Re-re-reviving my '81 Seca 750

That's awesome documentation, thank you. It seems like that might be in the right area for this sound, so I'll keep it in mind. In 27 years of ownership, I've never dropped the exhaust on this thing - guess it's overdue.

Edit - decided to just order some up to have on hand at that price!

 

Yesterday, with Len's patient guidance and a rubber mallet, I got the last of my brake lines installed. The tolerance on those anti-dive segments is very tight and I needed some gentle persuasion to get mounted up correctly. After work and dadding, I started the master cylinder rebuild around 10 p.m. and reminded myself what a gynecological exercise it is to get fluid in that system sometime around midnight. Woke up this morning to find a leaking banjo at the distribution block (left).

Now, here's where I confess. Those banjos are a bit obstructed by the forks. Can I get a socket on there? No. Did I think I could get away with a box wrench and eyeballing the washer crush, relative to the ones I COULD torque? Yes. Was I successful? Obviously not.

So, my noob-esque question to the group is - do I need to remove the forks to do this properly? I do, don't I? Confession time again, I was hoping to put off messing with the forks until winter. But unless someone can convince me otherwise, I guess I know what I need to do.

My 8 year old is going to be disappointed. She'd set a deadline of getting the bike ready for her local favorite car show, and the last one of the summer is tomorrow. But I can't rush this project, even for my kid, right?

 

Ok, big update. Feel free to skip to the middle for the 'What I've Done' summary and the bottom for the big question.

First, another confession - I did NOT pull the forks (yet). I used my box wrench and applied about 90 6"-lbs (tweaked until the leak stopped and then a little more). Do as I say, not as I do. But the car show is still off. Not rushing the rest, just moving along.

After fixing the leak and redoing the brake-handle tie-off 'trick' while I was at work yesterday, I got home to nice firm brakes BUT . . . there's an initial little 'pop' at first pull, and then the handle takes its time to return full-out. I'm not liking that, despite having stopping power. Going to removed the PITA remote MC again, pull it apart, and see what I missed. I had honed/1000-gritted the bore, but I'll recheck that as well as the way the seals are set in there. Tips on what to watch for appreciated, always. Might or might not get to that after the kids are in bed tonight.

Taking a break from the brakes, and the whole bike, I didn't wrench at all last night and instead revisited my old threads ( e.g. this one from 2006: https://www.xjbikes.com/forums/threads/carb-slide-sticking.1259/#post-10478 - should have continued that one I guess. Candidate for a thread merge?). This morning I returned to tuning my newly-built carbs. To get all on the same page, I've got:

New air filter (more on this later).
Valve lash checked ~2 weeks ago (room temp, mind you) all brought into spec.
New airbox-side boots (all seated correctly) from XJ4Ever.
Carbs rebuilt by @hogfiddles - squeaky clean (with XJ4E kits).
N.B. the bike is an '81, but the carb bank is off an '83 - I don't know if this will be important later.
Cables all lubed and free.
Engine-side boots are original, but gaskets were replaced in 2006, so old but not original, and boots pass carb-cleaner testing.
Vac caps are old/hard, but not in play while CarbTuning (and not noticeably different with them on).
Spark plugs are 'old' but clean and less than 2k miles on them. I have new, just misplaced them in my Dungeon of Dirty garage. *more sheepish confessions*
Syncing with CarbTune Pro (inverted (of course @chacal was right: https://www.xjbikes.com/forums/threads/carbtune-pro.9574/#post-672701 ), with restrictors) but more on THAT later)
I have a YICS tool and use it for final sync after I get in the right ballpark without.
Have ColorTune plug.
I've owned/known this bike since '95 (second owner), know its sounds and quirks pretty well. Ridden a lot with VAST years of neglect in-between, most recently 2011. Current mileage 37k (purchased with 11.5k).

When I first started it the other day (as seen in the prior video) and again today, I was getting a racing idle. Synced as close as I could but it was tough with it always running away. And the Colortune was showing VERY lean, often mis-firing. I was starting to blame the tools - the Colortune, the aux fuel tank, etc.

