Where could this water leak be coming from, FZR?

[mwhc]

IMO Honestly you'd be better off to find someone with a wrecked fz and buy the used midwall and start fresh

[RedG]

IMO Honestly you'd be better off to find someone with a wrecked fz and buy the used midwall and start fresh

this is option 1 if not then moving to the other

[TimeBandit]

A combination of age, oxidation, heat (lack of lube), and vibration had already damaged that mid-wall before you tried to disassemble it. Therefore, once you get things sorted out, I’d be especially attentive to proper coupler alignment.

As far as salvage/repair goes . . . it is certainly do’able. I’m not certain using a cadaver mid-wall would be any easier, if-not likely harder.
Just spit-balling here... this would be “my” repair approach :

1 Start by cutting/pulling/excavating all the loose bits of fiber chunks away.
2 If you can get/dig the remaining thread insert out, go ahead. But if not, leave it (as you will simply drill out the threads so a longer bolt will pass through it instead).
3 Electric hand buzz or orbit sander - sand the mating surface relatively smooth, yet using course grit, say 80-120. Make sure the mid-wall mating surface is now flat, clean, yet semi-rough.
4 Mix-up a small batch of “laminating epoxy” resin (aka Total Boat) : mix parts A & B, then add fumed-silica until you get a peanut-butter-like thickness. Then mix in a pinch of milled fibers. With a small putty knife, push this into all the broken voids of the inserts (including the insert that remains – if you couldn’t get it out previously in step 2), avoid trapping air pockets. Do not build up the resin filler flush with the surface (that’s another step), just insure the voids are back-filled. Might want to repeat step 3 to be sure this added resin hasn't built above the mating plane.
5 Next, we need a jig to simulate a smooth surface. Find something very flat and hard (not bendable), like a 1/4 piece of Plexiglass. Cut it to a larger dimensions than the IB housing body's mating surface. Important, wax it with a mold-release agent for releasing epoxies, bees-wax can work as well.
6 Mix-up another small resin batch as above. Putty-knife a thin layer where the IB would make contact with the mid-wall. Careful, not too much. Now push the jig on top. If it is clear plexiglass, you should see the resin underneath spread flat. Prop something against the jig to keep in-place while the epoxy hardens.
7 Wait an hour (whatever the curing time is), then because you waxed the jig plate in step 5, you should be able to pop-free it off the mid-wall, revealing a perfectly smooth new mating surface. With only an hour on the epoxy, it should also still be pliable enough to clean-up with a razor blade, any resin that may have oozed into the center mid-wall pocket and other unwanted places. If you left the one insert in, please drill out the center so a new bolt can pass thru to the back mid-wall.
8 Reinstall the jet pump, and bolt it secure so the drive shaft is at the mid-wall once again. We will use the drive shaft to best-center the new IB housing onto the mid wall, and mark the new holes to drill thru the mid-wall. If you left the one insert in, you can use that to help align as well. Note, the IB also has a “key” on the back, so remove the key or tap a shallow divot in the mid-wall for that key to line-up.
9 Bolt the IB in-place. Need 3 longer bolts to reach thru the IB and out the back mid-wall. Use fender washers and nus on the back. Good idea to add a small thin skin of RTV on the mid-wall surface so the IB’s rubber seal in-beds well.
10 Join couplers / align the engine. May need to "play" with engine mount spacer arrangements. Measure couplers on all sides for shop manual specs.

That’s just an overview, to give you ideas of how it could potentially be repaired. You might still need to improvise accordingly.

[RedG]

Thanks TimeBandit lots of great info and advise. I will definitely implement most of it, if not all.

I'm considering making an aluminum reenforcement for it as well. I'm also coming to the conclusion of fixing it after speaking to a couple of shops (both have told me "bro just drill it, and bolt it thru").

It seems that finding a replacement wall is next to imposible.

[RedG]

So finally after all go it working, and wanted to give an update in case someone in the future finds themselves on this position.

Also wanted to give thanks to all who chimed in with a posible solution, but overall TimeBandit for his comment on how he would go about fixing the wall, thanks man used many of the techniques you described fixing mine. Plus Dexterous thanks for the support and advise brother.

I decided to fix the wall after sourcing a replacement one turned out to be a mission, and once I finally found one, it was more of a mission to get it out of the donor ski.

I started by cleaning up the messed up wall by cutting the material jumping out and giving it a good sanding, my goal here was to leave it as smooth as possible while making as flat as possible.

Next was to fill the holes with the total boat epoxy along with fixing the big circumference where the mid-housing seals to prevent water leakage. Covering the guides to prevent epoxy there is a must.

Then using the guides I put the replacement WSM part and mark the holes for drilling. Found the perfect stainless steel screws at HomeDepot and got it mounted with the driveshaft in place to make sure everything was aligned. I used Permatex 85224 to seal it.

[RedG]

Testing it again the engine coupler and everything is looking good.

[RedG]

I decided to properly seal the transom plate while I was at it, my ski from day one would get a little water in and I always though it was normal, that is until I read one of Jerry's threads and saw how to fix it and replaced all hose clamps with stainless steels ones. Happy to report Zero water coming in now.

[RedG]

Lastly a couple of bold ons that were left to do. Pro Cooling kit, and Jim's cut. I also added two valves on the inlet lines for IC and engine (I know some say not necessary on Yamahas when towing) but from experience I think otherwise, plus provides a better flush if you close them. I like the extra insurance just in case.

[RedG]

Tested it today and burned a half tank of gas at WOT, moving through the whole RPM range and what a difference! this thing launches way better than before, most of the testing was done in a straight line, but little turns here and there I can defiantly feel the improvement on the gripping.

I was hitting the limiter all the times getting it to 81mph for its best.
I started with two shims on each front side as Jim recommended for speed, but was getting lots of bounce at 79.2 mph. Took out one from each side and less bounce and more speed 81mph.
I wanted to try it with no shims, and the stock spacers also, but sun came down and wasn't able to (maybe on the weekend)

After running ski it was bone dry, no water from the transom or the mid bearing housing. Mission accomplished, very happy with the results and being back in the water.

[TimeBandit]

RedG, you did a great job there !!
Thank you very much for taking all the added time necessary to document and post-up on how you went about fixing it. Great contribution to the forums here.