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Daves Mods - Problem

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Hey gang, finally bucked up and did Daves Mods lastnight. Pretty easy and straight forward.

Anyway, here is what I did:

De-Snorkel

Daves Mods

Supertrapp Slip On Exhaust

Started right up and ran perfect, idled nice. When I whacked the throttle a few times it hesitated in low to mid range (sorta like it was getting too much fuel?) then it caught up and the RPMS went up.

I did have the side cover and seat off and there is a foot of snow in the drive so no test rides for the next few days.

Could I be getting too much air, then the fuel compensates and the bog goes away?

Also, Ive been reading, the air screw is out 2 1/2 twists, Could this cause it?

My needle shim is around .027 mm I believe and sits around the top lip of the needle, and is seated right in the slide.

suggestions? Ill try w/ the side cover and seat on and maybe thats all it needs.

Besides that, anyone else have this problem?

I also read it could be the shim. Will check that after putting on the seat and side cover.

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if it's a bog spot in the throttle range when you crack it open, I'd give the screw a quarter turn in - that was the final touch on my mods that brought it all together at the end when everything else was fine - also when I made final adjustments to the screw, I had the seat and side covers on since that's how I intended to ride it - I wanted the airflow to be comparable to how it would be while riding

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Well you didn't mention what jets you are using but you prob have that under control. Yea, I agree that your mix screw sounds like it is out too far. You might want to try it with only one turn out, maybe 1 1/2 turns. The farther out the screw is, the more gas it gets. 2 1/2 is the max recommended setting.

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if it's a bog spot in the throttle range when you crack it open, I'd give the screw a quarter turn in - that was the final touch on my mods that brought it all together at the end when everything else was fine - also when I made final adjustments to the screw, I had the seat and side covers on since that's how I intended to ride it - I wanted the airflow to be comparable to how it would be while riding

will do, thanks

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155 main and 52 pilot jet.

Once I track down the right airscrew setting this should fix the bogging I suppose? For those of you who have this dialed in .... do you have hesitation at all from idle to wide open throttle? Gunning it?

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155 main and 52 pilot jet.

Once I track down the right airscrew setting this should fix the bogging I suppose? For those of you who have this dialed in .... do you have hesitation at all from idle to wide open throttle? Gunning it?

I'm new to the Dave's Mods..Just did my xrl a couple weeks ago, However, when I had the low end bog I found my pilot jet was to small, I went to 55/155 @4K feet with stock exhaust but everything else was done, smog air box filter.

Mid range bogging can be the needle set to high which will be too rich and bog it or if the needle is too low it will starve it and bog it...

I would question the 52 pilot jet as being too lean..what thinks those of you that know of such matters?

Edited by High Desert

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155 main and 52 pilot jet.

Once I track down the right airscrew setting this should fix the bogging I suppose? For those of you who have this dialed in .... do you have hesitation at all from idle to wide open throttle? Gunning it?

You have to test it on the road, with the seat and air cover on. When you have the correct jets, and the fuel screw adjusted correctly, it will not bog or hesitate at any throttle, or when it is whacked open. With the airbox cover removed, and the seat off, it could be getting too much air causing a hesitation. Also, make sure you don't have a vacuum leak in your float bowl gasket, or anywhere else. I was getting coughing when my throttle was whacked open, and it was because that gasket was bad. Also, did you use a number 4 washer under the needle?

As far as jetting, you want to figure out the pilot first. Make sure you have a fan on the bike because it will be idling and tends to heat up if you don't. At high idle (adjust idle screw to ~1800 RPM), and starting with the fuel screw 3 turns out, you want to SLOWLY turn in the fuel screw until the bike starts to idle down or die, then slowly reverse it back out until it hits peak RPM, and no further. That's your pilot adjustment. Make note of exactly how many turns out that position is. If it will not die or idle down when turned in, the pilot is too rich (unlikely since you are using a 52) and you would have to go one leaner. If it takes much more than 2 1/2 turns out to get to peak idle, the pilot is too lean and you'd want to go up one.

As far as the main jet, you want to get out on the road at wide open throttle in fourth and fifth gear. If the bike is sputtering, hesitating, and won't clean out at full throttle, the main jet is too rich. If the bike runs hot and feels really slow and flat at full throttle, the main could be too lean. Hope this helps.

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good advice, thanks!

putting her back together tonght and taking a ride tomorrow when the roads are better. playing w/ the air screw, if thats not it Im going for the needle shim I have in there.

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155 main and 52 pilot jet.

Once I track down the right airscrew setting this should fix the bogging I suppose? For those of you who have this dialed in .... do you have hesitation at all from idle to wide open throttle? Gunning it?

as mentioned above, no hesitation whatsoever...she pulls hard from a standstill when cracking it open

should be able to bring the front end up on power alone

fwiw the washer I used to shim the needle was .029, so you're right there

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So, I got the bike together and rode around the block. Noticeable power. Problem is it hesitates off the line.

