Author Topic: FZR carb conversion  (Read 31739 times)

fret not

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Re: FZR carb conversion
« Reply #40 on: July 19, 2016, 02:34:12 PM »
Walt, photos can help us see what you are actually dealing with, which may or may not help generate suggestions and ideas.  I think some of us are itching to do this mod also.

I have two sets of mostly trashed '82 carbs (broken off jet, etc.), and one set of hopefully salvageable '83 carbs.  So far I have not been able to remove the improvised plug (now an Allen bolt) where the freeze plug type cover should be.  Depending on what is under that Allen bolt these may be 'parts' carbs.  It's all heading for some improvement one way or another.

Thanks for starting this thread.
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Walt_M.

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Re: FZR carb conversion
« Reply #41 on: July 19, 2016, 05:23:22 PM »
From my present position, I would not spend 2 cents on broken or clogged standard carbs. They are too finicky at best and irreparable at worst. If you are thinking of doing this, first I suggest you get a set of FZR600 carbs so you can follow along, or lead! This will work.
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Prophet Of Doom

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Re: FZR carb conversion
« Reply #42 on: July 20, 2016, 08:52:03 AM »
I don't know what model the 600 uses but here's an interesting observation... (think that I posted this one before).  The specs for the FZR750 US Model says it runs a BD34 Carb, but BDST38 on the UK Model.  The BDST38 is common as muck - Ducati Monster, Yamaha Tenere, TDM, YZF and more.  This could be an interesting possibility for a swap.


UK specs BDST38mm:

-122.5 for cylinder 1&4 and 117.5 for 2 and 3(main jets)
-Main air jet, 50.
-Pilot air jet, 125
-Pilot Jet, 42.5
-Pilot Screw, 2 1/2 turns out.
-Valve seat size, 1.6
-Start Jet, 57.5
-Fuel Level, 7.8 to 8.8mm

US model BD34mm:

-Main Jet cylinder 1&4, 107.5. Cylinders 2&3, 105.
-Main Air Jet, 65.
-Pilot Air Jet, 125.
-Pilot Jet, 15.
-Pilot Screw, 2 turns out.
-Valve seat size, 1.2.
-Starter jet, 30.
-Fuel level, 7.3-9.3mm

Walt_M.

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Re: FZR carb conversion
« Reply #43 on: July 20, 2016, 10:27:56 AM »
The US 600 uses BDST32. I have a set of BDST38s from my TDM850 and I am pretty sure they would have fitment issues on the Vision as they are physically pretty large.  But, as they are available to me here and now I will have a look.
Ok, I looked and they would be a tight fit if at all. They are too large to fit the stock intakes of course and also too large to fit in the V if they did. They would require a complex curve of the intakes as they would have to move to the left and closer centers. IMHO, too much trouble and a lot of carb for the bike.
The 34s from the 750 may fit but they are more rare in the US
Attached some photos
« Last Edit: July 20, 2016, 02:53:20 PM by Walt_M. »
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Walt_M.

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Re: FZR carb conversion
« Reply #44 on: July 20, 2016, 03:01:32 PM »
Adding a couple more photos
I put a 38 and a 32 side by side on my bench. The size difference is not so apparent in the photo. I took my carbs back off and put the 38s in place and got a photo plus a photo of the carb to intake offset. This is far as I am going with this.
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fret not

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Re: FZR carb conversion
« Reply #45 on: July 22, 2016, 01:29:58 AM »
A set of YZF600R carbs should be on their way to me very soon, and I will begin the process too.  Hopefully they will be in decent condition.
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Walt_M.

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Re: FZR carb conversion
« Reply #46 on: July 22, 2016, 05:10:53 AM »
You will have to clean them of course. I got rebuild kits for mine but the gaskets and 'O' rings are neoprene and you may not need kits. Just pay close attention to the way the carbs are linked before you take them apart. BTW, today is 'jet' day for me. They came yesterday.
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Re: FZR carb conversion
« Reply #47 on: July 23, 2016, 12:43:40 PM »
So I am starting a mental list of who has a set of FZR carbs, Figure you need two which leaves you with two extra.  Soon this site will be thick with extra carbs.  ;)
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Current Projects: 1982 XZ550, 1986 XL600R, 1980 CB750SS

Walt_M.

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Re: FZR carb conversion
« Reply #48 on: July 23, 2016, 04:16:19 PM »
I actually have only 1 whole carb as one of mine had a broken dome which is why I got them cheap. Another issue is the 3rd carb has the throttle bellcrank and idle stop. No real problem for good fabricators, which I am most assuredly not. Also, from an FZR site, some carbs have float bowl vents and some do not. Mine have vents which are a minor problem to be overcome.
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fret not

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Re: FZR carb conversion
« Reply #49 on: July 24, 2016, 03:19:01 PM »
Walt, I see you have Mikuni carbs.  The ones I ordered and should arrive Thursday are Kehin.  Is the bowl vent thing associated with brand, or just specific models of carbs?

