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Rejetting for a PC platinum 2 pipe?? Is PC specs accurate??

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Hey guys im getting some info what to jet my bike to. 2007 Yz250

Now PC shows this

Main: 175

Pilot: 48

N3ew slide

Clip: 2nd groove i think

Air screw 1 out.

Now are these jetting specs accurate. My sst actually was jetted pretty decent in the summer and i had a tan color on the sprak plug.

Anyway, isnt it kind like risky to be running that lean? BEcause you know the stock main is a 178 and pilot a 48.

Im just worried about messing my motor up or something. Should i stick with a 178 or should i go with PC? Should i trust em??

Alsoim here i PA and i think im at like 1000-1500ft

any help would be highly appreciated!!!!!!

thanks

Alex

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I called them about that and that jetting is for race gas, if you run pump gas it will need to be richer if you use it for mx.

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I agree with MX614.

175 main is probably too lean for pump fuel. Try the stock 178 first.

N3EW needle is stock from 2007 up. 2006 and older used the N3EJ.

2nd clip is stock and works well on either needle.

The #48 pilot works well, that's where I have both my YZs.

The new bike came with a #50 which felt a little fat and it would load up if idled.

Your airscew will probably be right around 1 turn, but fine tuning will probably land you between 3/4 and 1-1/8 turns out.

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I have run 2 different FMF pipes on my 06 and the stock jetting works well. I am also around 1000ft. I run 50/50 race fuel because it pings under load on pump. I have actually gone back to using my stock pipe with an FMF shorty and like that combo the best. Good luck.

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I use the PC jetting on my YZ250 and run pump gas and I run my mix 40:1 and it works well it all depends where you live and I'm out in So Cal....but im just lending my opinion

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I'd personally start with a 178 main and the rest of their recommended jetting as a baseline. Do some plug chops and see where you need to go with it, might be close.

Any recommended Jetton is just that, a recommendation, not a definitive "this is what is perfect". Temperature, elevation, humidity, riding conditions (putting along muddy sigle track, or wot on a fast, deep sand mx track?), riding style (revver, lugger, clutch abuser, roll on throttle, snap throttle open, etc), fuel octane, fuel specific gravity, fuel distillation curve, etc etc, will all determine jetting.

I used to be super anal about, swapping jets and clip positions on my kdx before almost every ride depending if I were heading to higher elevations, weather that day, etc etc. After a while I realized it was an aweful lot of work for that last 2% of hp I nearly never used anyway. Now I jet slightly on the safe side, and only adjust if we are talking a 30f temp difference or 2000 ft elevation (which I never see living in Michigan now).

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Thanks guys!!! I would of posted back quicker but i was sleepinga ahahaha/

But now the bike i think has a 50 pilot in it, and i think its on the 2nd clip and i think it has a 178 main in it. Now i ride harescrambles, tight woods, sometimes wide open things. I like riding everything but mostly woods.

I just hope this pipe wont be a jetting pain like that fmf sst haha. Also im hopeing i notice more bottom end too. Should i leave the jetting stock?? OR should i make sure everything is to PC settings? Except use the 178 main?

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rc dude, jetting from pc's specs does not work well. Most of the companies are in California which means low altitudes and 68 degrees. I mean, who could live in conditions like that??? LOL...anyway....

We had that jetting chart floating around here a while back. It was interesting to see how temperature made as much difference in jetting as did altitude. I know it gets cold in pa and the summers are hot. If you jet for todays temp, it will be rich in the summer. If you use summer specs, it will be lean at 30 degrees. Thats why so many companies wont put out jetting specs.

I would try the specs you have in right now and see where your at. Its close to stock.

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Sweet thank you everyone!!!!!!!! So rcannon so would that 175 main from PC too lean?? I thought they were out of theri minds.

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Sweet thank you everyone!!!!!!!! So rcannon so would that 175 main from PC too lean?? I thought they were out of theri minds.

Like I said, lots of factors. I'm lower elevation then you and run a 172 main most the summer. 175 goes in if it's going to be 40's or 50's, and 178 as we get in freezing temps. If I were going ice racing I'd probably need to go 182 for constant wot.

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Sweet thank you everyone!!!!!!!! So rcannon so would that 175 main from PC too lean?? I thought they were out of theri minds.

I don't mean to answer for Roland, but here's the chart he was talking about with some thoughts.

YZ250VJetting.jpg

Basically this works for stock pipe/timing/mx on 91 pump. I have found the S/A to make a bigger difference than the pipe.

If you run retarded timing, a spark arrestor or higher octane, you can reduce a step for each.

Some other mods such as squish with reset chamber volume, reeds and easier off road riding can also allow reductions.

Increases come from hard mx, open/desert/sand, a reduction in chamber volume or advanced timing.

As an example, my -1 deg. timing/Fatty/Spark arrested/VF3/91 pump bike in off road conditions

ran best 3 steps leaner than the chart. But it was at the point where I had to make changes lower or cooler.

You have to take each scenario as a combination of parts/factors and decide how "optimum" you want to be and the work it takes.

Many will just run slightly rich so they have to jet less, and that's fine too. Also, each individual bike can be +-1 step from another optimally.

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:worthy:Thanks carver!!!!!

I was looking all over for that. BUt not trying to be rude or anything but is this jet chart pretty accurate?

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:worthy:Thanks carver!!!!!

I was looking all over for that. BUt not trying to be rude or anything but is this jet chart pretty accurate?

Accurate????The damn thing has been almost perfect for me. If I were forced to use the specs shown on the chart, I woudl live happily ever after.

Get a number 8 slide when you can, or have yours cut. The chart is then more accurate.

Sorry to imitate Carver. I'm scheduled to play him in the movie, so what the heck.

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Need a little help: I want to copy the chart to my spreadsheet program, the copy function while seeming the pick it up will not transfer the chart. Any help would be appreciated.

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LOL, the reports of my demise have been highly exaggerated,

however, my thumb still looks like it could have Olive Oyl on it.......

rcdude 2, thanks, like rcdude 1 said, the chart is pretty close.

I went on to explain the fine tuning adjustments below the chart.

The adjustments are for people looking for ultimate power/response on the lean side and/or safety on the rich side.

Reread that again and PM me with any further fine tuning.

Mrdirt, that's because it's a low res picture and not text.

You'll have to manually enter it all unless someone already

manually copied it in text (unlikely)

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Now whats the #8 slide for? What does it do? And how much does it cost? Is a yamaha product too? Or aftermarket?

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RC dude, you need to study the jetting sticky before you try anythign new.

The questions you are askign are answered there. Sadly, a person needs to knwo the answers before jetting. You can ask us all the questions, but until you understand the parts, terminology, and function, it will be a costly crap shoot for you.

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I know man. Im sorry for all these stupid questions. But where can i get this #8 slide and no affence i know that adam said it runs leaner down low but does that like add bottom end?

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RCDude, no more questions answered until you do your part. That means gettign the pipe, trying it, then deciding if you really have a problem.

The number 8 slide and source are mentioned in 30-40% of the posts on this forum. JD jetting sells these as do a thousand other carb suppliers.

Its going to mean nothing to you if we keep spoon feeding you this info. It all here. Its fine to ask questions, but somethign has to happen someday...right, or wrong.

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