🚀 go-pugleaf

In article <3f037787@shknews01>, "BadCRC"
<BadCRC@bbbbrrrrRrrRrrRraaapppPPP.com> wrote:

> Hello all!  I'm looking for some help...  I'm fouling plugs due to rich
> jetting.
>
> Long story short....   I have a PC pipe and silencer ("Factory Sound"),
> Boyesen power reeds, and use No-Toil filters and oil, other than that, the
> engine is stock.  I am running MX2T premix at 32:1 with pump swill.  Temp is
> around 80, elev. 5000.
>
> My question is this...  When I got the bike it had a 55! pilot (who knows
> why), 172 main, clip 2nd from top.  The stock settings are 48 pilot, 172
> main and 2nd clip from top.  I changed it to (stock) 48 pilot, 170 main, 2nd
> clip (left the same).  Before I changed anything it fouled like CRAZY!  Now
> it is still fouling but not as often.
>
> My question is this...  It seems like I foul when first getting going, and
> my plugs are always black (no matter if I foul them right away or after
> riding for an hour).  Would I be okay to go to a 45 pilot without worrying
> too bad about being too lean?  Seeing as how 48 is stock.
>
> Anyway, I know there is a lot to getting it to run just right, I just want
> to know if you guys/gals think I will be running the risk of damaging
> anything by going 3 sizes smaller on my pilot.  (45 is the next lowest my
> dealer had, and I'm going out this weekend.)
>

Just to compare, my '99 YZ250 is currently running:
45 pilot (std. is 50)
170 main (std. is 172)
N4DF jet needle @ 1st clip (this needle is one step leaner than std.; as near as
                            I can tell, it is .5 step leaner than running the
                            std. jet needle at the first clip)

Its using an FMF pipe/Turbine Core II sa/silencer, No-Toil filter oil, and
Boyesen power reeds, with Yamalube-2R at 36:1, Chevron 91 gas. Pretty
similar to yours.

I took it up to Foresthill, CA a couple weeks ago during a hot spell.
Elev. about 4500 feet, maybe less, temp around 85. Ran richer than
Saddam's closet. I'm a little surprised that it is still too rich, and
it's caused me to wonder whether I've got a transmission seal leak. I
built a crankcase pressure test system last week, and the crankcase never
leaked  even .1 psi during 2 tests, but now I've got to rule out a vacuum
leak. Other than that, I can only keep going leaner with jetting.

I'm sure others here with a lot more experience will check in (I hope),
but I don't think you should worry at all about going to a 45 pilot. Most
of the advice I've gotten here is to start with the pilot circuit, then go
to the jet needle, and then last fiddle with the main; Boyesen recommends
the opposite. There's been quite a bit on this newsgroup about jetting,
try a google groups search to catch up a bit.

--
Charles
'99 YZF600R
'99 YZ250