One point which has piqued my curiosity is how to set the fuel level in the float bowls, as they look like the float bowls will be at a significant angle.  This is not a concern for fuel injection systems.
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Walt_M.

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Re: FZR carb conversion
« Reply #50 on: July 24, 2016, 05:25:40 PM »
Well, you are on your own with Kehins. The bowl vent is a Mikuni thing. You will have to go to whatever bike site that uses your carbs for float level settings. Just curious though, why did you go to Kehins?
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fret not

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Re: FZR carb conversion
« Reply #51 on: July 25, 2016, 12:03:57 AM »
Well, in my experience they are a good company that makes generally good stuff, and they were less expensive than the others I saw.  Carbs and shipping came to $83.

My brother has already asked what I am going to do with the "leftovers", and I told him I have another XZ and might be inclined to make a "rat" bike.  If he can really use them he will get them.  They probably will be adapted to his "Moto Rodeo Superbo" (Honda 500 Ascot V twin with other suspension and a bigger tank).  He happens to be a skilled fabricator, worked in govt. aircraft biz for quite a few years.  Also, he has a decent muffler I can adapt to my KLR650.  I don't want it to be loud but I would like to hear it.

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Walt_M.

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Re: FZR carb conversion
« Reply #52 on: July 25, 2016, 09:01:19 AM »
I don't have any problem with Keihin either but the BDST Mikunis are true downdraft. Hope your Keihins are too but you are on your own with jetting, you can't help me and I can't help you.
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fret not

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Re: FZR carb conversion
« Reply #53 on: July 26, 2016, 02:05:15 AM »
Carbs arrived early and in nice condition.  There is a little bit of 'dirt' on the outside but the interiors seem quite clean.  After looking them over for a while and beginning the disassembly I think this will be a serious project.  Not rocket science but a challenge.  As Walt said, there is precious little room to fit two carbs in the V, so it will take a bit of fiddling for sure. 

These carbs are from a '01 Yamaha YZF600R, so they are designed to sit at the same angle as the Mikunis that some years used.  It looks to me the throats are supposed to be about a 10 or 12 degree angle from vertical.  Same style of enriching system as the Mikunis, but different manufacture.

Now I have to figure out which hoses do what.
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Walt_M.

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Re: FZR carb conversion
« Reply #54 on: July 29, 2016, 06:02:08 AM »
Finally got back to my jets. Got them installed and got it started. Only running on the front cylinder, wtf, over? Pulled the carbs and checked the rear pilot circuit and it was okay. Put it back and same thing! Okay, now some of you know what was wrong. Correct, leaking YICS hose. Quick trip to the local auto parts and she is running on both but I had enough for the day. I want to take the YICS off but I need to ride it first.
Well, I have it running good enough to ride, if I just had the seat and tank on it. Maybe tomorrow.
« Last Edit: July 29, 2016, 02:42:23 PM by Walt_M. »
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fret not

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Re: FZR carb conversion
« Reply #55 on: July 30, 2016, 01:34:55 AM »
Good going, Walt!  Each step is a step closer to getting it to work right and getting a good ride. I'm hoping you have very few and only small details to work out to finish this mod.

How is your knee behaving?

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Walt_M.

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Re: FZR carb conversion
« Reply #56 on: July 30, 2016, 05:21:55 PM »
I got the fuel pump hooked up today and the tank on. This is still in the testing stage but it is progress. I am going to have to use pod air filters as the carbs are about a quarter inch too low for the stock air box. But on the bright side, it looks like the fuel pump will not be needed as the float bowls are below the lowest part of the tank. I am still going to use one since I already have it connected and it works.
I plan to ride it tomorrow if my knee will let me. Maybe get some photos too.
Got my choke cable in today's mail but I am still going to put the seat on and ride it first.
« Last Edit: July 30, 2016, 05:54:54 PM by Walt_M. »
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Walt_M.

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Re: FZR carb conversion
« Reply #57 on: July 30, 2016, 07:44:55 PM »
Got some photos, didn't see the fuel line kink until I saw the photos.
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Rikugun

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Re: FZR carb conversion
« Reply #58 on: July 31, 2016, 09:44:08 AM »
Is that a remote idle speed cable in front of the filter? If so, I'd consider that to be another bonus to the carb swap - easier access to the idle speed adjustment screw.
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Walt_M.

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Re: FZR carb conversion
« Reply #59 on: July 31, 2016, 10:45:24 AM »
Good eye there. Yes that is the idle speed adjuster, just haven't figured where to put it.
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