Vacuum Lines on Carbs - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 9 (permalink) Old 08-14-2008, 07:03 AM Thread Starter
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Vacuum Lines on Carbs

Quote:
Originally Posted by SpockRob View Post
Hi Cindy,

I'm a new member of VN750, having bought a neglected '85 VN700 a few weeks ago. I bought the bike as a near-basket case that would barely run. I traced the problem down to the carbs (spark & compression was fine), and discovered that the fuel lines were set-up incorrectly - the lines from the petcocks ran directly to the vacuum lines! (primitive direct injection? LOL!). Anyway, using the excellent labelled pictures you've provided the forum, I was able to reorganize the fuel & carb vent lines to their correct locations/destinations... the bike now starts & runs fairly well... I just don't know what to do with the vacuum fittings on each carb.... any suggestions on how to rout them and to where?)... any help from you or any other forum members would be greatly appreciated!

Best Regards to All,

Rob (SpockRob)
LMAO I guess this already *was* in the carbs area! Oh, well, sorry 'bout that!

Ok, for the vacuum lines: On each carb there is a brass nipple that will accept the vacuum line. On the front carb, it should go from that nipple to the lower part of the petcock. Now, if the petcock lines are viewed as a 'T', the bottom of that is where you hook up the line from the front carb. Assuming the 85 model was a vacuum-operated petcock, that should do it. If for some reason your petcock is a gravity feed (or someone converted it), make sure the line is snugly on the front carb and then block it off with a golf tee or something.

The rear carb vacuum line should run from the nipple back to the emissions cannister (look for the small lead on the cannister - there's only one that's the right size to accept the vacuum line).

See if that helps - if not, there are other options we can collectively consider.

Oh, and again, welcome!!

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post #2 of 9 (permalink) Old 08-14-2008, 07:06 AM
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If the bike was coastered or marbled, then the rear carb vacuum line should just be plugged.

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post #3 of 9 (permalink) Old 08-14-2008, 07:08 AM Thread Starter
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Right-o. Forgot that!

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post #4 of 9 (permalink) Old 08-14-2008, 08:08 AM
 
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Hi Cindy & Ksmnet,

Thank you both for such quick replies! :-D I'll risk sounding very Newbie by asking what coastered & marbled means? It sounds like it's referring to a modification of some sort? Cindy, there seems to be a open spot where the emissions cannister should be... I'm thinking the previous owner removed it... The petcock is the T-shaped vacuuum operated model you mentioned.... should I just plug the rear-carb vacuum line or "T" it to the front carb's vac line before that one routs to the vac fitting on the petcock? Thanks again!

Best,

Rob
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post #5 of 9 (permalink) Old 08-14-2008, 12:17 PM Thread Starter
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Quote:
Originally Posted by SpockRob View Post
I'll risk sounding very Newbie by asking what coastered & marbled means? It sounds like it's referring to a modification of some sort?
That's why I was afraid to mention it 'cause it is a mod and I didn't want to confuse you. However, ksmet is spot-on and the fact taht you have no emissions cannister suggests that that's exactly what PO did. Marbling is just that - putting marbles in the two large hoses that fit on the side of each of your cylinder heads (or blocking off the reed valves that are actually on the cylinder heads). If all that stuff has been removed, i.e., you don't have those hoses, then PO blocked the reed valves internally. All you need to do is block off that rear cyl vacuum port (small piece of line and if you have one more golf tee, that'll do it!) and you should be in good shape.

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post #6 of 9 (permalink) Old 08-14-2008, 01:10 PM
 
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Vacuum Lines On Carbs

Hi Cindy,

Thanks for everything... I will try these mods tonight and see how they work, and let you know how it turns out. Talk to you soon. Thanks!

Rob
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post #7 of 9 (permalink) Old 08-14-2008, 01:14 PM
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Hey, no prob. We just speak from a tad (and just a tad) more experience than you. We were all newbies once, too!

2017 Indian Roadmaster (current ride)
2003 VN1600A (Traded August 2017 to #1 son for a Bushmaster AR)
2001 VN750 bought 4/19/08 w/2309 miles(Sold April 2010 with just over 12,000 miles)
VROC #33035
__________________________________________________ ________________
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post #8 of 9 (permalink) Old 08-24-2008, 11:54 AM
 
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Hello.
We are doing the same restoring of a 1985 Vulcan and have the same problem as Rob in not knowing where the fuel lines go. Can we get the
same pictures from Cindy and/or Rob? Especially need to know where
the Lines off the plastic black "T" go....
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post #9 of 9 (permalink) Old 08-24-2008, 12:59 PM Thread Starter
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https://www.vn750.com/forum/showthread.php?t=3413

See if these pics help. If not, I can take some more/revise these/whatever you need.

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