Help with Dave's mods...please


16 replies to this topic
  • pianoexcellence

Posted March 21, 2007 - 08:47 PM

#1

I just did Dave's mods on my 2004 xr 650l

I did the new jets (55\158) de-snorkeled it, and pulled the Baffle from the back
While in the carb, I also drilled the slider to 5\32.

When I put it all back together, I was noticing some popping when decellerating (using the engine as a brake) I think this is called afterburn...though I am not sure cause I'm pretty new at this. and I only rode for 10 minutes.

I did miss one step in the mods (the one with the washer for the pin) How crucial is that washer step. is the popping just really noisy because I took the baffle out?

Any replies would be greatly appreciated.:applause:

  • Denn10

Posted March 21, 2007 - 09:02 PM

#2

when you say decelerating do you mean let the throttle off completely or as you bring the throttle back its popping? If it pops when you let off completely the washer on the needle wont be it, that raises the needle so that it lets a little more fuel thru your main jet just a bit sooner than if it wasnt on there you kinda understand what im saying?

  • adam574

Posted March 21, 2007 - 10:38 PM

#3

popping on decel is a lean condition.. i am just the opposite of the other guy and thinking that washer you are missing would probably richen the bike up perfectly. or you could try the fuel screw and see if that does the trick but you already know you missed a step so just do the job right.

  • pianoexcellence

Posted March 22, 2007 - 05:08 AM

#4

Thanks guys.

The popping begins right as I let off of the gas, and stops when I reapply the throttle. I was definitely impressed with the low end power that these mods gave me...everytime I do something to my car I try to convince myself that it is actually faster...with the bike, it was absolutely obvious:applause:

thanks for explaining what the washer does. You're right, I need to get in there again, and put it in.

Where do I get the washer from? (home depot?)
Do I have to remove the carb again, or can I just tilt the carb in place and throw the washer in?

Great forum:thumbsup:

  • rebelventurer

Posted March 22, 2007 - 05:14 AM

#5

Your both wrong its the infernal smog pump, get the smog pump block off kit from IMS remove the smog crap and the popping and spitting will also be gone. No amount of richening will fix it till the smog stuff is gone! Yep, its afterburn all right, the smog pump injects fresh air into the exhaust ports to clean up the exhaust emissions.

  • pianoexcellence

Posted March 22, 2007 - 05:45 AM

#6

i bought the Baja designs block off kit but its backordered so I'll have to wait a week.

is the baja designs one as good?

Just so I'm straight...the smog pump is the wierd hoses hanging off the rider's left side of the bike (Just waiting to catch on a stick...)

  • Denn10

Posted March 22, 2007 - 05:46 AM

#7

Your both wrong its the infernal smog pump, get the smog pump block off kit from IMS remove the smog crap and the popping and spitting will also be gone. No amount of richening will fix it till the smog stuff is gone! Yep, its afterburn all right, the smog pump injects fresh air into the exhaust ports to clean up the exhaust emissions.


HAHAHAH who are you and who made you a "GOD" saying everyone is wrong!!! Put your suggestion in like everyone else and let it be at that!!!! AZZ!!! Maybe i didnt write what i wanted to say clearly enough but i know what im talking about, and probably couldnt understand exactly what was going on with his bike by the way he explained it. So dont come on and start with telling everyone there wrong like an idiot punk have some damn respect!!

  • XR650L_Dave

Posted March 22, 2007 - 07:50 AM

#8

Indeed, regardless of the washer the main circuit should have no effect with the throttle closed.

That could be subject to the slide actually closing fully when the throttle is chopped- I believe it does, but I have not confirmed this by riding around with the intake off and my head below the seat.

I'm sure the popping is louder because you took the baffle out, and it could be a skosh lean because of that as well.

How many turns out is the low-speed mixture screw?
If that's in too far (too lean), that'll add to the popping.

Even if jetted perfect, it will pop with the smog pump.


Dave

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  • goblin127

Posted March 22, 2007 - 08:14 AM

#9

The washers you need can be had from any hobie shop. .025 and up to .030. I was going to ask about the air fuel screw also. Seems to me back when I did my smog block off kit I realy didn't see much afect from it,but I'm still glad it's gone.

