Lost rear bolt for fuel tank, and some other compartment, xj650 4K0

Hi all.

Newbie question, but here goes:

After my long highway ride, I noticed, that the rear bolt for the fuel tank has gone missing.. It must have wiggled itself loose, and the bolt for some other compartment.

I have read, that the 4K0 bikes have a fuel tank "Clip", that should keep the tank fastened, however when I bought the bike, it came with som sort of home made device instead:




How important is that "clip"? Can I just get a regular bolt, washer and nut, and use that instead? Or will I just risk, that they will wiggle loose too?


About the other bolt that's missing in the green circle to the right:



I have looked online, and it seems to me, that its part number 11, 12, 13 and a nut (not mentioned in the schematic below) that's missing. Is that correct?

It looks like the "spring collar (nr. 14)", and "grommet (nr. 15)" is still in place.




When looking up the parts on cmsnl.com, it says that bolt nr. 11 is a hexagon 7f7, and theres no more info on the fueltank bolt.

So is these some special bolts, or can I just go to the nearest Home depot, and get some bolt?
and what sizes should I get? Diameter, length etc.


Hope I have formulated myself in an understandable way! (english is not my native language)


Many thanks!

 

I don't know what a 4ko is.
Can you post a picture of your gas tank? That doesn't look proper.
The tank on my XJ650 Maxim has a contour that matches the mounting 'bracket'.

 

Yamaha XJ650 (4K0) is the europe-model of the xj650. (XJ650 SECA is the american model).

The schematics of the fuel tank:

 

Oh. . . Ok, first cup of coffee bad vision. Your tank DOES fit the bracket contour.

Hmmmmm, what is #27 in the diagram above?

 

Haha, that is a very acceptable excuse!
#27 is a special "Tank clip", that is supposed to work as a "quick release" (as far as I can understand from various sources)

So I am a bit in doubt whether or not it is needed, or that a regular bolt, washer and nut would do the job just fine, without "wiggling" loose?

 

I have the 4k0 with that quick release. When i first got the bike i thought i had to take that bolt off, but it sat like hell and would not move, so then i realized that i could just lift the tank off instead. The quick release thing is very handy IMO! But i recon a bolt and washer would work too.

 

But how do that quick-release work? I can't seem to grasp how a bolt "isn't holding the tank" Do you have some pictures of it?
I have looked around on various sites, but none seem to be able to answer it

 

The bolt sits right but 10mm or so over the hole in the tank. The quick release is just punched in between the tank mount and bolt head. It's pretty loose, but it sits on that rubber anyways so it doesn't need to sit any tighter. I can try to take some photos when I get home from work.

 

Okay, but then I don't get why you can lift/remove the tank after the quick-release is removed? Isn't it still holding down the tank?

I would love to see some pictures of it!

 

There are two 'heads' on the quick-release bolt. On is snug to the base, and it fits through the hole in the tank tail. Then there is a groove that the clip fits into......kind of like a c-clip, but I'll call it a 'tuning fork' clip. Then there is the top head. It will also fit through the hole in the tank tail.

The bolt stays on the bike. The tank is lowered over the bolt and the the 'tuning fork' clip is side into place. This fork has a tang that slips over the top of the bolt and the end of it has a bump that helps hold it in place.......like the spring tip inside an electric guitar jack or headphone jack, etc.....

This clip simply makes sure the tank won't come off. It won't anyway...... The weight of the fuel, the weight of the tank, the hoses connected, and the front rubber mounts won't allow the tank to fly off. Also, the. Seat holds like the back end of the tank down anyway.

The size bump or bounce or jolt you'd take to make the tank bounce off the bike would be so extreme, you'd have more issues than a fly-away tank......you'd be dealing with your own fly-away body.

I have these on some bikes, but don't find it really any less convenient than just grappling the mm socket and removing the bolt and plate when I remove tanks.

The IDEA is cool, I just don't see an incredible need to use them instead.

Ymmv

Dave

 

Thanks Dave! I believe it starts to make more sense

Do you have any idea about the other bolt I'm missing, and what the black thing it's' supposed to tighten to the frame? It's the right green circle in the 2. picture.


And so that home-made "thing" I have shown in picture one doesn't really have any function at all, besides just ... well I can't actually think of anything it does except just "be there"?

 

The bolt has a slot in the head. The spring clip goes into that slot. The bolt holds the spring clip, and the spring clip presses the tank against the rubber damper and the frame underneath. The reason why that homemade clip doesn't work is because it's not made from spring steel.

Part #8 is a special washer that helps to spread the load onto the upper rubber damper so that the tank is only touching rubber parts.

The clip system is necessary on the Seca because the rear tank mount is pretty close to the underside of the tank, so using a wrench on the bolt that's used on the Maxim is slower and awkward.

 

This is the correct answer. There's just not a lot of space under the rear of the Seca tanks (650 and 750) to get a wrench in there to remove a bolt while the tank is installed......the Seca tanks, unlike Maxim tanks, do not have a protruding, exposed flange that a hold-down bolt/washer combo can be used on. The hold-down flange of the Seca tank is completely covered (shrouded) by the tank's rear edge, with just a small-ish, crescent-moon shaped opening. That's why the clip is used, it can be much more easily accessed. The bolt is there to give the clip something to latch onto.

 

Most of my seca's have just the regular bolt and I use an open-end wrench or box wrench for those. I have 2 with the clip.......I find the clip tends to be 'loose'. I prefer the bolt. I'll try to take a pic later today f I can.

 

So just to be perfectly clear: It shouldn't cause any problems using just regular bolt, washer and nuts, to replace the two missing bolts?

 

I use the regular oval plate on top of the rubber ring....... But if you have a washer big enough to overlap the edges of the hole, you're fine.

Again, I'll take pics

 

Ok--- here ya are---

Regular bolt


Double-shoulder bolt by itself


Double-shoulder bolt with clip and plate


Dave

 

Thanks! However I still can't understand, how that clip is the one holding the tank in place, and not the bolt, since the bolt is the one fixed to the frame

But that doesn't really matter. I'll just go out and get some bolts, big washers and nuts, and tighten things down with them. I suppose that should be good enough.

Many thanks for the replies!

 

It is snug to the plate; which is snug to the rubber ring; which is snug to the tank;which is sitting on a rubber isolator; which is sitting on the frame.

It doesn't bolt it down tight like a regular bolt/washer does.... it just holds it snug-- like the c-clip on the end of your carb rack. That c-clip holds the shim washer; which holds the throttleshaft seal.......