Rubber carb joints (XJ750) - Repair rather than replace?

On my bike the reserve gas line goes into the stem on 3.

 

Pretty sure you'll find that's the vac hose whch activates your petcock, just like everyone elses................. unless I missed the joke?

 

I opted to leave it alone, figuring he'd realize it's not a reserve line eventually.

 

On the 550s and 600s, the vac line was originally connected to intake boot #2.

On the 650/750 series, it was connected to #3.

It only matters on some of the later 600s, their #2 carb was jetted slightly differently, and I'm assuming that to be the reason why.

 

Wasn't trying to but ended up being the ass of it. I'm new to bikes so I assumed thats what it was. So I took it off and haven't had a issue since, which had been about 6 months.

 

Bald wonder, nice job. Perhaps ky jelly would assist the fitting process and a heated rod to make the stem holes?

 

iirc thejewishguy suggested using a single hole punch to make the the hole. Imo it's a good idea.

 

This is great!
My boots are bad and budgets is tight.
I don't have RTV but do have Pliobond.

I believe it would work swimmingly well.. . Anyone know other wise?

 

Go to the auto parts store. AutoZone, O-Reilly's, whatever.

Find black, adhesive high-temp RTV. It's made for certain automotive applications where they simply glue the cover on; there is no gasket. I discovered it because it's how you install the end cover on a Dodge/Mitsubishi 3.3L automatic transmission. Mean stuff, kinda silvery-black.

It'll cost you maybe $7 ~$8 for the tube. Screw Pliobond. Use it to fix your flip-flops. You gotta think automotive with this kinda stuff; not kitchen-drawer - hardware store.

 

Got the RTV adhesive sealant and did the deed.
Went really well, easier than expected, stretched right over the nipple and then a small puncture allowed the nipple to poke through without ripping.

Weird thing, boots 1 & 4 had no cracks, 2 & 3 were cracked up pretty good.
Any thoughts as to why that would have happened?

Thinking of maybe moving the insides to the outsides (1 swaps with 2 and 3 swaps with 4). Good thought? Bad thought?

P.S. flip-flops are now good for another 10,000 miles :lol:

 

Maybe it's because water can't evaporate as readily from the middle as it can from the sides and that aged the rubber faster. Or maybe the outer manifolds get more airflow than the inner and that keeps them cooler. I don't know, just throwing out some guesses. I'd be interested in hearing what the more informed have to say about it.

Either way, I'd advise against removing the manifolds, there are so many horror stories around these threads about those galvanized screws snapping. Plus, why would you want to put the ugly cracked manifolds on the outside?? XD

 

My guess is that a PO took the time to apply some kind of rubber restorer/protector on the outer two, but didn't want to get dirty and reach for the inner two.

 

Stump, I also had two that looked great and two that were checked, but it was my outers that looked rough; I'm guessing that someone on either your bike or mine swapped them over, and that it's either a function of engine heat (inners) or UV light (outers).

I guess the takeaway is, if you're really cheap... you should be able to make one nice set out of the manifolds from two parts bikes!

 

If you removed the vacuum hose on the stock petrooster and still running you will have a problem soon. The vacuum allows the petcock to stop the fuel flow when the bike is not running. You may end up with gas flooding the carbs and your engine. You may need to rebuild, or replace your pet rooster sooner rather than later.

 

To reply to multiple people without sounding to disjointed . . .

I already removed the intake boots - mine came off easy - actually too easy. Almost like the bolts weren't torqued properly - the gaskets were crispy and thin, so maybe 33 years ago they were torqued proper and then the aging gaskets created a 'looseness'.

Rubber restorer put on the outside boots kinda makes sense especially given that it sounds like something the PO might have done. Can't really see him skipping the inner ones - but they are a little tricky to get to if you don't remove the gas tank . . .

Heat, kind of make sense - the inner two boots are tucked inside - but one would ass-u-me that there is still enough air flow around the whole bike to keep things nominally cool.

I am going to flip-flop (not the footwear) 1 & 2 and 3 & 4 when I reassemble.

 

Looks like Im kinda late on this post, but it would seem cylinder #3 would be the best for the vacuum hose. My thinking is that all the carbs are syncronized with #3.