FCR vs. Edelbrock?


63 replies to this topic
  • jesusgatos

Posted December 09, 2007 - 03:28 PM

#21

...I have read some post about the Eddy starving for fuel when using an oversize tank with the pet-cock mounted at a lower level than stock. When the fuel runs low there was not enough pressure to fill the float bowl at full throttle.I think this has been corrected. ( some people had installed a small electric fuel pump.)I have had zero problems with mine (IMS 4g tank), and I love its simplicity. I hate fudging with jets when I can be out :banghead:

That's what I thought at first too (was running an IMS 4.5 gallon tank). But it has the same problem even after trying the stock tank, and now I'm running an IMS 3.2 gallon tank.

  • HawkGT

Posted December 09, 2007 - 04:01 PM

#22

If it's worth anything, Eddie Sisneros (aka Burned, jetting forum moderator) did some dyno testing on a DRZ of an Edelbrock vs. FCR.

Sisneros on the Edelbrock:

....controlling the whole fuel curve with the needle....doesnt work.


http://www.thumperta...ad.php?t=332629

I notice the owner of the bike says the bike runs pretty well and pulls hard on the road. Yet the dyno clearly shows it's not performing as well as an alternative carb would. I know Edelbrocks are popular among the XR crowd so the must be better than the stockers (right???) but I've just seen too much direct and anecdotal evidence that turns me off from Edelbrock. If I'm going to the trouble of upgrading the carb, I don't want to go half-way or make an improvement in one area only to degrade performance in another.


I've never heard of FCR's needing special rebuild intervals. :busted: In my experience with them on road-race bikes and off-road machines, they are as reliable as any Japanese carburetor (in other words, very reliable). :banghead:

$.02

  • martinfan30

Posted December 09, 2007 - 05:05 PM

#23

If it's worth anything, Eddie Sisneros (aka Burned, jetting forum moderator) did some dyno testing on a DRZ of an Edelbrock vs. FCR.

Sisneros on the Edelbrock:


http://www.thumperta...ad.php?t=332629

I notice the owner of the bike says the bike runs pretty well and pulls hard on the road. Yet the dyno clearly shows it's not performing as well as an alternative carb would. I know Edelbrocks are popular among the XR crowd so the must be better than the stockers (right???) but I've just seen too much direct and anecdotal evidence that turns me off from Edelbrock. If I'm going to the trouble of upgrading the carb, I don't want to go half-way or make an improvement in one area only to degrade performance in another.


I've never heard of FCR's needing special rebuild intervals. :busted: In my experience with them on road-race bikes and off-road machines, they are as reliable as any Japanese carburetor (in other words, very reliable). :banghead:

$.02


you have just said it all! no way can a single carb adjustment(ie the needle) compensate for various throttle setting issues. fcr's dont need maintenance like some say. they are built this way(a little more complex) for a reason. they work! just takes a little more thought to tune a good carb then just turning a single screw. the japanese have very reliable, performing carb's. this is why i wouldnt have bought an eddy for my 650L. i want the extra adjustment possibilities to get an engine to perform at ALL throttle settings.

  • Krannie McKranface

Posted December 09, 2007 - 05:52 PM

#24

FCR: -greater possibilities
-greater fuel flow at wot
-can be dialed in to suit riding tastes
the more finely tuned the jetting is, the more suseptible to altitude, gas, and moisture conent in the air
-can flood easily if bike drops on side
-preferred by pro's for max hp output

Eldle: -incredible throttle response
-not suspetable to altitude and weather (as much)
-offers a 'window of tunability, which you can push up or down the rpm range/ throttle opening range, but not both
- best for off road single track
- bike will not flood when dropped on it's side

  • jetfuel

Posted December 09, 2007 - 09:23 PM

#25

FCR: -greater possibilities
-greater fuel flow at wot
-can be dialed in to suit riding tastes
the more finely tuned the jetting is, the more suseptible to altitude, gas, and moisture conent in the air
-can flood easily if bike drops on side
-preferred by pro's for max hp output

Eldle: -incredible throttle response
-not suspetable to altitude and weather (as much)
-offers a 'window of tunability, which you can push up or down the rpm range/ throttle opening range, but not both
- best for off road single track
- bike will not flood when dropped on it's side


Good summary Krannie...

  • BWB63

Posted December 09, 2007 - 09:36 PM

#26

FCR is the best porformance choice but, the worst fit. To much grinding of the timing gear adjustment housing and heating of the fuel tank for bending for me. Work real slick on the XR650R once you make it fit.

