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Rebuilding 94 VFR carb tips ?


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Greetings fellow VFR fanatics, 

I did something VERY dumb and let my 94 VFR sit with crappy alcohol gas in the tank (and I knew better),  long story short it blocked the idle jets.

My bike has been garage kept since new with 14K miles original, regular oil changes never checked valves but it has been adult ridden...

 

Anyway I removed the carbs , cleaned the jets with a 25 gauge iv needle but appears that opened the idle jets up too much as my bike now at idle is VERY rich and almost appears there is a bit of light smoke (hopefully its just unburnt fuel not oil ),

 

Starts and idles fine but now without the choke (didnt used to)  and applying the choke stalls the bike when cold ,

The plan is to remove the carbs again and replace the idle and main jets with new factory replacements.... 

My question is about the proper size jets for the 1994 VFR factory air box and exhaust, 

I live in SE Forida so the bike is never run at altitude or in temps below 65F

 

Are the correct jet sizes Main Front #125, Rear #128 and #40 pilot jets on all four ?

Also any recommendations where is a good source for factory replacement jets ?

 

PS aso may be looking for some replacement right side fairings if anyone knows a good source for those as well.

Thanks and best regards

 

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I'm seriously doubting that you opened the jets up significantly enough to alter how it functions with a needle. Usually you need a drill to do that kind of damage.

 

I would go through and make sure you don't have something else going on first. Like a stuck float, or a leaking needle, or one of those fun things.

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Have you synced the carbs?  If you dismantled the linkages and separated the carbs, you'll need to do this or the bike will never run correctly.  BTW, I had to do the same thing on my Gen4 due to the crappy gas they sell in the states.  What a PITA.  I have a large bottle of fuel stabilizer I use for the fuel in all my bikes now.

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Hello and thank you for all the replies  especially Terry for the specs   ; )

 

In reply Marsman , no I did not separate the carbs although at the time I removed the jets I could have mixed up the front and rear.

I did not measure the floats and the float needles were clean and moved fine but going to order a float bowel measuring tool and check them this time ,

 

BTW I did notice two jets seemed to be smaller when cleaning them, at the time didnt stop and think they were front and rear specific... DOH !

 

I do not have a carb vacuum gauge set or a D tool yet,

Last time I worked on CV carbs was on my 1988 FZR 1000 otherwise the bulk of my carb experience was from 2 stroke Yamaha YZ's and RZ's with Mikuni carbs so assumed since it ran great before would just need the jets cleaned and replaced....so much for easy   : (

 

will post an update after I order the parts and have it apart again.

 

Thanks and best regards   : )

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On 1/31/2018 at 10:01 PM, YoshiHNS said:

I'm seriously doubting that you opened the jets up significantly enough to alter how it functions with a needle. Usually you need a drill to do that kind of damage.

 

My thoughts too :comp13:  So it must another fault.

 

What's the diameter of the needle you used ?  Using a  .010" steel wire is one way to clean out a plugged idle jet, and won't do any harm

   

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Just put the micrometer on the needle I used to clean the idle jets and it measures  0.22" inch

During the cleaning process I noticed it passed easily through two of them and the other two it took some coaxing.

 

 

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Assuming you missed a '0' there and it's 0.022"

If it passed through two of the pilots no problem, then the other two were just more clogged. Usually it just takes a bit of poking and some compressed air to clean out the pilot jets when I'm working on them. Did you do a visual check to make sure they were clear? You can tell if it's just a little bit clear vs completely clear by holding it up to a light.

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the largest wire that goes through a #42 idle jet is about .013", so if a .022" goes through, the jet is enlarged too much. somthin's screwy !  :wacko:

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Thanks for the replies.....My plan is to order new jets when I find the time to research a reliable vender....

had ordered an All Balls brand clutch master cylinder rebuild kit but the bushings are the wrong size and spring is too small ... DOH !

 

 

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Shopping for the parts tonight, ...Am I reading the chart correctly that the correct Jet sizes  for my 1994 VFR 750 (non Calif) are as follows

Front Main Jets  #128

Rear Main Jets #125

Idle Jets #40

 

Float height 13.7  (0.54)

 

Found a different chart from an online vender that has the front and rear main jets reversed so it reads  Front #125 and Rear #128

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Kinda having trouble finding the correct jet sets...anybody have advice on a good online vendor ?

 

Found a set online 

JRL 5pcs #40 Jet Slow Fit Keihin CVK PE PZ CB Carburetor

 

  • Thread Diameter: 6mm
  • Length: 28mm including 10mm Nut, 5mm thread
  • Nut diameter: 5mm
  • for CB400 CVK26/30 Universal pilot jet (applied on PE24-30 PZ26-30 CG125-200)
  •  

Would these fit not sure which carb designation fits,

if Im reading the chart correctly above mine has VP34A carbs ?

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  • 1 month later...

You're focusing on clogged jets, but don't forget about other possibly clogged passages, including air bleeds.  You might want some expert advice (or let an expert do it) to clean the whole carbs properly.

 

(note:  I am not an expert!)

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