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Did 1992 XR600R ever have Mikuni Flat Slide carb on them?

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I bought a '92 XR600R to mess around with while building an '87 XR600R, and i don't recognize the carb at all, it's got this big square block thing that the throttle cable attached to that came out of the top of it. I am guessing it's a Mikuni flat slide, just cause it's flat, and this huge block slides up and down.

it was leaking out the bowl vent tube, so I cleaned it out and reassembled. 

 

it looks stock, the airbox to carb and carb to head tubes line right up,  but I don't know if they are replacement parts or the mikuni just happens to fit. it's a weird looking carb though.

 

I am thinking of the FCR carb conversion,  but first I have to sort out the rear shock.I bounce for 30 seconds every time I hit a bump. 

I ordered a 93 XR600L shock off ebay that looks in good shape, hope that works....

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This is the carb,  I finally figured out how to get the float arm out,  I had to whack the pivot pin pretty hard to extract it but it finally popped out and I was able to clean out the needle seat. It doesn't appear to be leaking gas anymore. I also bent the little tab up a little to put more pressure on the needle so it'll seat a little harder.

 

 

still not sure if this is a flat slide or not, but it almost has to be. It looks stock in there, doesn't tweak the connection hoses or anything. 

 

20131015_200849.jpg20131015_200903.jpg20131015_200843.jpg20131015_200832.jpg20131015_201910.jpg

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No, they did not.  That looks like an aftermarket flatslide from XR's Only since it has the custom pressed on airbox adapter.  But no matter where it came from, it is a flatslide.  It is not, however, an FCR since it doesn't have an accelerator pump.

 

Just an FYI.  Any shock of that age should be rebuilt.  The other one is basically riding on the spring and has no dampening from the valving and hydraulic fluid.   Although the 93 shock may appear to work, it may also need a rebuild and a nitrogen recharge.   You can do it yourself with some basic tools, or send it off to be done for about a hundred to two hundred dollars depending on what is needed.

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it works but it's kinda odd.  At first it was leaking out the vent tube off the bowl. so I cleaned it up last night took it apart, cleaned the seats, blew out the passages etc.

 

now it's sticking slightly unless I goose the throttle. just a tiny bit right off idle, not a big deal but I also have no idea how to jet or tune it. I *think* it's running just a tad rich. it smells like gas when I drive it and run high throttle then go to no throttle and coast. 

 

I will pull the plug tomorrow and look at it.

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It's a two stroke carb so it may never work quite right on your bike. Two stroke carbs are about as simple as the tank on your toilet.

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It is an aftermarket TM flatslide from XR's Only, White Bros or Sudco. I've had several on 600s. They frequently have a dribble of fuel dumping out the overflow tubes. A new needle and seat fixes it but it always comes back sooner or later. PS Don't let the noise of the slide make you think you need to adjust your valves. High vacume from a 600 will cause the slide to knock against the carb body every intake stroke producing a rather loud clack clack at idle.

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It's a two stroke carb so it may never work quite right on your bike. Two stroke carbs are about as simple as the tank on your toilet.

2 or 4 stroke carbs are fundamentally the same. Slide cutaway is usually the only major variation. Jetting has to be different due to demands. The TM conversions work far better than the stock "4 stroke" carbs.
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its a great value or bang for buck mod...here was mine installed on my 88 xr600.

100_1077_zps9c289125.jpg

 

 

WHEN JETTED correctly it has much better throttle response and slightly better lower and midrange than the stock kehin pd8 carb...its a very simple carb to wrok on, has dual floats so it reacts better to angles and tipovers(can run a while on its side, unlike the stocker) so for racing and faster spririted riding it does great.

 

it bogs slightly less when whacking the throttle(not completely eliminated)

 

its also LIGHT, seems to be made of more plastic than aluminum...also there are certain parts that are hard to find...

