Yamaha Seca xj750 tank alternative ?

Hey guys!

Here a good noobs question... i am looking to change the tank on my seca and i am wandering wath kind of tank will fit?

Thanks a lot!

 

Direct fit? Maxim 750.
Will fit with work? Anything.
What is the goal? Larger tank? Smaller tank? Just different to look different?

 

It will be nice to have a direct fit! The goal is to have a different look and something nicer then the original ugly seca 750 tank. something more like a cb tank or a sportser tank.

 

Ugly? Take that back

 

Pulling together info that I have posted regarding tanks..... sometime I'll even re-write it to make a it a little more coherent and logical. Nonetheless, here's the info. Read through it, and maybe you'll find what you need:
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Just for giggles, I did swap some things around to see how things fit:

1 900rk Tank- does NOT mount onto the xj650 maxim, xj750 maxim, OR xj750 seca frame. The upper mount for the frame reflector contacts the seam edge of the 900 tank before the tank can slide onto the rubber mounts. If the reflector mounts were cut off, the tank would slide onto the rubber mounts, BUT the tail of the tank would still be about an inch too far back and will still not allow the tank to be bolted down.

2.750 Maxim tank - as we all know, the 750 maxim tank is a direct bolt-on swap for the 650 maxim tank. The 750 maxim tank WILL also bolt directly onto the 750 seca frame without any modification to the tank of the frame.

The seca seat will still work on the frame, but there is about a 1" or so gap between the seat and the 750 maxim tank.

The seca side covers will not mount onto the frame as the tail end of the maxim tank aims down at the back and interferes with the sidecover top-front edge.

3. 750 seca tank - WILL physically bolt directly onto the 650 and 750 Maxim frames.

The Maxim seat front edges need to be modified to fit the extra length and steeper angle at the rear of the 750 seca tank.

I did not have time to check on sidecover fit. However, due to the upsweep at the rear of the seca tank, the maxim side cover upper front point should still be ok and not interfere.

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Regarding 650 Seca / 650 maxim

Frames are different, I haven't done a seat-swap comparo, but I have done tank-swap comparo which is here in another forum......

That all said, if I get the time in the next few days, I'll try to do that for you.

In the meantime, a quick solution would be to pull the covers and foam, and the do a Seatpan swap..... The seat mounting is different

The 650 rj tank will fit the maxim frame, but you should use the 650rj triple clamps to allow clearance at the front if the tank.... Otherwise you'll run the fork tubes up against the tank on tight turns
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650rj tank on a 550r

650rj tank is slightly shorter in length, by about 1/4 inch at rear oval mounting hole. However, if the tank is pulled back just that tiny bit it will bolt into place. Doing that though, pulls the front hooks about 1/4" back, which leaves a slightly "loose" fit at the front.

The petcock just clears the valve cover but with enough clearance to not be an issue.

The bottom rear of the tank does interfere with the seat pan's lower front corners but they could be trimmed back and re-shaped a bit to allow the seat token and close again.

The front of the seat is too long, too, but if it is cut back and re-shaped and re-curved I could be made to fit nicely.

All that would cosmetic changes, and readily do-able.
The only "major" issue will be that the bottom of the cramped edge of the tank touches the top ends of the airbox. Once the tank is bolted down there will be pressure in the airbox. If the airbox is heated and softened, the two "channels" could be formed. I guess the tank could be trimmed, but I think that may weaken the seams and I wouldn't recommend that.

550r tank on the 650rj

The 550r tank is about1/4" too long, PLUS the front mounting grommets are just a little bit too wide for the tank to slide on.

When the grommets were removed the tank almost fits right in place.

However, the lower front edges of the tank interfered with the horns. If those are lowered or relocated, that issue will be easily resolved.

The rear of the tank tunnel interferes with the frame but if the tank rear is raised about an inch or so, it clears the frame. If some makes a riser/spacer to mount the tank just that little bit higher its right in line above the regular rear mount

The issues to really address would be --what to do about the tank grommets on the 650r, and the rear mount. Here are the solutions....

Two things must be done for the front:

1. The big ring on the mount needs to be moved in toward the backbone about 1/4" on each mount to allow the rubber grommets to fit in the slightly narrower tunnel of the tank.

2. Use the grommets from the 550r, as they are slightly less tall AND the have a little bit smaller diameter that the 650rj grommets.

For the rear of the tank--make spacer to mount the end of the tank about an inch or so higher above the original mount.

Long and short of it:

Either tank can fit on either bike with either seat mods and airbox mods to put a 650r tank on a 550r; or, minor alteration to the front tank mounts on the 650r, relocate the horns, and add a riser for the rear mount will allow the 550r tank to fit on the 650r

Dave Fox

 

Cool, thats nice. Thanks for all the info. I will check the maxim tank. I am still looking to find something more costom like a sportser tank. Their is a few new tank on ebay but the fitting doesnt seems right... http://m.ebay.ca/itm/231558251051?nav=SEARCH

 

Nothing other than what Dave listed will fit without having to modify either the tank, or the tank mounts on the frame, or both.

 

hi all, just want to add that a 650 SECA tank will NOT fit a 650 MAXIM frame. just tried it... now I have a 650 SECA tank for sale. perfect condition.

 

Is this the issue you're having with fitment @Lakermatt , or does Dave have incorrect info? Inquiring minds want to know!

 

I do NOT have incorrect info---- that write-up was done by me, with swapping the tanks and frames by me, using equipment and parts right here. That is first-hand source.

As I stated, the 650rj tank WILL fit the frame BUT you have to use the 650 non-turbo fork clamps, otherwise the tank will hit the forks.

