Topic: 77/78 750K carb insulator boots

[climbingaz]

As many of you already know, it is extremely difficult to track down brand new carburetor insulator boots for the '77 & '78 750K's.  For clarification, I'm referring to the rubber boots between the engine and carburetors, not the airbox.  The '76 and earlier carbs were slightly smaller, thus the boots are different.

I've been forced to try the chemical bath of xylene & wintergreen oil on my old crusty boots with fairly good results.  The rubber has really softened up quit a bit.  But I'd still like to have brand new boots if possible because a few of my old ones have developed cracks and I'm worried about leaks, etc.

So, this brings me to my questions!  If you call any of the dealers who sell OEM Honda parts, they'll tell you that they can get you the #1 and the #3 carb boot, but the #2 and #4 have been discontinued.  Because all four boots have a different part number, you'd think you're #$%* out of luck.  What good is it going to do to have only two when you need all four?

But what if Honda meant all along to have you spinning the #1 boot 180 degrees (upside down) to fit the #4 carb and the same for the #3 boot to fit the #2?  Does this make sense?  If I look at the boots, the bends in the #1 and #4 are distincly different from the #2 and #3.  But the #1 and #4 look identical and the #2 and #3 look identical.

Am I missing something??  What do you think??  

 

[cycleman]

A couple of years ago I replaced the carb boots on my 80 Yamaha Maxim and went to the local Yamaha dealer & that's basically what ended up happening.  They had the same deal with some being out of production but via chasing part numbers we managed to get four. You had to flip two of them around to make it work.  It's something you'd have to try with the honda.

Maybe others have tried this on the Honda.

[Henning]

But what if Honda meant all along to have you spinning the #1 boot 180 degrees (upside down) to fit the #4 carb and the same for the #3 boot to fit the #2?

This is the case on the earlier bikes. The no. 1 insulator has a "1" cast into the rubber - turn it upside down and it has a "4" on it. Same with 2 and 3. But they do also have the same part numbers. It seems odd that yours should be different, since manufacturers generally try to keep the part count down, and this is a no-brainer. I would guess that you can get your 1 and 3 to work on 2 and 4.

[climbingaz]

But what if Honda meant all along to have you spinning the #1 boot 180 degrees (upside down) to fit the #4 carb and the same for the #3 boot to fit the #2?

This is the case on the earlier bikes. The no. 1 insulator has a "1" cast into the rubber - turn it upside down and it has a "4" on it. Same with 2 and 3. But they do also have the same part numbers. It seems odd that yours should be different, since manufacturers generally try to keep the part count down, and this is a no-brainer. I would guess that you can get your 1 and 3 to work on 2 and 4.

The 77/78 boots most definitely have four distinct part numbers which has thrown a lot of us off.  Gives you the impression the the four boots are in fact different from one another.  I'm very tempted to order 2 of each and give it a try, but really would like to hear from others before I spend the money.

[750]

They are not the same.  Let's put this to bed.  I asked this vary same question a month or 2 ago.  Anyway, without getting a good answere I bought #1, #2, #3, but I couldn't get #4.  So what did I do?  I bought 2 number 1s and flipped one over.  Guess I should have looked closer before I decided to do this.  Anyway, I bolted them up and yes, you can get everything to bolt up and seal.  But if you look @ your carb after everything is bolted on you'll see the number 4 boot is completely angled wrong.  It's not the left to right angle that doesn't work, its the up and down angle that doesn't work when the boot is flipped.  Now, all that being said, I did manage to get a seal by flipping them upside.  For how long? I don't know, because of the way the clamp goes on, the boot doesn't make a great connection with the carb like it should.  I ended up taking everything back apart and re- using my old number 4 with some silicone sealer and that did the trick.  Do what you will but if I were you I wouldn't waste my money
Good Luck

[scamper03]

my #4 boot had a big crack and I couldn't repair it with silicon.  After searching the internet for months for new boot and decided to use #1 and it works fine for me.