Dr650se: Fmf powercore 4

[FuzzBall87]

So I just got done installing the FMF powercore, and I let the bike warm up a bit, and started to hit the throttle a little bit and hear what how it sounded, and when I reved it up high enought it shot flames out of the muffler, my first thought was, "THATS FREAKIN AWESOME" but then changed to...I wonder if it's hurting anything.

Any thoughts on that?

[FuzzBall87]

I would assume its running too rich, but It's been years since I adjusted a carburetor, and i don't know which direction to turn the screw to get it to run leaner.

[FuzzBall87]

Uhm, and tell me where the screw is too, cause now that I'm looking at it I'm not sure where it is...

[thumpididump]

Probably going to take a bit more than just turning the fuel/air mixture screw to fix this. Have you taken it for a ride yet?

If your carb is stock, then you'll probably at least want to start by moving the clip on the needle by one notch to raise it a little. A DynoJet kit is usually the way to go when you install an aftermarket exhaust, and that usually goes hand-in-hand with removing the snorkel in the airbox and cutting a larger hole to allow more air to enter the intake system. While you're doing all of this, drilling another small hole in the slide will greatly improve throttle response.

FWIW, the screw you're looking for is located on the bottom, just in front of the bowl, but from the factory it's got a plug covering it. Most people punch out the plug and replace the screw inside with a longer one. If you're not familiar with any of this, then you should be doing some reading first. There's plenty of info on this forum about it.

Also, be sure to check the DR650 wiki:

http://dr650.wikia.com/wiki/Intake

[thumpididump]

and this is a great piece of info:

http://www.advrider.com/forums/showthread.php?p=7088424#post7088424

[FuzzBall87]

This would lead me to my next question, if I leave it like it is for a while before I do any other kinds of mods to it, will I be hurting anything? I mean i took it for a ride to day, it rode well it just backfired a lot when decelerating. On friday I have the powerbomb header coming in the mail which I plan on putting on, which, I'm guessing, wont help the problem.

the most I have ever done with a carburetor was pull one apart and clean it, with my dad, about 11 years ago, I was already thinking about the possibility of re-jetting it, but I wouldnt know where to start, since alot of terminology ends up going above my head. (I spent a few hours last night reading about carburetor adjustments and such)....

[NordieBoy]

Go get a DynoJet kit.

We'll wait....

You just won't have the adjustability/control without re-jetting.

[FuzzBall87]

so if I wait a month or two to save up for the jet kit, i'll be fine?

[thumpididump]

Have you checked one of the spark plugs to see how lean it's running?

[FuzzBall87]

Hmm...no, I'll do that and get back on here... give me like 10 minutes

[FuzzBall87]

well, my spark plug is black... so i'm guessing rich

[thumpididump]

oily black or sooty/powdery black?

While running rich is not ideal, it's safer than running too lean. Are you sure your carb is stock? I'm guessing it's not. Normally, DR's are jetted quite lean from the factory so the black plug is unusual if your carb is completely stock. You should think about opening up a nice hole in the top of the airbox to let the engine breathe in enough air (now that it can breathe out enough air through the new exhaust)... But you'll also want to know what jet sizes you have in there, as well as the needle height.

[FuzzBall87]

Yeah, i'm sure its stock, I bought it with 1 mile on it, out of the dealership, I am first owner.

And to answer you're other question, black sooty

[thumpididump]

hmm. sounds odd to me for a stock setup... but sooty black plugs definitely indicate a rich mixture. So give it more air through the airbox. You could start slowly by simply removing the goose neck snorkel at the top of the airbox - that will allow a little bit more air to flow into the carb.

[FuzzBall87]

Thanks, I was in the air box messing with some things, but i don't see how that snorkle comes off, you said slowly remove it...does that mean I can partially remove it to give it more air?

I hate sounding like such a n00b, but I haven't really done any bike modifications before and don't know alot of this stuff. but tonights getting late and I gotta stop doing this stuff before the neighbors start complaining, cause that muffler is pretty loud.

and I've heard you mention moving the clip on the needle, do you know of a direct link I can go to to read up on how to do that if for some reason I actually do need to do that?

[FuzzBall87]

BTW, I messed with it a bit, and figured out how the snorkle came off, and now I see what you mean (that it doesnt partially come off or w/e, i just misunderstood you) Anyway, I guess I'll find out tomorrow if it changes anything, cause I'm definitely calling it a night. Gunna find something to do that doesnt annoy the piss out of my neighbors.

[thumpididump]

Didn't mean to remove it slowly, rather I meant giving the intake system more air slowly (like, in stages... first remove the snorkel, see how it works, then cut a hole in the top, and see how it works).

As for adjusting the needle height, see my earlier post (post #5) and read the info on that link.

[FuzzBall87]

it seems to be running a little better with the air snorkel removed. Rode it about 30 miles today to get a real feel for how its running. when I get on the throttle it seems to run perfect, great throttle response and everything. but once I let off the throttle it backfires and pops and just plain sounds like shit.

On my ride I stopped at the dealership and asked them a few questions, all of their responses were that it should be running leaner with the new muffler on there, not richer. ...Do you think that when I put the powerbomb header on it, it might, force it to run leaner? (cause i'm starting to think I should stop messing with it, until I get the header on there, so that any modifications I make wont have to be reverted two days later.)

[mxrob]

it seems to be running a little better with the air snorkel removed. Rode it about 30 miles today to get a real feel for how its running. when I get on the throttle it seems to run perfect, great throttle response and everything. but once I let off the throttle it backfires and pops and just plain sounds like shit.

On my ride I stopped at the dealership and asked them a few questions, all of their responses were that it should be running leaner with the new muffler on there, not richer. ...Do you think that when I put the powerbomb header on it, it might, force it to run leaner? (cause i'm starting to think I should stop messing with it, until I get the header on there, so that any modifications I make wont have to be reverted two days later.)

Decel popping is going to happen... especially with a powercore muffler. Even the Q2 (Q4) decel pop (or any other performance exhaust system for that matter). It's a normal lean condition that happens under high vacuum on pretty much any fourstroke engine. Not a problem for the machine. The only way to mask it a bit is to over richen your pilot circuit.... but this can lead to actual problems if you take it too far. ?

[FuzzBall87]

You say its running lean, but if it was lean, my plugs wouldnt be sooty and black, and still why would it shoot flames out of the muffler at times?