A bit of sheet aluminum might be better that gaffa tape to shim the handlebar.

And for future reference Gw..  Brake calipers almost never leak from the piston seals. The pistons don't slide on the seals in operation. The seals jamb on the piston under pressure and flex to allow the piston to move the tiny distance they need to press the pad on, then it's their un-flexing that pulls the piston back a tiny amount. Even with rusty pistons they don't seem to leak more than enough to catch a bit of dust.

And what sorts of old bikes do you work on ? I have lot's of manuals, paper and pdf, for old british stuff. Matchless, ajs, bsa triumph, norton.. Worked on all of them and some of the smaller british and euro stuff.

[Gwbarm]

Thanks for the tip on the caliper never had one leak there like you said, but I have had them get stuck where you could not move them.

Right about the tape it works, but I don't think its a long term solution, I will try the aluminum sheet. 

I have mostly Vintage Japanese bikes. All of the honda 305s from the 60s, two  Kawasakis from the 60s, Samurai 250 and Roadrunner 120, 2 stroke, both Yamaha Big Bears from the 60s, 250 and 305, 2 stroke. I do have a triumph Trident 1973, my favorite year, Suzuki RE5 Rotary from 1976. Oh and 2 Black Bombers 450.

I have been collecting for quite a few years and my plan was to restore all these when I retire, I got a few done, but I forgot to calculate into the equation, was the energy level decline as you get older. 

[Gwbarm]

Went out today to check the differential fluid, the front bolt came out, not without  a fight, a normal ratchet wouldn't do it, had to get my 24 inch out, the rear one is an Allen or appears to have started out its life as an Allen, it is stripped, appears it might have been worked on with an SAE too small not metric. Im afraid im going to have to chisel it off. Front was 17mm bolt, this appears to have been a 5mm, I got a 6 in there but it wouldn't get it. Im going to try smoother things tomorrow,

 

[ldrrn]

The jets are the same in the aftermarket we ordered.

[Mech]

Who.. very cool collection Gw..  The 305s were a classic..  and the rotary. ..  Good work preserving them even if you never do get to restoring them.

That allen key will be 6mm.  4,6,8,10 are what the japs use.  At least it's got the big flange head to tap around huh.. 

[QuadMan49]

Good work Gw,

Did you weld the extended foot rests, or the previous owner? I'm thinking of doing something similar to my quad. The reason is because stock setup does not have much of a foot rest.

Edited June 8, 2023 by QuadMan49

[Gwbarm]

They were already there when I got it, this quad was really set up nice in its day, it also has an aftermarket 2w/4w disengage, cable operated made by Warn, and a very nice warn winch, haven't got to those yet to see if they are working, evidently this model didn't have a electronic 2w/4w disengage switch, it been a trip bringing it back but its almost there. Thanks!

[Gwbarm]

Thanks Mech I have been collecting for about 25 yrs, back when you could get them cheap, Ebay kind of put a stop to that.

The Allen was 6mm as you said, completely stripped, ended up using a chisel and 2 pd hammer and it still fought me but I got it out.

I was going to just ignore it since the front was full, or so I thought. Drain plug 21mm

This is what I drained out of the rear, it was low. Supposed to be double that. Color wasn't too bad maybe a little milky, the seal on the drain plug was bad.

I pulled the plug on the front 10mm hex and got nothing but dribbles of water, then took the top plug completely out and the oil came it was fairly full but very black. Im really glad  I went ahead and checked it.

 

I know this is everyday work for a lot of you guys, I mainly post it to to help others who might want to do this this for themselves, and have never done it before.

[Gwbarm]

I got all my fluids changed, went and took it for a ride today, first real ride in who knows how long. It did really good ran flawlessly , good throttle response, powerful, no hesitation, thanks to the new Mikuni, shifted through all the gears good went into reverse perfectly, good front brakes, and surprisingly rear brakes still work, just need a little adjustment. The only problem I had was getting it back out of reverse it did not want to come back out easily, also finding neutral, I knew I had it in neutral but the light wasn't coming back on, came back a little later ,turned on the key and the neutral light was on. I may have to do a little shift linkage adjustment, im going to check it and see if it is in spec. Just curious, any of you with Big Bears have this problem or is this normal for an old machine.

[Gwbarm]

Update: I sprayed my plastics with rattle can clear engine enamel looked really good, spilled I drop of brake fluid on when I was doing the master cylinder, it took it right off, so not a good choice, I figured engine enamel would be better for fluid spills, but it is not, I guess if you use it on your engine be careful not to let gas leak on it.

