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Motorcycles » rec.motorcycles.dirt » Fouling Plugs on a '91 YZ250
| Re: Fouling Plugs on a '91 YZ250 [message #785549 ] |
Thu, 20 July 2006 15:40 |
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I'm sure broken reeds will cause a high idle, will broken or worn reeds
cause a rich condition?
-Mike
Tiago Rocha wrote:
> Mike Beaty wrote:
> > I haven't. What is the the best way to go about doing that? In a car,
> > I know you can spray carb cleaner around the intake to see if the
> > engine surges. Anything similar on a dbike?
>
> It is the same way on bikes, but I use WD40 instead of carb cleaner.
>
> Re: reeds, you check them by removing cage and looking against light,
> if they are not fully seated you will see light through the cage, reeds
> are worn out. With the time, they flip up so many times they get "used"
> to be a little lifted, not sealing properly...
>
> -- Tiago
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| Re: Fouling Plugs on a '91 YZ250 [message #785584 ] |
Thu, 20 July 2006 18:43 |
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"Eat Dirt" <no_email [at] no_email.no> wrote in message
news:no_email-D60790.01073920072006 [at] isis.cybersurf.net...
> American arrogance at its typical.. always making ASSumptions..
> FYI (god, why do I even bother??)
Please do NOT bother.
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| Re: Fouling Plugs on a '91 YZ250 [message #785599 ] |
Thu, 20 July 2006 22:15 |
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Is the idle screw the same thing as the throttle screw? I don't see an
idle screw listed on Fiche.
-Mike
Murray wrote:
> On 20 Jul 2006 05:27:03 -0700, "Mike Beaty" <beatymj [at] gmail.com> wrote:
>
> >Another test & tune session last night, and I still can't get a plug
> >that isn't black. I did first try to figure out the idle. The only
> >way I could get the idle to actually calm down was to turn the air
> >screw in all the way, and then back out about a half turn. I checked
> >the throttle cable, slide and other areas for leaks and found nothing
> >out of the ordinary. The slide was fully seated in the bottom of the
> >carb as it should be. I did not check the reeds. I don't even know
> >what I'm looking for on the reeds...just anything that looks broken I
> >guess. Would a broken reed cause high idle? I put in the two step
> >leaner pilot, still too rich...black plug. I then put in a two step
> >leaner main. That's all I had to mess with, so that's what I did. The
> >only positive out of this test was that I did actually lean things out
> >at full throttle. My buddy and I could both feel it. I think the main
> >needs to go back to where it was & I need to stop messing with it:)
> >
> >So the air screw really isn't the way to adjust the idle, but it's the
> >only thing that worked. I know this made the bike richer, and probably
> >messed up my test. Am I way off on the idle adjustment? It seems like
> >ever since I started messing with the pilot, the idle has been high.
> >Even when I put the stock pilot back in, it was still high. Makes me
> >wonder if there is something else going on. Where is a good place to
> >have the air screw? Or is the air screw/pilot jet combo that you're
> >looking for?
>
> You need to adjust the air screw to make it idle as fast as possible.
> Then turn the idle down with the idle screw. The idle screw adjusts
> where the slide stops. If you can't adjust the idle down to where it
> dies your not adjusting the right screw, also if your setting the idle
> with the air screw your not ever going to get it to run right.
>
> First set the idle high with the idle screw, then adjust your air
> screw to where the idle is running as high as it will go. Then back
> off the idle screw to where you want it to idle. Note- if the air
> screw is out more than 3 turns you need to go leaner on the pilot jet,
> if your within 1/2 turn of all the way in, you need a richer pilot.
>
> If you still have problems with erratic idle, check for air leaks.
>
> Murray
> >
> >HardWorkingDog wrote:
> >> In article <1153314717.236749.324630 [at] m73g2000cwd.googlegroups.com>,
> >> "Mike Beaty" <beatymj [at] gmail.com> wrote:
> >>
> >> > I made my way to the parts store and got a variety of jets for my carb.
> >> > Last night I did a little test & tune. When I put in the smaller
> >> > pilot, it was still a little rich, and the idle was way too high.
