After rejetting...full throttle farts out at 5000 rmps! BOooooo o o

motokurt · October 30, 2008, 06:48:20 AM

Hey,

So, given the Cobra exhaust and the poor running (cut out at 3000), I put in larger pilots and main jets, backed the mix screw out 3 turns, I also pulled the needle up the distance of the pastic washers that are in the assembly (didn't have any spares so I just put those on the other side to bring it up) aaaand....

The lower end is now nice and strong up to 5000 rmps, once you hit that it just falls flat and farts. I tried really opening it up on the on ramp and it surged dangerously around 7000, also, 5th gear wide open on the throttle and I couldn't get it past 65 mph just puttered. Lame!

Is it running too rich, or still too lean?

Cobra f1r, stock air filter...

What up!?

Thanks,
-K

Mdow · October 30, 2008, 07:14:57 AM

did you turn the mixture screw 3 times out more? or did you screw it in and then back it out 3 turns?

motokurt · October 30, 2008, 07:16:55 AM

Hey,

I went all the way in, then back out three, then tried: all the way in, out 2, 2.5, 3, 4, 5...same issue? Was I supposed to be backed out a total of 6?

Thanks,
-K

The Buddha · October 30, 2008, 07:41:30 AM

Oh yea genius ... you lifted the needle by the thickness of the retaining collar ... OK be happy that it even runs ...
Why do you think that collar even sits on top of the needle

Yea, the spring sits on it ... else the needle is free to move about as you hit bumps etc etc etc ...
Lift the needle using a washer, 1 washer that is ~.25-.5 mm thick is plenty. I use #4 washers but your call. Pay me like $1 and I'll mail ya some if you cant buy em at lowes/HD/Ace/Hardware store.
Cool.
Buddha.

motokurt · October 30, 2008, 07:44:42 AM

Yeaah,

Well...at the time it seemed like a good idea, late, cold, dark...frustrated, desperate times.

So, is that right then, screw the mix all the way in, then back it out a total of 3?

Later,
-K

motokurt · October 30, 2008, 07:59:16 AM

Hey,

I didn't move the spring retaining washer down, just the smaller plastic guide...so it looks like this:

http://faq.f650.com/FAQs/Photos%5CCarbnJetPhotos%5CNeedleSequence.jpg

Pretty sure that's the order I put them back in as...which means it was in there wrong initially?!

OR am I way off...

Thanks,
-K

The Buddha · October 30, 2008, 09:14:56 AM

Ok what needle is that ... euro

Ok ... lowering clip 1 -2 slots is OK. 1 at a time ....
Cool.
Buddha.

Kurlon · October 30, 2008, 10:17:09 AM

On my GS, I ended up going down on the mains from what everyone was recommending after running into the same problem. Ended up with DJ 122 mains, stock needle with no shims, stock pilots at 2.5 out. That's stock exhaust though.

The Buddha · October 30, 2008, 10:45:50 AM

122 DJ mains ... could be anything ... it may be 350 in mikuni or 93.1 in keihein ... could be anything ...
Cool.
Buddha.

Kurlon · October 30, 2008, 11:43:57 AM

Quote from: The Buddha on October 30, 2008, 10:45:50 AM
122 DJ mains ... could be anything ... it may be 350 in mikuni or 93.1 in keihein ... could be anything ...
Cool.
Buddha.

I don't have my conversion table in front of me, but they're roughly like 118 Mikuni's if my memory is correct. Hence why I said I'm lean compared to the normal recommendations. : )

motokurt · October 31, 2008, 09:53:32 AM

Hey,

Running much better now. Tried to put more shims on the needle, but they were too big in diameter or such and the needle retaining assembly didn't seat well.

Right now the it goes on the needle from the tapered end to the top:

plastic collar, thin washer, thicker washer, clip, spring, retainer

Before it was:

thin washer (which was stuck in the bottom of the housing), plastic collar, thick washer, clip, spring, retainer

I am running at about 4 turns out and it has a little bogging WIDE open throttle at 5000k or so. Then at 7000 it seems you get a little extra umpphf in the power band...

If i could iron out that bog at 5000k, it would be smooth as silk. Sometimes it seems inconsitent, but that could be me...or fuel level in bowls?

Thoughts?

Thanks,
-K

pic earlier was from a KLR650, oops!

The Buddha · October 31, 2008, 09:58:52 AM

5K to 7K bogging ... OK needle ... take out the fattie washer ...
BTW you running 125 mains and 40 pilots right ?
Cobra F1-R (whichever is snout less) is rather restrictive ... it used to be advertised as a non rejet pipe.
Cool.
Buddha.

motokurt · October 31, 2008, 10:54:02 AM

Hey,

No I got bigger mains and pilot in there...can't remember off the top of my head though...142.5 and...nope, can't remember, mids the same. So, if I take the fatty out (which might be a stock part i just moved around) it would run leaner?

What do you think is happening exactly?

Is there a link to what the needle assembly looks like stock somewhere? Pic/Diagram? Not sure it came stock, PO may have tried some tweaking too?!

Thanks,
-K

The Buddha · October 31, 2008, 11:27:02 AM

Mids

you have a 04+ ...
OK get the stock mids back in, 60 is stock, get 132.5 mains in (+1 from stock) and you should have 20 pilots.
You're running cobra pipe and stock paper filter in the airbox right ... then yea +1 is all you need, and stock mids are OK.
I have most them parts, in a way I take some of the mistakes out of the picture when you do jetting. But always good to know what you're doing so ...
Cool.
Buddha.

motokurt · October 31, 2008, 11:34:29 AM

Hey,

Recap!!

2002 gs500

142.5 mains
60 mids
20 pilots

Cobra exhaust

Stock Airfilter

Is it running rich causing the bog, or lean?

Running outta riding weather, runs way better than when I got it, just needs some minor fine tuning, eh? You think I should make the mains smaller?

Thanks,
-K

The Buddha · October 31, 2008, 11:46:46 AM

OK 2002 - you need 130 mains, all else is OK. In fact. I'd leave the washers in and try it.
Bog when opening throttle is always rich ... most problems when opening throttle always are rich. Only exception is if you get a misfire as you open the throttle ... that is neal.
You're definetly 4-5 sizes rich.
Cool.
Buddha.

motokurt · October 31, 2008, 12:31:08 PM

Hey,

What's a misfire feel like when riding v. a bog to make sure I am describing the right thing?

Anyway I could dial the mix screws back a bit to lean it out some? I don't think I'll get around to pulling the carbs off til spring... . . . . .. . . . too many things to batton down before it snows!

Other suggestions?

Pop in a K/N or such nonsense? Poke holes in the filter?!

Thanks,
-K

The Buddha · October 31, 2008, 05:41:46 PM

Take off the float bowls and swap mains ... you put allen heads in the bowls didn't ya ...
Nothing else will cure 5-7K without killing some else ...
Misfire will not be mistaken for anything ... it will in fact make good power and take off well ... Lean = more power ...
Cool.
Buddha.

News:

After rejetting...full throttle farts out at 5000 rmps! BOooooo o o