Rejetting Question

[Slater1601]

In the wiki matrix for rejetting....if it says 2 washers, does it mean 2 washers plus the e-clip, or is it counting the e-clip as a washer?

I just finished and things sorta seem to be better. I have stock exhaust and K&N drop in. The bike has an ever so slight hesitation when I crack the throttle, but then roars up the power band no problem. However, when I close the throttle the bike smoothly comes back down til about 4k and then slows up a bunch and takes a moment to come back down. What would I look for to fix this?

[coll0412]

Did you remove the cover on the idle mixture screws and adjust them 2.5 turns out.?

Did you remember not to loose the little o-ring under the vacuum port on the top cover?

Did you check the condition of the vacuum caps that attach to that port?

[Slater1601]

I went 3 turns out as per the matrix, but yes to the rest.

[Wrecent_Wryder]

Dunno... hesitation on cracking the throttle is usually too rich, and hanging at higher rpms at idle is usually too lean.

In any case, the washers in the matrix are in addition to the e-clip and any stock spacers... but I don't recall a section for the K&N drop-in filter.

If it's right, it should be MUCH better.

[Slater1601]

Maybe bring the mixture screws back in slightly?

[Gisser]

Hesitation is a side-effect of shimming the needle.  One washer should be aplenty with the K&N drop-in.   

[Wrecent_Wryder]

Hesitation is a side-effect of shimming the needle.  One washer should be aplenty with the K&N drop-in.  

And, of course, there's Gisser, chiming in yet again to contradict what everyone else has found to be the case. "Hesitation is a side-effect of shimming the needle".  Generalize much?

Have you actually DONE any of this stuff, or do you "just know" we're all wrong? Because we've gotten that latter message loud and clear, but I don't actually recall ever hearing about your mods and how they've progressed....

[Slater1601]

Actually he could be right. I got it out and road tested it yesterday, and at traffic lights and stop lights it would almost flame out when taking off from a stop. It feels much better, but maybe slightly on the soggy side. I still have the restrictor ring in the air filter, so I'm gonna try taking that out first. Then I'll try turning the mixture screws in a half. If all that doesnt help I'm gonna drop back to 1 washer and see. Thanks for the diagnosis' so far fellas.

[bosozoku]

In the wiki matrix for rejetting....if it says 2 washers, does it mean 2 washers plus the e-clip, or is it counting the e-clip as a washer?

I just finished and things sorta seem to be better. I have stock exhaust and K&N drop in. The bike has an ever so slight hesitation when I crack the throttle, but then roars up the power band no problem. However, when I close the throttle the bike smoothly comes back down til about 4k and then slows up a bunch and takes a moment to come back down. What would I look for to fix this?

Another thing to look at: did the previous owner (if any) attempt to Dynojet the bike?  If so, your slides may have restrictors threaded in them.  Drill out, see if it runs better and stops hanging up...

-b.

[Slater1601]

Nope, everything looked normal with the slides. 

[Wrecent_Wryder]

I'm not sure what your setup is at the moment, or what you changed. If it was bogging because it's too rich, then taking the shims off will help some. If too lean, it will make it worse... you really don't say what jets you're using.

As I said, I don't remember a section of the Wiki for a drop-in filter (maybe it's there), so if you re-jetted for a lunchbox, it will definitely be too rich... the shims will be just a small part of that. If that's the case, I'd take out the restrictor first, and go from there.

[Gisser]

And, of course, there's Gisser, chiming in yet again to contradict what everyone else has found to be the case. "Hesitation is a side-effect of shimming the needle".  Generalize much?

I'm flattered by the attention.    Yes, in general, hesitation is a common side-effect of shimming the stock needle.  That's the difference between DIY and...say, a Dynojet needle--which is designed to allow adjustment from groove 1 to groove 6 with little or no effect below 3000 RPM.  But, I think we're all on the same page now.

[Slater1601]

This is my current setup per cell A-3 of the rejetting matrix...


K&N Dropin

pilot 40
main 127.5
washers 2
turns 3

[Slater1601]

Turned the mixture screw back in a half turn, so now i'm at 2.5 turns out. Didn't really seem like it did anything. Still have the slight hesitation when taking off in 1st gear.

I understand what you're saying about dynojet being slightly more precise cause of the grooves. I even saw slight differences in the thicknesses of the 4 washers I used. As long as I'm in the general ballpark of where I should be, I don't mind.

[The Buddha]

Who said hesitation at take off from a stop  is needle ... its not.
The first and foremost take off jet is pilot. Followed by float level.
BTW ... taking off under 3K = asking waaaay too much off a entry level primitive carbed 500 twin. You're gonna need rpm.
Cool.
Srinath.

[Wrecent_Wryder]

Who said hesitation at take off from a stop  is needle ... its not.

Like I said, Gisser again.

Near as we can tell, he just makes this stuff up and presents it as fact.

[The Buddha]

Duuude ... 0-1/8th throttle is pilot jet. - Mikuni and experience backs it up. You wanna kill your take off. Run 42.5 pilots Just 1 size larger. Every thing else will be perfect ... I ran a GS with 42.5's all the way from 95 august to 99 april. How many times I stalled at lights and was nearly run over ... I cannot even count.
The next in line is float level, any time you open the throttle that comes into play. Again mikuni tuning guide. (or is it factory - whatever but its out there).
Needle doesn't even start being the main factor till you get over 1/2 throttle.
Again, jetting depends on throttle position, not on RPM. You can run 5K at take off, but in 1st gear with clutch partly out, you're still under 1/4 throttle. In 6th gear, yea 5K will be close to1/2 throttle.
In the US they used to measure emmissions at 3500 rpm under no load. That was why suzuki put 37.5's in it, when they put 40's in the whole rest of the world.
Read the jetting chart (no idea where it exactly is at this time ... but factory site will have it) and go by that.
Cool.
Srinath.

[Gisser]

Good points.  When poster initially said he cracks the throttle and roars up the power band I did assume he meant more than 1/8 throttle in neutral. 

Still, poster is running 40 pilots...just like you recommend...just like the rest of the planet.  Assuming non-bleed, why a problem now?  OK, there's float level, fine, but then I infer that this is a new glitch that came with the meddling.  Blame the 40's?  Transition to needle begins as throttle rolls on (take out the needles and see if you can get to 1/2 throttle ).  Subtracting a needle washer is certainly easier than dicking with the floats...but poster can decide his next move.   

[The Buddha]

Extra washer will not affect as much as float level. Take off is pilot followed by float level and I didn't mean his pilots are off, I actually sold him the jets not a week ago. My point was, that his next step is float level. And needle is required I agree but to illustrate its importance we dont remove it ... remember ... needle is an obstruction with a taper. DJ replaces the needle with a much thinner one and to compensate for that they give you much much smaller mains. That just proves ... there can be more than 1 correct needle main combo.
In any case if you were to remove the needle entirely, you will start and idle fine albeit a shade rich ... and run great over 3/4 throttle by fiddling with mains alone ... 1/4th to 3/4th throttle is all needle - this is just a theory, never tested it.
In any case, his next stop is float level, if the start and run gets better, but 1/4 throttle and up is bad, then take out 1 washer.
Just cos he's got 2 washers dont mean all his problems are due to that.
Cool.
Srinath.

[The Buddha]

<snip>
Subtracting a needle washer is certainly easier than dicking with the floats...but poster can decide his next move.   

More generalisation here
But theright answer is ... no ... not if he's replaced the float bowl screws with the allen head ones I sent him. Take off bowls as it sits on the bike with allen wrench, measure and adjust and re fit. Easy.
Cool.
Srinath.