> >>
> >> Good start. Now, go one step smaller on the pilot again, and test. But first,
> >> figure out why the idle is too high.
> >>
> >> > I threw a one step smaller main, and back to the stock pilot. Still rich
> >> > & high idle. I put in yet another step smaller main, still high idle,
> >> > clean on the top end.
> >>
> >> I'd hold off trying to change too many things at once. Your first step was
> >> right. Now, you're muddying things up.
> >>
> >> > So, I think I have the top end figured out, it's
> >> > just the bottom end that is rich & idling funny. I adjusted the
> >> > throttle screw to 1 turn out, and it still idles like crazy.
> >>
> >> Not sure what you mean here.
> >>
> >> > The air
> >> > screw was turned way out too, probably 4 turns. Shouldn't putting a
> >> > smaller pilot jet in make it idle slower? I just wanted to double
> >> > check that going from a #45 to a #40 pilot will lean out the bike. Is
> >> > that correct? Could I have messed something up in the carb while
> >> > taking it apart & putting it back together?
> >> >
> >>
> >> Yep, the 40 pilot is leaner. The air screw adjustment shouldn't really affect
> >> idle *speed*, but more the quality of the idle. The idle speed adjustment is
> >> another device. On my Keihin, it's a black knurled disc near the top of the carb.
> >>
> >>
> >> The idle being too high makes me worried. Could there be an air leak in the boot
> >> between carb and reeds? Did you get the carb slide in backwards? (Don't be
> >> insulted, it happens.) Throttle cable misrouted?
> >>
> >> --
> >> Charles
> >> '99 YZ250
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| Re: Fouling Plugs on a '91 YZ250 [message #785604 ] |
Fri, 21 July 2006 00:12 |
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On 20 Jul 2006 06:40:11 -0700, "Mike Beaty" <beatymj [at] gmail.com>
blathered:
>I'm sure broken reeds will cause a high idle, will broken or worn reeds
>cause a rich condition?
Broken reeds won't cause a high idle.
MX Tuner
'03 Honda CRF480R
'06 Suzuki Hayabusa 1300
'06 Nissan Titan LE
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| Re: Fouling Plugs on a '91 YZ250 [message #785605 ] |
Fri, 21 July 2006 00:16 |
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On Thu, 20 Jul 2006 01:07:39 -0600, Eat Dirt <no_email [at] no_email.no>
blathered:
>American arrogance at its typical.. always making ASSumptions..
>FYI (god, why do I even bother??) I had "the other one" as the stock -
>just couldn't remember the name, ergo 'the other one'. Not hard to
>figure out for most people, it surprises it escaped you, the self
>proclaimed know-it-all of the two wheels world.
Self proclaimed? When did I *ever* claim to know anything about
dirtbikes?
>Which makes me wonder: for someone that is acclaimed to know so much
>about dirt bikes, why have you not offered to share your wisdom with the
>original poster? More of that arrogance at work?
Arrogance? Hardly. Seems he has some help and is heading in the right
direction. Why should I get involved rather than to correct the
Canadian misinformation?
MX Tuner
'03 Honda CRF480R
'06 Suzuki Hayabusa 1300
'06 Nissan Titan LE
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| Re: Fouling Plugs on a '91 YZ250 [message #785624 ] |
Fri, 21 July 2006 03:40 |
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Mike,
The throttle stop screw (idle speed adjustment) is on the side of
the carb, and will have a spring on it.
Your idle air screw is further to the rear and lower (on the same side
of the carb.) It is usually a smaller screw than the throttle stop
screw..
>On 20 Jul 2006 13:15:39 -0700, "Mike Beaty" <beatymj [at] gmail.com> wrote:
>Is the idle screw the same thing as the throttle screw? I don't see an
>idle screw listed on Fiche.