Then I remembered my old threads and my OLD tuning situation (2006). After my first rebuild (everything shy of shaft and fuel seals back then), things were rough and I ended up getting the ColorTune. What I found then was I needed to bring the mixure out to 5.5 turns as opposed to the fac. spec. 2.5. At the time, I blamed shaft seal leaks, and/or the K&N reusable oil-based air filter I'd been running. With carbs fresh from Hog's Summer Spa and a new OEM-style air filter, I figured I should be back around the bench-set 2.5 turns on the mixtures. But for Grits and Shins today, I backed off to 5 turns. She fired up and though idling high, setting the screw brought her down and she didn't stumble and die. Not only was I able to sync more reliably, I was getting enough pull to use the CarbTune right-side up. Initially confused myself by not swapping the hoses back around, but got there. Sync, adjust idle, sync, idle, etc. She's sounding GOOD. No creeping RPMs and twisting the throttle gives a snappy response. Of course, we'll see how she does under load once finally road-worthy, but it's in a good place.

For fun, I popped the ColorTune into #1. Backing off to 5.5 ran orange. Screwing down to 4 was getting white and stumbling again. So back around 5 it went. Didn't niggle with the ColorTune on the rest of the cylinders as I had to get to work, but I'm a lot more stoked than I was yesterday.

So, XJ Hive Mind, I ask you, WHY would this carb bank and bike be so much happier around 5-5.5 (in the olden leaky shafts days) turns out than closer to the factory spec? Should I care, or should I just chalk it up to PFM? Does it matter that the bank was pried from an '83?

Thanks for playing along.

 

It’s odd that it would be that far out, and I was surprised during the rebuild how far out they were. But, the 2.5 is an initial setting, not a final target. So, yours is apparently an oddity and want them to be turned out more. What kind of air filter is now on the bike?

 

I put in one of these: http://www.hiflofiltro.com/catalogue/filter/HFA4609 Despite the brand name confusingly being shortened to HiFlo, it's my understanding (both from their website and a bit more googling) it should not be any 'higher flow' than OEM, but I'm willing to be corrected.

Might be 'fun' to one day get an OEM from Len and compare, but I'll have to get a bit further down my 'To Do' list before I'm that bored. For now, I'mma call 'er good.

 

HiFlo are known for good quality products.

 

While I'm waiting for a string of hours where I can do the final work I need to get road-worthy, I've been realizing how much I'm liking the look of the bike naked (and it takes up less room in the garage, too). So I've been daydreaming/brainstorming. I do want to retain the OPTION to mount the fairing. It's as simple as a couple hose clamps, and a 9-pin connector. But I was also thinking of getting another connector/pigtail and being able to wire up a light and signals. Riding my WR250R dual sport has really gotten me to enjoy the bare wind and lack of helmet-buffeting from the windshield.

I'll attach some pics of the current situation. Headlight bracket was retained, but I never saw the original light, aux, turn signals - the fairing has XS1100 signals mounted inside it. The front "Yamaha" nameplate bar is gone as well. The main wire bundle is (not currently, but usually) stuffed into a vinyl bag up behind the fairing. And even after 41 years, they're still pretty clean. I'd probably do the same - find a way to keep it tidy, since with splices for the fairing pigtail, I'm not sure it would fit in a stock bucket anyway. Yes, it'd be more exposed to elements than behind the fairing, but if I'm in crappy weather riding season, I'll probably have the fairing back on, anyway, so it'd be down to the occasional bath due to lousy weather forecasting. I've seen a couple sets of original signals available online, in various states of completeness, but I haven't been able to tell from pics or diagrams how they attach. Is there a clamp missing from my fork tubes? Or do they attach via the fork pinch bolts? Or the front 'nameplate' bolts? Clarification appreciated.



Option 1: Initial thought was source an XJ-correct parts, bucket and Aux light (the fairing makes no use of the Aux, BTW, it's capped), signals and nameplate, but honestly, as much as I like to leave things stock, I've never really been a fan of that look.

Option 2: I'd prefer a round headlight and thought one of the Maxims might fit and perhaps go that route. But since it's not 'stock' that way anyway, seems a shame to take a Maxim headlight out of circulation, even if it would/could be made to fit. So . . .

Option 3: Perhaps and aftermarket option, for at least the headlight (probably skip on the Aux) with either stock or aftermarket signals.

I won't be buying parts or doing anything until the snow flies, but anyone have any thoughts? @hogfiddles or any other hoarders have parts burning a hole in their pockets? Recommendations on headlights and/or signals or ones to avoid?

Thx.

 

I've just fallen down the 'resistor plug' rabbit hole and it seems the BR*R*7ES plugs I was sold are not as 'direct replacement' as I was lead to believe, right? So probably good I hadn't swapped them yet. Now, where was that receipt? Or, I could keep them until I'm ready to deal with the caps . . . Ugh.

