XJ750J Refurb

K-Moe reminded me I should post all in one thread for this bike. And since I've got a simple question at the moment, I figured this is a good opportunity.

For reference points, previous threads regarding this bike are here:

Starting point: https://www.xjbikes.com/forums/threads/differences-between-82-750-seca-and-750-maxim.114990/page-2
master cylinder: https://www.xjbikes.com/forums/threads/brake-master-cylinder-next-after-circlip-screw-out.115627/
forks: https://www.xjbikes.com/forums/threads/circlip-on-fork-xj750j.116859/#post-584710
spin-on oil filter: https://www.xjbikes.com/forums/threads/the-bolt-that-defies-everything.117408/
carbs: https://www.xjbikes.com/forums/threads/carb-3-spring-butterfly-linkage-alignment.118810/
intake boots: https://www.xjbikes.com/forums/threads/check-intake-boots-for-leaks-without-carbs-on.119986/
Shifter: https://www.xjbikes.com/forums/threads/hard-shifting-things-to-check.120065/

Now, on to my latest question: While checking the shifter return springs and all that, I noticed that the shifter-to-airbox breather hose is a little cracked. It's not bad, but worth replacing. XJ4ever lists it as a discontinued part. I've got some RTV and splicing tape, but that would be tacky on that part. I haven't gone and looked for a hose at the auto store yet - waiting for payday.

What size would I get... or should I just wrap it...or does somebody know where I can track down a new-old-stock formed breather hose?

 

What about some rubber hose from HD or Lowes or Tractor supply with the same ID ? if the hose will bend without linking it'll work. You might need to get larger hose clamps.

 

you could clean it with carb spray and then coat it with black oil/fuel resistant rtv work it into the cracks. just like with carb to manifold boots


https://www.ebay.com/itm/82-YAMAHA-...:ifMAAOSwBLlU3itO:sc:USPSPriority!03570!US!-1

 

If you get creative with some properly sized conduit you can form the required bends as needed and use short pieces of generic hose to attach at each end. You could then polish or paint said conduit or whatever tubing you find suitable to fit your desire. The only part that could then go bad are the short rubber connector pieces which should be infinitely replaceable. Just a thought.

 

I have a couple of xj750j maxims I’m parting out. Pm me with a shopping list

 

Would shrink tubing work?

 

on another topic... I'm thinking about how I wanna tackle the petcock on this bike. I'd like to rebuild the existing vacuum petcock (assuming its still good - I haven't got it off the tank yet, but it isn't leaking)... I was considering also adding an inline fuel shutoff. This way, on the rare occasions I forget to turn the inline valve off, I have the vacuum petcock as a backup... and I like the idea of keeping my bike mostly original equipment.

Maybe I'm overcomplicating and over-engineering. I think I just have too much time on my hands, some days. But the inline fuel valve plus a rebuild kit seem a more affordable path than buying a new manual petcock.

It's just a thought... your thoughts? Anyone else done this? Or are there issues with it that I'm not seeing?

 

The manual petcock I'm running on my bike was under 15 bucks shipped to my door. I have been lucky and the time or two I forgot to shut it off, I didn't manage to flood the crankcase. On the Gf's bike however, I forked over the cash for a brand new OEM vacuum petcock. I will keep my reasoning to myself

 

Whoops! I guess my memory ain't what it used to be! Finally pulled out the tank to take a look - it's been stored out of the way for the last 4 months.

No OEM petcock for me! I've already got one a manual one. Not sure if I need to worry just yet about rebuilding it - maybe I should though. Let alone, if it's one that Chacal even has parts for.

 

the kind with the glue inside of it would but that size is not cheep to buy

 

gf.. vacuum... petcock.........................

 

Now, let’s not go down that road

 

The petcock in your picture is an after market , I had one the PO put on my seca , works ok ...till I forgot to shut it off ( before I did my carbs)only down side . I bought a stock petcock off of of eBay and a rebuild kit , I really prefer the vacuum feature.

 

I might do the same. I'm just not fond of the gamble. The two I see on ebay right now don't look like they've been taken apart in a while. With my luck, there will be pitting inside and I basically will have bought .... Christmas ornaments. hah! (there is an oem up there, but I can't splurge $140 at the moment.

These look like the right ones to me...
https://www.ebay.com/itm/1982-Yamah...im+750+petcock&_from=R40&rt=nc&LH_TitleDesc=0

https://www.ebay.com/itm/1982-82-YA...im+750+petcock&_from=R40&rt=nc&LH_TitleDesc=0

 

I have a couple of petcocks that I know are good just removed from bikes full of gas and no leaking.
Pm if you are interested

 

Not for long. It isn't fuel or oil resistant(none that I've seen is anyway), and the breather tube comes into contact with both in the form of vapor.

