The OSKRG`s Identification Guide and What Fits

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OSKRG Research/Restoration Bulletin #2C
66-71Tillotson Carburetors
VS.1
This research and restoration bulletin was created with input and
assistance from members of the OSKRG. The report consolidates
the best available information at the time of creation and may be
updated or revised at a future date. If errors are identified, or
there is additional information on the subject of this report that
has not been included, please send corrections or additions to:
graino@comcast.net & sklange@comcast.net
© 2014 By OSKRG
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Forward
As the opening statement on page 1 states “This research and restoration bulletin was created with input and
assistance from members of the OSKRG. The report consolidates the best available information at the time of
creation and may be updated or revised at a future date. “This work is by no means definitive. A realistic
expectation of this work would be that there are going to be errors but at least it is a place to start the
conversation from. Consider this bulletin to be a living thesis, as empirical evidence presents itself this document
will be modified to more accurately reflect what was original equipment on the Sportsters from 1966 through
1971. It addresses the Tillotson series of carburetors. There are a number of models and years that remain a little
unclear like which HD carb was used on the 71 models and were any of the HD2 series carbs ever stock on any of
the Sportsters. If you have a bike that you are confident has its original carb on it we would love to hear from you.
Within the document we have a “score card” of sorts to track what carb people have on their original bikes, this
score card can serve as an important validation tool. Hopefully over time we can mold this document into a
valuable tool to help enthusiast in their restoration efforts.
© 2014 By OSKRG
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Table of Contents
Section 3, 66-71 Tillotson Carburetors: Page 50
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© 2014 By OSKRG
Tillotson Carburetor Model, Tillotson Carburetor Part Number, Jet Diameter/Number & Comments
Tillotson Carburetor Significant Part Number Changes from Parts Book to Parts Book
What Is Actually On Your Bike-Please Let Us Know
XLH & XLCH Gas Tank Fuel Valve & Outlet
66-71 XLH & XLCH Air Cleaner Back Plate, Cover & Filter
Tillotson Choke Assembly 1966 Only XLH & XLCH
Tillotson Choke Assembly 1967-1971
Tillotson “Tickler” & Main Jet Size vs. Needle Turns Out
Comments about the Tillotson Series of Carburetors by Bob Evans
Comments about the Tillotson Series of Carburetors by “Dr. Dick”
Additional Comments about the Tillotson Series of Carburetors by Dave C.
Section 3
66-71Tillotson Carburetors
Green Indicates Some Degree of Confidence Carb was Original Equipment-Yellow indicates Uncertainty (R12)
Tillotson Carburetor Model
Part Number
Tillotson Factory
Original Drawing Dates
1966
1967
1968
1969
1970
HD-1A
27162-66
Sept. 1964
HD-1A
Tillotson Factory Comments: The HD label was created specifically because of the Harley motorcycle, so that would be the earliest year you would see a Tillotson on a Harley.
1971
It could have been as
much 1 or 2 years later, depending on how much testing they did. The last modification to the drawings was in August 1969.
Comments by Others: XLH-XLCH. 1 year only choke lever. Believe that the HD-1A & HD-1B were used with staggered duals. (Dave C.)
HD-1B
27162-66A
Jan. 1966
HD-1B
Tillotson Factory Comments: The last modification was in October 1969.
Comments by Others: Service bulletin # 547, dated Oct.24 / 66 all XLCH's produced after Aug.10 / 66 (from VIN 66XLCH10611) will have the new inlet
valve; new carbs identified as HD-1B. The upgrade (repair) kit for HD-1A use ordering # 27588-66. (Lloyd G.)
XLH-XLCH. Believe that the HD-1A & HD-1B were used with staggered duals. (Dave C.)
HD-1BC
27162-66B
Jan. 1967
May be some
late 67s with
the HD-1BC
HD-1BC Run
Change to
HD-1C
Tillotson Factory Comments: I think this was an intermediary bridge between the B and the C. I wouldn't be surprised if it was some kind of minor midyear running change that eventually morphed into the C.
