Topic: Remove needles without taking carbs off the rack?

[jakec]

I'm working this set of 400F carbs that I bought and I want to get to the needles to check that they are OEM parts and also at the right height setting. Is it possible to get to them without taking the carbs off the rack? I've been told to leave the carbs ON the rack unless you really really need to take them off.

[bryanj]

If you have tiny hands and the correct tools you can get the float bowls off with the carbs on the bike BUT the correct procedure for setting float heights mean they have to come off the bike. There is rarely a reason to split the carbs from the mounting bracket, only one i can think of is a fuel leak at the ter piece(s)

[robvangulik]

I think he means jet needles, and yes you can get them out while on the bike, but as several components are VERY small, it is much safer to do it on a flat workspace like a kitchen table.....
And now i'm not reading right, Brian is right, leave them together, just take the tops off

[mattsz]

My first thought was that he meant carbs off the bike, but without separating them - leaving them all attached to the plate (rack) that holds them together.

I thought this because I'm thinking along those lines - my carbs are off the bike, and I'd like to give them a good clean without separating them.  They sat in storage for a couple of years with some fuel in them, which must have evaporated fairly quickly; they look pretty good, though - dry and dusty vs. varnish-y and sticky.  All the o-rings accessible via the float bowl need replacing.  But the previous owner (I know him) insists the bike ran like a swiss watch before he had to walk away from it, so I'd like to get a benchmark before I really tear into things.

All the instructions and tutorials I've seen have you separate the carbs as a matter of course, but can you accomplish a decent cleaning and inspection (including jet needle condition and position) without separating them?  Seems a shame to muck up their adjustment and balance if it isn't necessary...

[bryanj]

Like i said you can do everything needed EXCEPT the tee piece O rings with the carbs on the rack. But it is worth filling the carbs whilst they are off to see if those O rings leak!!!

[mattsz]

Like i said you can do everything needed EXCEPT the tee piece O rings with the carbs on the rack. But it is worth filling the carbs whilst they are off to see if those O rings leak!!!

That's a good tip!  Once the other o-rings are all renewed, fill the carbs through the fuel supply line and see what happens...

[DaveBarbier]

When we say off the rack, we mean to separate each individual carb. It’s advisable to keep the carbs on the rack. Removing the carbs from the motor is standard practice for certain maintenance procedures.

Unsure of the 400f carbs, but it’s likely you’ll need to remove the carbs from the bike. Sometimes you can remove the tank and the top caps off the carbs and fiddle with it on the bike. They don’t need to be taken off the rack to remove the needles (i.e. individual carbs separated from each other)

[Deltarider]

Removing the carbs from the motor is standard practice for certain maintenance procedures.

I disagree on this. It is true that in order to have a good view when the bike is new to you, it is handy to have the carbs bottom up on the table. But... once you've had a good view of the inside, you can do all future maintenance with the carbs in situ. I've done it quite some times and can do it blindfolded. This is true for the oldstyle Keihins. Replacing the crossheads by allen screws helps a lot.

[bryanj]

Only problem with capscres is its sooooo easy to strip out the threads

[jakec]

Hey! Wow you guys get started early. Sorry that I wasn't more clear on my description. The carbs are OFF the bike. I just don't want to separate them from the rack because i've heard that they may be more likely to leak after reassembly.

Also yes, I am talking about the emulsion tube needles. I can't see a way to get the throttle slide out without taking the carbs off the rack, because the linkage rotates on an axle that faces the axle from the neighboring carb. Not sure how to back that axle out without removing the carb.

The axle I'm referring to is assembly #98 toward center of image) here. Assembly #97 can somehow be disconnected from the axle (at a ball joint) without removing carbs from the rack? I have completely diasassembled a set of carbs before following the manual.

[Don R]

 I'd plan to replace those o rings while they are off anyway. It sucks to do it twice, I've done it twice on a couple bikes recently so I speak from experience. When they dry out they shrink and are hard.

[Tim2005]

Yes, you can. You can even remove the needles with the carbs on the bike, though the little Philips screws that hold #98 down onto the slides are best replaced with allen heads, to make on-bike reassembly much much easier. Note, there are two #98 assemblies in that diagram, I am referring to the left one shown under #88/#84. In that, you loosen the top bolt, having first undone its tab washer, and then you can pop it sideways off the ball joint. Beware, there some very tiny parts in there.

[Deltarider]

Yes, you can. You can even remove the needles with the carbs on the bike, though the little Philips screws that hold #98 down onto the slides are best replaced with allen heads, to make on-bike reassembly much much easier. Note, there are two #98 assemblies in that diagram, I am referring to the left one shown under #88/#84. In that, you loosen the top bolt, having first undone its tab washer, and then you can pop it sideways off the ball joint. Beware, there some very tiny parts in there.

