Main jet needles different lengths?

[garyS-NJ]

I'm working on this 86 xvz13 after somebody tried to clean the carbs but couldn't get them back in.. Well it leaked fuel overflow so then I got the clips on the floats. Still wouldn't rev so off with the carbs and cleaned the jet blocks and sprayed all passages. Still no won't rev and noticed the two right bank piston valves not fluttering as much as the left. Tried my ignetek ignition, still won't rev and then patched two tiny holes in diaphrams. Looking close at piston valves I see the main jet needle 1NL-1490J-00-00 NEEDLE SET, for rear is about 6mm longer than that of the front.. Are these needles different lengths or supposed to be shimmed that much different? Exhaust port temps were close..

 

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[cimmer]

Gary, are you saying the jet needles themselves are different lengths to each other?

Looking at the parts listing, it appears they are all the same part number no matter which carb then go into. I was wonder if you can see any writing up near the top of the jet needles that might indicate what needles they are. It is my understand that there is a part number on the jet needles them self. My service manual mentions 5DZ3-1 with the needle jet being a Y-0. This is for the 86-93 Venture.

I did do a search on the Mikuni 5DZ3-1 jet needles and one of the docs had total length for a 5DZ3 jet needle as 50.50 MM in total length.

Hope this helps, I do have a spare set of carbs here that I could pull a part and check the needles if that helps you...

Rick F.

[garyS-NJ]

Hey Rick, thanks.. I didn't remove the needles from the piston valves and so I didn't see a number on the needles nor get to measure total length. One of the needles protrudes from the piston 1.5 inches and the other needle is about 1 9/32 inches. But you are confirming whatnot saw which is 4 same needles shimmed the same. Attached find pics. Hopefully before I get back there I can get the proper length from the piston and get the right needles..

 

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[yamagrl]

No. They should be the same length and the protrusion through the slide should be the same on all four.

 

6mm is a lot. The spacer on the needle has an alignment pin that is likely not seated in the corresponding hole in the slide.

 

These 2 different threads about diaphragm replacement highlight what I'm referring to.

http://www.venturerider.org/forum/showthread.php?32121-Ebay-Carb-Diaphragm-Replacement!

 

http://www.venturerider.org/forum/showthread.php?19271-Carb-Diaphram-Replacement

[garyS-NJ]

I thought about the alignment pin then wondered how it could account for that much difference.. I see my 84 xvz12 has needle set 26H-1490J-00-00, same p/n as the '86 except the prefix. So I assume same p/n, same length... And I can pull one out of my carbs to check length then pull all the needles out that '86 and check the shim assembly .. Thanks all! Again!

 

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[cimmer]

Gary, it is my understanding that the 83-85 needles are different from the 86-93 in that the clip that holds the needle in postion is adjustable on the 83-85 due to different slots cut around the top of the needle. The 86-93 only have the one slot for the clip. I know I and a bunch of others removed the plastic spacer and replaced it with washers that when stacked were shorter then the plastic spacer. This was to lean out the motor a bit due to it running rich and getting a carbon buildup at the end of the mufflers.

I am planning on one of my winter/spring projects is a complete rebuild of the carbs on my 89VR as I doubt it has ever been done. I have replaced the diaphragms and did the shotgun cleaning on the carbs but it is time for a total cleaning and rebuild.

Hope this helps you.

Rick F.

[mmaleney]

I think it was only the 83 carbs that had the 4 slot needles, 84 and 85 were single slot and a very different taper on the needle than the 86 Mk2.

[yamagrl]

I think it was only the 83 carbs that had the 4 slot needles, 84 and 85 were single slot and a very different taper on the needle than the 86 Mk2.

@cowpuc or @Venturous Randy should know the answer to this. Randy has mentioned to me about tinkering with the spacers. @skydoc_17 probably has an answer about it also.

[garyS-NJ]

Interesting, the tapers on the long and short needles I have here look same.. Do I need to msg those folks or are they "tagged"here for a notification. They have always been helpful.

 

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[yamagrl]

Interesting, the tapers on the long and short needles I have here look same.. Do I need to msg those folks or are they "tagged"here for a notification. They have always been helpful.

 

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I think they'll get a notification.

 

I have been "pouring over" the parts diagrams and I see there are subtle differences in the part numbers. Some of the jets are larger in the 1300 than on the 1200. But, I'm not sure about the needles an emulsifier tubes (main nozzles). There could be differences but I'm pretty sure there is not 1/4 difference in the needle lengths. Have you removed the needles from the slides and stood them on end?

