Author Topic: Carb Install Boots Issues CB750K1  (Read 526 times)

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Offline pjandrew99

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Carb Install Boots Issues CB750K1
« on: December 03, 2023, 10:35:07 AM »
Had some cut carb boots which I am replacing with a used set I picked up on Ebay. Softened them up with the Xylol/Wintergreen mix.
Put the boots on the motor and proceeded to install carbs with the ratchet method. Couldn't get them to fit properly. Took the boots off and installed them on the carbs for curiosity sake to check out alignment. One thing I noticed is that boots 1-4 are longer than 2-3. Moving the boots in various positions showed no difference. Shouldn't they all be the same length?
Also, has anyone tried mounting the boots to the carbs first then installing on to the motor?
Thanks!
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Offline evinrude7

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Re: Carb Install Boots Issues CB750K1
« Reply #1 on: December 03, 2023, 10:37:57 AM »
2&3 are shorter. Rotate them until all line up flat where they meet carbs.

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Offline Don R

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Re: Carb Install Boots Issues CB750K1
« Reply #2 on: December 03, 2023, 10:42:14 AM »
 If you mount them to the carbs first, you are fighting the angle of the intake nipples. Be sure they are all rolled to the correct angle. I've seen them expand while soaking, that might account for the length. I like to heat them in my ultrasonic cleaner and install right away with a smear of silicone grease but any way to warm them helps.
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Offline newday777

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Re: Carb Install Boots Issues CB750K1
« Reply #3 on: December 03, 2023, 11:34:25 AM »
Install them on the head first, then have a flat 1x4 board(sight it/use a straight edge to insure it is flat) flat against the rubbers and turn them so they are even and square to the board.
Then heat the rubbers with a heat gun and add a little rubber grease, then start the carbs in with the ratchet strap.
Stu
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My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
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Offline pjandrew99

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Re: Carb Install Boots Issues CB750K1
« Reply #4 on: December 03, 2023, 12:46:59 PM »
Thanks everyone! Much appreciated!
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Honda CB750K1
Yamaha SR250
Honda SL350 K0

Offline ekpent

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Re: Carb Install Boots Issues CB750K1
« Reply #5 on: December 03, 2023, 05:50:48 PM »
Did you see any numbers stamped on them to help with proper location ? and yes on the heat gun !!

Offline RAFster122s

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Re: Carb Install Boots Issues CB750K1
« Reply #6 on: December 03, 2023, 10:43:18 PM »
Isn't there a dot or mark molded into the ribbers to mark either up or down vertical plane...?
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Offline pjandrew99

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Re: Carb Install Boots Issues CB750K1
« Reply #7 on: December 04, 2023, 01:57:10 AM »
Did you see any numbers stamped on them to help with proper location ? and yes on the heat gun !!

Yes, the numbers are stamped and facing up and readable. They are in the proper position.
Current Projects

Honda CB750K1
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Honda SL350 K0

Offline pjandrew99

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Re: Carb Install Boots Issues CB750K1
« Reply #8 on: December 04, 2023, 02:05:50 AM »
Isn't there a dot or mark molded into the ribbers to mark either up or down vertical plane...?

Never heard that before. That would be helpful. I'll take a look. FYI, I did attempt to install them again and was not successful. It's not like I haven't done this before but it's been awhile. I do remember each time I did it it was a PITA.
I'm going to make a tool to make this easier. Especially now that I'll be trying out different jets.
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Honda CB750K1
Yamaha SR250
Honda SL350 K0

Offline willbird

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Re: Carb Install Boots Issues CB750K1
« Reply #9 on: December 04, 2023, 04:03:21 AM »
Isn't there a dot or mark molded into the ribbers to mark either up or down vertical plane...?

Never heard that before. That would be helpful. I'll take a look. FYI, I did attempt to install them again and was not successful. It's not like I haven't done this before but it's been awhile. I do remember each time I did it it was a PITA.
I'm going to make a tool to make this easier. Especially now that I'll be trying out different jets.

I have been messing around installing a rack that is not actually the correct center to center, part of an ongoing project. It has worked best with the boots on the throttle bodies, and then starting with the front of the rack pointed up, this lets the boots get lined up,m then push in and wiggle while rocking up to straight. I am using about the cheapest boots I could find on that project to start with.

Offline Scootch

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Re: Carb Install Boots Issues CB750K1
« Reply #10 on: December 04, 2023, 06:59:24 AM »
I don't have much experience in this area but... I use channel lock pliers with tape on the jaws. While holding pressure on the carb rack rock each rubber side to side coaxing the rubbers to seat on the head and the carbs. While doing the rocking motion you can watch the rubbers crawl and fully seat on the head and carbs.

Offline madmtnmotors

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Re: Carb Install Boots Issues CB750K1
« Reply #11 on: December 04, 2023, 08:02:23 AM »
Had some cut carb boots which I am replacing with a used set I picked up on Ebay.


I would recommend buying new boots. I consider these a maintenance item and replace them when they are no longer pliable. This helps prevent vacuum leaks as well.
TAMTF...


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Offline BenelliSEI

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Re: Carb Install Boots Issues CB750K1
« Reply #12 on: December 04, 2023, 06:38:05 PM »
Had some cut carb boots which I am replacing with a used set I picked up on Ebay.


I would recommend buying new boots. I consider these a maintenance item and replace them when they are no longer pliable. This helps prevent vacuum leaks as well.

+1 to this