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Oring mode on accelerator pump

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Is that true that on a rmz 250 k8 there no need to do the oring mode on the acc pump? I want to get rid off the esitation bog on my boke when I open the throttle when engine is under load like up hill or at low rpm. It does it not neccessaraly when at wot but also let say at 1/2 throttle and if I try to open more whem bogging it gets worse, It wants to shut off

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Yes it will help. Wrap the oring over the screwand the arm on the throttle cam . Open the pump cover on the bottom and file down the rivet on the diaphragm. About to half its original size. Now open up the bowl and pull the leak jet out. Its the smallest one under the pump. Look at the size. But id throw a 45 or 35 in there. They sell adjustable leak jets. Those are awesome.

Take out your air filter backfire screen.

Suerte

EZ

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Ive done this on every fcr carb i have. The rmz is an 04. I have a fi 10 also.

The purpose is to make the accelerator pump squirt happen sooner and longer. Sooner is what the o ring is doing. Longer is the diaphragm rivet and smaller leak jet. Doing this and a next size up pilot helps alot. And screw the backfire screen, you already got a little explosion and a gas tank under your nuts. Don't be scuurrrred

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screw the backfire screen, you already got a little explosion and a gas tank under your nuts. Don't be scuurrrred

haha awesome!!

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Hahaha! Tru i guess. The little things add up. And finding hidden power for free is not easy. I have never had a fire. Ive had plastic gas tank cracks and leaked onto headers. Pipes falling off shooting flames by my leg. Ive thrown my bikes down mountain sides unscathed. Cranks grenade. Im not gonna stay hung up on a very minimal chance of a fire. I have more a chance getting killed by a cow. The fcr accelerator pump mods are great for being free. Nothing will ever get rid of bog completely. Just the nature of the carbeurated beast.

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The back fire screen is already off.

Now about the rivet is this in the pics that your are talking about?

The reason I amasking about this if is needed on a rmz 250 k8 is beasause I did read some where on this forum that the rmz k8 is perfect as far as low jet and acc pump.

1398571967531.jpg

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Yes, im sure its perfect for someone. But its not perfect for you if you have bog issues.

Everyone has different fuel, air temp, humidity, air pressure, so on and so forth. So a "perfect" carb at sea level won't be the same at 6000'. Or seaside vs desert. Carbs are touchy and minor changes make big differences. Good or bad.

Yes that metal nipple in the center of the diaphragm. The side the rod contacts. File it down a bit.

Take out your spark plug and post a pic. If its white ish its probably lean. Sounds like you could use a bit more squirt on demand. If the plugs black and rich, you need to tune the pump circuit to squirt less. That's the leak jet. The oring mod attempts to activate the pump quicker/sooner to avoid that temporary lean condition at sudden throttle wacks.

Basically Carmelo, buy a new pump diaphragm, buy the very next bigger pilot jet to the one you have, abd buy the very next smaller leak jet than the one you have. Try the original set up. Then pit in bigger pilot, smaller leak. Put oring on and the filed diaphragm in. See the difference. A $20 experiment.

Smaller leak = longer squirt

Dont get caught up on what yiu read. The carbs easy to work with. And a little quality time with her will supply hours of snappy throttle response.

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I do not want to piss you off and do not get me wrong if I insist in one thing. For sure I am going to try to file the rivet down a bit and the leak jet but as far as the pilot jet my bike is ok because my problem is from 1/2 throthle to wot only if engine is under load or uphill but not all the time. Since now no matter what jettings I have tried I always had the same issue. But offcourse I have changed the main jet and needle.

P.s. I forgot to mention that I have jd jetting kit. 185 main, 42 pj and red needle or blu (not sure) to 3 clip pos.

I will post I pick of the spark plug in a bit I got to find it fist

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Carmelo, as things are right now, take off your airbox and leave the carb and tank on. Look into the card intake bell. See that little brass nipple? Twist the throttle (engine off) And watch the squirt. Now get to where you think half throttle is and hold it there. Now observe the squirt from half throttle on. You may be past the point where tuning that circuit will help. I could be wrong. Thats where the rivet filed down helps. Helps hold more fuel in the pump. Id also look into different needle clip positions. That sounds more to effect that throttle range.

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Notorious I am sorry but I just find out I had an oring on the ap. (I did think I took it out).

So the oring does not help me. I also re adjust the acc screw gap to 2.75mm . (Oem gap)

My question now is this: with out the oring I should have more squirt is that right?

Off course I will try what you told me.

P.s. I really appreciate your help and also for being so kind.

Grazie grazie grazie

Edited by carmelo1970

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The oring and closing the gap makes tge squirt happen sooner. Not neccessarily longer. Just earlier. The leak jet meters a cetain amount of fuel to "leak" back into the bowl. The smaller the leak jet, the less fuel goes back into the bowl and is forced out the jet in a longer squirt.

I do suggest you observe your squirt with the airbox off. It makes sense.

Your problem might not be in the throttle range where the ap effects it. Sounds like a needle and main. When's the last time you checked the actual float height? Could be a small factor

I wish i could help more. This is something i need to feel first hand

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Wow that is a very nice site that expalins it all.

But I was thinking since I have cecked it all like the squirt does not it the slide the oring was there and all after wards still had the issue I think is a metter of a float hight being less than what it should be. I say less because my bike never spill gas from the overflow unless I tilt it.

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