MT40 Mikuni needs major jetting change to work, most MT40's are setup for the Harley and only the pilot and main are changed for use in the XR650R. This is by far not good enough. Once the air jet, pilot, needle, needle jet, main and pump jet are changed, this carburetor is real close to as good as the FCR 41. 1.2 air jet, 22.5~25 pilot, 90JY1, Y-4 needle, 137.5~140 main.

Latest, Edelbrock with a #19 needle at 16 clicks out from full rich is wonderful all around carbuetor. It self adjusts for altitude, does not flood when the bike is on it's side, easy to adjust. Down side; it can not do everything. Inspite of what everyone thinks it does have a main jet and it is changable. It has been change over the years for the XR650R from Edlebrock. I have had the plessure of spending many hours at Edelbrock, over many trips and they showed me how this carb. works and how they do flow tests. I have had four Edelbrock bored larger by Edelbrock and I think this is an impovement for those that want to race. I have the idea that it also need to have a little richer main jet and a pilot circuit. The Edelbrock is not a race carb. as Chis from Edelbrock told me but, an easy to use, all around carb. and it does that well. I have mine on the 680cc bike bored to 42mm and it does everything real well.

Mikuni HRS42 is much like the TM40 but, way to much squirt for a stock bike.

  • Thumpmeister

Posted December 09, 2007 - 11:38 PM

#27

So after reading all this, the eddy sounds like a good carb, but will it pull as hard on WOT in the top range as the stock will?

Heres my issue... I'm trying to do soft sand hill climbs; ones that are STEEP. I can have it pegged in thrid gear, but when the bike starts to dig, it starts to go down on power, and this is with the throttle at WOT. Will the eddy cut out on the hill climb in the top range, or run out of power compared to the stocker, or what?

  • weskc35k

Posted December 09, 2007 - 11:52 PM

#28

The DRZ400 dyno report is just that a report for a DRZ400 not for an R or an L.
There will be some similarities but not enough to go on.

  • XRMANU

Posted December 10, 2007 - 04:21 AM

#29

To much grinding of the timing gear adjustment housing


Use the XR400 timing adjustment housing bolt, no more grinding needed :banghead: :busted:

  • jetfuel

Posted December 10, 2007 - 09:33 AM

#30

As far as plastic tanks and the edelbrock... keep in mind even though your carrying more fuel with a larger tank it is divided up by the arch for the frame back bone and is carried lower so if you do more street riding the fuel will not get sloshed around nearly as much as off roading hence utilizing less than its full potential and the eddies check valve does seem to need a little more fuel weight to open so giving it a good healthy lean to the left to transfer the fuel if you street ride alot helps. I personally have never had any issue with mine. but I rarely ride the street.

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  • jesusgatos

Posted December 10, 2007 - 09:41 AM

#31

Thanks for the suggestion. That might help some people, but mine still does it even with a full tank (and I think you meant 'lean it over to the right).

  • jetfuel

Posted December 10, 2007 - 09:50 AM

#32

Thanks for the suggestion. That might help some people, but mine still does it even with a full tank (and I think you meant 'lean it over to the right).


My clarke tank has the petcock on the left side. so its to the left for mine. sorry I probably should have mentioned that. If yours is doing it with a full tank something is definately malfunctioning. or are you referring to the poor WOT performance??

  • BWB63

Posted December 10, 2007 - 12:16 PM

#33

So after reading all this, the eddy sounds like a good carb, but will it pull as hard on WOT in the top range as the stock will?

Heres my issue... I'm trying to do soft sand hill climbs; ones that are STEEP. I can have it pegged in thrid gear, but when the bike starts to dig, it starts to go down on power, and this is with the throttle at WOT. Will the eddy cut out on the hill climb in the top range, or run out of power compared to the stocker, or what?


With stock header you will [COLOR="Red"]not[/COLOR] see a difference between the stock and the Edelbrock on the top if tuned right but, a giant difference bottom and mid. (as in good difference) Dropping into a wash and grabbing a handfull to blast out, is a hug difference. Once you go to a free flowing exhaust the top gets a little soft. If you adjust the needle to have more fuel at top it gets a little soft in the bottom. I think this would be fixed with a low end circuit or a bigger main jet. All of mine are bored and on has a bigger main (installed by Edelbrock) I have no idea on the different size jets they have for a main and how you would even get one besides getting ahold of Edelbrock. The down side is side even with a freeflowing exhaust is so small and it is a trade off but, what you lose with a free flowing exhaust on the bottom the Edelbrock more then makes up for. It is a different carburetor and has a different feel. Some try to make it feel like the stock and it is just a different way of carburation all together. For most I think the Edelbrock is the best all around carburetor. I do not say this just because I have a few, I like the power delivery of the FCR and TM40 better. It is because it takes care of so many things at the same time. No flooding, self adjusts for altitude, way easy to adjust. Once bored it puts out more power then the stock, everywhere.

