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    XR250R/XR250L Carburetor Notes

January 23, 2018 version

Click pictures to supersize.

CONTENTS
   XR250 / XR250R generations
   External similarities
   Cylinder head connection
   Air box connection
   Rebuild Kits - OEM and aftermarket
   Comments


A few observations on the US 1986-2004 XR250R and the 1991-1996 XR250L carburetors.

The purpose of this web page is to provide riders with information to mix-n-match various US XR250R and XR250L carbs and parts. Note that UK and AUS carbs may be similar, but as far as I know, the bikes are road versions and some have electric start. Other countries around the world have a dizzying variety of XR models/carbs. I will be discussing the US carbs only.

US carbs come in 49-state and California (CA) versions and some carbs come in one version only. I will not specifically address the CA versions. The primary difference between the two versions is jetting.


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XR250 / XR250R generations

Gen 11979-1980XR250 twin shock
Gen 21981-1982XR250R single shock
1983skipped
Gen 31984-1985XR250R RFVC head, single shock, short stroke,  B x S  75.0 x 56.5 mm
Gen 41986-1995XR250R RFVC head, single shock, long stroke,  B x S  73.0 x 59.5 mm
Gen 51996-2004XR250R RFVC head, single shock, long stroke,  B x S  73.0 x 59.5 mm, oil in frame

The US XR250L is based on the US 1986-1995 XR250R model.
XR250R Gen 4 and 5 and all XR250L models (91-96) are the focus.
Other XR250 / XR250R years are not considered herein.


Honda was surprisingly consistent using a distinct carb for each Gen 4, Gen 5, and L bike group, as shown below.
PD05, PDG1, and PD79 carbs come in variations determined by jetting component differences.

I have decided to use data from only one carb from each group - the first carb in each group. Subsequent carbs generally have minor changes, mostly jets, and otherwise maintain the same configuration.

XR250R carbs - Gen 4

86-89
 
PD05A-A
 
16100-KT1-014
16100-KT1-652
90-95PD05B-A16100-KZ1-671

86-95 are not available from Honda dealers.


XR250R carbs - Gen 5

96-97PDG1A-A16100-KCE-671
96-97PDG1A-C16100-KCE-672
98-99 49PDG1A-A16100-KCE-671
98-99 49PDG1A-C16100-KCE-672
98-99 CAPDG1C-A16100-KCE-771
98-99 CAPDG1C-B16100-KCE-772
00-04 49PDG1A-C16100-KCE-672
00-04 CAPDG1C-B16100-KCE-772

96 and newer are available from Honda dealers - about $250 and up.


XR250L carbs

91 49PD79E-A16100-KV6-671
91 CAPD79F-A16100-KV6-681
92-96 49PD79G-A16100-KV6-690
92-96 CAPD79H-A16100-KV6-730

91-96 are not available from Honda dealers.


Some carbs are available from aftermarket vendors, on eBay, and from private parties.


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External similarities

I have never had the opportunity to hold all 3 carb models in my hands at one time, but I have held each of them at one time or another. I first thought about comparing them when I bought my 1991 XR250L and began to study that bike's carb to see if I could improve it's performance using XRR jetting parts. I was able to physically compare the XRL carb to my 86 XR250R carb and make decisions about parts swapping. As I create this web page, I have NONE of the three carb models available, so I will resort to parts fiche and old notes.

Belay that last remark. Friends have seen to it that I have physical samples of the carbs I'm describing; I will be posting many carb pictures with explanations and observations. Stay tuned....

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DISCUSS choke, AP, inlet, outlet, length, height, width.
Jets are chosen by vendors, and are not necessarily the sizes you should use. Jetting is dependent on riding elevation, temperature, humidity, and the state of engine tune (performance modifications).


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Cylinder head connection

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The first item of note is the carb insulator, which connects the carb to the cylinder head: it is identical between all three carbs.
The o-rings are identical, also.

The mounting bolts differ, as well as the metal bands and bolts.

The evidence suggests that the three carb models have identical fronts. All three are PD variants, and this supports the conclusion.

Honda part numbers are shown in the table below.


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Air box connection

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The air box connecting tube front opening fastens to the back of the carb, and the band clamp size reveals the size of the back of the carb bell.

86-95 XR250R A AIR CLEANER
BAND, AIR CLEANER CONNECTING TUBE (52)  90652-GHB-690  95018-52250
  ↑ same ↓
91-96 XR250L A AIR CLEANER
BAND, AIR CLEANER CONNECTING TUBE (52)  90652-GHB-690  95018-52250
  ↑ different ↓
96-04 XR250R A AIR CLEANER (A)
BAND, AIR CLEANER CONNECTING TUBE (60)  90652-GHB-730  95018-60250

52 mm = 2.05" = 2 1/1686-95 XR250R carbs and XR250L carbs have 2" rear spigot/bell
60 mm = 2.36" = 2 3/896-04 XR250R carbs have 2 1/4" rear spigot/bell

Honda part numbers for parts shown above are listed in the table.