[Gwbarm]

I went out and rode the Big Bear again today I had to pull my trailer around to the back of the property, ran flawlessly and pulls like a mule, but I noticed this yesterday after it warms up smoke starts coming out from under the seat, at first I thought it was just oil burning off where I took the exhaust leg saver off, but it should have burned off by now, unless lots of oil got in the pipe, I did soak it heavily when freeing up the engine, and it seems to get worse the more I run it. Then I thought maybe there is a pin hole in the exhaust pipe there but that couldn't be it because it not smoking out the back. So im not sure where it's coming from yet, any thoughts.

[Mech]

If it's not coming out the pipe at the back..  it should burn off.. unless it's getting new oil thrown on it from an axle..  or a head leak..  Either way I just ride it.. the more the better..

[Gwbarm]

Thanks Mech, I will do that , I have a few loose ends to check out, plug the fan back in, see if I can chase that down, fan runs all the time when key is on, check lights, and see if its charging, that will finish it up, then on to my next project, its going to be interesting.

[Gwbarm]

Doing some checking today, lights all work glad to see that, low beam out on one of the headlights, tail light works, plug the fan motor back in and it didn't come on , and its not supposed too, but it was before, and I was trying to remember, I don't think I had the electrical system all hooked up when that was happening, so I may be alright, that would be good because that controller ia a 170.00 part. Hooked the winch cables to the battery and got a nice light show, so some problems there, I am going to have to double check all the wiring on the winch relay, something is shorted. So everything else seems to be working now +++++.

[Mech]

Excellent.. Things like the fan not behaving, even though we know the wiring isn't all attached, can lead us on a merry run around alright.. Like trying to run/fix things on jury rigged fuel tanks, only to eventually discover they need fuel pressure.

It's always a problem though when we start on something unknown and just want to ascertain it's viability first..  Well done on finding the pragmatic way through..

[Gwbarm]

Digging a little further none of the wires are color coded, but I did find one that had a red crimped terminal, maybe the positive, and side of it a black, they must be the ones that go to the battery, wires are the right length, so I hooked them to an external battery, incase of another light show, I didn't want to fry my electronics. No light show, winch didn't work either. I should have done this first, got down and looked at the winch, no wires connected or anywhere to be found, I guess it wouldn't work. Found them stuffed away in the tool box, I will try to rewire it tomorrow. Getting kind of late.

[Gwbarm]

Doing a little closer looking, this is a warn A2000 nice little winch, a little small but OK for anything I am going to do, if I was buying one I would have bought a bigger one maybe 4000.

The problem is it is wired with all black wires looks like gauge #8  no color coding at all. It should have a Yellow to #1 post on the winch and Blue to go to number 2 post, both are black, of course red and black to the battery, the solenoid is mounted in the tool box at the very back of the machine, with two black wires going to the battery connection, this is why I got a light show, my deductive reasoning was evidently flawed. No markings on the control pack either, I found out later they are on the back of the control pack, labeling you will never see again once you mount it, not a lot of thought went into that one. Stilll trying to figure out which wire goes where I should have done this while the plastics were off. Kind of hard to wiggle a wire in the back and see which one is wiggling in the front at the same time.

[Gwbarm]

Did a little wire chasing today, but before I did that I put 12v to the winch just to see if it works , it works fine maybe a little noisy I will have to put a load on it to be sure. Found which wires were supposed to be yellow and blue and hooked them up to the winch accordingly. Found the battery hook up wires, located a hole to run them through to the battery.

Which one would you have guessed to be positive, yes I would have also, except it wouldn't reach the positive battery post. Good thing, I probably would have hooked it to positive. Except I am questioning everything I find on this rig. 

Got them at least color coded correctly.

After all that it didnt work, but I had to do all that anyway. I suspect it might be corroded in out switch. Or maybe the main controller.

 

They make it pretty simple if you use their wires, blue and yellow to winch, and black and red to battery. Either part is very simple to replace.

[Gwbarm]

Changed the oil again today on the Big Bear dosent look like pond water anymore, it does look darker than I expected this oil probably only has 1 hr of running on it, if that much, pretty dark, so im getting the engine interior cleaner. I put in the Castol Actevo, Im going to run that for a while to finish cleaning things up and then change to Yamalube. For those who didn't catch the beginning, when I got this bike the engine was stuck and had no plug in it, and very little oil, if you want to call it oil, very green looking.

 

[Gwbarm]

I did do another oil change and put in yamalube 10w40 hasnt really used it much since. So its been sitting a few months covered.