 

Here’s a pic of one

 

i thought about these before i pulled a blade of grass out of mine
https://www.usplastic.com/catalog/item.aspx?itemid=31262&catid=858

 

Need opinions! I'm having an internal debate... First, just to make sure I'm looking at the right thing, the pictures below are of the oil level sensor, right?



First - is there any sneaky way to replace a possible leaking o-ring in that without removing the exhaust system. Doesn't seem conceivable, but doesn't hurt to ask.
Second - can I feasibly remove just one pipe header? This also doesn't seem doable. I'm assuming the collector makes that not possible.
Third - should I even do it (yet)? I'm not 100% sure my leak is there. The whole lower area has a little oil film, like it could just be the crush washer needs replaced on the drain plug. (nothing up higher, so I think the jugs and head are just fine.) I can't really get a clear visual at the moment - oil's been mostly drained for a while (recent oil filter upgrade and upcoming clutch rebuild).

I think my issue is that I'm not keen on messing with the exhaust just yet, and risking a broken bolt. There's not any sort of exhaust leak.

Basically, the slightly lazy half of me is saying 'replace the drain crush washer and worry later'. The overachiever/glutton-for-punishment part of me is saying 'screw it, might as well drop the whole exhaust and renovate that while I'm at it'

I think I'm getting impatient to get this ol' girl on the road!

 

I have extras, as does Toomanybikes

 

That should be the neutral switch. The oil level switch is further back on the pan, more toward the center. The oil level switch has a pigtail coming out of it, where the neutral switch just has a single wire attached by a crosshead JIS screw.
Degrease it and find the weeping oil.
The exhaust collector has to be removed in order to get the sensor out.
The collector is difficult to remove with the headers still in place, and pretty impossible to remove separately if it's been on long enough for rust to build up around the gaskets.

 

hmm... Too bright out now, I think, to get a good look now. Couldn’t spot it. I’ll have wait til dark and try with a flashlight. Maybe i figure out which wire and trace it down to the pigtail.

 

do easy first replace the crush washer just a couple of bucke
the neutral switch can be removed with a special socket with exhaust in place

 

Yeah, I think that's the approach I'll take now. I've moved on to a starter rebuild.

But... tell me more about this special tool for the neutral switch? I don't need to bother with it now, but I'm curious about adding that tool to my arsenal!

 

it is a socket that has been cut away on the sides to fit into the cramped space
xj4ever sells them
Neutral Switch Tools:

HCP15718 Aftermarket neutral position switch REMOVAL SOCKET. On many models, it's almost a physical impossibility to remove the neutral switch from the crankcase "well" without removing the exhaust system or removing the engine from the frame.....the left lower frame tube conspires with the exhaust system to make it unbelievably difficult to access the switch. This special "open side" socket is the proper size to squirm through those restricted spaces and make it possible to remove and re-install the position switch without going through a tremendous amount of effort. Standard 1/4" drive socket should be used with a 3" extension bar, or, it's even easier to use when attached to the HCP13516 flexible shaft driver listed below.


HCP13516 Aftermarket flexible "spring shaft" 1/4" SOCKET DRIVER TOOL, just the thing to use with the HCP15718 socket above to reach the neutral switch. Large plastic handle with 6" long flexible shaft.

 

I spent a little time cleaning up/dielectric greasing a few connections on the bike today, and I'm curious about a couple things around the regulator/rectifier area:

You can see in the photo below, there's a relay (ignition? brake switch?) zip-tied to the frame. I haven't found yet in the manuals where that originally should go. Also, I noticed that the plastic plate that the regulator/rectifier are mounted to only has one screw, where it attaches to the old chain & lock cubby hole. It's got the frame clips up top... but the way that thing shifts back and forth, I wonder if there's another anchor point that it's supposed to have? Not seeing one, but I figured I'd ask.

 

oh...maybe that's the starter circuit cut-off relay? oh.. damn. nope. That's under the tank. ok... still stumped.

 

It would have had a rubber holder that goes on this peg

 

By any chance, anyone got one of the little relay boots that the sidestand relay sits in, under the cdi?

Basically, one like in this pic: https://i.ebayimg.com/images/i/182788132526-0-1/s-l1000.jpg

 

The 4U8 is the sidestand relay, it should have a spot of blue paint on the latching tab.

HCP11105 Aftermarket rubber RELAY HOLDER for original metal-lid "cube" type safety system, headlight, sidestand, fuel pump, etc. relays. This grommet has a square opening (it's a copy of the original grommet), and molded of a thick-wall rubber compound. NOTE: does not fit the later style plastic-lid cube relays. Each:

 

Hah! I made the assumption you wouldn't have those... Silly me!