1986 XR250R1991 XR250L1996 XR250R
Carb to cylinder head
 6INSULATOR, CARB16211-KT1-003-
 6INSULATOR, CARB16211-KT1-013 6INSULATOR, CARB16211-KT1-013  8INSULATOR, CARB16211-KT1-013same
 7BAND, INSULATOR16223-MJ0-000-
 7BAND, INSULATOR16223-KS5-000 8BAND, INSULATOR16223-KS5-00010BAND, INSULATOR16223-KS5-000same
13O-RING91302-KR0-00314O-RING91302-KR0-00317O-RING91302-KR0-003same
17BOLT, FLANGE (6X22)95700-06022-0018BOLT, FLANGE (6X22)95701-06022-0711BOLT, FLANGE (6X22)90004-GHB-660diff
17BOLT, FLANGE (6X22)95701-06022-00-
15SCREW, PAN (5X25)93500-05025-0G16SCREW, PAN (5X30)93500-05030-0G12BOLT (5X28)90023-MM5-000diff
 7NUT, SQUARE (5MM)16222-MV4-300 9NUT, SQUARE (5MM)16222-MV4-300same
Carb to air box
BAND, AIR CLEANER TUBE (52)90652-GHB-690BAND, AIR CLEANER TUBE (52)90652-GHB-690BAND, AIR CLEANER TUBE (60)90652-GHB-730diff
95018-5225095018-5225095018-60250diff

Stock Honda part numbers from:
Dillon Brothers Motor Sports - partsfish.com      Partzilla - partzilla.com


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Rebuild Kits - OEM and aftermarket

OEM kits

Honda groups some carb parts into sets; other parts are listed individually. These sets make do as rebuild/repair kits. I show the Gasket Sets for the three carbs of interest.

86-95 XR250R GASKET SET 16010-434-305  $22.18 RMAM (Rocky Mountain ATV/MC)
96-04 XR250R GASKET SET 16010-KCE-670  $21.74 RMAM
91-96 XR250L GASKET SET 16010-KR6-305  $23.01 RMAM

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The parts are keyed to these tables ↓ and the fiche shown in the aftermarket kits section below.

 1986 XR250R 
1GASKET SET16010-434-305
1aFloat bowl gasket 
1bFloat bowl bottom bolt o-ring 
1cFloat bowl drain screw o-ring 
1dFuel screw o-ring 
1eTop gasket 
1fAir cut-off o-ring 

 1996 XR250R 
1GASKET SET16010-KCE-670
1aFloat bowl gasket 
1bFloat bowl bottom bolt o-ring 
1cFloat bowl drain screw o-ring 
1dFuel screw o-ring 
1eTop gasket 
1fAir cut-off o-ring 

 1991 XR250L 
1GASKET SET16010-KR6-305
1aFloat bowl gasket 
1cFloat bowl drain screw o-ring 
1dFuel screw o-ring 
1eTop gasket 
1gAir cut-off base o-ring 
1hFloat bowl rod o-ring 
1iAccelerator pump rod o-ring 

The XR250R carb Gasket Sets are identical; the XR250L carb Gasket Set differs slightly due to the accelerator pump and the absence of a float bowl bottom bolt and air cut-off. You can see a list of the other sets by looking at the comprehensive master spreadsheet near the bottom of the web page.


Aftermarket kits

There are several vendors who offer carb repair or carb rebuild kits at prices substantially less than the corresponding Honda OEM sets and parts. These kits are actually an aggregation of several Honda OEM sets into one package. A few Honda OEM parts are not represented in the aftermarket kits.

These kits are similar to each other, differing in regards to the accelerator pump etc just as the OEM Gasket Sets differ.

Most parts in these kits are of acceptable quality, with the notable exception of the fuel screws, needles, main jets, and pilot jets. The fuel screws are identical to the early OEM fuel screws, and they are really too short. A longer aftermarket fuel screw is much better. I did not measure the needles to compare them to the OEM needles. They are a very light weight brass or alloy and I don't trust them; I prefer OEM needles. The same goes for the jets; I prefer OEM Keihin jets, available from Honda dealers or JetsRUs.


Shindy carb rebuild/repair kit XR250R 1986-95 - 03-734  $21 eBay  $24 RMAM

The aftermarket parts in the Shindy rebuild kit (left picture just below) are keyed to stock Honda parts shown in the table and fiche. The parts break-out shows parts in each Honda set. Honda does not uniquely number each part in a set, but I have numbered these parts so they can be located on the fiche.

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          ↓ Honda sets - parts break-out

 1986 XR250R 
1GASKET SET16010-434-305
1aFloat bowl gasket 
1bFloat bowl bottom bolt o-ring 
1cFloat bowl drain screw o-ring 
1dFuel screw o-ring 
1eTop gasket 
1fAir cut-off o-ring 
2VALVE SET, FLOAT16011-KG0-891
2Float needle and bail 
3NEEDLE SET, JET16012-KA6-004
3aNeedle jet 
3bNeedle clip 
3cNeedle, 5 position  D700 
6CHAMBER SET, FLOAT16015-KA6-004
6fFloat bowl drain screw 
7SCREW SET A16016-385-681
7bFuel screw washer 
7cFuel screw spring 
7dFuel screw 
31JET, MAIN #12599101-357-1250
31Main jet, 125  no logo 
32JET, SLOW #4099103-437-0400
32Slow jet, 40  no logo 

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Shindy carb rebuild/repair kit XR250R 1996-04 - 03-735  $22 eBay  $24 RMAM

The aftermarket parts in the Shindy rebuild kit (left picture just below) are keyed to stock Honda parts shown in the table and fiche. The parts break-out shows parts in each Honda set. Honda does not uniquely number each part in a set, but I have numbered these parts so they can be located on the fiche.

