September 22, 2017, 04:21:17 pm

Author Topic: 1986 VF1000F Keihin VD 82A Carburetor repair kit  (Read 153 times)

JuhanOks

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1986 VF1000F Keihin VD 82A Carburetor repair kit
« on: July 28, 2017, 04:29:10 pm »
Hello!

Lately my VF1000F has started to stall when in idle and it's possible to drive only choke opened.

So I'm hatching idea to clean carburetors, of course I just could adjust the idle speed, but performance isn't the same anymore and fuel consumption is 10+ L/km - so I think it's a good idea.

Now, has anybody had any experience with this carburetor and can tell me which repair kit to buy?
I googeled for Keihin VD repair kits, but can't be sure. Also do You have suggestions which parts may have been damaged with time and also need replacing when I take carburetors out?

Engine code is SC15E-2004551 if it helps.

Best regards,

Juhan

Jays100

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Re: 1986 VF1000F Keihin VD 82A Carburetor repair kit
« Reply #1 on: August 22, 2017, 05:41:50 pm »
I'm surprised nobody has jumped on this.

I just replaced my '85 VF1000R carbs with a set from a '86 VF1000F.  the PO on my bike was a hack, had welded on the float covers and so on, they were not salvageable.  So, I had to source a second set.

I am verifying the jet sizes everywhere and so far, they're all the same.  The differences seem to be in how the float drains are sealed and how they communicate vent and fuel pipes from carb-to-carb.

Circling back around, it looks as if it's ok to use a rebuild kit from either the VF1000R or VF1000F and be ok.  Hopefully someone who's actually done this too, will be able to chime in.

t'wer me, I'd just clean them and while inside, assess what needs changing and fix that.  Jets dont' wear out, but they do clog and a pilot jet clogged is what you're describing.

Hope this helps!

Jays100

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Re: 1986 VF1000F Keihin VD 82A Carburetor repair kit
« Reply #2 on: August 24, 2017, 01:03:15 pm »
updated information VF1KR vs VFR1KF

I mentioned above that I've replaced my unuseable R carbs with a set sourced from a VFR1000F.  While they mount identically, there are some differences.  Here are two that I noticed last night as I was reassembling from cleaning.  (holy cats, what a job that was! 1.5 hrs just to mount the bare bodies, springs and linkages)

1. Needle jets are different.  the R' needles have a bit more aggressive taper and are smaller diameter at wide open. Ergo, they allow more fuel at any given slide opening as compared to the F' needle.

2. The slide return springs are shorter.  That's on the order of 8-ish inches long vs. 10-ish inches.  Ergo, will start to open with a lower differential pressure across the diaphragm.

Coupled with the needle noted in #1, the R' carb specs will allow more fuel, and more fuel is my friend.

Jays100

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Re: 1986 VF1000F Keihin VD 82A Carburetor repair kit
« Reply #3 on: August 25, 2017, 01:11:47 pm »
Slide difference

The air passages on the vacuum side of the slide (downstream of the needle) are larger on the R carbs.

The result is the slides respond slightly quicker with the ability to move more air thus evacuating the diaphragm chamber in a shorter time.

As to the original question, this won't affect any kit you get as the slides are not typically replaced.

What is important is that if you have a slide with a tear needing replacement, be sure you get the correct match or you'll have one cylinder running slightly imbalanced to the others.

Jays100

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Re: 1986 VF1000F Keihin VD 82A Carburetor repair kit
« Reply #4 on: August 25, 2017, 06:46:16 pm »
ok, I admit this is driving me crazy.

I looked in the F workshop manual and it appears both the F and R use a combination of needles and springs.  So, the new correct information is this:

Cylinders 1 & 3 (rear bank) use the thinner needles and shorter springs
Cylinders 2 & 4 (front bank) use the thicker needles and longer springs

as mentioned before, the slides are also different with the air flow holes (downstream of the needles) larger on the R model and smaller on the F model.