XR650L best carb VALUE ? ? ?


19 replies to this topic
  • machman

Posted November 03, 2006 - 09:54 PM

#1

What I'm trying to figure out is, what carb offers the best value for an XRL with the following modifications:
-10.5:1 piston
-hot cam
-full exhaust
The goal is to achieve the best mid-range horse-power for wheelies and other childish shinnanigans.

Options I've seen

-XR650R 40mm non-pumper ~$75 on eBay
-Keihin 41mm FCR Pumper ~$525 on XRsOnly
-Mikuni 41mm Flatside Non-pumper ~$230 on XRsOnly
-Mikuni 42mm Pumper ~$435 on XRsOnly
-Mikuni 45mm Pumper ~$435 on XRsOnly
-Edelbrock 41mm(?) Pumper ~$400 on eBay

So, feel free to chime in with your personal experiences with any of these carbs, paying particular attention to the mods that will go with it.

Note: I'm not willing to pay an extra $100 for .05HP. If the cheapest carb gets me 3 mid-range HP for $250, the $500 carb must get me 6 mid-range HP.

Thoughts?

  • martinfan30

Posted November 03, 2006 - 10:25 PM

#2

all that ive read indicates you need the keihin fcr.

  • goblin127

Posted November 04, 2006 - 03:33 AM

#3

I don't have the mods that you have,but I have the mikuni from XRs only and I've had the best of luck with it so far. It's the non pumper one.

  • Wheels up

Posted November 04, 2006 - 05:45 AM

#4

PM sent

  • xr650l bum

Posted November 04, 2006 - 10:21 PM

#5

I to am looking at uprgading my carb. My Question to all is, out of those carbs mentioned, which will be the best to use if going from sea level to 7,000ft. ? I would like to be able to adjust carb without taking apart! Xr650l Basic mods done with full yoshi exhaust. What is a pumper carb? Thnx

  • goblin127

Posted November 05, 2006 - 04:12 AM

#6

I to am looking at uprgading my carb. My Question to all is, out of those carbs mentioned, which will be the best to use if going from sea level to 7,000ft. ? I would like to be able to adjust carb without taking apart! Xr650l Basic mods done with full yoshi exhaust. What is a pumper carb? Thnx


You would want the edelbrock Quick silver carb. A pumper carb has a fuel pump vs. vacume caused by the engine only.

  • xr650l bum

Posted November 05, 2006 - 07:15 AM

#7

Is the quicksilver a pumper carb? If it has a pump in the carb, does it have to hook up to power? Will that carb also be good if I go through and uprgade motor ( bore,piston,cam)? Thnx

  • daddyk

Posted November 05, 2006 - 08:13 AM

#8

They're talking about a accelerator pump built into the carb. It gives the engine a squirt of gas when the throttle is twisted.

  • jbird710

Posted November 05, 2006 - 08:35 AM

#9

My engine is stock. I've added a WHite Bros. E2, smog block off, removed the snorkel, and put in a K&N filter. I went with the Edelbrock from Barnums Pro and it came with everything you should need. There's no jetting to fiddle with; you use different size needles in the slide to adjust air/fuel ratio. It also comes with new throttle cables and adjusting thumb screw that fits on top to do low speed adjustments. It is night and day better than the stock vaccum operated slide, even with Dave's mods. I have seen some other posts about folks having some issues with theirs, but I've had mine for 8 months and haven't had the first hint of any problems. I run at sea level up to maybe 100 ft. above, so I can't say what it would do at 7000 ft.:mad:

  • xr650l bum

Posted November 05, 2006 - 08:40 AM

#10

Well I did a search to see what people thought about the QS carb! WOW!!! Huge controversy regarding reliability. Lots of people say it sticks. Lots of sending them back to Edelbrock. The posts started back in 04. Somehow the forum stop me from finishing the thread, so I dont know if this problem ever got resolved! Is running the xr600 model with the larger mm on the xr650l better, or do they make different models for the 650l. Also looking at the Edelbrock, they say for 95-on. I have a 93, and dont see why it would be different. Special bitchin first year model!!!! Lots of questions need to be answered. Help!!

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  • Rideaide

Posted November 05, 2006 - 03:46 PM

#11

Look at the 42mm or 45mm Mikuni Pumper carb here. Works really well and easy to adjust.:mad:

http://www.xrsonly.c...emart&Itemid=77

  • thumprr

Posted September 19, 2008 - 01:53 AM

#12

I just installed a Mikuni 42mm Pumper carb that I bought from XR's only. I also installed a BigGun full exhaust. I already had done "Dave's Mods" before. I have a 2000 Honda XR650L with about 7500 "pampered" miles on it. Now it cranks good, idels good...but it has no "snap" to it at all? I told the guys at XR's Only what mods I had done, it was suppose to come pre-jetted for the type mods I informed them of.I have a UNI airfilter installed. Any suggestions before I pull it back out? This thing is such a tight fit for me to get in and out. I am sure if I get it right, it will be well worth the time, effort and money spent on it.Thanks in advance for any help.:lol: :excuseme:

  • thumprr

Posted September 19, 2008 - 02:26 AM

#13

I didn't see my response in new posts so I wanted to bump once to see if it moves to recent posts.

  • thumprr

Posted September 20, 2008 - 07:48 AM

#14

bump once more.