Comments by Others: Service bulletin # 571 dated May 21 / 68 says late ' 68 Sportsters will now have the new 27162-66B Tillotson carb with new
checkball in the plastic pump body to stop air bleedback. The new carbs are stamped HD-1BC and HD-1C. To order just the new plastic plate with the check
ball the order # is 27804-66A.
HD-1C
27162-66C
Nov. 1967
HD-1BC Run
Change to
HD-1C
HD-1C
HD-1C Run
Change to
HD-1CD
Tillotson Factory Comments: Last modification in 1969.
Comments by Others: XLH-XLCH. HD-1C was 68 at least in California which used the "Bronson" pipes in 68 & 69, HD-1D running change from HD-1C in
1970. (Dave C.)
HD-1CD
OCT. 1967
HD-1CD Run
Change to
HD-1D
Tillotson Factory Comments: The dates were scratched off but I could read them as October 1967.The drawings specifically note that it is the same as the
HD-1D so again I think it was some kind of transition numbering.
HD-1D
March 1970
HD-1CD Run
Change to
HD-1D
HD-1D
Tillotson Factory Comments: From what people remember, the 1's were all in succession so my guess is that the 1A was used sometime between 1964
and 1966, then it went to a B and C until 1969 then the D took over as the final model. I suspect the modifications to the A-C were fixes that were carried
back for replacement purposes. I think you can assume that Harley stopped ordering the older models for NEW production on or very near the date of the
drawings for the new model.
Comments by Others: HD-1D running change from HD-1C in 1970. Believe this may have been a running change with the 1970 switch from the more costly
"Bronson" exhaust to the Bagpipe, which had even smaller diameter exhaust pipes than their predecessors. (Dave C.)
HD-2C? or
HD-2C
HD-2D?
Comments by Others: HD-1D was 1970 and 71 believe Harley used HD-2C's or HD-2D’s or whatever was left over from Big Twins fitted with Tillotsons
from 67 to 70. (Dave C.)
HD-2C? or
HD-2D
Nov. 1967
HD-2D?
Comments by Others: HD-1D was 1970 and 71 believe Harley used HD-2C's or HD-2D’s or whatever was left over from Big Twins fitted with Tillotsons from
67 to 70. (Dave C.)
General Comments: Some of this is verified by the sundial date code on some Tillotson bodies. The model change with the exhaust change is a fairly logical story.
(Dave C.)
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66-71 Tillotson Carburetors
Tillotson Carburetor Significant Part Number Changes from Parts Book to Parts Book vs.1
Note: A column Part Number Color Change Indicates a Part Number Change. Text in Red Indicates What the part is Supposed to Fit has Changed.
Parts
Book
Year
Carburetor
Complete
Part
Number
Possible
Tillotson
Carburetor
Model
Inlet
Needle,
Seat &
Gasket
1967 PB
27162-66
66 XLH &
XLCH
27162-66A
67 XLH &
XLCH
HD 1A
27597-66
66 XLH &
XLCH
HD 1B
27588-66
67XLH
27162-66C
66 to 71
XLH & XLCH
????????
27588-66
66 to 71
XLH &
XLCH
1971 PB
Parts Book Year
Stud, Carburetor
Adaptor-2”
Inlet Lever,
Needle,
Seat &
Gasket
Stud, Carburetor
Adaptor-1 & 5/8”
Carburetor Main Jet
Bracket
Throttle
Cable
Throttle
Shaft &
Lever
27615-66 .057” STD.
27616-66 .061”
27617-66 .053”
27618-66 .055”
27619-66 .059”
27620-66 .063”
27448-57
57 to 66 XL,
XLH & XLCH
27449-66
67 XLH &
XLCH
27708-66
66 XLH &
XLCH
27708-67
67 XLH &
XLCH
27615-66 .057” STD.
