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daves bog mod

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Hey guys I've had my 650l for about a year let me give you a run down. Fmfq2. Header weld mod. Daves card mod running larger of the sugested main jet, uni filter snorkle removed. Other than that rest is cosmetic stuff. Is the wot bog from idle just the cv carbs or can I go with a manufactured kit to cure this annoying prob. Any help greatly appreciated. Anyone looking to ride around charlottle area let me know

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I'd start with a spark plug inspection. You're likely to find that it's a bit dark from unburnt fuel. If that's the case, go down a size on the main jet.

Bigger jets don't mean more power. Engines actually produce the most power when they're on the lean side. You want the mixture just rich enough to keep the spark plug a very light tan color, that'll make sure it's not running too lean.

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A certain amount of bog on a CV carb is normal,,,if you wack the throttle open it goes lean before it catches up,,,a pumper carb shoots fuel into the intake,,,,,,alleviating that issue..

B

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I ahve the same issue on a 91 600r. Its mainly annoying when trying to go up hill in a slow and tight area. Then hit the throttle only to kill the dnag thing where its really hard to kick start it again. Other than this one little issue, she runs prety darn well.

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Ok let me clarify a little plug is good and tan. Makes great power if you crack it from 1/8 or 1/4 to wot. Just bogs if you crack it wot from idle. Not have the jwahr is. Also have the emissions block off kit from baja designs on it. I was wondering if anyone has the same issues with the fmf kit or dynojet or factory pro. I would consider a pumper but theyare just too expensive. Bike is a 2000 with 6k on it only paid 1500 so I don't want to spend 500 on carb. Makes me want a fuel injected bike or sell it and get the 650r.

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Try bumping the idle up a bit, then open the needle jet 1/4 turn at a time until the bog goes away. If you get more than 3turns out on the needle go one size larger on the pilot jet And readjust.

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I'm wondering if drilling out the holes in the carburetor slide to make them bigger is partly responsible for this bogging condition.

I've done everything else listed on "Dave's mod" except drilling the slides, and I can whack the throttle open from idle without any bogging.

Opinions on this?

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I'm wondering if drilling out the holes in the carburetor slide to make them bigger is partly responsible for this bogging condition.

I've done everything else listed on "Dave's mod" except drilling the slides, and I can whack the throttle open from idle without any bogging.

Opinions on this?

Does your CV respond immediately to the twist of the grip? I found that with my OEM carb, I had a slight hesitation when I would whack the throttle. Just enough to dump the front end into an unexpected rut instead of lifting the front wheel over the rut:banghead:

With FCR-MX pumper...no hesitation. Whack the throttle and the front tire gets light... right now.:smirk:

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Does your CV respond immediately to the twist of the grip? I found that with my OEM carb, I had a slight hesitation when I would whack the throttle. Just enough to dump the front end into an unexpected rut instead of lifting the front wheel over the rut:banghead:

With FCR-MX pumper...no hesitation. Whack the throttle and the front tire gets light... right now.:smirk:

It doesn't instantly jump like bikes with flat slide pumper carburetors that I've ridden, but it doesn't slow at all either. My interpretation of "bog" is that the bike actually slows a little bit. That's different from taking an extra fraction of a second to respond.

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Well I guess I will try messing with it this weekend. Never really got an answer if anyonr has had luck with the aftermarket kits. Might try posting a vid if that helps bescribe it better. Its not bogging to the poit of cutting off just annoying when you crack it wot and it take a second to make power. Guess im impatient. I have a similar issue with my bandit 1200. Both bike have cv carbs maybe its just the carb characteristics

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Well I guess I will try messing with it this weekend. Never really got an answer if anyonr has had luck with the aftermarket kits. Might try posting a vid if that helps bescribe it better. Its not bogging to the poit of cutting off just annoying when you crack it wot and it take a second to make power. Guess im impatient. I have a similar issue with my bandit 1200. Both bike have cv carbs maybe its just the carb characteristics

It is characteristic of the CV carb. The throttle is not directly controlled by the cable. It will not open until there is adequate airflow through the carb as doing so would lead to a lean condition stumble. A pumper on the other hand opens on demand and compensates for the lack of fuel flow with the accelerator pump.

Ya need one of these here gizmos:

2011-12-03153216.jpg

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It is characteristic of the CV carb. The throttle is not directly controlled by the cable. It will not open until there is adequate airflow through the carb as doing so would lead to a lean condition stumble.
The throttle is the flat plate behind the slide that is directly controlled by the throttle cable. It's the slide that doesn't open until there is enough airflow, which allows it to keep the correct air/fuel mixture without a pump.

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The throttle is the flat plate behind the slide that is directly controlled by the throttle cable. It's the slide that doesn't open until there is enough airflow, which allows it to keep the correct air/fuel mixture without a pump.

hmmm... isn't that what I typed???

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hmmm... isn't that what I typed???
You said: "The throttle is not directly controlled by the cable."

I was just clarifying that actually the throttle is directly controlled by the cable. That's all.

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You said: "The throttle is not directly controlled by the cable."

I was just clarifying that actually the throttle is directly controlled by the cable. That's all.

Ahhhh... semantics. Got it. Thanks

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While we're on the subject, I rode my XR650L at lunchtime today and wanted to find out how it really behaves as opposed to how I "remember it".

When the engine is not running all that fast in second or third gear - I'm guessing 3000 rpms or so - if I'm cruising along at a steady speed and whack the throttle wide open, it misfires for about half a second (it feels and sounds like two compression strokes), then takes off. In other words, it sort of bogs first. If the engine is going faster - maybe 4000 rpms - it takes off smoothly.

I've realized that I don't tend to just whack open the throttle. I tend to normally take about a second to get it all the way open and the engine is always smooth when I do that.

I guess if you need instant throttle response at low RPMS to clear obstacles, you need to buy a flat slide pumper carburetor. Otherwise you may have to use the clutch to help you out a little bit.

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Ok let me clarify a little plug is good and tan. Makes great power if you crack it from 1/8 or 1/4 to wot. Just bogs if you crack it wot from idle. Not have the jwahr is. Also have the emissions block off kit from baja designs on it. I was wondering if anyone has the same issues with the fmf kit or dynojet or factory pro. I would consider a pumper but theyare just too expensive. Bike is a 2000 with 6k on it only paid 1500 so I don't want to spend 500 on carb. Makes me want a fuel injected bike or sell it and get the 650r.

What jets are you using? Is it bogging while you are riding it, or just sitting and idleing, then cracking the throttle? Mine didn't like the Dynojet 165 main jet, I used the 160, you also need a larger pilot jet that the dyno kit doesn't come with. All CV carbs have a slight lag. Not to many 4 stroke carbed bikes can handle the crack it wide open at idle test.

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I had to switch back to my CV carb temporarily at one point from my FCR carb and the riding felt like it went a little like this:

Me: throttle on!

CV carb:...uh, did you need something?

Me: uh, yeah, I was trying to briskly accelerate...

CV carb: oh...did you need me to do that today?

Me: well, yeah, if you wouldn't mind...

CV carb: Hmmmm...well...ok...here ya go...(braaaaap!)

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I had to switch back to my CV carb temporarily at one point from my FCR carb and the riding felt like it went a little like this:

Me: throttle on!

CV carb:...uh, did you need something?

Me: uh, yeah, I was trying to briskly accelerate...

CV carb: oh...did you need me to do that today?

Me: well, yeah, if you wouldn't mind...

CV carb: Hmmmm...well...ok...here ya go...(braaaaap!)

Thats pretty funny. Soon you'll be preforming at the Comedy Cellar. :smirk:

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