  • Kenzo

Posted September 21, 2008 - 08:19 AM

#15

I just installed a Mikuni 42mm Pumper carb that I bought from XR's only. I also installed a BigGun full exhaust. I already had done "Dave's Mods" before. I have a 2000 Honda XR650L with about 7500 "pampered" miles on it. Now it cranks good, idels good...but it has no "snap" to it at all? I told the guys at XR's Only what mods I had done, it was suppose to come pre-jetted for the type mods I informed them of.I have a UNI airfilter installed. Any suggestions before I pull it back out? This thing is such a tight fit for me to get in and out. I am sure if I get it right, it will be well worth the time, effort and money spent on it.Thanks in advance for any help.:excuseme: :lol:


try the jetting board for info on dialing in ur carb...



as far as best bang for the buck L carb...i'm very pleased with my R carb swap that's well documented on this board...

get's rid of the CV slugishness and the price is right...

there is a bit of a bog if u wack the throttle too fast off idle but the more i read a pumper does not totally eliminate this issue ether...unless ur a sumo racer usally smooth throttle input is better anyway :excuseme:

:banana:

  • they call me thumper

Posted April 23, 2015 - 08:46 AM

#16


try the jetting board for info on dialing in ur carb...



as far as best bang for the buck L carb...i'm very pleased with my R carb swap that's well documented on this board...

get's rid of the CV slugishness and the price is right...

there is a bit of a bog if u wack the throttle too fast off idle but the more i read a pumper does not totally eliminate this issue ether...unless ur a sumo racer usally smooth throttle input is better anyway http://www.thumperta...R#/thumbsup.gif

http://www.thumperta...DIR#/cheers.gif

does the R carb make a huge difference? Even from Dave's mod? if it really is about 50 bucks I might have to try it if it makes a difference

  • XR650L_Dave

Posted April 23, 2015 - 08:50 AM

#17

does the R carb make a huge difference? Even from Dave's mod? if it really is about 50 bucks I might have to try it if it makes a difference

 

A manual slide carb, even a non-pumper, will give better throttle response than the best you can make the CV carb perfrom.

 

You can get rid of the CV carb bogging and outright hesitation, but it will always open a little slower than your wrist if you flick it open.



  • they call me thumper

Posted April 23, 2015 - 08:55 AM

#18

A manual slide carb, even a non-pumper, will give better throttle response than the best you can make the CV carb perfrom.

You can get rid of the CV carb bogging and outright hesitation, but it will always open a little slower than your wrist if you flick it open.

Sorry but you are going a little over my head. What is a CV? ( Cylinder vaccum? ?)
And what is the difference from a manual slide?
sorry I don't havery any experience... just a speed itch

Edited by they call me thumper, April 23, 2015 - 08:58 AM.


  • D0T-C0M

Posted April 23, 2015 - 09:41 AM

#19

@OP none of the carbs will give you more noticeable horse power unless you increase your mass air flow by going to a larger bore carb.  Bigger bore carbs will mostly only affect your WOT power but larger bore carbs also mean you get less low/mid range throttle response.  What your trying to achieve by upgrading the carb is to get better throttle response.  In stock configuration the XRL is VERY sluggish.  Trust me its night and day.  If you want your bike to pull instant wheelies and other childish "shinnanigans" then you want a FCRMX carb.
 
Here is my experience,  I tried the stock carb with dave's mods which is slight less boggy/sluggish from stock.  The advantage is that it does help and its cheap.  The XRR carb is not as sluggish as the CV carb but it still suffers from bog and also throttle sticks at idle over time but its still fairly cheap.  I do not recommend getting an eldebrock as they are discontinued and parts can be hard to find and I've read and talked to a few respected members here that have had problems with them.  Finally the OEM FCRMX carb, excellent throttle response and by FAR the best of them all.  Instant throttle response which is very VERY noticeable.  It has a different slide construction and it doesn't stick and it easier to open under vacuum. Do yourself a favor if your going to upgrade go with a FCRMX pumper carb.  The mukuni pumper is another good alternative from what I've read but I only have experience with the FCRMX.
 
Get an OEM carb (07/08/09 CRF250R and the 07/08 CRF450R) that has the new AP linkage and diaphram. Do not buy a sudco carb because they still use the old AP linkage and will require modding.  You can get the right FCRMX carb for about $200-$300 on ebay.  Then get a NOSS adapter, use your stock throttle cable and my recommended jetting below and you should be very close to perfect.
 
With your mods at 0'-1000' elevation I would recommend:
 
NCVT needle 3rd clip from top
158 or 160MJ
42 PJ
35 LJ or completely solder it shut
 
Here is a great thread to read up on on upgrading to a FCRMX carb.


Edited by D0T-C0M, April 23, 2015 - 12:01 PM.


  • XR650L_Dave

Posted April 23, 2015 - 02:15 PM

#20

Sorry but you are going a little over my head. What is a CV? ( Cylinder vaccum? ?)
And what is the difference from a manual slide?
sorry I don't havery any experience... just a speed itch

 

The CV stands for constant velocity- the way it works is there is a throttle valve between the slide and the cylinder. that controls how much throttle you want, then air flowing through the carb actually sucks the slide up using the pressure difference between the air in the throat under the slide and the air above the slide.

If the spring below is weaker the slide can mive up MORE for a given throttle setting.

If the hole SVP is bigger, air can get sucked out from above the slide FASTER.

The slide also controls the mixture between 1/8 throttle and full throttle, so how it moves needs to be co-ordinated with the needle position and shape to make sure it never gets too rich or too lean.

 

The pic below omits the vent under the diaphragm (DIA).

 

CV_Cutaway.jpg

Note, not my pic, just a handy one I found


Edited by XR650L_Dave, April 23, 2015 - 02:24 PM.






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