27616-66 .061”
27617-66 .053”
27618-66 .055”
27619-66 .059”
27620-66 .063”
27449-66
67 to 71
XLH & XLCH
27708-67
66 to 71
XLH &
XLCH
Insulating Block,
Carburetor Mounting
Insulating Block,
Carburetor Mounting
1967 PB
1971 PB
Wire Block,
Throttle
Lever
1962-1973
Supplement
© 2014 By OSKRG
24825-66
66 to 71 XLH & XLCH
27012-67
67 to 69 XLCH
27015-66
66 to 71 XLH, 66 XLCH
& 70 to 71 XLCH
Wire Block,
Choke
Lever
Choke
Shaft &
Lever
Lever, Inlet
Valve
27740-63
66 XLH &
XLCH
27740-66
67 XLH &
XLCH
27740-66
67 to 71
XLH & XLCH
27715-67
67 XLH &
XLCH
27716-55
67 XLH &
XLCH
27716-67
67 XLH &
XLCH
27718-66
66 XLH &
XLCH
27718-67
67 XLH &
XLCH
27715-67
67 to 71
XLH & XLCH
27716-55
67 to 71
XLH & XLCH
27716-67
67 to 71
XLH & XLCH
27718-67
67 to 71
XLH & XLCH
Friction Spring,
Choke Shaft
27671-66
66 to 67 XLH & XLCH
24824-67
67 to 69 XLCH
Retainer
Clip, Choke
Wire Block
27671-66
66 to 71 XLH & XLCH
27671-55
66 to 71 XLH & XLCH
(Replaces 27671-66)
Welch
Plug, Check
Ball
713
66 to Early
70 XLH &
XLCH
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What Is Actually On Your Bike-Please Let Us Know
1966
Tillotson Model
XLH
1967
XLCH
XLH
1968
XLCH
XLH
1969
XLCH
XLH
1970
XLCH
HD1A
HD1B
HD1C
HD1D
HD2C
HD2D
OTHER
© 2014 By OSKRG
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1
XLH
1971
XLCH
XLH
XLCH
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Tillotson Restored by Dave C.
© 2014 By OSKRG
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XLH & XLCH Gas Tank Fuel Valve & Outlet
PN 62125-55 “Fuel Valve Assembly” is listed as
the valve through the 67 Parts Book for 57
through 67 XL & XLH. It is listed for the XLCH
from 65 through 67. The 71 Parts Book list PN
62125-55B for the 57 through 71 XL & XLH as
well as the 65 through 71 XLCH. At this time I
am unaware of a “PN 62125-55A”
PN 62125-55
PN 62125-55A if it Exists?
© 2014 By OSKRG
PN 62125-55B
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66-71 XLH & XLCH Air Cleaner Back Plate, Cover & Filter
Note: Above Part 36 has a 29205-69 Part Number, may have been used on 69-71?
Backing Plate
© 2014 By OSKRG
Air Filter Element
Air Cleaner Cover
Air Cleaner Trim
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Tillotson Choke Assembly 1966 Only XLH & XLCH
© 2014 By OSKRG
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Tillotson Choke Assembly 1967-1971
1967-1971 Choke Assembly
© 2014 By OSKRG
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Tillotson “Tickler” & Main Jet Size vs. Needle Turns Out
© 2014 By OSKRG
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Comments about the Tillotson Series of Carburetors by Bob Evans
Sundial; Best I'll conclude is that it is a 'cast date code' since it is cast in. It did not show up until later in production, (1968 I think?).
