YZF carburator P38 Lightning device

[Floris]

Hello, I just saw this device on MX south's website. Here's the URL that brings you directly to it: http://www.bews.com/mxsouth/perp38lit.htm

Has someone tried it ? Is it worth the money ? What does it do ? I saw this device on MX south's website.

Thanks.

Floris.

[Hick]

Its a new accelerator pump housing. On the page it claims to aid in starting while hot or cold. I don't see how that is possible.

I wonder if it just increases the amount of fuel delivered by the accelerator pump?

You can change the timing and duration of the stock accelerator pump by adjusting the carb throttle shaft.

[Taffy]

go to WR site & read up on "WR with P-38 rips!" from two weeks back by Erik in So Cal.

i'm disappointed for Erik, he posts info on a go faster goody & everyone ignores him!!!

i have plenty of experience of APJ's. the more tuned your bike the less fuel & the shorter the period you want it squirted in for.

reading the publicity bullshit, it sounds like this is some kind of atomizer? if it is i would imagine their claims to be true.

[So_Cal_Erik]

Originally posted by Taffy:

go to WR site & read up on "WR with P-38 rips!" from two weeks back by Erik in So Cal.

i'm disappointed for Erik, he posts info on a go faster goody & everyone ignores him!!!

i have plenty of experience of APJ's. the more tuned your bike the less fuel & the shorter the period you want it squirted in for.

reading the publicity bullshit, it sounds like this is some kind of atomizer? if it is i would imagine their claims to be true.

NOT ONE RESPONSE!!! Thanks to Taffy for reading my post and commenting in a positive manner. With all the "bench-racing" going on on this website, and all the talk about squeezing every ounce of performance out of these bikes, it's amazing that this posting was ignored.

Yes...it's sad that people would rather spend $450 or more for a pipe or a carbon-fiber goodie, and yet they won't spend $75 for a part that helps their bike accelerate faster! ?

The P38 does make the fuel atomize by forcing the fuel thru the hole in the accelerator pump quicker; thus causing the fuel to mist rather than the usual "squirt" method.

------------------

So Cal Erik

Visit my club's site at <A HREF="http://www.ruts.org

" TARGET=_blank>www.ruts.org

</A>

[Taffy]

erik

presumably they do a WR & a YZ kit due to the flywheel weights. why am i guessing!!!

YOU tell us what happened.

we're waiting!!!

[So_Cal_Erik]

Okay...okay already, I was out with my wife today visiting with her grandma - what else could I do? (Considering that getting a hall pass to go to the track was out of the question ? )

Now to get to the jist of things. Here's my experience with the P-38:

I had originally ordered a P-38 for my '99 WR YZ-timed & jetted with DVP needle 48 pilot and 180 main jet (FMF PC/IV sq. spark, stock header). After I put it on I started the bike and adjusted the pilot screw. When I gassed it, the dead spot (off idle) was worse than with the stock pump cover. I originally thought it (P-38)was made to eliminate the off-idle dead spot.

So, I called Factory R&D and talked with Ken (owner) who said to come by & he'll get it running right. When I arrived, Ken had various sizes of P-38's which allowed the accelerator pump/push-rod to open to various lengths. He informed me that since the bike is a 4-stroke, it was not designed to eliminate the flat spot.

We tried about 5 or 6 different ones 'til we found the one that worked best. What we found was the WR does not accelerate nearly as fast as the YZ (due to the heavier fly wheel weight). That's why we had to use a different P-38. We were able to get the flat spot back to where it had originally been.

When I went to the track 2-days later to really test it out, it seemed to rev slightly faster from the low to mid range. I'm thinking about changing back to my YZ pipe from my FMF Power Core Four-Square Sparky to help rev out better mid to top. (I'll be going to the track again this Tuesday to re-test with various pipes.)

From my experience with pipes the stock YZ pipe with DMC header works the best.

Hope this helps out. If anyone has any questions...I'll be logged in this site for a few more hours tonite. Otherwise, I'll check back in tomorrow.

Later....

------------------

So Cal Erik

Visit my club's site at <A HREF="http://www.ruts.org

" TARGET=_blank>www.ruts.org

</A>

[This message has been edited by So Cal Erik (edited 07-15-2000).]

[Guest Guest]

Eric,

Sounds good, your logic about the $75 makes sence. What do you know about the P-38 for 426's

[So_Cal_Erik]

I dont know what a WZ is either,(WR-YZ timed?)... Anyway, I dont want to mislead any one into buying an aftermarket product for their bike that hasnt been tested and proven under various settings and conditions.

I want to get this thing totally dialed in, so I can pass on the best combination of jetting needle, pipe and p-38. I do know that factory r&d has the YZ400 and 426's set up perfect. Remember that I, like many others on this site have hybrid (WZ)converted bikes, and this p-38 is designed to make the bike rev faster (and it does on the YZ models also on the KTM's that I've personally ridden ) but they dont have flywheel weights to deal with,

so the difference on those bikes are much more pronounced. Also, since Ive read the postings on the EKP needle I ordered one to try and that might make a difference too.

I'm just waiting for that to come in at the dealer. They told me it was on back order, so if you can tell me where I can get one fast please let me know.

One more thing, is there any way to get this topic transferred over to the WR side? maybe

we could get some input from one of those guys with the carbon airbox who may have tried one of these things.

Thanks,

------------------

So Cal Erik

Visit my club's site at <A HREF="http://www.ruts.org

" TARGET=_blank>www.ruts.org

</A>

[So_Cal_Erik]

Taffy,the flat spot off idle i'm talking about is when you whack the throttle open really fast a couple of times and the bike makes that wup--uhhhh wup--uhhh sound. When I had my bike WR timed I had more bottom end and less wup, more uhhhh, you know what I mean? Getting the pilot screw adjusted properly was what helped me get the P-38 flat spot dialed in better also.

------------------

So Cal Erik

Visit my club's site at <A HREF="http://www.ruts.org

" TARGET=_blank>www.ruts.org

</A>

[James_Dean]

Erik,

I didn't post earlier on your P-38 comments, but read it a bunch of times. Thankyou (albeit late). I'm concerned also about the P-38 not being a fully developed product. If it was endorsed by more people on the site out of the box, I would get one. Yamaha has more than one diaphram listed in the OEM parts for the accelerator pump. I have no idea why. Anybody else have any idea? It may do the same thing.

------------

There is an equivalent needle to the EKP. It is EMP. Get it from Sudco or Carb Parts Warehouse. Set it one clip richer. EKP#3 equals EMP#4. It is brass and not the plated aluminum. It will only be about $8 !!

James Dean

[Floris]

Has anybody have some feedback about the P38 for a 426 ?

Thanks.

Floris.

[Taffy]

Erik

the bike ran with a flat spot, you are YZ timed i presume? it moved but you got it back to where it used to be. so the six changes you made were from what to what. smaller atomizer, shorter duration?

it's alright for you living down the road from the factory, the rest of us would have to buy new bits. so what number digit in the P38 should my WR with YZ (is this the WZ that filly was refering too?)timing come with. what are the differences you know of that would suit the YZ & the WR?

you've kept your flat spot off tickover? but got an increase in performance is it at 1/4 throttle onwards?