XRL FCR or Edelbrock ?


11 replies to this topic
  • axarob44

Posted September 15, 2007 - 12:22 PM

#1

I'm looking to get a pumper carb, but I know nothing about them. What is all involved with the swap? I don't want to do any modifications if possible. What I mean by that is, I don't want to change the intake boots on either side of the carb unless new ones come in a kit. I don't want to change or remove anything from the air box( meaning cut or drill or mangle). I assume the kit comes with all the required parts (cable, throttle tube assy., jets, clamps)? Where is the best place to get either? I need your input guys. Thank You.:thumbsup:

P.S. Please tell me there are other places to get a carb kit than XR's only.

P.S.S I am searching as we speak

  • hill5150

Posted September 15, 2007 - 01:36 PM

#2

I would opt for the edelbrock, it is highly suggested that you uncork your bike assuming it's an "R". The side panel cut out is a real benefit to the bike, as it needs to breathe.I believe the stock boots are used, and it comes w/ all cables and throttle. You can get the Eddie at Barnums. My .02.......

  • jbird710

Posted September 15, 2007 - 03:17 PM

#3

+1 for the Edelbrock. I got one from Barnums Pro for my XR650L and have been extremely happy with it. Night and day better than the stock CV carb. It comes with the carb, 3 different needles, and throttle cables. There are no jets to change on the Edelbrock. All of the metering is done with the slide needle. It also comes with a adjusting knob that fits into the top to allow fine tuning. There are no modifications to the engine intake nor the boot from the air box. As Hill5150 suggested, you may want to remove the snorkel on the air box to get a little more air and I replaced my pipe with a White Brothers E2. Here's the Barnum's web site :
http://www.barnumspr...vlet/StoreFront

  • axarob44

Posted September 15, 2007 - 03:17 PM

#4

Thanks Hill5150, but I have a XRL.

Thanks Jbirb, The Edelbrock sound pretty good. From what you saying its pretty user friendly. Oh, I should have stated in my first post that I already have all the usual mods for the XRL done already. I guess I should ask then, will the Edelbrock give me as good of perfomance as the FCR?

  • rmhrc630

Posted September 15, 2007 - 09:37 PM

#5

Thanks Hill5150, but I have a XRL.

Thanks Jbirb, The Edelbrock sound pretty good. From what you saying its pretty user friendly. Oh, I should have stated in my first post that I already have all the usual mods for the XRL done already. I guess I should ask then, will the Edelbrock give me as good of perfomance as the FCR?


Prob not the performance. I beleibe they are easier to fit however.

ON my 628 with estart I fitted a more modern FCRMX41mm Keihin which rips the house apart.

I had to machine the back of the carby - but it fitted and it works really well.

I also decided to fit the CRF450R throttle cables and throttle so that I not only had the best carby but the smoothest and easiesth throttle pull.

The heavy stock XR throttle action is really tiring. The FCR slide runs on bearings so it's super smooth.

  • HawkGT

Posted September 16, 2007 - 01:09 AM

#6

Sudco sells an FCR carb kit for the XRL. I'd call and ask what, if any, mods are needed for fitment. As far as outright performance, I don't think you can beat an FCR. They're not the OEM carb of choice on the fast majority of competition (or just high performance) off road bikes for nothing. I'm not saying the Edelbrock is not a reasonable choice. I'm sure it wouldn't be so popular among the XR crowd if people weren't satisfied.

However, my personal (and admittedly dubious, since I've not actually tried one first hand) opinion of the Edelbrock design amounts to moderate skepticism. Easy to adjust? Sure. Easy starting? Apparently. But I don't see how a single adjustment (and a single fueling circuit) can offer optimum fueling. The a/f ratio traces (from dyno runs) I've seen of Edelbrock equipped bikes have had downward sloping (i.e. increasingly rich as the rpms build) shapes. Fix one end of it and you screw with the other. Just food for thought! I know there's lots of happy Edelbrock owners around here.

Whatever you choose, take the extra time, effort, and expense to have it tuned on a dyno with an a/f meter and competent operator. Really, the ideal scenario would be to dyno your bike first to get a baseline and then tune the new carb on that same dyno. Then you'd be able to quantify the new carbs benefit beyond the often deceiving "set of the pants" feel.

$0.02

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  • jbird710

Posted September 16, 2007 - 04:17 AM

#7

I can't compare the Edelbrock with the FCR as I haven't ever worked with the FCR. The Edelbrock is easy to install and fairly easy to tune. As Hawk mentions, I do believe it does run a little richer closer to top end. But; it's better than running leaner.

  • axarob44

Posted September 16, 2007 - 11:50 AM

#8

A lot of food for thought here. The dyno tuning sounds like the right way to do this. There is a guy local that could do that for me. I was leaning towards the FCR to begin with, but like was said, there are a lot of guys here that like the Edelbrocks. I'm going to check out Sudco for the FCR kit. I think I saw in a recent thread about an FCR model that has a choke and unless you ask for that model from Sudco, you get the model without?

  • HawkGT

Posted September 16, 2007 - 01:13 PM

#9

See what Sudco says. I'd be surprised if their kit was anything but an early model FCR. I didn't think those were available with an enrichening circuit (none of them really have chokes, per say). Current FCR-MX models have evolved a fair amount and are available with enricheners, hot starts, and other features. If you include OEM supplied FCR's, there must be dozens of various FCR configurations. Any FCR is still an outstanding carb but perhaps they could supply an MX model with the features you want and the appropriate spigots to make it mount up. Expect to pay through the nose however! Personally, an early model FCR would not be a turn-off for me. I have a pair of early 39mm's on a 90' Honda NT650 twin and they are great carbs.

FWIW, I had a 400cc RFVC Honda engine with an accelerator pump equipped carb and a butterfly-type choke. I removed the choke and just used the AP to prime the engine for cold starts. It's nearly the same effect as having a enrichener to get the engine to light off. Once fired, careful throttle inputs kept it running until it got some heat in it--just had to babysit the throttle for a bit. I don't think I ever tried to start it in less than maybe 45 degree weather. In comfortable riding temps (or even colder than comfortable) I never had any starting issues by using the AP as a substitute "choke". YMMV

  • jbird710

Posted September 16, 2007 - 01:27 PM

#10

With the Edelbrock, I just open the petcock, wick the throttle 3 - 4 times, and hit the starter. The bike always starts right up and will idle. I'm sure the FCR would work the same way.

  • rmhrc630

Posted September 16, 2007 - 01:28 PM

#11

If you get a FCRMX make sure it's the aftermarket version NOT OEM.

41mm is the size you want.

Machining the back of the carb is not too difficult. Apart from that it fits in perfectly. Also it provides super easy throttle action with 450R throttle system.

Posted Image

  • martinfan30

Posted September 17, 2007 - 07:21 AM

#12

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But I don't see how a single adjustment (and a single fueling circuit) can offer optimum fueling. The a/f ratio traces (from dyno runs) I've seen of Edelbrock equipped bikes have had downward sloping (i.e. increasingly rich as the rpms build) shapes. Fix one end of it and you screw with the other.

this is why i chose the fcr. i got the sudco kit, slant body, no choke. i have zero problems starting cold. highly recomend it. if you rewally want a choke ask for the mx version.





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