Author Topic: Among the interesting things I have learned recently in life...Carb Cleaner is t  (Read 6589 times)

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Offline afastman

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For those of you that have 77 and 78 F model carbs with the accelerator pump, HEAR this warning:  the choke and throttle rails have felt bushings which are made of some pretty unobtainable stuff.  They are at the oopenings of the carb bodies where these rails push through.  I believe there are 6 on each rail.  The rail kits from Honda are the only OEM source for these.  They are $350 and $380 respectively.  The bugger of the situation is that carb cleaner eats these guys out of their little races.  Just manages to melt them away.  Brake cleaner works better for externals as it evaporats faster...or elbow grease and non-solvent cleaners are even safer.  Learn from my mistakes.  Hand punching and alligning these guys is damn difficult, and although i thought felt is felt, well, it ain't

Afast-
creul, nasty, neurotic, paranoid, antisocial...but basically happy



Offline wannabridin

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    • 1976 CB750K, under construction:
damn good information to know!!  i have a set of PD carbs from a 78 i believe, and i was about to start cleaning them up!  could you post some pics of their exact location and anything else you think is important??  thanks a bunch fast!!!!!
1976 CB750K, currently under construction:
http://forums.sohc4.net/index.php?topic=64468.0

-And if you don't do it this year, you'll be one year older when you do...



Offline afastman

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Here is a how-to link from a fellow member on how to replace these guys if...there are images in there as well
http://autos.groups.yahoo.com/group/cb400f/files/
creul, nasty, neurotic, paranoid, antisocial...but basically happy



Offline Gaucho

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Nice info.
I wish I knew it three weeks ago!... :'(
Now my carbs are sparkling clean after a day in acid.
Gaucho



Offline wannabridin

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    • 1976 CB750K, under construction:
Here is a how-to link from a fellow member on how to replace these guys if...there are images in there as well
http://autos.groups.yahoo.com/group/cb400f/files/



only problem is you have to sign up and be a member, and you have to wait for moderator approval over there...  i requested it, so i dunno when or if i'll get it.  hopefully i would so i can view your link!!
« Last Edit: February 25, 2010, 08:35:27 AM by wannabridin »
1976 CB750K, currently under construction:
http://forums.sohc4.net/index.php?topic=64468.0

-And if you don't do it this year, you'll be one year older when you do...



Offline BobbyR

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Straight Simple Green will eat the varnish and not the felt. Soak the parts for about and hour. These are pumper carbs so pay some attention to the pumps.
But we were boys, and boys will be boys, and so they will. To us, everything was dangerous, but what of that? Had we not been made to live forever?



Offline cb750k77

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i cleaned mine with elbow grease and a tooth brush! some carb cleaner and tooth brush hit up the bad area's! then i sprayed carb cleaneer though all the ports and it was a breeze from there! installed my carb kit and cleaned the jets with a jet cleaner tool and the carbs were as good as new! also i replaced the Accell pump and sent the "air" gap to factory specs!

once installed do a good SYNC these PD's are easy to sync!
CB750k77 rebuilt (almost)



Offline wannabridin

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    • 1976 CB750K, under construction:
looks like i got approved for membership.  were you talking about the file "how to make felt o-rings?"
1976 CB750K, currently under construction:
http://forums.sohc4.net/index.php?topic=64468.0

-And if you don't do it this year, you'll be one year older when you do...



Offline wannabridin

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    • 1976 CB750K, under construction:
anyone know if the 77K carbs have felt washers like this?  i have some '77K models, haven't had a chance to tear them down yet...
1976 CB750K, currently under construction:
http://forums.sohc4.net/index.php?topic=64468.0

-And if you don't do it this year, you'll be one year older when you do...



Offline afastman

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Not sure on the K models.  I know the carbs from the '77 and '78 F models are unique in this respect.  The goal is to not HAVE to rip all 4 carbs apart from one another if at all possible. 

The synching is INFINITELY easy on these.

The file is in fact the one you looked at, wannabridin.  For anyone else, moderator does approve all fairly quickly.
creul, nasty, neurotic, paranoid, antisocial...but basically happy



Offline mystic_1

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So what's the gist of the process for making felt rings?  I don't feel inclined to join a Yahoo group just for that info.