 

I would never question you, Dave! I assumed your info was reliable. I have followed your parts swap threads with much interest. I just wanted to seem like I believed lakermatt. Kidding, of course, but is that the problem you're having, Matt?

 

Well, laker is correct in that the tank is not a drop-in swap. It requires the additional swap of the triple clamp assembly. I THINK you have to use the 65rj forks, too--- I can't remember if they are the same diameter or not.... Something in the recesses of my brain says not----- but even so...... the 650rj front is dual-disc brakes, so may as well upgrade the whole front.

 

NO. the problem I am having is that the tank mounts on the front are too close together. it will not pass the ignition coils to get to the pins on the frame where the little half moon mounts are on the tank. basically the under side of the front is too narrow. I took the stock tank and the seca tank and flipped them upside down on the table and it is clear as day... too narrow. I am comparing a 1982 XJ650 frame with a 1983 SECA 650 tank. it will not work....

 

Ok, here is my 650 Seca tak that I JUST bolted on to a 650 maxim frame. Perfect fit. Maybe you have different coils, or they aren't mounted correctly. The tank mounts are the same width on 650rj and 650j.

 

Now the 650 maxim forks are in on the 650rj triple clamp, on a maxim frame, with a 650 Seca tank.

Again, this picture has:
650 maxim frame
650rj tank
650 maxim forks
650rj triple clamp

 

My bet is that you have a 550rj tank that you THINK is a 650rj tank. THAT will be a little narrower a not fit.

 

ok... my coils look to be mounted correctly... I will go back in the garage when I get home and so some rechecking. can you send me a picture on how the coils SHOULD be mounted?

 

that's probably what it is... because those coils look to be oem and bolted correctly.. I will go back to where I bought it and swap it out... they have 4 others out there.

 

Exactly. The 550 tanks are narrower in the front mounting damper location.

 

P.S. XJ550 tanks use screw-on YAMAHA emblems, and thus have a welded metal bracket (with threaded holes to accept the screws), while the 650RJ tanks used glue-on emblems, thus no bracket and no screw holes in the emblems..........

 

P.S.S. extra nice pictures Dave!

 

Here

 

well that confirms it... has the screw holes. I will return and get a new one. thanks!

 

that's how mine are mounted. screw holes is the confirmed deal. thanks Hogfiddles!

 

If you need to see the 550r tank next to the 650r tank, I can show you that too--- let me know

 

sure!! send em!

 

650r - white
550r - red

Notice:
1. As Chacal pointed out, 550r badges screw on, 650r badges stick on

2. 55or rear mount extends from end of tank, 650r rear mount is recessed under the tank

3. 550r tank is slightly shorter, and narrower... Tunnel is also slightly narrower

 

100% guarantee I have a 550... thanks guys.

 

how much bubby, and can you post pics

 

He does not have a Maxim 650 tank. He bought a Maxim 550 tank that was misidentified. He's also probably not your bubby (grandmother).

 

Lakermatt--- get your correct tank yet?

 

Is XJ650 Seca front end a direct fit on XJ650 Maxim? Thank You

 

If you swap the WHOLE front from the triple clamp, forks, etc...

The rake/trail will change slightly.

 

"The rake/trail will change slightly" in the bad way or all right way (ride-able)? How about 750 front end? Will the fork tubes hit the 650 seca tank on tight turns? Thank you

 

1. It would be perfectly rideable… The only change is from 650 Maxim rake and trail to 650 Seca rake and trail. The difference is due to the actual position relative to centerline of the forks, And how far forward the forks are from the head spindle. The Seca triple tree puts the forks slightly farther forward than the maxim

2. The 750 maxim front will Swap with the 650 maxim, but it does not change fork position. If the forks are not moved forward, they will hit the Seca tank. I have not tried swapping just the triple tree, and maintaining the Maxim forks… THAT may present rake or trail problems

 

Thank you very much. I think ill go with the 650 seca front end, not hitting the tank and dual disc brakes upgrade. And just want be 100% sure, 650 seca front end will just bolt on as easy as 750 right?

 

Normally

 

FWIW.... I'm standing here looking at both sets of forks and triple clamps---

I THINK that handling won't change drastically. There will probably be some difference, though.... Just have to learn the new feel. Here's what I know and see:

1. As said before, the 650 Seca triple tree moves the forks a little farther front than the 650 maxim, and the 750 maxim/Seca.

The 650 Maxim and 750's have the forks center roughly 1.25" forward of the spindle's center---

The 650 Seca has the forks center roughly 1.5" forward of the spindle's center.

Here's where the extra geometry comes in though---

The 650 maxim and 750 maxim/Seca forks have an axle-forward design... The axle center is roughly 1.25" forward of the fork tube center line....

The 650 Seca forks have an in-line design... The axle center is in line with the fork tube center line.

I am not measuring degrees of rake at the head tube.... If you want to do comparisons there, check with Len--- or do your 'net homework.

Have fun with all that

( the measurements I have are approximates with a ruler, not detailed metric ones, so don't really get too deep into the measurements given.... They are for approximation at this point.

Dave Fox

 

Wow man, Thank you Dave. If I end up swapping the 650 seca front end, Ill post pictures. Still undecidable between 650 seca or R6. . Each has weaknesses and strengths, Seca is cheaper and old classic look; R6 is more performance and modern look, but $$$.

 

What will fit the 550r seca . I don't have a tank and can't find one anywhere.

 

We should have a good used tank available for the XJ550 Seca models, please send a note to us for all the details: info@xj4ever.com