[garyS-NJ]

Thanks! And no, haven't disassembled the slides. Figured I would try to verify correct needle and proper protrusion length first.

 

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[CaseyJ955]

Thanks! And no, haven't disassembled the slides. Figured I would try to verify correct needle and proper protrusion length first.

 

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Once you have the side fairing off and the carbs exposed it takes only a few minutes to remove the slides and pull the needles out. As mentioned there is a tiny little white nipple on the collar that goes at the blunt end of the needle. When I'm reinstalling needles I put them back in the slide and put that little spring and nylon screw back on only a turn or two at first, leaving me room to push the needle up against spring pressure, gently, and gently twist it until l I feel it click downward again before snugging the nylon screw down. This lets me know without any doubt that the nipple has fallen into that little hole. You can hear it and feel it click in. Also make sure that the above mentioned white collar with the little nipple is slid all the way up to the end of the needle and seated firmly against the C-clip at the blunt end. Sometimes they can be a little stiff, especially if you have needles with multiple C-clip adjustments. When you put that fat little nylon screw over the needle and spring, just barely snug. Resist the urge to over tighten it.

 

When you take the slides and needles out make sure all the parts stay with their respective carbs. I'm sure this disassembly will reveal the reason for the needle length variance.

[garyS-NJ]

I'm waiting on a friend with an '86 whose gonna give me the needle protrusion measurement

 

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[yamagrl]

I'm waiting on a friend with an '86 whose gonna give me the needle protrusion measurement

 

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First things first... I'll betcha a dollar that they are not seated properly.

 

 

1. Just take 'em apart, then make certain that the white spacer is in place against the cir-clip. Drop the needle with the spacer and cir-clip into the slide.
   
2. While holding the slide in one hand twist the needle while applying a gentle outward pull on the needle. When it finds it's place hold it firmly and insert the washer and spring with something such as hemostats . Then put that plastic nut on. This can be a bit tricky.
   
3. Do all four slides.
   
4. Measure
   
5. Refer back to "First things first"
   
6. ​Send dollar.
   

[CaseyJ955]

I'm waiting on a friend with an '86 whose gonna give me the needle protrusion measurement

 

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I'm not 100% on this, but 86 - current should be the same. I have my 89 1300 apart right now because I found pinholes in 3 of the 4 diaphragms. My experimental repair with Permatex PL S30 Roofing sealant is done but takes like a week to cure completely. Anyways, I just happened to have all the slides out and pulled/replaced the needles just to check for the presence of shims. The needles protrude from the slide ~ 1 17/32" and are single position needles without shims. It would be interesting to see if the 86 is the same and what type of needles it has.

[cowpuc]

Sorry about being a day late and hope I aint a dollar short on this one (that Yamagrl snuck one in on me:big-grin-emoticon:) - been having to lay low trying to get some blood clots under control while getting ready for my next biopsy this Monday,,, at any rate,,,, here's what I know.. This is STRICKLY from an 83/84 MK1 1st Gen perspective (all I have worked on) so keep that in mind.. The needles are all the same length. The American market 83/84's did NOT have the adjustable metering rods - I have heard that the Canadian models did come with the notches to move the e-clip up and down for adjustment but I have never owned one of those so I cant confirm. I did have to adjust the metering rods in one of my 300k bikes due to the emulsifer wearing (bike could not handle the extra fuel from the main jet) - I did so by purchasing nylon washers and replacing the little plastic collar and lowering the needle 1mm - this made a HUGE difference and worked perfectly. From that I highly suspect that someone - somehow put the wrong metering rod in your scoot Gary as the differences you gave between your metering rods is a LOT more than what I am talking about.. Here is a short thread about what I did with some pics: http://www.venturerider.org/forum/showthread.php?86325-Carb-metering-rod-question/page2&highlight=metering

 

Concerning patching up diaphrams. I have experimented a LOT with finding just the right patching method (keeping old 1st Gens has been an on going experiment ). I have found the best sealant to use is Yamabond #5 . Clean and dry the outside area of the Diaphram real well with spray carb cleaner and make sure its dry. Lightly smear #5 on the pin hole slightly larger than hole. Let dry. Make another light smear over that only a little larger and let dry. I have successfully ran diaphrams patched like that for MANY MANY miles.

 

Hope this helps!

Puc

[garyS-NJ]

wow Puc, good luck with that medical mechanics.. and my problem, I thought I followed up here, was the one needle plastic thingy tab not seated. took apart, reassembled and right on 1 17/32" long off the slider. She's running now and waiting for a new rear tire then I'm gonna sync the carbs and send her off.