sea level jetting

serrow · Feb 9, 2008

I was all set to pull the carbs, check the jets and revert to stock. I have a sneaking suspicion that the prev owner goofed stuff up with aftermarket exhaust, then swapped the stock exhaust back on leaving me with a bike with richness issues and horrible gas mileage.

so, I was going to revert to stock jets

PAJ1: 90
PAJ2: 170
PFJ: 37.5
Main:152.5
***** are PAJ1, PAJ2, MAIN all considered SUPER BN Mikuni N102/221???? What abt the pfj? whats it called?

till i found this posting http://www.venturers.org/Tech_Library/index.php?action=article&cat_id=001012&id=238

I live in HONOLULU - sea level - OH YEAH!!! Based on this posting, the author suggested the following jets.

4 main jets in the size of '145' (3G2-14231-29-00)
4 pilot fuel jets in the size of '42.5' (4G0-14142-42-A0)
4 pilot air jets number 1 (PAJ1) in the size of '95' (3G2-14231-19-00)
4 pilot air jets number 2 (PAJ2) in the size of '160'" (3G2-14231-32-
00)

any thoughts? the author listed YAMAHA part numbers but I assume for all but the PFJ i'd be looking for SUPER BN small round type right?

maleko89 · Feb 9, 2008

I'm unsure about the settings you mention. He bumped up the pilot fuel jet two sizes and it'll run very rich at idle. He decreased PAJ2 four sizes and that'll make your off idle into lower midrange mixture richer but then he increased the PAJ1 up two sizes to lean it back down.

Vmax jetting with stock exhaust is setup for sea level so try stock first. Then, set your idle mixture using the mixture screws. Make sure all your float levels are the same...either 16 mm or 17 mm. Get a good sync and new plugs and see how it runs by looking at those.

When you go back to the aftermarket leave your pilot jets alone and just adjust your mixture screws and see how it runs up top. You may have to lower a main jet size.

Mark
#1098

serrow · Feb 10, 2008

Thanks.

I tore into her today. she has stage 1 needles and the clip was on the 2nd from the top. This bike is very gassy smelly. so i dont know why that would be. I do have issues with my idle that i need to keep it kinda high or it will die. 2 of the needles had the washers on the wrong side so that was kinda weird. just a tad off but wonder if getting things right could help.

The MAINS had a big 160 on them but nothing like the example of the DJ in the pic. assuming this is the DJ160 that would be about a MIKUNI 150 thus making it a little too rich right? well, no real answers cept i am going to buy some 152.5s to get her back to stock. I also moved the clip to the 3rd position. not 100% sure that i need the stock needle. anyone have 4 laying around? for that matter the 152.5s too.

I have a few other parts to order so I'll button her back up, put bike back on and sync while i wait for some parts (vboost boots) and the jets. wonder how she will run in the interim.

Thanks

one2dmax · Feb 10, 2008

you're running rich because of the stage 1 needles. Try putting the clip on the very end (blunt side) and see how that helps.

Sean

maleko89 · Feb 10, 2008

serrow said:
Thanks.

I tore into her today. she has stage 1 needles and the clip was on the 2nd from the top. This bike is very gassy smelly. so i dont know why that would be. I do have issues with my idle that i need to keep it kinda high or it will die. 2 of the needles had the washers on the wrong side so that was kinda weird. just a tad off but wonder if getting things right could help.

The MAINS had a big 160 on them but nothing like the example of the DJ in the pic. assuming this is the DJ160 that would be about a MIKUNI 150 thus making it a little too rich right? well, no real answers cept i am going to buy some 152.5s to get her back to stock. I also moved the clip to the 3rd position. not 100% sure that i need the stock needle. anyone have 4 laying around? for that matter the 152.5s too.

I have a few other parts to order so I'll button her back up, put bike back on and sync while i wait for some parts (vboost boots) and the jets. wonder how she will run in the interim.

Thanks

I agree with Sean....use stock needles with stock exhaust. If you want to go to the full exhaust then go back to square one and use stock jetting there too....and tune. Most likely you can keep PFJ, PAJ1 and PAJ2 stock. Just adjust your idle mixture with the pilot screws.

Mark
#1098