And there are later HD1C's and D's that don't have it, so? WTF? But you’re A, B, C & D's seem correct. Off the top of my head I view
it this way; HD1A, 1966 only and no 'forked fuel inlet lever' as shipped. This became a running change probably late in 1966
production when the hard starting complaints received attention. The original lever depended upon gravity for the fuel inlet needle
to drop off its seat, allowing fuel to enter the diaphragm area. If the cycle was not started often enough, the fuel would begin to
dry out slightly, effectively 'gluing' the needle to the seat and no fuel could enter the carb. (My all original 1966 XLCH had this early
inlet needle and lever along with Zach R’s personal notes on the cycle stating why he finally gave up riding it with only 1,300 miles
on the clock. He constantly complained in his notes of what a bastard it was to start. After I won the cycle at auction I brought it
home and knew what to look at first as I had previously read the HD service bulletin on this. Sure enough, it had the original parts. I
changed them out and the cycle started on the fifth kick! Also as you mention, 1966 was a one year only choke lever. 1967 arrived
with the HD1B, presumably with the changed choke arrangement and the forked inlet lever which allowed manual priming of the
carb through the tiny air hole in the bottom of the diaphragm cover. By physically sticking a toothpick or straightened out paperclip
through the hole you lifted the fuel needle off its seat allowing fuel to enter and freeing up the needle from the seat. The
aftermarket offered 'Tillotson ticklers' which screwed to the bottom of the diaphragm cover to make this task easier. 1968 may
have 'B's or 'C's on them. There are no changes that I am aware of except for the possibility of a different main jet. As we all know
the idle and midrange are adjustable so no likelihood of a change there. 1969 may have 'C's or 'D's on them, otherwise same as
1968. 1970 and 1971 only ever had HD1D's on them, every stock cycle that I've ever seen. And 'HD5' carbs were KR, XLR and iron
XR carbs that had no accelerator pump, a plain stamped steel diaphragm cover and adjustable main jet rather than fixed. Andrew's
Products offered their 'Super 45' variation of the Tillotson around 1973. It was usually stamped either HD137 or HD138, had no
high speed venturi, (aka bomb site), and was bored out to 45 mm. I had one and it worked great. There may have been main jet
changes depending on exhaust system options. Finally, I will repeat what I read in a cycle magazine article about Tillotsons some 45
years ago; Though both the HD1's and HD2's may appear identical, there is one major difference that has driven guys crazy
when trying to get a HD2 to idle properly on their Sportster. The tiny idle bleed holes are larger in the HD2 causing an always rich
mixture on a smaller engine. Regards, -Bob-
© 2014 By OSKRG
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Comments about the Tillotson Series of Carburetors by “Dr. Dick” & Some Pictures
Also
Comments by Dave C.
“Dr. Dick” wrote:
Here’s what I think. I don’t know for sure. 66 HD1A no forked inlet needle, no cotter pin at throttle block to arm attachment, riveted
instead (some with friction spring some without). No check ball in plastic cover. 67 HD1B was opposite of the above. 68 HD1C
difference in idle porting positions and maybe a difference in economizer jet size. 69 I don’t know. 70 and 71 HD1D.
© 2014 By OSKRG
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Insulator Blocks and Stud info:
 66 blocks had no drill point; it used the Linkert throttle bracket.
 67 the point was added, but there was no PN change. In mid 67 the lower stud got lightened for plug wire router.
Feast your eyes on this.
More of my silly tilly ramblings
http://xlforum.net/vbportal/forums/showthread.php?t=1567534
Post 36
Dave C wrote:
Jerry,
Kudos to Joe on the K Model site post regarding the one year only (HD1A) riveted throttle wire mount and no check ball in the diaphragm cover (check it
out). That needs to be added to your write-up. We learn something new every day. I will make these changes to my restored 1A for my 66CH restoration.
About the only adder to the Tillotson section is the idle adjustment screw (the big one on top) was tapered in 66 and incorporated a step stop on the
HD1B, possibly late HD1A's. The service bulletin that Scott posted some time ago had this description with a drawing. The change was made to prevent
over tightening of the screw and distortion of the idle fuel metering hole.
Presently I am of the opinion that the 68's had HD1C's due to the mix of exhausts that year.
Other than the HD1A idle needle and 1C's on the 68, I believe we are good to go (if that ever happens).
Dave C
© 2014 By OSKRG