The Edelbrock has a 38mm X 42MM or baybe it was 36mm X 42mm? oval venture, this is what helps with the volosity flow at the bottom end. The valume of the venture is almost 40mm and doesn't flow real well at that. Once bored the carb flows much better and is then bigger then the stock carb. The Edelbrock also has a sticky float valve issue, if you trailer the bike with fuel in the bowl or let the bike be stored with fuel in the bowl the float valve has a good chance of sticking closed. Once I got into the habit of running the bike dry before trailering or storing it I have not had a problem. We have had this problem on two Edelbrock's of ours and one that a friend has. I still like the carburetor for what it is and am not loyal just because I piad big bucks so, 'it must be good'. It has it nitch and it better then the stocker in a lot of ways. Stocker is better wide open but, not many live there and those that do it isn't a large % of the time. I am for any pumper on an XR650R that you can get tuned to work right.:banghead: The pump makes a big difference in the grin, fun, and blast factor.:busted:

  • Agent2

Posted December 10, 2007 - 12:28 PM

#34

I have a Edelbrock on my 650r, love it except it feels like I lost a little on the top end. 19E needle about 15 clicks out, average of 2500-3000 feet elevation. Thought I had read that some other riders had the same issue.

  • Thumpmeister

Posted December 10, 2007 - 03:53 PM

#35

So far I'm running a white bros R4 exhaust, with an e-series header. I drilled the airbox cover out, and am running a stg. 1 hotcam. I also had the head machined while it was off. Right now I'm running a 70s with I think a 180 or 182 main.

It makes GREAT power in the low end. I can take the bike down to idle, and it will almost always snap right out of it. Mid range is killer too, but it feels like there is room for just a little more.

So, will I be able to get an eddy that has been bored over as you say?

  • jesusgatos

Posted December 10, 2007 - 05:47 PM

#36

So, will I be able to get an eddy that has been bored over as you say?

I think Edelbrock stopped doing that for customers a while ago.

  • weskc35k

Posted December 12, 2007 - 02:54 AM

#37

OK so with the Edelbrock if you get the top end right it leans out the bottom?
Would a home made power now deal richen up the bottom enough.
This thing a blade that fits in the carb inlet is on a horizontal plane to the carb ending very close to the slide it speeds up the flow therefore bringing more fuel with it.Does the eddy have a slide?
All carbs have to jet a size or 2 leaner on the pilot for this thing.
Am thinking of making one for the stock carb,as it is supposed to improve bottom end grunt and snap.
The kids on the WR/f site here have it wired.

  • XRMANU

Posted December 12, 2007 - 03:35 AM

#38

Am thinking of making one for the stock carb,


Stock XR choke plate = power now ....:banghead:

  • BWB63

Posted December 12, 2007 - 07:05 AM

#39

As weskc35k said, the power now plate ends very close to the slide. The plate is very smooth and cuts the carburetor in half to stop eddies from spinning on the slide slowing down the volocity of air wich slows the pull of fuel threw the pilot. The choke plate is to far away from the the slide so the eddy of air coming down the slide is directed down right at the slide more. The choke plate also has that stupid choke flap, that should be removed.

The problem with the edelbrock is that all adjustment is being done with a wedged needle that is flat on one side. This needle regulates the fuel flow through a jet that is shaped like the needle. There is a changable jet at the bottom of this like a regular carb. but, there is no pilot curcuit. Nice idea but, this perset idea just can't do everything for every situation. I have, like you wanted to make a power now type plate for the edelbrock but, time and the excitement to do it never come around at the right time.

  • jesusgatos

Posted December 12, 2007 - 11:03 AM

#40

Let's do it! It wouldn't be much work. I'll make the CAD drawings that we could use to have parts cut if someone can take accurate some measurements. I don't feel like ripping my bike apart right now. Bruce?

Let's make a couple of these and see how they work. I have a PowerNow on my WR250F and it made a noticeable difference. Read this and this.

I can host the CAD files on our website, where anyone could download them and have parts cut. Or we could just run a batch of parts and do some type of group buy.





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