>
>-Mike
>Murray wrote:
>> On 20 Jul 2006 05:27:03 -0700, "Mike Beaty" <beatymj [at] gmail.com> wrote:
>>
>> >Another test & tune session last night, and I still can't get a plug
>> >that isn't black. I did first try to figure out the idle. The only
>> >way I could get the idle to actually calm down was to turn the air
>> >screw in all the way, and then back out about a half turn. I checked
>> >the throttle cable, slide and other areas for leaks and found nothing
>> >out of the ordinary. The slide was fully seated in the bottom of the
>> >carb as it should be. I did not check the reeds. I don't even know
>> >what I'm looking for on the reeds...just anything that looks broken I
>> >guess. Would a broken reed cause high idle? I put in the two step
>> >leaner pilot, still too rich...black plug. I then put in a two step
>> >leaner main. That's all I had to mess with, so that's what I did. The
>> >only positive out of this test was that I did actually lean things out
>> >at full throttle. My buddy and I could both feel it. I think the main
>> >needs to go back to where it was & I need to stop messing with it:)
>> >
>> >So the air screw really isn't the way to adjust the idle, but it's the
>> >only thing that worked. I know this made the bike richer, and probably
>> >messed up my test. Am I way off on the idle adjustment? It seems like
>> >ever since I started messing with the pilot, the idle has been high.
>> >Even when I put the stock pilot back in, it was still high. Makes me
>> >wonder if there is something else going on. Where is a good place to
>> >have the air screw? Or is the air screw/pilot jet combo that you're
>> >looking for?
>>
>> You need to adjust the air screw to make it idle as fast as possible.
>> Then turn the idle down with the idle screw. The idle screw adjusts
>> where the slide stops. If you can't adjust the idle down to where it
>> dies your not adjusting the right screw, also if your setting the idle
>> with the air screw your not ever going to get it to run right.
>>
>> First set the idle high with the idle screw, then adjust your air
>> screw to where the idle is running as high as it will go. Then back
>> off the idle screw to where you want it to idle. Note- if the air
>> screw is out more than 3 turns you need to go leaner on the pilot jet,
>> if your within 1/2 turn of all the way in, you need a richer pilot.
>>
>> If you still have problems with erratic idle, check for air leaks.
>>
>> Murray
>> >
>> >HardWorkingDog wrote:
>> >> In article <1153314717.236749.324630 [at] m73g2000cwd.googlegroups.com>,
>> >> "Mike Beaty" <beatymj [at] gmail.com> wrote:
>> >>
>> >> > I made my way to the parts store and got a variety of jets for my carb.
>> >> > Last night I did a little test & tune. When I put in the smaller
>> >> > pilot, it was still a little rich, and the idle was way too high.
>> >>
>> >> Good start. Now, go one step smaller on the pilot again, and test. But first,
>> >> figure out why the idle is too high.
>> >>
>> >> > I threw a one step smaller main, and back to the stock pilot. Still rich
>> >> > & high idle. I put in yet another step smaller main, still high idle,
>> >> > clean on the top end.
>> >>
>> >> I'd hold off trying to change too many things at once. Your first step was
>> >> right. Now, you're muddying things up.
>> >>
>> >> > So, I think I have the top end figured out, it's
>> >> > just the bottom end that is rich & idling funny. I adjusted the
>> >> > throttle screw to 1 turn out, and it still idles like crazy.
>> >>
>> >> Not sure what you mean here.
>> >>
>> >> > The air
>> >> > screw was turned way out too, probably 4 turns. Shouldn't putting a
>> >> > smaller pilot jet in make it idle slower? I just wanted to double
>> >> > check that going from a #45 to a #40 pilot will lean out the bike. Is
>> >> > that correct? Could I have messed something up in the carb while
>> >> > taking it apart & putting it back together?
>> >> >
>> >>
>> >> Yep, the 40 pilot is leaner. The air screw adjustment shouldn't really affect
>> >> idle *speed*, but more the quality of the idle. The idle speed adjustment is
>> >> another device. On my Keihin, it's a black knurled disc near the top of the carb.
>> >>
>> >>
>> >> The idle being too high makes me worried. Could there be an air leak in the boot
>> >> between carb and reeds? Did you get the carb slide in backwards? (Don't be
>> >> insulted, it happens.) Throttle cable misrouted?
>> >>
>> >> --
>> >> Charles
>> >> '99 YZ250
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