Author Topic: Why are the carbs and airbox so freaking hard to get off and back on the bike???  (Read 7102 times)

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MrHellpop

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Finally got everything back together!!! What made everything go MUCH smoother: taking the bottom half of the airbox off! With only the top half in the frame it's much easier to get the airbox boots onto the carb. A twisting while pushing motion gets those boots on much better than just pushing. Once everything is clamped tight, it's a snap to screw the bottom half of the airbox back on. I salute the Honda engineers for their design prowess, but easy removal/reinstall of the carbs don't win any props in my book  :P

Offline Gordon

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because I know what a pain boots are, I have been removing my carbs along with the intake manifold. Sure, its eight nuts and washers, but it sure beats the pain of dealing with the boots.


These bikes don't have an intake manifold.  Which part are you talking about?

Offline HondaMan

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because I know what a pain boots are, I have been removing my carbs along with the intake manifold. Sure, its eight nuts and washers, but it sure beats the pain of dealing with the boots.


These bikes don't have an intake manifold.  Which part are you talking about?

I think he's talking about the 550....  ::)
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Offline HondaMan

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I think you can find it at most natural foods type stores, maybe pharmacies, or probably your best bet might be aromatherapy type shops.

http://yp.yahoo.com/ypResults.py?stp=y&stx=96296287&city=Lakewood&state=CO&uzip=80226&msa=2080&slt=39.7038&sln=-105.081268&cs=4&qtx=aromatherapy

Thanks, Alan! There's one near here. I think I'll go visit them: I have three 750s in pieces in the back, waiting to become whole again. The boots are in boxes, so I know how that's going to go...  ::)
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline tbpmusic

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I think you can find it at most natural foods type stores, maybe pharmacies, or probably your best bet might be aromatherapy type shops.

http://yp.yahoo.com/ypResults.py?stp=y&stx=96296287&city=Lakewood&state=CO&uzip=80226&msa=2080&slt=39.7038&sln=-105.081268&cs=4&qtx=aromatherapy

Thanks, Alan! There's one near here. I think I'll go visit them: I have three 750s in pieces in the back, waiting to become whole again. The boots are in boxes, so I know how that's going to go...  ::)

The wintergreen oil is completely unnecessary, and expensive too.
Try plain ol' Xylol from the hardware store.
Diesel also works, too - this is what an auto-glass buddy uses to soften up winshield gaskets in place before removing..

The part will swell somewhat initially - I soak the rubber in Xylol for a couple of hours, then let it rest for a couple of days. It will regain its initial size and shape, but will be flexible for some time.
Eventually however, it will get hard again - you can only reverse the effects of Time for a short while.
"If you can't fix it with a hammer, then it's an electrical problem"

Bill Lane
 '71 CB450 Mutant/ '75 CB200/ '81 CM200/ '71 C70M

Offline ev0lve

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+ however many folks have said it. Struggled to get mine back on. Finally stuck the boots under a work light for an hour or so rotating every 15 minutes to get them evenly heated and life became much better at that point.

I wonder if there's enough water in them for a microwave to do anything? Probably not. I suppose you could drop them in a bowl of water and nuke them that way if you can't wait. Hmmm,, probably ought to try that  ;D

Offline MCRider

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+ however many folks have said it. Struggled to get mine back on. Finally stuck the boots under a work light for an hour or so rotating every 15 minutes to get them evenly heated and life became much better at that point.

I wonder if there's enough water in them for a microwave to do anything? Probably not. I suppose you could drop them in a bowl of water and nuke them that way if you can't wait. Hmmm,, probably ought to try that  ;D
people are saying a heat gun works. They get kinda hot. So a compromise between a heat gun and a work light might be a hair dryer. I keep one of the missus cast offs in the shop. Has helped on things, but I keep forgetting to use it. Helped get the screen out of the oil pump.
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline andy750

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You guys are making it hard on yourselves....

A couple of years ago i bought new boots (both engine-carb can carb-airbox) and yes it makes a huge difference. However the biggest difference is lining up the carb-engine rubbers so that they are orientated correctly. When they are they should form a flat straight line so that all you need to do is press the carbs in (with your hands not a 2x4! do you think Honda engineers had a 2x4 lying around the factory  ;)). Occassionaly if its particularly cold (and in winter in Boston it gets a bit chilly) I might pre-heat with a hairdryer.

The carb-airbox are even easier with new boots and yes only using half-the airbox is the key.

