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