Went to start the Big Bear today and the neutral light would not come on havent reaally used it since i started working on the eiger, it was a little iffy before, come on then not come on or slow coming on, a little tricky somewhere between 1 st and reverse, finally got it to come on and it started ran good good throttle response, idle was a little slow, i tuned it when it wasnt quite as hot as it was today, i will start tracing that down. May have to pull the switch and clean it.

[Gwbarm]

Took the Big Bear out for a ride today did very well but did have a major issue. Engine ran well carburetor did exceptionally well after i turned the choke off. I rode it probably 30 minutes it continuously wants to get stuck in reverse i can usually get it out but this last time it wasnt having it, i had to get off and play with it for a while, rougher than i like to to get it back to first, anyone else ever have this problem, this is my first Big Bear so nothing to compare it to. Im still trying to locate the neutral switch light still not working i went through the manual and never could find the location im sure its there somewhere i just missed it. Most of these i have worked on just has a little nub sticking out of the engine housing with a wire on it, this one doesnt have that, it must be inside the case. 

[Mech]

Yeah the manual says the gear position switch is inside the case, near the clutch. Rearwards of the clutch..

output.pdf

[Gwbarm]

Thanks! I missed that, rathar annoying to get to especially since i just changed the oil ,again, i am going to check the wiring good because i did get it to come on once yesterday, its been troublesome since i have been working on it, i would get it in neutral and then it would come on 15 seconds later.

[Mech]

The fifteen second thing's a bit strange..  I'd find the wire and short it to the engine and see if the light comes on straight away.

I think that should start in gear as long as the back brake light is on..  if that's the main problem.

 

[Gwbarm]

Correct it will start in gear when the brake lever is pulled, that how i was able to use it today, and then it got stuck in reverse. So it appeaars its not quite finished yet, but maybe one of this age and abuse level is never finished.

[Mech]

Not a problem for a mechanic..  I just ride them unless they won't go anymore.. or stop.. Then I fix them if I have to.

[Gwbarm]

I finally found the airbox inlet hose at a price i was willing to pay, i have found plenty of used ones which i dont mind buying even with the grease and mud still on it, but not for  60 or 70 dollars. I found this new one, looks like it has been sitting on a shelffor 20 years but it was new in original packaging, so i got it for 40. You can see the whitish residue from sitting in packaging for a while. 

I dont use Ebay a lot, only for unobtanium parts, and when i do i have a system i follow. I know what im willing to pay before i look and if i dont find anything in that price range, i keep looking, if i find something i think is really good i will up my anny a little, i dont want to cheat anyone want to pay what its worth. This part he had listed for 75.00 i put it in my cart willing to pay the 75 , and forgot about it , a few weeks later he sent me an offer for 40. It was his offer so i accepted it.

 

 

I made one out of radiator hose and has been working fine for a while, hose was smaller and i was a little concerned it might not be getting proper air flow at high revs. The hose was a little smaller.

 

The new one fit better and now has a place to hold the vent lines that were just flopping around.

 

 

Not a very exciting read but thought i would just throw this in  since things are a little slow right now.  

 

[Mech]

Whoo. Score. Patience is a virtue.. As my gran used to say.

 

[vlxerdon]

22 hours ago, Gwbarm said:

I finally found the airbox inlet hose at a price i was willing to pay, i have found plenty of used ones which i dont mind buying even with the grease and mud still on it, but not for  60 or 70 dollars. I found this new one, looks like it has been sitting on a shelffor 20 years but it was new in original packaging, so i got it for 40. You can see the whitish residue from sitting in packaging for a while. 

I dont use Ebay a lot, only for unobtanium parts, and when i do i have a system i follow. I know what im willing to pay before i look and if i dont find anything in that price range, i keep looking, if i find something i think is really good i will up my anny a little, i dont want to cheat anyone want to pay what its worth. This part he had listed for 75.00 i put it in my cart willing to pay the 75 , and forgot about it , a few weeks later he sent me an offer for 40. It was his offer so i accepted it.

 

 

I made one out of radiator hose and has been working fine for a while, hose was smaller and i was a little concerned it might not be getting proper air flow at high revs. The hose was a little smaller.

 

The new one fit better and now has a place to hold the vent lines that were just flopping around.

 

 

Not a very exciting read but thought i would just throw this in  since things are a little slow right now.  

 

I thought this whole thread was a great read and very helpful to anyone with a big bear. Many thanks.

[Mech]

Yup. Gw's a treasure..