Author Topic: Another carb installation vacuum line question  (Read 762 times)

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Offline racer1735

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Another carb installation vacuum line question
« on: May 28, 2017, 05:23:00 pm »
Ok guys,  i'm confused.   Got my carb rack back from Steve and I am ready to instalL.  Had taken notes when I disassembled and labeled vacuum lines and have everything back like it was  ( which does not mean it was right because the bike ran like crap when I bought it).   It is a California bike and I have removed all emissions  paraphernalia ,  including the air cut off switch and installed Murphs block off plates.  He included two  caps which I have put on carbs one and four as they were connected originally.   And carbs two and three were connected.   I know one of them is supposed to go to the fuel tank,  but from the way this thing was hooked up originally that didn't happen    Should I cap carb three as well and run a line from carb two to the fuel valve?  Having three carbs camped should two of them not actually be vented ?
« Last Edit: May 28, 2017, 06:09:32 pm by racer1735 »

Offline Steve in Sunny Fla

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Re: Another carpet installation vacuum line question
« Reply #1 on: May 28, 2017, 05:30:52 pm »
we're talking brass nipples here, with emissions stuff gone... cap 1-3-4; 2 goes to the petcock. the vents are th 8mm black plastic t's between the carb bodies of 1/2 and 3/4. HTH, Steve
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Offline Harry Martin

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Re: Another carpet installation vacuum line question
« Reply #2 on: May 28, 2017, 05:59:45 pm »
2 goes to the petcock.

Is there something unique about 2?
I think I'm currently feeding 1 to the petcock on my C10.
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Offline racer1735

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Re: Another carpet installation vacuum line question
« Reply #3 on: May 28, 2017, 07:17:37 pm »
we're talking brass nipples here, with emissions stuff gone... cap 1-3-4; 2 goes to the petcock. the vents are th 8mm black plastic t's between the carb bodies of 1/2 and 3/4. HTH, Steve

Non-California models vent to the atmosphere so is it not detrimental to cap them?

Offline Steve in Sunny Fla

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Re: Another carpet installation vacuum line question
« Reply #4 on: May 28, 2017, 07:37:20 pm »
we're talking brass nipples here, with emissions stuff gone... cap 1-3-4; 2 goes to the petcock. the vents are th 8mm black plastic t's between the carb bodies of 1/2 and 3/4. HTH, Steve

Non-California models vent to the atmosphere so is it not detrimental to cap them?

do not cap them. And no, nothing unique about using #2 for the vacuum signal other than the hose routes the best there. Steve
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Offline racer1735

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Re: Another carb installation vacuum line question
« Reply #5 on: May 28, 2017, 07:59:06 pm »
 I do have your overflow tube so didn't know if that served the purpose of venting?

Offline Steve in Sunny Fla

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Re: Another carb installation vacuum line question
« Reply #6 on: May 28, 2017, 10:42:51 pm »
  If you choose to cap the vents, the overflows will act as the vent. and it might serve to slow some evaporation when the bike sits... but it also could stall the fuel flow if some condensed gas blocks the tube from venting. Steve
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Offline racer1735

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Re: Another carb installation vacuum line question
« Reply #7 on: June 01, 2017, 03:24:40 pm »
I got everything put back together, hooked up, etc.  Installed freshly charged battery, set fuel tap to 'Prime', watched clean, ethanol-free fuel flow thru the inline filter and on towards the carbs, then set the tap to 'Reserve' (I only added a couple gallons to keep the tank light).   Gave it full choke, pressed the starter button and the engine fired up immediately!  Settled quickly into a smooth, fast idle and I was able to lower the amount of choke to about 1/4.  After about 30 seconds I removed choke completely and set the idle to 1,000 rpm (indicated).  WOW!!!  What a testament to the work Steve in Sunny Florida does.  If that isn't evidence of money well spent then I don't know what is??
I had forgotten over the years just how noise an engine the C10 is (esp. with the fairings removed).  Lots of mechanical clatter.  Thanks again, guys (or  gals) for all the advice the past few months.  Engine work is Complete!  Now time to overhaul the brake system and front fork!

Offline who me?

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Re: Another carb installation vacuum line question
« Reply #8 on: June 01, 2017, 04:41:21 pm »
 If that isn't evidence of money well spent then I don't know what is??
Wait til you get it on the road
I have no idea about anything.
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Offline Blue808

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Re: Another carb installation vacuum line question
« Reply #9 on: June 14, 2017, 12:17:00 am »
My carbs were to you for service, Steve, by previous owner (according to him).  I see '2 minute mod' foam in place, and have confirmed overflow tubes present (by blowing thru a line attached).  I don't know extent of service.  If you keep records, could I privately ask if you may have?

Reason for my post - I don't have any overflow hoses installed, for whatever reason.  I see them shown on Shoodaben Engineering site. I'm not sure how critical they are, but would like to inquire - would these be available for purchase?  If not, I could try to construct. I've got some 3mm silicone vac hose that seems to fit. I would just need the 3 T's, and some careful cutting....

Offline cmonSTART

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Re: Another carb installation vacuum line question
« Reply #10 on: June 14, 2017, 12:24:45 am »
The overflow tubes are not the hoses you're referring to...  they're brass tubes machined and pressed into your float bowls on the inside.  You can't see them but they are there and when things malfunction, they relieve the excess fuel in the carbs, preventing it from going down into your engine... 

Trust me man, send them out. 
« Last Edit: June 14, 2017, 12:55:54 am by cmonSTART »