Author Topic: Newb here with carb rebuild question  (Read 1431 times)

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treemagnet

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Newb here with carb rebuild question
« on: August 07, 2009, 08:23:03 PM »
hey guys. i have been lurking for a while and have searched but could not find the answer i was looking for.
can someone tell me the chances that i will have to move the clip on the needle if i have a set of cb400f carbs that i plan to put on my cb350f? Only reason that i think the carbs are from a 400f are because the jets are labeled "40" and the cb350f has 35's.
it looks like a PITA to get to the needle and clip. I have torn down and rebuilt the carbs without doing this before but wondered if i would be doing myself a disservice if i skipped this step. Also if i do not HAVE to teke the needle out and adjust the clip - how do i get the guide that the needle goes down into out of there? a couple came out but the others are stuck and i know i should clean the little holes. any ideas? i have sprayed carb cleaner with no luch

lastly - how would one measure the float height? special tool. I know it should be 21mm but i'm not sure how to measure it.

thanks

Offline tomsweb1

  • '78 CB750A
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Re: Newb here with carb rebuild question
« Reply #1 on: August 07, 2009, 09:20:02 PM »
I measure the height of my carbs with a precision slide ruler... or something like that. just make sure your measuring device is accurate enough, and check both sides of each float.
As for the jets, I would simply change them to what they're supposed to be. Don't fart around with the needles if you don't have to. Though, if your jets have been changed, the needles have probably been moved too. If you can see the slot that the clips are in on your needles, And they're at stock height, leave them alone for now.

First thing is first though, Clean you carbs. Clean them well. Learn the routing for all the little orifices. Make sure they all have something coming out the other end. Very important you do this before playing around with anything else.
Present: 1978 CB750A, 1978 CB400A, 1983 Nighthawk 550, 1984 CM250C

Past: 1977 XL100, 1982 KZ1300

treemagnet

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Re: Newb here with carb rebuild question
« Reply #2 on: August 08, 2009, 06:31:36 AM »
i have cleaned well, have new jets or cleaned the old ones well, new gaskets ect. and almost ready for reassembly although i need to measure float height first. Anyone know if the cb400 needles or needle position is different than that of the ones on my cb350f carb? if so i have to do some swapping around.
Also how do i get the needle "sleeve" out?  - the part that the needle sdies down into? i ahve gotten 2 but the other 2 will to budge. PB blaster for a couple days?
thanks again.

treemagnet

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Re: Newb here with carb rebuild question
« Reply #3 on: August 09, 2009, 01:40:14 PM »
are these just stupid questions?

Offline 1timduke

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Re: Newb here with carb rebuild question
« Reply #4 on: August 09, 2009, 02:51:13 PM »
No stupid questions here ;D

If you got two out and the other two are frozen, try the PB, then a little heat (hair dryer).   That will help loosen them up.

Float height is measured when the float arm touches the needle valve, then measure from the carb housing to the top of the float.   Little metal ruler works well.

-Tim
The only thing I miss about the South is Waffle House!

treemagnet

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Re: Newb here with carb rebuild question
« Reply #5 on: November 17, 2009, 01:03:01 PM »
great. I'll give it a try tomorrow. finally back on this project.
thanks guys