 

Once you what parts you need, I have a fair amount of 750 seca parts available. You got my number, just text me with what you’re looking for, and I’ll check.

 

Were I not already bald, I'd be pulling my hair out over this master cylinder.

Status:
Fresh braided stainless lines from XJ4E (got a proper torque on the distribution banjos using a crow foot wrench).
Freshly rebuilt calipers.
Anti-dive not refreshed, but not leaking and at the end of the line.
Master cylinder rebuild kit from XJ4E but reused body, piston, and spring (may be starting to regret that).
Only thing not removed from bike were anti-dives and distribution block, but it was cleaned with a bore brush.

As mentioned earlier, I had built pressure, but was getting a disconcerting 'pop' at initial lever pull like the seal was hanging. I had time and a buddy last night, so I pulled the MC, disassembled, and hit the bore again with 1000 grit wet paper (brake fluid lube) on a 1/2" slotted dowel (a single freakin' dowel rod is $7 these days, WTF?). Felt there might be a little burr around the main port, so got that smooth. Verified both ports are clear (guitar string and fluid test) and the seal is in the correct direction. Rinsed out a few times w/ more fluid (thank goodness I bought the big bottle) and reassembled. On the bench, it felt a lot smoother than last time, no hanging, and it built pressure over my finger.

Mounted it up and tried a reverse bleed since I already had fluid in the lower bits. It took a little bit of fluid, but then stopped/built pressure (at the lower syringe). Lever did not build pressure, though. Made a mess when the lower hose broke free from too much pressure. Swore. Decided to hit the bit and hoses with the massage gun, tie the lever off, and leave it overnight.

At early-morning dog-feeding, I was hoping to find a firm lever, but when I untied it, it just sat there. Did not spring back. I had to tap it several times to finally get it to come out. Once it did, action was smooth again, but still no pressure at the lever. Tried a traditional bleed, got a bit of fluid out the bottom on the first squeeze, but then the MC didn't seem to refill/pressurize. Left it tied again, and no, 5-ish hours later, it was the same, lever was stuck IN until I tapped on it several times. Not building pressure. And I'm suspicious of that spring.

So, somehow I've made things worse. At least on the first go, I built good lever pressure. Disappointing. Any guidance/encouragement appreciated.

I'm going to go out there now and set up the rev. bleed again, probably shower myself with brake fluid again, and crack the upper tube bolt and see if I get fluid or air. Just to do something.

 

Tracked down possible a small leak at the pipe going into the distribution block. Not sure if that was new fluid or from assembly. But given the amount of air I was pulling again . . . I started second-guessing my 'the anti-dives are OK' boldness and decided to do a good flush forcing fluid into the caliper and out the AD per side. Fluid came out clean, which was good peace of mind. After more (and more (and MORE)) reverse, traditional, and vacuum bleeding (I really think the orifices are too damned small for MityVac to be much good with this system as opposed to my WRR or other bikes I've used it on - or I just need more patience - but it's good for keeping air from back-flowing into the system), I am finally getting slight pressure and good return from the piston. Tied the lever down again for the workday and we'll see if I come home to any magic tonight.

At least I got my other bike fixed to ride today - it's been a week.

 

Whatever you do, don't get brake fluid in the vacuum pump:

By the way, I'm starting to suspect that some of the magic of tying the brake handle and leaving it for a few hours is as much about taking a mental break as it is about time for the system/air to settle.

 

I just put on a new mc and twitched the lever just past where the switch clicks for a while before the air bubbles stopped in the reservoir and fluid ran from the banjo. Then had to run about a full 12oz bottle of fluid through the bleeder screw in a couple sessions over a 24 hour period to get all the air bubbles out at the caliper.

 

Took a break from the brakes (tore down the MC a 3rd time. Bled yet again. Ready to ignite everything.) and attacked my muffler rattle. Updated in this thread: https://www.xjbikes.com/forums/threads/xj700n-exhaust-collector-to-can-gasket.130066/#post-672867 Took a LOT of grunt, but got them off intact. Dumped a lot of crud out.

 

Wow, never seen those riveted plates on the muffler cans, typically that information is just stamped (engraved) into the metal. Very fancy.........

 

Oh, collectible! I don't know if it has any bearing, but it's an early run '81, I believe February build. Before they even stamped the full VIN on the neck, just the crappy half worn-off sticker on one side and the abbreviated stamp on the other.