 

fuel overflowing is common, if youcant eliminate it by changing the float valve you need to buy the whole jet assembly that needs to be pressed into the carb

 

most owners give up by that point and buy a pumper...

 

your topspeed will be the same as stock with this carb however feel, MPG increases by around 20%, throttle response and ease of starting after a flood is why this makes it better than stock.

 

THIS IS A HALFWAY POINT CARB, from stock to full blown fcr41mm...this is midrange performance.

 

just for reference, BALLARDS, the asutralian safari guys, and most endurance riders of the early 90s almost specifically used THIS carb for their race bikes. Xrsonly later started marketing them.

 

peace

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It is an aftermarket TM flatslide from XR's Only, White Bros or Sudco. I've had several on 600s. They frequently have a dribble of fuel dumping out the overflow tubes. A new needle and seat fixes it but it always comes back sooner or later. PS Don't let the noise of the slide make you think you need to adjust your valves. High vacume from a 600 will cause the slide to knock against the carb body every intake stroke producing a rather loud clack clack at idle.

 

 

Man! I'm glad you said that! I have adjusted the damn valves on this bike twice now and it was still clattering!  haha, second time the valves were ok, but still noisy as crap.  I couldn't figure out why. it's got to be that carb rattling.  it is pretty noise at idle.

 

ElsavadorXR6,

 

Thanks for posting that pic,  that perfectly describes the throttle response,  very slight bog/lag right off idle. I love the fact it gets better mileage. I am not a racer, this is a dirt trail rider and wife hauler around for rides bike. So fuel efficiency is great.

 

 

i may run it a while and see how it does.  I have fixed the fuel leak for now,  by bending the tab up and cleaning the seat.  so I'll expect it to come back eventually it sounds like.

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its a great value or bang for buck mod...here was mine installed on my 88 xr600.

100_1077_zps9c289125.jpg

That looks just like my L did before I changed out the carb for a Delortto pumper, 89 dual header, hi vol oil line and all. Edited by valvesrule
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the high volume oil line and all was unintended but actually helped a bit with keeping the cam and rockers helthier...the size of the inner diameter oil line was the same size as the outer diameter of the metal pipe stock...I noticed a very mild decrease in oil temps...

 

the reason I did it was because my original ´pipe got damaged by some headers in a fall and flattened out a bit. I actually sold the bike this way and all was good

 

goneballistic what jetting are you running btw? a little tweak here and there on the pilot does wonders to eliminate the slight bog...

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I put the oil line on just to reduce heat conductivity from the header. The stock steel line has no insulation value whatsoever. Didn't seem wise to preheat the oil going to the cam.

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No clue what jetting I'm running. I couldn't really tell based on the numbers on the main jet. I couldn't read anything on the pilot jet.

 

 

do I have to pull the whole carb to get them out again? Or can I pull them through the bowl?

 

here's the main jet...

20131015_201910.jpg

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I put the oil line on just to reduce heat conductivity from the header. The stock steel line has no insulation value whatsoever. Didn't seem wise to preheat the oil going to the cam.

YUP! that was the unintended benefit...a slight reduction in temps to the cam. I also used reflective tape on the frame downtube that was closest to the headers...that helped a bit too...

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goneballistic I see a 180 but I cant tell what brand that is...the mikunis have like a star m on it...

 

usually most places send a 230 main. I used a 210, 230, and once a 250.

 

pilot 10, 15, 17.5 or 20.

Edited by elsalvadorXR6

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thanks for covering this. I just picked up a xr600r frame with a 650l motor and one of these carbs in it. I was excited but it also made me wonder what tracking down parts was going to be like. I do need to get a new throttle and throttle cable. Anyone know what I need to look for?

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thanks for covering this. I just picked up a xr600r frame with a 650l motor and one of these carbs in it. I was excited but it also made me wonder what tracking down parts was going to be like. I do need to get a new throttle and throttle cable. Anyone know what I need to look for?

PM me, I might have something if your not in a rush. In my warehouse at a different location.

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