434 fcr-mx: 38 pilot still too rich, 160 too lean at the top?

Hi all,

I'm getting confused as hell on what's going on with this. Long story short:

I got an FCR-MX from Eddie back when my bike was:

- stock bore

- 434

- hotcams

- MRD (standard i.e. has cap in the end).

Since then I've installed a 434 kit.

I believe the FCR-MX (39) came with

- 160 main

- 48 pilot

- no PAJ

- EMN clip 3?

- temps here are about 70f

- I'm at about sea level

I've got one of these: http://www.innovatem...products/db.php wideband guages (in hindsight I should've got the LM-2 but oh well).

What I'm finding is that with the fuel screw all the way in it's still running rich at idle once warmed up. I've gone all the way down to a 38 pilot but I'm finding that with it only 1 turn out it's in an ok range cold, it's felt like the wrong thing to do, yet the bike's been running better, so maybe it's right?


- When warm it idles at about 12.5 with the 38 pilot jet mostly in. I'd like it to be 13.5+

Basically when I go to a good stretch of closed road and do a run in fourth gear I find:

- As soon as I open the throttle it shoots rich, to 12ish or so. This is probablyy the wired AP linkage( I know, been meaning to pull the carb and try tuning without it, don't think it explains my other issues though?).

- most of the mid-range is around 12.5-13. I might try emn-2

- after 3/4 throttle it shoots up to 14.5 or so, with the 160. So I should go a jet size richer? Two?

What I'm wondering, is would I be going on the right track to order a 35 pilot jet, and a 162 & 165 main ? This seems like I'm off on the wrong track based on what the normal recommendations are. (I've tried to read a *lot* of threads).

Should I be trying a different needle?

Appreciate any help, really don't know what's going on.

Heh, forgot to mention, it's a DRZ-SM if it makes a difference.

Edited by pacifist

Lower your idle speed to where it can just idle. Then adjust the fuel screw, then raise the idle sped back. The screw adjustment procedure will get you very close without the widband.

I assume you are not using an alloy fuel screw, that thye sprin, washer and oring are intact.

To accurately check jetting, you want to be in 3rd or 4th gear, steady throttle, going up a hill.

12.7/13.2 is what you want, and then closer to 12 WOT.

Do not over analyze, you will mess it up.

R&D flexjet; http://www.r1dean.co...&products_id=48

With the 38 pilot I can screw it all the way in and it'll still idle, though very inconsistently. The wideband will vary a bit but still be in the mid 12's, mostly.

Mostly I'm justt surprised though that all the recomendationns I've seen have been for something like a 45 pilot, EMN-3, 155 main for a 434 with cams. Where I seem to need a far leaner pilot and a *far* richer main.

Edited by pacifist

Before you screwed the fuel screw in, did you lower the idle speed? Fuel screw adjustment is done at the lowest possible idle speed. Once set, you raise it back up and are slightly on the needle.

Just over 1500 rpm; i guess I could try setting it lower but I've normally got it set about as low as it'll reliably run anyway. I'm still having trouble believing I'm going to get different results though when there seems to be evidence that that jet is still way too rich.

The fuel screw with the 38 pilot is letting me adjust between I think 12.5 down to below 10 on the afr... and the bike behaves and sounds like the readings are true. The o2 sensor is on a welded bung near the mcct.

I'll repeat it again. You must set the idle speed as low as possible (1200 rpm or so), adjust the fuel screw then reset the idle to a normal idle speed (about 1,850).

You are still over analyzing. You are on the pilot circuit AND the needle.

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