I imagine that leather punches of the appropriate sizes would do the job.

mystic_1
"When you are wrestling for possession of a sword, the man with the handle always wins. "  - Neal Stephenson, Snow Crash

My build thread:  http://forums.sohc4.net/index.php?topic=68952.0




Offline wannabridin

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    • 1976 CB750K, under construction:
yup, a piece of grade "A" felt, some hollow punches (1/4" and 3/8"), a golf tee and a watch pin remover.

punch the outer size, then the inner, put new washer on golf tee, golf tee in hole, start to position with watch pin remover, remover tee, place all the way with watch pin tool, reinsert tee to seat the washer, and voila, you're done!  

PM me and i'll send you the file, whoever wants it.  it's too big to attach onto here (2.25 MB)
1976 CB750K, currently under construction:
http://forums.sohc4.net/index.php?topic=64468.0

-And if you don't do it this year, you'll be one year older when you do...



Offline wannabridin

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    • 1976 CB750K, under construction:
so just so everyone knows, the '77K model carbs do have these felt washers!  i found a couple or old rubber o-rings in one of the carbs, the rest are felt.  nicely placed under the retaining ring.  now i'll have to make some new ones, dammit!!!

1976 CB750K, currently under construction:
http://forums.sohc4.net/index.php?topic=64468.0

-And if you don't do it this year, you'll be one year older when you do...



Offline mystic_1

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Thanks for the file, process is more-or-less what I expected. 

Google turned up a few sources of A-Grade Engineering Felt aka SAE Felt:

http://www.feltshop.com.au/categories.asp?cID=9&c=42021

http://www.britishfelt.co.uk/engineering-felt-1106-0.html

http://www.thefeltstore.com/Portal.aspx?CN=14F3FF81B1EE&MN=D55F532D6DE9

This site has some good info on the different grades of engineering felt:  http://www.sefelt.com/saeover.htm


Also it occurs to me that Dremel buffing disks are made of high-density felt, I wonder if you could carve some rings out of that in a pinch.

mystic_1
"When you are wrestling for possession of a sword, the man with the handle always wins. "  - Neal Stephenson, Snow Crash

My build thread:  http://forums.sohc4.net/index.php?topic=68952.0




Offline wannabridin

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    • 1976 CB750K, under construction:
i saw the first couple, but all we really need is a couple square inches, tops!  what thickness do you think is appropriate?

i just don't see the point in buying a bunch if i don't need to!  maybe they'll ship me just a couple pieces of scrap for the cost of postage...  also, about the discs, aren't those sewn together?  i don't think a layered pad would suffice for this application?
1976 CB750K, currently under construction:
http://forums.sohc4.net/index.php?topic=64468.0

-And if you don't do it this year, you'll be one year older when you do...



Offline mystic_1

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The dremel flannel buffs are sewn, but there are also solid felt buffs in different sizes.

I'm thinking of:

the #429 1" wheel:


the #414 1/2" wheel:


and the #422 polishing point:


Perhaps some creative use of razor blades and punches could yield useful sections out of these.  Maybe I'll cut some up and compare them to the NOS felt swingarm grease seals that I have, think that'll be similar to what's in the carbs?

mystic_1
"When you are wrestling for possession of a sword, the man with the handle always wins. "  - Neal Stephenson, Snow Crash

My build thread:  http://forums.sohc4.net/index.php?topic=68952.0




Offline afastman

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Good news is that the felt can be crammed into the grooves, so engineering precision is not required.  I have found that 1/8" is adequate.  The 1/4" tends to be too thick to punch with leather punches and get clean perpendicular cuts.  The 1/16" incidentally does not like to be punched.  It strangely is too thin?  It does not cut cleanly and there is alot of wispy residue that strings out of the sides.  At cost per piece, the dremmel parts are too costly.  I would also question the grade of their felt.  Small pieces are available.  I found a couple of places through Amazon.  I think it was $3.99 for a 4"x6" piece which was more than adequate for all 12, 6 in each size (did I mention that the choke rail and throttle rail are different diameters?)