  • pianoexcellence

Posted March 22, 2007 - 01:43 PM

#10

My Air screw is turned out about 2 and a quarter full turns (from lightly closed).

Here's a question. i just went out for a quick ride this morning. It seems like the low end response is drastically improved, but it dies away in the upper engine speeds. I remember it doing this before, but it seems like it is more drastic now.

Does it just seem more drastic because of the improved lower end power?

When i get the unifilter and smog block off kit will the upper end power improve?

Or is this just something i need to accept with a 650l?

The replies have been helpful, thanks so much

  • goblin127

Posted March 22, 2007 - 02:50 PM

#11

you need to shim your needle that will give you more on your main jet and will give you more throttle above your pilot. It will flow more. As for the smog block off; Well lets just say it will be gone.

  • Adamsvh67

Posted March 22, 2007 - 03:50 PM

#12

Listen to Dave. From reading on here, he knows the L's like no other. My '07 is stock except for snork removal and smog removed. Popping on decel went away. Spring now, so starting to look for pipe, jetting, etc...

  • XR650L_Dave

Posted March 23, 2007 - 08:34 AM

#13

My Air screw is turned out about 2 and a quarter full turns (from lightly closed).

Here's a question. i just went out for a quick ride this morning. It seems like the low end response is drastically improved, but it dies away in the upper engine speeds. I remember it doing this before, but it seems like it is more drastic now.

Does it just seem more drastic because of the improved lower end power?

When i get the unifilter and smog block off kit will the upper end power improve?

Or is this just something i need to accept with a 650l?

The replies have been helpful, thanks so much



Get the whole slew of 'dave mods' done ( drill, shim, de-snorkle, toss stock air-filter, 55/158), and you'll have a little more top end.

You will feel the exhaust limitation on the top end, but there's always a price to be paid for stealth.

Dave

  • crbowen1

Posted January 18, 2010 - 03:28 PM

#14

I did Daves mods and I'm noticing zero popping.

55 pilot
158 main
.022 washer under needle.
Smog pump still installed.
K/N filter
Snorkel removed
Pilot screw 2.5 turns out
Two holes drilled out to 5/32 in the slide

Popping is usually caused by a lean condition. Make sure you have the clamp on the fromnt of the carb clamp peoperly . If it is leaking air...it will lean out your mixture and cause the popping.

Hope this helps.

  • brianhare

Posted January 18, 2010 - 05:03 PM

#15

I did Daves mods and I'm noticing zero popping.

55 pilot
158 main
.022 washer under needle.
Smog pump still installed.
K/N filter
Snorkel removed
Pilot screw 2.5 turns out
Two holes drilled out to 5/32 in the slide

Popping is usually caused by a lean condition. Make sure you have the clamp on the fromnt of the carb clamp peoperly . If it is leaking air...it will lean out your mixture and cause the popping.

Hope this helps.



Wow,,,,,,3 year old thread....think it`ll help now:lol:

Sorry,,,just funin....Welcome to TT..

Brian

  • 4runnerman88

Posted January 19, 2010 - 07:15 PM

#16

HAHAHAH who are you and who made you a "GOD" saying everyone is wrong!!! Put your suggestion in like everyone else and let it be at that!!!! AZZ!!! Maybe i didnt write what i wanted to say clearly enough but i know what im talking about, and probably couldnt understand exactly what was going on with his bike by the way he explained it. So dont come on and start with telling everyone there wrong like an idiot punk have some damn respect!!


I agree with you! my bike does the same popping noise, and since I have never had the smog pump on my bike, and have completed Dave's mod's, I just thought that was a by-product of there being more fuel pushed into the cyl. So before the next person accuses anyone of being "WRONG" check your facts.

  • GINORMOUS

Posted January 19, 2010 - 08:05 PM

#17

i did daves mod, did it correctly as well. have the smog crap off, uni filter, baffle removed big gun exhaust, 55/160 2.5 turns out on mixture drilled slide, .025 shim etc etc... and i get popping on decel when i get the engine revved high then let off gas. everything is tight. i am at 5200 ft in denver. i might go richer or adjust the mix screw out .5 turns first.





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