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FZR carb conversion

Started by Walt_M., May 18, 2016, 06:09:43 AM

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fret not

Digging around the spec sheets I found the YZFR1 up to 2001 used 40mm Mikuni downdraft carbs.  2002 and later used fuel injection.  That is 4 of them for 1000cc engine, or one 40mm carb per 250cc cylinder.  That sounds like a LOT of carburetor, maybe even enough for one 40mm carb to feed both cylinders of a XZ550.  My thinking here is that it is easier to adjust one carb than it is to adjust two. ;)

Walt, I'm hoping very much that your carb mod is a raging success.  I think you're on to a good idea.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Rikugun

Tuning one carb would be simpler but there may be a performance handicap even with the 40mm. There is also (potentially) a clearance issues to consider. I'd think making a 2 into one manifold would add some height that takes away from available space for air filtration in the finite space under the tank.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

Walt_M.

My original goal was something anyone with a few tools and patience could duplicate. I am not a welder or a machinist but it would help. Also, I am not so patient as I need to be. I put the carburetors back on it yesterday, using the K&L manifolds I have had for ten years, still uncracked, and expected it to run. It wouldn't even pop! I was gutted. But when I pulled the carburetors back off, I saw I had failed to put the clamps on! Tomorrow is another day.
Whale oil beef hooked!

QBS

Maybe a shot of Starter Fluid would get it running.

Walt_M.

Massive vacuum leak due to operator head in ass.
Whale oil beef hooked!

Walt_M.

Decided to get a battery yesterday.  I have been jumping it off the lawn tractor and just got tired of it. Went to wally world thinking I could just get a cheapie like I had done in the past.  Well it is not like it used to be. They didn't have one and the shelf where they were was marked $74.88! Wtf, over. I checked at Advance Auto parts and they had one for $50. I thought about getting a Lifepo like I did for the RZ but not now I guess.
Whale oil beef hooked!

ChrisV

Quote from: Walt_M. on July 10, 2016, 12:12:12 PM
Decided to get a battery yesterday.  I have been jumping it off the lawn tractor and just got tired of it. Went to wally world thinking I could just get a cheapie like I had done in the past.  Well it is not like it used to be. They didn't have one and the shelf where they were was marked $74.88! Wtf, over. I checked at Advance Auto parts and they had one for $50. I thought about getting a Lifepo like I did for the RZ but not now I guess.

So far I have had a good experience with the LiPo I got off of amazon.  Battery tender brand. This is on my TW200.  So small and light that my battery box now has room for a small tire pump.
Chris Vogel
Current rides: 1987 TW200, 2004 TW200, 1992 R100GS, 2014 ZUMA 50.
Current Projects: 1982 XZ550, 1986 XL600R, 1980 CB750SS

Rikugun

#27
Quotemy battery box now has room for a small tire pump.
Given the volume of those TW200 tires, probably a good idea!
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

Walt_M.

IT RUNS! Got most of the air leaks taken care of and it started right up. Only had about a cup of gas in my pony tank so I didn't do any pilot screw settings or anything else but I am quite pleased. It would idle right down to maybe 500 rpm and revved to 4000. There is much yet to do but if anyone is having carb problems, this can be a solution.
Whale oil beef hooked!

fret not

That is great news Walt!  Thank you for the inspiration you have created with this project.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Rikugun

Very cool indeed. I'm looking forward to hearing more running test results and especially fueling manners whilst under way.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

Walt_M.

Had to take today off but I should do a recap. My original carburetors were ruined by ethanol and redkote. The bike sat for several years. I saw the FZR carbs on another site and got a set with one broken diaphragm dome for cheap on fleabay. First look said they wouldn't fit so I let them sit in the box for a year and went back to my RZ. Had my knee problem with looming surgery and forced down time. Got some work finished on the RZ before the surgery that I would not be able to do after. Decided I could do fiddly carburetors work even if I couldn't walk. Got the Vision carburetors off and opened them up to assess and they may not be worth trying to clean, the needle valve and seat are a one piece lump. Okay what about the FZR carbs? They are unified interconnected bank, throttles, chokes fuel feeds and bowl vents. The carburetor bore spacing is far too narrow to directly bolt directly to the Vision so I have to separate them. Checked the carb fit to the intake, not close. Also there is not enough space in the vee to fit the carburetors that low. Decided I am going to continue so I ordered viton rubber rebuild kits from Thailand for the FZR carbs. Bought a variety of 'O'rings to use for my adapters. In my search for suitable pipe to make the adapters, I was looking for inch and a half aluminum conduit but found splice joints for inch and a quarter steel conduit that seemed to fit my dimensions. Got the carb rebuild kits and started rebuilding the carburetors. I only need two but which two? I wanted to use the two outboard carbs due to the extra fuel inlet on the middle pair. But the third carb has the throttle cable bellcrank and idle adjuster. So I am using the left carb as the front and third as the rear. Had to remove the throttle interconnect arm from the front carb and drilled the center of the throttle shaft so I could extend the shaft to mate with the bellcrank of the rear carb. Used the interconnect arm from the second carb for this, very careful alignment is required here for proper throttle plate positioning. For the chokes I used the linkage from the Vision carbs. I made locating tabs from aluminum. I have rethought this and need to make another tab for the front carb to mount the cable. Of course I will need a longer choke cable since the chokes are now on the lower right side. But I will cover that when I get it. More later, maybe try to get photos.
Whale oil beef hooked!