OR

we should nominate a keeper of felt and have a group buy for a larger quality and doll it out as required (I AM NOT VOLUNTEERING)
creul, nasty, neurotic, paranoid, antisocial...but basically happy



Offline wannabridin

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    • 1976 CB750K, under construction:
well as long as it's close to engineering grade "A" felt, i don't think there will be a problem.  the engineering felt is tough and has the capability to slightly absorb the fluid it's close to so it can seal against it.  it also acts like a slight carrier bearing for the shafts, so it can't crush under weight.  i think these felt pads might work though...  where'd you find them?  and where can you get hollow punches?  hardware store?

i am not volunteering either!!!  i would ask if you have any felt leftover, or if you remember what you looked for on amazon?  what are the sizes of the choke rail?  i noticed this too during disassembly, arg!!!  damn dirty hard-to-find/make parts!!!
« Last Edit: March 03, 2010, 06:07:30 PM by wannabridin »
1976 CB750K, currently under construction:
http://forums.sohc4.net/index.php?topic=64468.0

-And if you don't do it this year, you'll be one year older when you do...



Offline Nikkisixx

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I would reccomend McMaster Carr, they are my go to for odd-ball shtuff:

http://www.mcmaster.com/#felt/=62k4hz

A 12x12 sheet of 1/8" high grade wool felt is $13.10.  This thread reminded me to replace the o-rings that I had used  ::)  I just ordered some stuff from McMaster this morning, and a square foot should be enough for a bunch of these doodads.  I have hollow punches, can knock out some extras for ya'll. 
It is a proven fact that modifying a SOHC Honda in any way will bring on the apocalypse.



Offline wannabridin

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    • 1976 CB750K, under construction:
would you be so kind??  if you did this, i'd def. pay you for your troubles and shipping!!!

is the 1/8" stuff thick enough?  also, what kind of carbs do you have?  like we said earlier, there are two different sizes on these i believe.  please keep us posted, i call dibs on a set!!!   ;D
1976 CB750K, currently under construction:
http://forums.sohc4.net/index.php?topic=64468.0

-And if you don't do it this year, you'll be one year older when you do...



Offline Nikkisixx

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I have a '78 750k with PDs, and my '74 350 four also has felts.  The o-rings I used are 0.070" thick which is about 1/16.  My concern is 1/8 may be too thick, but according to afastman 1/16 does not play well.  I ordered both 1/8 and 1/16 - we'll see which works.  Shipped ground, should see them middle of next week.
It is a proven fact that modifying a SOHC Honda in any way will bring on the apocalypse.



Offline wannabridin

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    • 1976 CB750K, under construction:
hell ya!!  i can take a measurement of mine when i get back home, they've been sitting out of the carbs for awhile, so at least it's a starting point.  also, there's the retaining rings on top of them, but with the density of the felt required, i don't think they would compress down that much... 

i have a 77K w/ PD, and according to the fiches, they're the same!  this will be so helpful!!!  i can't quite get measurements on the choke lever ones though, as mine are pretty much shot...
1976 CB750K, currently under construction:
http://forums.sohc4.net/index.php?topic=64468.0

-And if you don't do it this year, you'll be one year older when you do...



Offline afastman

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Throttle rail:
ID: 7/16" (11mm)
OD: 5/8 (15mm)

Choke rail:
ID: 1/4" (6mm)
OD: 3/8" (9mm)

I will root through my junk space/home office/workshop/computer room (Ok so I live in a shoebox unit) and see if I have any of the 1/8" felt left over.  If I have any, I am more than willing to share the wealth. I know I have 1/4" but it is way too big.  If the 1/8" is too thick, it can be sliced down with a straight blade (xacto, olfa, razor blade/box cutter). 

I got my punches from Amazon.  THere was a 9.99 set which was 13 pieces for 9.99.  The plastic case was for sh!t, but the punches were more than adequate.  for those so inclined to collect cool pieces of machinery, McMaster has a 99.99 set which is set up to cut gaskets.  You can set both punches and get perfectly concentric holes.  That was pushing it in my book for 12 pieces.
creul, nasty, neurotic, paranoid, antisocial...but basically happy



Offline wannabridin

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    • 1976 CB750K, under construction:
unless someone wanted to start making these?  if you said $10 a pop + shipping and sold 10 sets, then you'd get all your money back for the most part?  i'd be down, but i would want to make sure i had enough people interested first!  so there should be 6 of each washer for the carbs correct?  and this is the only place anyone has found these on the carbs?  ha!
1976 CB750K, currently under construction:
http://forums.sohc4.net/index.php?topic=64468.0

-And if you don't do it this year, you'll be one year older when you do...



Offline MattFreeman

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Does anyone know if this is a problem with the F1 carbs? I didn't see anything that could get eaten away but I did use the carb cleaner liberally.

Just wondering if I'm in for trouble.