The above should only take less than 5 min otherwise you are not doing it correctly....proper alignment is the key!

cheers
Andy
Current bikes
1. CB750K4: Long distance bike, 17 countries and counting...2001 - Trans-USA-Mexico, 2003 - European Tour, 2004 - SOHC Easy Rider Trip , 2008 - Adirondack Tour 2-up , 2013 - Tail of the Dragon Tour , 2017: 836 kit install and bottom end rebuild. And rebirth: http://forums.sohc4.net/index.php/topic,173213.msg2029836.html#msg2029836
2. CB750/810cc K2  - road racer with JMR worked head 71 hp
3. Yamaha Tenere T700 2022

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Online ofreen

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Andy is 100% correct.  If someone receives new boots that are as hard as 30+ year old ones, they should return them.  Get new ones, odds are good that when those are too hard in 30 years, you won't care.  In the meantime, make life easy on yourself.  Fresh boots seal better, anyway.
Greg
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Offline Hush

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No comparison with old and new carb isolators, I was using a 30 year old set and it was like trying to put your grand kids gumboots on!
A forum member sold me some new ones cheap (thanks again Soos) and the carbs just about fell into place, don't know why I persisited so long with the old ones that also had a leak which ruined my tuning.
I think the thing I most like about motorcycling is the speed at which my brain must process information at to avoid the numb skulls who are eating pies, playing the ukulele, applying make-up etc in the comfort of their airconditioned armchairs as they make random attempts to kill me!!!!!!!

Offline jmckinne

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The most important part of Andy's post is the part about having the correct lineup of the intake boots on the cylinder head. It really isn't necessary to use 2x4 type pressure even with old boots.

1) Make damn sure you have the cylinder side boots set on there correctly. Correct number on each cylinder facing up, etc.

2) Leave the boots on the cylinder head but have the clamps on the cylinder side loose.

3) Press the carbs into place, a few taps with a rubber mallet will do just fine. The boots will "self-align" on the cylinder heads.

4) Tighten all 8 cylinder side boot clamps.

Once you've done that one time the cylinder side boot alignment should be fine and it will be easy next time.

On the airbox side, doing just the top half first is the key, but getting all four airbox rubbers on far enough always pisses me off. If anyone has any great tips on that I'm all ears.

« Last Edit: June 21, 2009, 06:33:19 AM by jmckinne »

Offline HondaMan

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I think you can find it at most natural foods type stores, maybe pharmacies, or probably your best bet might be aromatherapy type shops.

http://yp.yahoo.com/ypResults.py?stp=y&stx=96296287&city=Lakewood&state=CO&uzip=80226&msa=2080&slt=39.7038&sln=-105.081268&cs=4&qtx=aromatherapy

Thanks, Alan! There's one near here. I think I'll go visit them: I have three 750s in pieces in the back, waiting to become whole again. The boots are in boxes, so I know how that's going to go...  ::)

The wintergreen oil is completely unnecessary, and expensive too.
Try plain ol' Xylol from the hardware store.
Diesel also works, too - this is what an auto-glass buddy uses to soften up winshield gaskets in place before removing..

The part will swell somewhat initially - I soak the rubber in Xylol for a couple of hours, then let it rest for a couple of days. It will regain its initial size and shape, but will be flexible for some time.
Eventually however, it will get hard again - you can only reverse the effects of Time for a short while.

Well, diesel is cheap (so am I  ;D  ), and whatever would be left over can go into my old parts cleaner soaking can, since that's what came in it in "the old days" (diesel + detergent = clean aluminum). Maybe I'll start there, since I'm currently broke and need some more carb body cleaner stuff: kill two birds, as they say...

When I'm rich, I'm still gonna try wintergreen: the idea of a pine-scented 750 in Colorado just has a ring to it.  :D
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline lowmileage

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750 is the easiest one to do.
Just put top part of airbox on first, assemble lower section after its fitted correctly (and be glad you don't have a 350/400f)

PJ

Thanks for the hint.  It's impossible any other way - well, unless you use a sledgehammer.
1975 750 K5 Original owner -  11K miles.  On the road 8/09 after 26 years in storage.
2004 Harley Superglide - bought new
1973 Honda CL350 - sold in '75 to buy the "750"

Offline 76CB5WI

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The 750 is a literal peach to work on after the 550 which can turn
a good day into a bad one..with those clearances..
87 FJ1200
72 CB750
76 CB550