Jump to content
Sign in to follow this  

DRZ400SM 435, Stage 1 Hot Cams, E base gasket FCR jetting help

Recommended Posts

So I've been messing around trying to get my DRZ dialed in this season on the FCR39MX from the TT store. I just put together a 435 kit with stage 1 hot cams and increased compression with E base gaskets. I live in Wisconsin at about 1000 feet above sea level. Besides the engine I have the 3x3, K&N filter, and a full Yosh RS2. I've tried with and without the spark arrestor. Currently I'm running:

 

45 pilot

1.75 turns out on fuel screw

pilot air jet removed

EMN needle clip 4 from the top

160 Main jet

 

The AP screw has the O-ring mod, timing has been giving me trouble though. I set it to 2.75 mm as recommended by the JD website and started from there. It just seems like my mid range isn't what it should be and I don't know what to do. I've tried clip positions 3, 4, and 5 from the top on the EMN needle and it seems like 4 is the best right now. I'm considering coughing up for a JD kit in the future but I could really use some tips.

Share this post


Link to post
Share on other sites

No need for a jet kit with the FCR, you can achieve the best performance by using keihin jets and needles.

This is a little beyond my knowledge for jetting so I will let the people that know what they are doing help you out with that.

You wouldn't happen to be close to Waukesha, WI would you?

Share this post


Link to post
Share on other sites

I think you could be a touch on the Rich side .. Main and needle .

Try a 155 main and the next leaner needle down from the EMN on the 3rd clip .( it's the EMR or EMP ) Craigo485(sm) would know of a more suitable needle . He is the Man :aussy:

You say E base Gasket(S) ?

  • Like 1

Share this post


Link to post
Share on other sites

No need for a jet kit with the FCR, you can achieve the best performance by using keihin jets and needles.

This is a little beyond my knowledge for jetting so I will let the people that know what they are doing help you out with that.

You wouldn't happen to be close to Waukesha, WI would you?

I'm in Madison. I just can't get the throttle response to feel right. It just felt gutless on the third clip and way better on the fourth. The other needle that came with the TT kit was the EMR. I'm gonna get a 155 on Monday, and I'll see what I can do for needles.

Edited by essplode

Share this post


Link to post
Share on other sites

Well hopefully he doesn't hit any concrete pylons because I need to figure this out.

  • Like 1

Share this post


Link to post
Share on other sites

Use 155 main jet

EMN needle , clip 3

45 pilot jet

2 turns fuel screw.

O ring mod

No pilot air jet

Put the AP timing screw back where it was when you received the carb, and then turn it in 1/2 turn....

 

 

 

OP, what is exactly not right about the way it's running?....list all symptoms 

Edited by Craigo 485sm
  • Like 1

Share this post


Link to post
Share on other sites

It mostly just feels a bit gutless. I had it running a little better before but when I roll on hard in second it doesn't even power wheelie. Forget about third.I can feel some surging at what I think is the pilot to needle transition but it could be needle to main.

Any tips if I'm an idiot and can't remember exactly where the AP screw was when I got the carb? I got it on the bike over a year ago before the engine build and I've been messing with it for a while.

Edited by essplode

Share this post


Link to post
Share on other sites

It mostly just feels a bit gutless. I had it running a little better before but when I roll on hard in second it doesn't even power wheelie. Forget about third.I can feel some surging at what I think is the pilot to needle transition but it could be needle to main.

Any tips if I'm an idiot and can't remember exactly where the AP screw was when I got the carb? I got it on the bike over a year ago before the engine build and I've been messing with it for a while.

 

Stock AP setting should be around 3 1/4 turns out from fully in

Don't use the arrestor or insert in the end of your pipe.....A corked open pipe with an fcr often suffers from bogging on quick throttle applications.....