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          ↓ Honda sets - parts break-out

 1996 XR250R 
1GASKET SET16010-KCE-670
1aFloat bowl gasket 
1bFloat bowl bottom bolt o-ring 
1cFloat bowl drain screw o-ring 
1dFuel screw o-ring 
1eTop gasket 
1fAir cut-off o-ring 
2VALVE SET, FLOAT16011-KCK-910
2Float needle and bail 
3NEEDLE SET, JET16012-KCE-670
3aNeedle jet 
3bNeedle clip 
3cNeedle, 5 position D701 
6CHAMBER SET, FLOAT16015-KCE-671
6fFloat bowl drain screw 
7SCREW SET A16016-402-004
7bFuel screw washer 
7cFuel screw spring 
7dFuel screw 
32JET, SLOW 4599103-KPS-0450
32Slow jet, 45  no logo 
33JET, MAIN 13299113-GHB-1320
33Main jet, 132  no logo 

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Keyster carb repair/rebuild kit XR250L 1991 - KH1066NA  $38 eBay

The aftermarket parts in the Keyster rebuild kit (left picture just below) are keyed to stock Honda parts shown in the table and fiche below. The parts break-out shows parts in each Honda set. Honda does not uniquely number each part in a set, but I have numbered these parts so they can be located on the fiche.

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          ↓ Honda sets - parts break-out

 1991 XR250L 
1GASKET SET16010-KR6-305
1aFloat bowl gasket 
1cFloat bowl drain screw o-ring 
1dFuel screw o-ring 
1eTop gasket 
1gAir cut-off base o-ring 
1hFloat bowl rod o-ring 
1iAccelerator pump rod o-ring 
2NEEDLE SET, JET16012-KV6-671
2aNeedle jet 
2bNeedle clip 
2cNeedle, 1 position D344 
6SCREW SET A16016-KC2-970
6aFuel screw washer 
6bFuel screw spring 
6cFuel screw 
13VALVE, FLOAT16155-413-751
13Float needle, short, no wire bail 
14HOLDER, NEEDLE JET16165-473-004
14Needle jet holder 
35JET, MAIN #12299101-GHB-1220
35Main jet, 122  no logo 
36JET, SLOW #3899103-KV6-0380
36Slow jet, 38  no logo 

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A picture of all three rebuild kits showing all parts at a glance so differences can be easily seen.
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Rebuild/repair kit summary

The similarities between kits, with the notable exception of the accelerator pump on the 250L, indicates how interchangeable these carbs and their parts are.

When I modified the carb on my XR250L, I wrote:

The accelerator pump carb on the XR-L looks like it has potential. Pumper carbs can be jetted to get rid of that nasty four-stroke hesitation on the bottom and give good power on top too. However, the non-pumper carb from the XR is ultimately a better performer because it is designed for more air/gas flow. The needle and seat on the pumper carb are designed to make the bike EPA legal (lean) and are the biggest impediment to performance.

Where I wrote 'needle and seat' I should have written 'needle, fuel screw, main jet, and pilot jet' because these items collectively limit the carb's performance so it conforms to EPA standards. I suspect that changing the needle to an XR250R needle would provide a significant improvement in performance. Getting the jets correct for your riding elevation and setting the fuel screw for optimal off-idle pickup would be the final tuning steps necessary for best performance. Setting up the accelerator pump would be the icing on the cake. I actually think a correctly set up XR250L carb would be the perfect carb to install on 86-95 XR250R bikes.

I plan to set up a 250L carb for a local XR250R rider, and will post up results when they are available.


A picture of the master spreadsheet showing all carbs parts at a glance so differences can be easily detected. The lower case 'd' in columns D, H, and L indicate part number differences. Although there are instances where Honda has changed a part number and the new and old parts are actually the same, it's more often the case that different part numbers means different parts.
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Comments

When the 1991 XR250L arrived, many of us saw it as a derivative and extension of the XR250R Gen 4 line that began with the long-stroke 1986 engine. As we delved into the XRL, we saw that it was just an XRR with street-legal additions (lights, horn, battery), and we knew the path from a street-legal XRL to a more dirt-oriented XRL could be facilitated by the simple replacement of XRL parts with aftermarket-improved XRR parts.

When the 1996 XR250R was studied, it was clear that it was a next-gen bike, and moving parts from this newer model to the XRL might not be so easy or productive.

All of this is to say that it is important to mention the YEAR and MODEL when talking about which parts crossover.

  

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