Actually it is shown on youtube somewhere.

[Deltarider]

I'd plan to replace those o rings while they are off anyway. It sucks to do it twice, I've done it twice on a couple bikes recently so I speak from experience. When they dry out they shrink and are hard.

So far I didn't have to replace any of the 42 year old T-joint O-rings, in spite of being treated bad by me. But I don't store my carbs dry during hibernation... I keep everything in its natural state: wet. Also you must realise that if you do store your carbs dry, in spring some seals, may need some time to swell up again. I once or twice stored my carbs dry and was shocked to see how much the floatbowl seals had shrunk and I had some leaking. Never again.

[jakec]

Thank you Tim, that is the answer I needed. These carbs are from a 350F and they will be going on my 400F. So I need to get at the needles. And I can't get the emulsion tues out from the buttom so I'll push them from the top once the slides are out.

[flybox1]

Hey! Wow you guys get started early. Sorry that I wasn't more clear on my description. The carbs are OFF the bike. I just don't want to separate them from the rack because i've heard that they may be more likely to leak after reassembly.  No need to separate them.

Also yes, I am talking about the emulsion tube needles. I can't see a way to get the throttle slide out without taking the carbs off the rack, because the linkage rotates on an axle that faces the axle from the neighboring carb. Not sure how to back that axle out without removing the carb.  Just a little sideways shimmy and it will come off...slide it sideways and turn the slide...it will pop off the end.

[flybox1]

Use a dental pick, (orsomething similar) and pull the emulsion tube out from the main jet side. 
There's really no need to take the slide needles out unless they are bent, or have worn the needle jet slot out-of-round....

[mattsz]

Thank you Tim, that is the answer I needed. These carbs are from a 350F and they will be going on my 400F. So I need to get at the needles. And I can't get the emulsion tues out from the buttom so I'll push them from the top once the slides are out.

I was able to bump the emulsion tubes free on mine by raising the slides (by rotating the throttle lever), exposing the top of the tube (and a portion of the needle).  A little nudge with a small wooden stick and the tube dropped down enough to grab it from the bottom...

[jakec]

Just found this thread while looking for 350f needle position. Looks like a helpful description with photos.

http://forums.sohc4.net/index.php?topic=96392.0

I just want to make sure the needle position is correct, mainly. When I rebuilt the carbs on my '81 dohc one the needles was one shim higher than the others. doesn't hurt to check.

[flybox1]

check down in the slides at the screws holding the needle in place.  very easy to strip as they are tight AF, and many PO's didnt use JIS.
If they look unmangled, leave'em 

[jakec]

Thanks for the tip. I figured the needle position would be different for the different engines. I have read that jetting is different.

[Don R]

I'd plan to replace those o rings while they are off anyway. It sucks to do it twice, I've done it twice on a couple bikes recently so I speak from experience. When they dry out they shrink and are hard.

So far I didn't have to replace any of the 42 year old T-joint O-rings, in spite of being treated bad by me. But I don't store my carbs dry during hibernation... I keep everything in its natural state: wet. Also you must realise that if you do store your carbs dry, in spring some seals, may need some time to swell up again. I once or twice stored my carbs dry and was shocked to see how much the floatbowl seals had shrunk and I had some leaking. Never again.

 I'm just saying it's awfully easy when they are sitting on the bench.

[jakec]

Today I started to go at the throttle arms to remove the needles. however I noticed that the tab washers were all very uniformly bent, which makes me think that the needles have never been out. OK. Maybe that's true. However I want to throw this whole rack in the ultrasonic cleaner, and I've read on here that you should try and remove all the brass before doing so. Am I ok to put the carbs in the ultrasonic cleaner with the needles still in?

Also, I pushed the emulsion tubes down from the throttle bore with a flathead screw driver. It took considerable force, though. I don't know if I will be able to remove them without being able to push straight down (needle and slides removed). THoughts?

[Tim2005]

I don't know much about ultrasonic cleaning, but would have thought it'd be ok to leave them assembled, maybe others can advise.

As for the emulsion tubes, you have taken the float bowls off first? They normally come out pretty easily then. Maybe you could screw in something to the main jet hole to pull them out with, or to push down you could use an allen key with a 90 degree bend?

[jakec]

I agree, usually they come pretty easily.. These took a FIRM press with the screwdriver, and then kinda POPPED down when they finally budged. I can't do the allen key thing because th needle is in the way... I guess it all comes down to can I leave this brass in here for ultrasonic cleaning or not? (Even though I know I should really take out the emulsion tubes considering they're stuck)