 

Ended up borrowing an oscillating multi-tool from a friend to get enough of the old copper exhaust gasket off of the collector stubs to fit the new ones back on. Only munch them up a little bit. Took the opportunity while I had the cans off to give him a pretty good polish with some never dull and a buffing wheel. Not perfect, but cleaned up pretty well. Some before/after side by sides:



Got them bolted back on, and as @chacal implied in the other thread, it didn't entirely fix the problem. Greatly improved it though, and I think I can live with that. Maybe a really small shop vac nozzle down the collector could have gotten out some more gunk from in there, but just getting the chunks out of the cans is better than nothing.

Brakes are still not bleeding. Going to rip apart the master again and probably order some more parts from Len in a couple days. That part is really frustrating me, especially because I had a decent brake lever pressure the first time around but it wasn't good enough.

Had hoped to be able to ride this weekend, but oh well. Better safe than sorry.

 

I hold them upright, fingers splayed wide across the openings. , and shake up and down with a slight circular/oval-ar arc and continue one direction til nothing more comes out. Then, change direction..... the turn the opposite end up, the change direction. Etc..... I do that until there is no more rattles in any direction. I can feel the grit, particles, etc.... bounce past my fingers, and eventually there’s no more to feel it hear. It may be an hour or more of that but they eventually empty out. Just gotta get the crap to bounce into the correct tube inside in order to fall out. It takes time and patience.

 

That's pretty much what I was doing. Seemed to get everything but the most minute bits out of the cans. If I'm bored over the winter I might dive back in, but for now, they're good.

Full focus on the brakes again this evening. One more try ad getting things primed and bled, then I'm throwing in the towel and buying more parts and/or looking for a known-good master. It's gotten beyond risidculous.

 

I am SO close to being able to ride this thing, but I'm at my wit's end with these brakes. Any suggestions welcome from @hogfiddles @chacal @Jetfixer et al.

Recap ('81 Seca 750 REMOTE master):
Rebuilt master cylinder with kit form Len, reused plunger, piston, and spring.
Piston had been hanging on return, but I honed it again and polished w/ 1000 grit wet sandpaper, and it operates smoothly now.
Main hole and relief hole both confirmed clear w/ guitar string and compressed air.
New S.S. brake lines from Len.
New banjo bolts and crush washers.
Rebuilt calipers w/ kits from Len.
No current leaks detected.

Things NOT rebuilt/replaced:
Aforementioned reused MC parts.
Reservoir diaphragm
pipe between MC and distribution block
distribution block
anti-dive (was last rebuilt circa 2006, IIRC - no sign of leaking)
bleed valves

Over the last few days I've tracked down under-tightened fittings on 'pipe,' an under-tightened bleed valve, and I've had MC out and apart countless times to get where I am, which is CLOSE but still not there. And yes, I cleaned everything out thoroughly after honing/polishing. I've gone through SO much brake fluid (like 1.5 of the big bottles) and my freshly-painted calipers and showing it, sadly.

Symptoms:
If I reverse bleed up to the MC/pipe junction, and instal the MC primed, I can get one good bleed push (squeeze handle, open bleed valve, fluid comes out w/ no air, close bleed valve), but the MC never seems to refill. Reservoir is full but not overfull. I can pump it, or leave it sit all day, the lever returns via the spring, but it never builds pressure. If I reverse bleed, I can get a semi-stiff lever (about half-squeeze, can NOT put lever to handlebar), but even if I try the tie-down and sit a few hours routine, it doesn't get any better. If I just let it sit, it seems to get mushier. I've tried the trick of vibrating the lines and components, but the last little bit of air/spongieness remains, and again the MC never seems to refill from the reservoir after a bleed. I can pump it 100 times, fast or slow, and it doesn't build pressure unless I put pressure in from one of the bleed screws (reverse bleed). I've read a bunch of threads where eventually things just work for people, and that's what I remember happening in the past - being frustrated, and then things suddenly working as expected - but I've now been at this a full week, and I'm still not quite there yet.

Any guesses on what the problem is - port(s) blocked by air or debris (any time I bleed, top or bottom, the fluid is coming out as clean as it went in. In the 4 or more times I've had the MC apart, I've yet to find even the small port blocked)? Improperly seated seal? Worn non-replaced components? Something else? Help me, Obi-Wan, you're my only hope!