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FCR slant style carb jetting

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Hi!

 

I need some help, can't figure it out.

I've got a slant style FCR carb from a DRZ400E 2001 and installed it on DRZ400E 2007 instead of Mikuni. Removed CE. Air box is opened as it is an E model, Exhaust is original.

Now I have Main 142, Pilot 45, Pilot air 60, idk what needle. Probably the largest problem is in Main, as it starts on choke well, but doesn't like opened throttle at least on low RPMs (dies completely if remain fully opened in neutral or on the run). Rode it recently on some hill climbs, it runs surprisingly well, would not stall (but had to raise idle RPMs to idle) using just up to around 1/2 of the throttle, anyway want to fix it to be as it should.

I tend to by individual jets from JetsRUs, but I've found several advices and can't really pick one. 

#One is: Main 160, Pilot 38, Pilot air 70, EMM needle. 

#Then there is Main 160, Pilot 45, Pilot air 100, EMM or EMN needle. 

I've seen also some different setups, but these two tend to prevail. 

I will run it mostly in MD, VA, up to around 1000ft.

 

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did you plugged or connected the ports  on the left side of the carb? installed on s/sm model?

with stock needle 160-165 is mandatory, do not run it wide open with 142 + opened air box, it will be extremely lean.

if you need to run 142 you can tape the air box to original size

Edited by 30x26

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27 minutes ago, 30x26 said:

did you plugged or connected the ports  on the left side of the carb? installed on s/sm model?

with stock needle 160-165 is mandatory, do not run it wide open with 142 + opened air box, it will be extremely lean.

if you need to run 142 you can tape the air box to original size

ports are plugged individually.

It's a 2007 E model. Air box was opened originally, but the carb was Mikuni.

 

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ok , you current setup does not work because main jet  and pilot air jet are way too small.

the cheapest mod would be : connected ports , 160 main , stock needle at 5th clip , maybe 48 pilot

next step would be the second one listed above,  because you do not need to buy a new pilot jet and because 100 or preferable adjustable air screw are easier to find than 70/73   

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So it would be Main 160, Pilot 45, Pilot air 100, EMM or EMN needle?

Is there a difference which needle with this setup? I don't mind to buy those jets, just want everything to work as it should :). 

Do I need to connect those CE ports in this setup?

 

Thanks a lot for helping me out :)

Edited by Yanka

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100 air + plugged ports  is slightly richer at idle than stock jetting with connected ports.  emm is sligtly richer at idle than emn. 

you can play with these differences.  for example installing emM with plugged ports, then if too rich (pilot screw below 0.75 turns) you can connect ports making it leaner.  

 both needles are an improvement over stock dxp, both work fine.  probably emM would be my first choice, emn is easier to find. 

Edited by 30x26

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Thanks, man appreciate your help. Now I have smth to start with :)

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Continued:

So the carb is FCR39 slant on 2007 DRZ400E.
When I rev it up and close the throtlle it revs higher than idle for some 3-4 sec. and then returns to idle revs. Don't have a tacho, but I would say it revs about 2000-2200 and then returns to 1200-1300

What are possible causes to that? Air leak? wrong jets? wrong fuel mix?

My current setup: 
Main 160, Pilot 45, Pilot air 100, EMM needle from JetsRUs

Fuel mix screw unknown, tried to turn it with homemade tool and now I really don't know where I am :D  Probably on the rich side.

But the symptoms chased me from beginning to the end.

Edited by Yanka

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I doubt your bike is running at 1200-1300, it works but its a very rough idle.

Trying turning the idle screw counterclock wise about half a turn

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Well, it stalls from time to time, but if I turn it up then the high idle is even higher and I don't like that. When I fix it, I will turn it up a bit. 

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41 minutes ago, Yanka said:

Well, it stalls from time to time, but if I turn it up then the high idle is even higher and I don't like that. When I fix it, I will turn it up a bit. 

You say you don't have a tach? 

Have you ever heard a DRZ idling at 1200 RPM?

If not, it is probaby actually idling between 1500-2000 rpm

turn the idle screw counter clockwise which will lower the slide. It sounds like the slide is too high to me

 

Edited by Dramabeats

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you would need to know the position of the screw, then put it at 1,5 turns from closed and retry the bike.

probably you are rich at idle , with a too high slide to make it run.

does it start cold without choke?   it should need choke for a 3-4 seconds , then as soon you remove choke it should run at noticeably lower rpm than when it's hot

Edited by 30x26

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