On a side note, mine definitely has the blue mark, but I swear it says 4U6-00.. I've looked at so many angles trying to see if it's an 8 with the number scuffed, but it very much looks like a 6.

 

Gotta be an 8.........there are no 4U6 relays. Time for new glasses!

 

I've pulled the clutch cover and taken out the plates. I'm looking at the basket wear, and .... hmmm... I think its ok with a little smoothing, but maybe not? On a few spots, I can feel the wear edges by running my fingernail along each rib. Maybe not all of them, but definitely a few.

I want to get more experienced opinions. I'm not sure that'll smooth out with just a scotchbrite. Maybe I'm being overly cautious. Dare I file on those edges a little and suck out the filings & dust?

Here are some pictures, as best I could manage. Not sure if they'll give a good idea of the wear. The outer basket seems ok at first glance. It's the inner basket I'm a little concerned about.

 

While I'm waiting for an oilstone to come in the mail so I can clean up the baskets... I've found a mystery washer.

Walked up to the work table this morning, and saw this little washer sittin' there lookin up at me, all lonely-like. No idea where it came from. The only recent parts on the table have been the starter and the Clutch cover + clutch pressure plate. And I don't think it goes to any of those things. oh, and I rebuilt the gas cap. I know it's not the washer that goes in there, because I've got video of myself putting it back. But that is close to what it looks like

Figured I'd see if somebody recognized it before I chalked it up to mischievous ghosts trying to confuse me.

this thing:

 

Looks like a crush washer from oil drain plug? Or a brake line crush washer ?

 

I think that's just the lighting and the gunk on the washer. it's steel. I should've cleaned it before the photo instead of after. At least I'm feeling a little more like it's not some essential part trying to escape.

 

Spacer washer for the armature shaft in the starter motor?

If you had specific dimensions (ID, OD, thickness, material) that might help to identify it.

 

ok - I'll get dimensions when I'm home tonight. Is there another one, aside from the 'thin' washer and 'thick' washer that are on the armature? Maybe I didn't notice a 3rd washer?

 

Ok.. dimensions for my mystery washer.

Outer diameter = 17.3mm
Inner diameter = 11.9mm
Thickness = 1mm

I’m pretty sure it’s steel.

 

So... I threw together a video of replacing my steering head bearing... but I wouldn't call it my best work... at all.

I can't bring myself to put it in the 'how-to videos' section. Maybe y'all can get a laugh out of it and decide for yourselves?

 

Exceptional (and funny, you're a great narrator/editor). Of course it needs to go into the how-to section!

 

Your video is good definitely need to be put in the how to video file.

 

Wellll, bummer. Taking suggestions on something....

I cleaned up the fuel sending and added new gaskets. Before putting it on the bike, I threw a little gas in to make sure it wouldn't pee all over the place.

But it did.

Here's a before & after pic. Now I suspect the PO tried (badly) to fix the wrong spot. It's leaking around the plastic insulator for the green wire attachment. Any thoughts? I could probably put a little... something... around it, but then I'm just doing same as the last guy. Or give up and get a new one? I so hoped to get this bike started this weekend -- and not have to buy a new sending unit.

 

Thourghly clean area mix up JB weld (not JB quick) let it set 24 hours at least 50 degrees or above . Cover area over bolt head and around area washer . I have an aftermarket aluminum engine case in my 71 VW 1776 cc the oil pressure sending unit boss cracked off , I fixed it with JB WELD about 8 years ago it withstands 60 plus psi of oil pressure with no leaks .

 

yeah... I figured that might be the suggestion. I covered the connection with Ultimate Black J-B weld an hour ago. Time to work on other stuff, I guess.

It annoys me that there's a NOS sensor on eBay for over $100 bucks. I guess it's become unobtanium. (or is it unWantium?)

 

Let it set up over night .

 

that is a good price for new old stock. not many used ones because you need it to sell a fuel tank. if you do not need the fuel guage xj4ever sells a blanking plate

also a used tank may be an option, but considering that you have an XJ750J that bike is a 1 year model, just as the XJ750K is a 1 year model (style)

 

Yeah, I might get the blanking plate eventually. I wanted to keep everything as original as possible, but I understand these are apparently no more reliable or accurate than poking a stick in - or just looking.

 

I use my trip meter to tell how much fuel I have in the tank my fuel guage is just to fickle to the slosh to be reason I get fuel.

 

Yep! The RTV took care of that leak! Today I put the tank on, and managed to get it started. Keeps dying after about 10-20 seconds of running, So I gotta figure that out tomorrow....
but it's sure nice to know she's still kickin' after a year of being silent!