ChrisV

Congratulations on making this work.  big +1
With this ghost exercised you may have the best running Vision on the road.  Maybe Yamaha will be so impressed they will dust off the tooling and give this motor the frame and running gear it deserves.  OK that is a bit overboard.

If I am looking at the correct carb, could you go old school and just put a knob on the end of that en-richer (choke) plunger?  Lose the whole cable mess.
Chris Vogel
Current rides: 1987 TW200, 2004 TW200, 1992 R100GS, 2014 ZUMA 50.
Current Projects: 1982 XZ550, 1986 XL600R, 1980 CB750SS

Walt_M.

That isn't the same carb. My chokes are down and to the left. When I start it I stand on the right side, operate the choke with my left hand and push the starter with my right. Not exactly convenient. I pulled the cable out yesterday to measure it and looked some more. Did a rude and crude routing, secured it with a tyrap and got it useable. Started it and could hear a vacuum leak but it still runs. Just need to mention this, I am not working on this full time but I am so happy not to be dealing with the wretched standard carbs. I am going to make this work.
Whale oil beef hooked!

Walt_M.

Well, I spent a nice long session with the Vision yesterday. I got tired of the problems I was having with my pony gas tank leaking so I decided to just use my NOS '82 tank and the electric fuel pump. I got it started okay and ran it long enough to kick the cooling fan on. The pilots are far enough out that the screws have no effect but it will idle and rev. I had to adjust the throttles again as I haven't loctited the shaft extension yet. I have decided that the stock FZR jets are too lean so I am starting around Vision setup. I ordered 130, 132,5 and 135 mains. There is another jet in there in addition to the main, 62.5 so I am bumping those to 75. The pilots are 32.5 which I am upping to 40. I could not find the correct length emulsion tube or a richer needle so I am not changing anything there yet. It is running up the tab though, $54 to JetsRUs. 
Whale oil beef hooked!

jefferson

Going by the Kevin Cameron article you should have to go leaner to get them jetted right. Each carb was serving a 150cc cyl and now they are on a 275cc cyl which sends a stronger signal and draws more fuel. Maybe it isn't an absolute though.

ChrisV

#36
This is a tricky question.  You may be drawing a greater volume of air, which on the same engine would create a greater vacuum and stronger venturi effect, so you would need a smaller jet.  But, the vision may be actually creating a weaker draw on the carburetor due to slower engine speeds.  This is starting to look like a kind of mathy question.
Chris Vogel
Current rides: 1987 TW200, 2004 TW200, 1992 R100GS, 2014 ZUMA 50.
Current Projects: 1982 XZ550, 1986 XL600R, 1980 CB750SS

Walt_M.

Thanks for the input but my thinking is from my observations. While running it does not smell rich and no black smoke. The carbs are much less restrictive than the stockers so the vacuum is probably less. It is a little slow to rev from idle. I have a base to work from so I will know more when I get my jets.
Whale oil beef hooked!

ChrisV

Again very cool project.  All kinds of impressed.
Is this going to mate up with the stock air filter or are you going to do something else?
Chris Vogel
Current rides: 1987 TW200, 2004 TW200, 1992 R100GS, 2014 ZUMA 50.
Current Projects: 1982 XZ550, 1986 XL600R, 1980 CB750SS

Walt_M.

I was planning to use the stock air box but without the flapper.  I have a Unifilter for it but I might use pods. I have the stock box and Uni on it right now,  kind of hoping the restriction might richen it up a little. I wasn't able to get anything done yesterday, emergency room day with my 92 year old father-in-law. Nothing serious, he is just old and whiney. I did find some different fittings that I might use for carb to manifold adapters. I am just now happy with the JB weld plugs I had to use for now.
By the way,  input is welcome. Right now I have a set of FZR intakes that I wanted to try but the bolt holes do not line up and the angle in different. I could maybe make adapters for the bolt holes and change the angle but it would be pretty tall and might have problems getting filters on. But I may cut the carb mounts off and clamp them to my adapters. I might get some photos but sometimes that just gets in my way.
Whale oil beef hooked!