Dont know if Im gettign too much fuel or too little (like float bowl isnt filling??)

So, it will hesitate, then take off. I did move the air screw in 1 turn. So, the hesitation is caused by the air screw as mentioned before. Could the needle have anything to do w/ initial rpm hesitation?

what could cause this?

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I'm betting you need to go up on the pilot to 55...which is a bet on it's not getting enough fuel at the low end due to smaller jet size...

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I read something about the slosh guard and the pilot jet being flush with the bottom of the carb. anyone have this and not modify the slosh guard?

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I read something about the slosh guard and the pilot jet being flush with the bottom of the carb. anyone have this and not modify the slosh guard?

When I went to a long pilot, it ran funky until I trimmed the slosh baffle.

Dave

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In order to point yourself in the right direction as to wherein the problem lies, you should note the EXACT throttle position where it happens. Are you using the stock needle? If so, it's NOT going to be the problem. There is no such thing as arbitrarily turning in/out the fuel screw. It needs to be set at peak rpm like I mentioned previously. It sounds like you may have a vacuum leak. Also, a hesitation off idle doesn't necessarily mean too lean, it could be too rich as well.

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thanks, I will work on the idle screw (~1800 rpms w/o a tach) and do what you said. Hard w/ the exhaust pipe in there to get under the carb to turn this gas/air screw. getting some ice ready 👍

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You'll figure it out, just take your time and try to be patient. I went through the same thing as you. I bought my bike at sea level, and I'm at 5000 feet. I had no good starting point, and a number of problems including the wrong jets, a leaking float bowl gasket, and an after market needle which I got rid of. Read those links I posted, and they'll be helpful.

Edit: Apparently the links I posted were on another thread. At any rate, here are a few which helped me greatly. Please note that while the bike models are different, the same principles apply. Here they are:

http://www.4strokes.com/tech/4sjetting.asp

http://www.4strokes.com/tech/honda/carbadj.asp

http://www.atlanticmx.com/archives/00000135.shtml

Edited by MountainBear

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really appreciate it. man, I cant get my hand under there to adjust the screw. driving me nuts. the last link shows a hand in there. I have the stupid octopus on one side and hot exhaust on the other. I guess Ill stare at it for a while and try to figure out how to get this done.

I cant twist the carb because it wont be the same way as I drive it and Ill have air leaks.

geez, this sux

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Hey 97XR650L

I remember the exact same problem when I first did Dave's on my 2008.

I dont remember an exact fix, you know, turn the screw and whala, fixed.

Here is what I remember I did:

I pulled the seat off and set the snorkel back in place (it should just sit there) and wacked the throttle. Result: the bike did not respond as quick (less air all at once) but hesitation was about gone.

I remembered a post about the vacum slide getting over whelmed by the massive rush of air on some Cv carbs..

That said, no way was I going to run the thing with the the snorkel in ..

Now, if I remember correctly, I changed my pilot jet to a 52 (was trying 50/155) that helped.. I also fiddled with the mixture screw-

One thing to keep in mind, and this is a big one, if you were used to riding 2 strokes-- this pig will never rap up like that--

I think one of the biggest issues I had when I did mine (was a new bike and I was 2 stroke guy) was I was hitting the throttle way to fast for that CV carb and that big single.

If it is idling smooth, then I doubt you have a vacuum leak, they tend to show up worse at idle (cant set iddle, high iddle etc.)

If the bike hesitates when in gear, hard throttle roll on, then you need to track it down.

If sitting on the stand from idle, then wap full throttle, with that CV you will probably get a bit of hesitation from the vacuum slide.

I must have pulled my carb off 30 times while setting this bike up. Now I ride from 5000 ft Denver to 10,000 ft. Daily commute 70 miles round trip to work then up to tree line on 4x4 trails and have not touched the carb in a year..

Just keep messing with it, you will get it tuned in...

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I had to make myself a little tool to turn the fuel screw with the bike running. Here's what I did:

I took a picture hanger thingamajig (seriously- that weird shaped metal thing which has a nail through the center that you hammer into the wall and you hang a picture frame wire from), and cut off about three quarters of the straight flat piece with the little triangle on the end, discarding the rest. I wrapped STICKY duct tape in a ball around the triangular part, leaving the flat end exposed for use as a tiny flathead screwdriver. The gooey duct tape makes it so the tool does not fall out of my hand as I am using primarily my fingers to turn the screw. If I am careful, I can adjust the screw from the header side. It is probably best to go from the other side so as to not lose skin as I have on occasion. I hope this helps. If you are really frustrated, go to an auto parts store and buy one of those bendable screwdrivers that mechanics have. It might work well.

Oh, yeah, I wanna go riding with you guys out in Colorado. The Sierras are awesome, but I want to see some new country.

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