Edited by Craigo 485sm

Share this post


Link to post
Share on other sites

So I tried the 155 main, doesn't feel like a huge improvement. The weather has been way hotter here for the last couple days, like 70-80 degrees and humid. I can feel and hear the bike spluttering at what feels like the throttle position where the carb transitions from pilot circuit to the needle. I'm guessing maybe the EMN needle is too rich so the root diameter is too small? I'm still trying to find the right AP timing setting. It feels like it doesn't want to power wheelie in second, and it certainly won't do it in third. I can't tell what exactly is causing it but I would think that the needle effects roll on more than the main jet.

 

Edit: I think I might try to track down a DVQ needle. Actually, I have no &%$#@!ing clue.

Edited by essplode

Share this post


Link to post
Share on other sites

You are perhaps realizing now that when you start messing with a carb their can be downside , unless you know what you are doing....

The "As Received" state from the TT store is pretty much ready to go , except for a couple of minor tweaks...(paj removal, o ring mod)

 

If there is an improvement in this issue with the airbox door removed, try a leaner EMP needle, clip 3.......

If no difference I suggest the AP timing screw needs some more adjustment...

 

 

The following is a write up by William1 outlining the procedure for resetting the AP timing screw...

 

The AP timing screw. 
Resetting the AP timing to 'stock'
Method #1 - Most accurate
Turn the idle speed screw so the slide is completely closed (count the turns and note it) .
Turn the throttle wheel, raise the slide, slip a .8mm drill blank under the slide, release the throttle wheel, pinning the blank.
Turn the AP timing screw so the play just barely goes away.
Remove the drill blank, reset the idle speed to where it was.
Fine adjust the AP timing screw by test riding, turning in 1/2 turn increments to where the bog is just gone. Should be less than 2 turns, if at all.
Method #2 Not as accurate
Back out the idle speed knob (count the turns and note it) until the screw end of the idle speed cable is no longer touching the theottle wheel - Throttle cables may have to be fully lossened.
Ensure the slide has bttomed out on the carb bore'
Set the timing gap between the cam and the screw to be .010"
This should be checked and set, if needed. This will be the initial adjustment point. 99.9% of the time, the squirt occurs a little late. Get your bike fully heated up at your riding place. Test ride. If you still have a bog, turn the AP timing screw in (CCW) 1/2 of a turn and test again by riding normally. Do not force a bog. I can make any carb bog if I want to. Do not test revving the bike in your garage. Test it by normal riding. At most, you will have to turn it 2 turns. Often none to 1/2 is plenty. Four down!

Now that the bog is gone, re-visit the Leak Jet and try a larger one. If the bog returns, you can adjust the Timing screw again but you do not want to turn it more than 2 turns from the initial factory setting. 

Edited by Craigo 485sm

Share this post


Link to post
Share on other sites

I definitely realize now that I should have just left the AP screw alone. I'll try an EMP needle and I'll follow that write up to dial in the AP screw.

Share this post


Link to post
Share on other sites

Really? Every single thing I've ever read about the newer model FCR-MX is that it should be run without the PAJ. I know Sisneros has fallen off the face of the Earth but I'm inclined to trust his DRZ knowledge. Regardless, it's free to try so I might give that a shot if I'm not happy with the EMP needle performance.

Share this post


Link to post
Share on other sites

Really? Every single thing I've ever read about the newer model FCR-MX is that it should be run without the PAJ. I know Sisneros has fallen off the face of the Earth but I'm inclined to trust his DRZ knowledge. Regardless, it's free to try so I might give that a shot if I'm not happy with the EMP needle performance.

I know, i tried running a 45 pilot without the air jet, ran really lean. Tried a 48 and it ran stupid rich. Now im at 100 paj and 45 pilot jet runs ok, still just a bit rich im gonna try a slightly larger paj Edited by ryansgotacbr

Share this post


Link to post
Share on other sites

With the pilot air jet out I get the correct response from the fuel screw, but I guess I've never tried it with the PAJ in so I can't really compare the two.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×