2000 Yamaha Big Bear 400 No Spark

[Mech]

You mean the metal tag is there ? It's not a magnet, just mild steel.

If the tag is there then you need to check the trigger coils has a magnetic core. If the bike sat for a long time the magnet may have got weak. If it's a magnetic core coil, you should be able to get some very small voltage from it by passing a piece of metal closely past it.. the faster the better..

If it's not a magnetic core then it's the more modern type that needs power going through it to induce a magnetic field which then gets changed by the metal tag going past. The cdi detects the change of resistance caused by the change in magnetic field.

It will work in one of those two ways, or have a problem related to which sort it is and how it's meant to operate.

And finally, make sure there are no flakes, or little accumulations of rust powder, that could rise up and bridge the gap between the metal tag and the trigger coil's core. That will stop either sort working.

[Mech]

That core needs to be close to the metal tag as it goes past. Much the same as in older versions, a few thou is about right..  I suspect it's position won't be adjustable, so unless it's the wrong version it should be right unless it's an eighth of an inch away. A sixteenth of an inch would be about the max gap I would think..  

[p5200]

16 hours ago, EugenM said:

Morning from Romania again!

are you sure the sensor is in the right position? surely it shouldn't be put the other way around? I made a drawing on the picture.

 

Hi, is that the pulsing coil?

[Gwbarm]

Yes

[Mech]

Oh I just realised what Eugen was saying..  Yeah good point Eugen.. it does look like it could get flipped over...

[p5200]

Not sure if this is any help or not.  

 

[EugenM]

1 hour ago, Mech said:

Oh I just realised what Eugen was saying..  Yeah good point Eugen.. it does look like it could get flipped over...

sure it's the sensor upside down, if you look closely at the gasket you can see it is cut out so it can be fitted, which means the pickup sensor is fitted wrong

[EugenM]

in 20 years of mechanics I have yet to come across gaskets that need adjustments/modifications to fit...(except Chinese chainsaws)

[Gwbarm]

I was thinking it didn't look right being proud of the side cover like that. 

[Mech]

Ha..  God spotting Eugen.

The end might be in sight Gw.. 

[Gwbarm]

Good eye Eugen, I didn't even notice the chewed up gasket, I am going to remount it and see if it works, thanks for the video p5200 I did notice that his was mounted like mine but the mounting tabs were lower in the case and the coil didn't stick up out of the case like mine, and Mech great information on how to test it. If still no spark I will check to see if it is putting out voltage and if it is I will have replace the CDI.  I have read several posts of the same thing happening , put in upside down, It just amazes me that they didn't notice how the old one came out, and didn't even question their work and just give up.   

[p5200]

Looks like you might just have it up and running soon. 👍

[Mech]

Yes I was wondering how many of these get put in wrong.. 

 

[p5200]

I always try to take photos each step of the way especially, on electronic components with all their connections.

[Gwbarm]

Im hoping, the engine seems okay 130 compression a little low but I think this had been sitting since 2019, there is a date on the CDI, hand written, im assuming that's when they bought the CDI, not sure if used or new, and am certain it never ran with the coil in upside down.

[EugenM]

Did you forget that last week I had one exactly the same?....only it was grizzly....and that one can be mounted in wrong position...we are human and we make mistakes....I'm glad I was able to help you!

Gwbarm send us a video with the engine running!😉

[Gwbarm]

I really appreciate your help, you caught it when I didnt

[EugenM]

12 hours ago, Gwbarm said:

I really appreciate your help, you caught it when I didnt

I'm happy for you Gwbarm!

I'm glad that we managed to find out the problem!

Cheers!

[Gwbarm]

 Eugen, I do have spark now, didn't look very hefty , but im going to check it later when the sun goes down, it was kind of bright outside, now that I have worked on it, I retract the statement I made earlier about  things going back together like they came apart, when working with aftermarket parts they do not go back together like they came apart, I have run into this before with aftermarket parts, wiring is too short and does not fit back exactly like it supposed to. I am still trying to route the wiring back the way the original was and its just not going to happen. I will post some photos a little later. 

[EugenM]

Good luck with that! I'm sure it will be a good job in the end!

[Gwbarm]

The rotor cleaned up fairly well I thought it was more pitted than it was.

[p5200]

Looking Good! 👍

[Gwbarm]

Still messing with it, need a new gasket but I did put it back together long enough to see it spark, the coil fit in nicely the right way, thanks to Eugen for catching that.

[p5200]

When he mentioned it, I thought it looked like it should be closer to the Stator coil. I'll be surprised if it doesn't start now.

[Gwbarm]

Nice to see it sparking.

 

 

 

[p5200]

Looks like good spark to me!

[Gwbarm]

Success short lived, Went out this morning to start cleaning the carb to work on  get it started, and I have no power, no neutral light, no nothing, thought it might have blown a fuse , they were all good, so I am going to start tracking that down. 

[p5200]

It's probably something minor and a quick fix.

[EugenM]

1 hour ago, Gwbarm said:

Success short lived, Went out this morning to start cleaning the carb to work on  get it started, and I have no power, no neutral light, no nothing, thought it might have blown a fuse , they were all good, so I am going to start tracking that down. 

For sure something minor....

No power... it's easy...start from battery and follow the power 

[Gwbarm]

The last thing I did was video the plug sparking and it worked fine, and then unhooked the battery,i always unhook the battery after testing just in case, don't want my junk to catch fire when im not around until I feel confident about the wiring.. I thought the battery cable could have possibly hit the frame and blew a fuse, but no fuses were blown, unless there is one I haven't found yet, I checked the main fuse box with 4 fuses and the soloenoid with 2 fuses all were good.