Riders Of Vision

General => TechTalk => Carburetors => Topic started by: mephiston on May 23, 2016, 01:14:15 PM

Title: Connecting 83 Carb to 82 tank / petcock possible?
Post by: mephiston on May 23, 2016, 01:14:15 PM
Hi visioneers,

at the moment I have a full 82 set up. I hope that I can improve the overall performance with the vacuum flapper airbox and a 83 carb. I have both ready, but:

How can I connect the 83 carb to the 82 petcock / tank? There are 2 hoses to be connected on the 83 carb. The 82 petcock has only one connector.
Will the vacuum operated airbox fit under the 82 tank?

Thank you for any help!
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: Walt_M. on May 23, 2016, 07:34:24 PM
I am sure you have your reasons for wanting to use '83 carburetors on your '82 but you will not get more power. But you are looking for help. Some time ago somebody put a fitting high up in the saddle of the tank and connected the return line to it thus avoiding the complex and expensive '83 petcock. As for the vacuum flapper, it was supposed to be a dealer retrofit on the '82s but, obviously not all were done. To directly answer your question, yes it will fit.
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: Rikugun on May 23, 2016, 08:02:33 PM
If you were to stick with the '82 carbs, would you also need the proper carb top in order to take advantage of the flapper airbox? All mine came equipped so I'm a bit fuzzy on the install details.
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: mephiston on May 24, 2016, 02:15:10 AM
The power is ok, but my stumble is really heavy. I want to know if it gets better with the 83 carb and vac. airbox. Additionally, I have idle problems that I cant eliminate. I tried for two years now and I am pretty sure that I did everything possible except playing with different jettings. Iginition is perfect and new, carb + jets ultra clean, everything is tight, no wrong air. Carb is synced with a expensive electronic tool... but when I hit the throttle hard the bike is nearly going to jump for about a sec before accellerating. That sucks....

Previous it was a german low power model. I changed the cams and the carb, set the jets to the standard 82ยด setup 64hp. All in all, overall performance is very good, it kicks like a beast, but the stumble is heavy. The airbox is without damage but I didnt put any weights on the flapper yet.
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: Walt_M. on May 24, 2016, 12:20:16 PM
Does your bike still have the YICS? They often get internal leaks that cause rough running. If you have it, try removing it and cap off the intake fittings. If that makes it better you can then reset your pilots.
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: mephiston on May 24, 2016, 12:26:23 PM
Yep it has the YICS, a new stainless steel replica. No plastic parts that could rot and leak, so this point should be eliminated. The bike is running a little bit better with it.
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: Walt_M. on May 24, 2016, 05:33:19 PM
I have been reading too many threads. I solved a similar drivability problem on my '83 by giving the accelerator pump more stroke. It was a trial and error thing but I think I got it pretty quick.
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: Rikugun on May 24, 2016, 05:39:11 PM
That's a good point and may be often overlooked when addressing a stumble. Replacing the diaphragm with a supple new one makes a huge difference too. Unfortunately, it may only be available as part of the complete carb rebuild kit.
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: mephiston on May 25, 2016, 02:39:04 AM
Thanks for the accerlerator pump advice. This is indeed a part I never lay hands on. But back to my first question: How can I connect the 83carb to a 82 petcock?

Do I simply need to close the return fuel hose? (the upper one?)

I rebuilt my 83 carb now and it stands shiny in the showcase, waiting for its fielding ;)
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: Walt_M. on May 25, 2016, 06:03:53 AM
You could a put a fitting in the fuel tank and connect the return line to it. I believe that line is here to circulate fuel to help prevent vapor lock. I may have to add a return line to mine if the FZR carburetors don't work.
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: jefferson on May 25, 2016, 08:33:13 AM
The simple fix is a t in the fuel line coming from the petcock. Then you have place to hook up the return line from the carb.
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: mephiston on May 29, 2016, 03:36:33 PM
Thank you. I will give the t piece a try.
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: Ken Williams on May 30, 2016, 09:12:10 AM
Assuming you have an 83 fuel pump with the 83 carbs, then the fuel return must be above the carbs for the pump to be effective.  It won't pump fuel above the highest point of the return line.  If you t the return line into the supply line below the petcock, you might as well remove or bypass the pump. 
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: mephiston on May 31, 2016, 02:22:12 AM
Sorry to ask again:

Did I get this right, when I t the return line directly into the input line from the petcock, I cant use all the fuel remaining in the tank?

If that is so, would it be better to connect a 82 fuel pump and plug all return fuel connectors on the carb?

Thank you very much!
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: jefferson on May 31, 2016, 09:42:47 AM
I don't think there is any difference in the fuel pumps. The difference is the carb has the return line off of it and the petcock has the return port on it. The pump just pumps.
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: Rikugun on May 31, 2016, 10:47:50 AM
The '82 pump has an integral regulator/bypass component. Does the '83 carb set have this feature as well?

I only have a photo of '83 carbs to go by and I don't see one attached to the pump housing but there is another diaphragm set elsewhere on the carb body - is that it?
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: Ken Williams on May 31, 2016, 07:59:56 PM
The 83 pump does not have the integral regulator/bypass feature.  Plug the return and it will likely overpower the carb floats.  Mephiston, you are correct in your most recent post, Rikugun also. 
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: Rikugun on June 01, 2016, 08:02:05 AM
Thanks for the clarification Ken.
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: Jirik on June 01, 2016, 08:10:22 AM
I hope, this is also to topic:
I have this spare carbs:
(http://www.rajce.net/f1045705369/600px)

I think, they're 82 with some 83 parts (front carb, top, ,,vacuum" filter+ flap). I don't know, if they work. I bought them from one canadian visioneer, who says they worked.
Now I have them after ultrasonic cleanning and going to reassemble and adjust them. So I will see.

I have small problem: Does anybody know, if this small o-ring and washer are from carbs? Diammeter is same as in pilot screw (pos.62), but I'm not sure.

(http://www.rajce.net/f1045705370/350px)

(http://www.rajce.net/f628123719/600px)

Thanks Jiri
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: devotee on June 01, 2016, 02:39:46 PM
It may be the O-ring that goes on the float bowl drain screw. Was it just extra in the parts kit? There should be two (one for each bowl drain). Item 56 in the diagram above.
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: Jirik on June 02, 2016, 12:34:47 AM
Drain screw has a bigger diameter. This two small pieces I found in the bottom of my ultrasonic cleaner after cleaning rear carb and Suzuki petcock. It doesn't look from petcock, so it has to be from carb. But I don't know, if I didn't pour into a drain this two from front carb. They wasn't there during assembling. :-\
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: Rikugun on June 02, 2016, 08:28:08 AM
QuoteI have small problem: Does anybody know, if this small o-ring and washer are from carbs? Diammeter is same as in pilot screw (pos.62), but I'm not sure.

Yes they are for the pilot screw. When you removed the screw, I'm guessing the spring fell out but washer and O-ring stayed in the carb body. Assemble the spring on the screw, then the washer followed by the O-ring.

Oh, and the picture you showed on the previous post are '82 carbs. Why not just use them?
Title: Re: Connecting 83 Carb to 82 tank / petcock possible?
Post by: The Prophet of Doom on June 03, 2016, 06:03:16 AM

Yup Rikugun, Looks like a late 82 carb with upgrade top for vacuum flapper. 
Not an 83, they have outlets by the chokes