Tank - Coil interference

[Redman]

Had tank off, and I noticed a place on bottom, just behind the front mounting, that looked like something wearing against it.
Then noticed same on other side, mirror image.
Both places the wear looks current.

Looked on the bike, and noticed that seemed to be the outside front corner of the coils, and that corner is obviously worn off to a bevel.

I dont think the corner of the coils are worn down to any active part of the coil.

Am a bit concerned that the tank is worn thin in those two places. And with further wear could be a problem.

Doesnt look like any easy way to alter the coil mounting to lower them or move them back.
So when I reinstalled the tank, I moved it back within the range of movement in the mounting on the back of the tank.

Yes, I have the rubber bumper things on the front mounting.

Anybody notice anything like this before?
Maybe the front rubber bumper things on the front mounting are old and maybe shrunk, but they do not seem to be deformed out-of-shape.

 

[Redman]

Humm.... Dont know why I thought that moving the tank back would clear the interference.
I should evaluate more, maybe moving the tank forward would be better.

 

[GregT]

Usually it's the back rubber pad that shrinks/wears. Can you mount the coils under the frame tabs rather than on the top?

 

[Brendan W]

Could it be as simple as mounting the coils the other way around?
I see a lot of bikes with the HT leads facing back when period pics show them forward.

 

[Steve]

I see that the coils are not the original coils. :-k

Yes, they have the proper part number, but it's a new, superceded part number.

No idea when the part number was upgraded, but those are likely not the coils that were on the bike when it first left Japan 36 years ago.

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[chuck hahn]

Is the black pad at the rear of the tank there??? Should be a pad that sets on the frame that holds that tank up a bit which "may" add clearance. Just a thought.

 

[Redman]

Usually it's the back rubber pad that shrinks/wears. Can you mount the coils under the frame tabs rather than on the top?

Maybe not under the frame, but maybe I can modify the spacers that are used in the mounting.

Could it be as simple as mounting the coils the other way around?
I see a lot of bikes with the HT leads facing back when period pics show them forward.

Hum.....

I see that the coils are not the original coils. :-k

Yes, they have the proper part number, but it's a new, superceded part number.

No idea when the part number was upgraded, but those are likely not the coils that were on the bike when it first left Japan 36 years ago.

.

Amazing observation.

Is the black pad at the rear of the tank there??? Should be a pad that sets on the frame that holds that tank up a bit which "may" add clearance. Just a thought.

Yes, pad on frame near rear of tank is there. And the proper cushions on the rear mounting screws.




I did take another look, and having the tank pushed forward (within the range the rear mounting allows) seems to provide the most clearance, so I felt comfortable with that.
And then later I was thinking that maybe the problem happens when hit a bump. So that gave me reason to want to take tank off again, and look at the coil mounting again. Maybe do that today or tommorrow, while still have about no gas in the tank. Will report back later.

 

[Redman]

Mounting as found included what seemed like an extra nut.
Maybe that is there just to hold on the spacer during assembly.

So I took it all apart. The hole in the frame is not threaded, and the nut underneath is not retained. Difficult to get a wrench on, especially the coil on the right with more wiring harness in the area.

Saw that the coil would still fit in the area without that "extra" nut, so reassembled without that "extra" nut so the coils are a bit lower to avoid the interference with the tank.
Getting the nuts underneath into place was a bit frustrating, and garage getting hot and humid, so am taking a break before finish up with the tank and seat.

Now, I suppose someone is gonna say the coils needed that extra clearance from the frame for electromagnetic concerns or something.

Hum, maybe that "extra" nut was so can tighten that one tight, and then not need to tighten down on the laminations of the core in the coil. Maybe so, but I cant have the coil wearing a hole in the tank.

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[jsandidge]

My coils have that "extra" nut too. I think it just holds everything in place when fitting the coils to the frame. My guess would be that your original coils had shorter spacers and an "extra" nut.

 

[GregT]

If that doesn't give you the clearance you need, I can't see anything stopping you from simply inverting the coils....

 

[Cipher]

I wqould cut the spacers and grt the coils as close to the bottom bit of fram as I could without rubbing.

 

[Steve]

Mounting as found included what seemed like an extra nut.
Maybe that is there just to hold on the spacer during assembly.

I just went through the process of removing and re-mounting the coils on Mrs. Steve's bike. I also had difficulty with the nut at the bottom, so I put the bolt in from the bottom, put the spacer on and locked it down with the "extra" nut. TRIED to put the coil on, it would not fit. It hit the center rail on the frame, preventing lining up with the bolts, so I had to remove it all, put the bolts back down through the coils, install the spacers, then use the "extra" nuts to hold it all together. Then I slide the entire assembly into place and locked it there with the nuts from the bottom. Not quite as fiddly as I thought it might be.

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