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Savage422

Fcr41 jetting

94 posts in this topic

So I got an email back from jd jetting, and he sent me a picture of a fuel mixture screw. I looked at it and realized that I don't have the upper O ring. 

I'm going to pull the bowl to make sure it didn't get stuck in the carb somewhere. But I bet I dropped it at some point when I first installed it. I wonder what effect that could have on my jetting. Especially since that's one of the first things he asked me. 

Edited by Savage422
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It allows fuel or air to freely flow past without the metering effect , it'll have poor adjustment due to lack of control, probably dripped fuel out the threads as well ?

 

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Edited by jjktmrider
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17 minutes ago, jjktmrider said:

It allows fuel or air to freely flow past without the metering effect , it'll have poor adjustment due to lack of control, probably dripped fuel out the threads as well ?

 

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Well I may have gotten down to the bottom of it.

The o ring is likely in place in the carb (I didn't know it would stay) no fuel has been leaking. 

But I told jd jetting my needle part number and they said it is way too big. I think it's an nycr? So I ordered a new needle and jet not from them that should straighten me out.

Fingers crossed

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Pulled the carb out and confirmed I'm missing the o-ring on the mixture screw. So, between that and the leaner needle, it looks like I may have this solved. 

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Big shout out to jd jetting. My kit arrived 2 days earlier than expected. 

I just put the red needle in on the 4th clip. Put a 45 pilot in it instead of the 42 that came with the kit. And installed a 170 main. I'll likely need a 175 main I think. And I put the o ring on my fuel screw that was missing.

 I can't wait to put the carb back in tomorrow

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Big shout out to jd jetting. My kit arrived 2 days earlier than expected. 
I just put the red needle in on the 4th clip. Put a 45 pilot in it instead of the 42 that came with the kit. And installed a 170 main. I'll likely need a 175 main I think. And I put the o ring on my fuel screw that was missing.
 I can't wait to put the carb back in tomorrow

How did it work out?
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20 minutes ago, ohiodrz400sm said:


How did it work out?

Well I don't know if I'm closer or further away lol.

I swapped out the needle. Ran the 45 pilot and the 170 main

Wouldn't idle unless I turned the idle way up. And hard start

Put the 152 pilot back in, and the 175 main, left the needle on the 4th clip. 

Idles best at about 3 turns out. And I can lower the idle adjustment to reasonable spot.

Tried the needle on the 5th clip and the idle hangs real bad.

Dropped it back to the 4th clip, took it for a spin. Not missing as bad at part throttle, but still not right and down on power. Throttle response is solid though. Idle seems a little choppy bouncing from 1790 to 1890. That could just be normal though. 

Here is my thought.  Either I am so fat that I'm past the tipping point, lol, or I really do need a 55 pilot with this set up.

No air leaks at all.

Edited by Savage422

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With that kit my bike wasn't even ridable at operating temperature.
I had to drop to a 40 pilot to make the red needle work 3rd clip(39mm FCR). Are you getting any black smoke if you crack the throttle to around 1/4?

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Just now, ohiodrz400sm said:

With that kit my bike wasn't even ridable at operating temperature.
I had to drop to a 40 pilot to make the red needle work 3rd clip(39mm FCR). Are you getting any black smoke if you crack the throttle to around 1/4?

No black smoke.

Yeah it doesn't want to run right until it warms up. If it matters, it is running at 230 degrees Fahrenheit while I'm trying to time it. Fan kicks on and it stays right and 234/235.

It starts with the choke and once warmed it will start right away warm no choke.

I may try to go the extreme other direction and put a 38 pilot in it

Also, I just remembered I out the clip on the 3rd and it seemed to idle a touch better.  

Having said that, it's acting just like before where smoothest and highest rpm is at 3.5 to 4 turns out.

Jd jetting told me to not go by peak rpm, but find the stumble and then open it up 1.5 turns. 

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As another side note:

Searching the jetting database on another forum, a handful of z400 guys with exact setups as mine are running anywhere from 55 to 62 pilots

I'm wondering if the larger.overlap on the cams is cause a lot less vacuum. That's typical.of car cams, but that is my background and I'm not too sure how it translates to bikes 

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As another side note:
Searching the jetting database on another forum, a handful of z400 guys with exact setups as mine are running anywhere from 55 to 62 pilots
I'm wondering if the larger.overlap on the cams is cause a lot less vacuum. That's typical.of car cams, but that is my background and I'm not too sure how it translates to bikes 

They also are using a very different EX400 airboot or no airbox at all. Their main jets are changing to the 180's too.
I have the same cams with less CC's. Your bike should want equal or smaller jets then what I have.
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1 minute ago, ohiodrz400sm said:


They also are using a very different EX400 airboot or no airbox at all. Their main jets are changing to the 180's too.
I have the same cams with less CC's. Your bike should want equal or smaller jets then what I have.

Maybe I am just too fat for my own good.

The recommendation from jd was the red needle 4th clip, 42 pilot and 168 main.

Maybe I'll start over there and see what happens. 

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Pipe isn't doing anything to cause jetting issues , they just allow airflow . This is the one big reason I avoided FCR's most of my life , you have to really like spending a lot of time changing jets ,needles, leak jets, accel pumps adj ,ect.., ect... If you can get them right they work ,but not all work as described. I've been trying to get both of my KLX's jetted right for going on a year, with 50 things to change or adjust ,more time is spent taking the bike apart to try another jet or needle or waiting for new needles/jets to be mailed than riding the dang things , and I have wideband meters to know which way to go . I put the CVK back in one for now .

 

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17 minutes ago, jjktmrider said:

Pipe isn't doing anything to cause jetting issues , they just allow airflow . This is the one big reason I avoided FCR's most of my life , you have to really like spending a lot of time changing jets ,needles, leak jets, accel pumps adj ,ect.., ect... If you can get them right they work ,but not all work as described. I've been trying to get both of my KLX's jetted right for going on a year, with 50 things to change or adjust ,more time is spent taking the bike apart to try another jet or needle or waiting for new needles/jets to be mailed than riding the dang things , and I have wideband meters to know which way to go . I put the CVK back in one for now .

 

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That actually makes me feel better, lol.

 

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Sorry if I missed it but what kind of fuel screw do you have? If aftermarket, what kind ?

 

 

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6 hours ago, ohiodrz400sm said:

Sorry if I missed it but what kind of fuel screw do you have? If aftermarket, what kind ?

 

 

I'm running a jd one now.

Update: progress has been made.

After talking with jd and looking at a bunch of stuff, this card has a hot start. The hot start was just blocked off with a Allen bolt. There is no plunger in it and because of that, there's a massive air leak.

Also, it has a tps but I'm not running one. I need to buy a Honda to just to block it off because air is leaking from there also.

Ordered the plunger from sudco and now I'm searching for a used busted honda tps

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I know it doesn't matter if I run a tps or not, but I ended up ordering a tps to go from the Honda style fcr to my drz. I figure it can't hurt. 

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I know it doesn't matter if I run a tps or not, but I ended up ordering a tps to go from the Honda style fcr to my drz. I figure it can't hurt. 

I think the Honda has a different style plug, at least the 40mm I had did.
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6 minutes ago, ohiodrz400sm said:


I think the Honda has a different style plug, at least the 40mm I had did.

It does. The place I got my carb from makes a Honda to suzuki harness specifically for that fcr in a drz

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