Domino controls (comandi) are made in Italy since the 1950’s. Domino controls are found on most Italian mopeds, such as Arciero, Aspes, Baretta/Piccoli, Beta, Bianchi, Cimatti, Concord/Fantic, Demm, Gadabout, Garelli, Malaguti, Motobecane Sebring, Motomarina, Motron, Negrini, Pacer/Italtelai, Snark, late 80’s Tomos, and Vespa/Piaggio. Other Italian mopeds had PV, OSL, or Ci.Ti controls. Domino has made, and still does make, many other high quality motorcycle controls.  

In the 1980’s Domino part numbers began with “D”. The “D” parts were for sale to the public through independent distributors. Domino also made controls specifically for Vespa, Garelli, and possibly others. Those parts were only sold through Vespa or Garelli dealers. They never did have a Domino part number. Myrons Mopeds made up the “V” and “G” part number prefixes to agree and mesh with the corresponding “D” prefix items and labels. For example the Vespa version of Domino control “DB2” is “VB2”, and the Garelli version is “GB2”.

Domino “70’s chrome” moped controls:

Vespa “70’s chrome” (sliding block): In the 1960’s most countries did not require motorcycle control levers to have balls on the ends. These VA and VB “70’s chrome” controls are the same as the VA0 and VB0 “70’s chrome” controls that follow below, except the tips of the brake levers do not have balls. The lever blades are chrome, stamped from sheet metal. The cast aluminum housings are painted silver. The throttle is a sliding block type, where the twist tube (barrel) has a spiral slot that moves a sliding block back and forth. The sliding block also contains a pinch bolt to attach the cable wire. These are for a 1969 to 1977 Vespa Ciao, but there are many other 1960’s Italian mopeds that were equipped with them. And there are other makes of 1960’s Italian levers, such as Ci.Ti, which are similar.

 

Domino “70’s chrome” (sliding block): In the early 70’s US mopeds had Domino “1970’s chrome” levers. The lever blades are chrome, stamped from sheet metal. The cast aluminum housings are painted silver. The throttle is a sliding block type, where the twist tube (barrel) has a spiral slot that moves a sliding block back and forth. The sliding block also contains a pinch bolt to attach the cable wire. So there is no cable end piece needed at the throttle end. This means the throttle cable is “universal” or “single-ended”. On the other hand, these throttles need frequent lubrication (oil or grease), or they become sticky and eventually wear out.

 

Because the twist tube is steel and the sliding block is aluminum, it’s the sliding block that wears out first, causing further sticking. This earliest version from before 1978, had no flange or provision for a throttle return helper spring on the twist tube.

Some DA0 right controls have an M5 adjuster as a stop for the throttle cable, and some don’t. The kind without an M5 adjuster may be for early 1970’s Vespa Ciao without a right-handlebar engine stop switch. All of the “V” type right controls made by Domino special for Vespa (Piaggio) do not have M5 threads for a throttle cable adjuster. All of the other “D” and “G” types of right controls do have threads for an M5 adjuster.    

 

Domino “70’s chrome” (sliding block): These controls are exactly the same as the previous ones, except for the grips. The Domino aftermarket controls have different grips or different housing colors than many of the Domino OEM controls. To get the exact style and color, you had to get the part through the moped maker’s parts distributor network, such as a local Garelli dealer. The Domino controls made to order for a particular maker have a part number that begins with the maker initial. V is Vespa, G is Garelli, and C is Cimatti. The Domino aftermarket parts all begin with D. The Marina Mobili part numbers are used here, from the late 1980’s. They were the #1 moped parts importer/distributor in the United States at the time. 

 

Garelli “70’s chrome” (sliding block): Before 1977, Garelli mopeds had Domino chrome levers with plain silver housings. The right control was a standard Domino DA1, with no assist spring. The left control was like a DB1, except the Garelli start cable hole was bottomless and threaded M6x1. The grips were D21 and D22 “waffle” style. The threaded start cable hole was also used on later Garelli left controls, GB2 (77-80) and D3BM (79-84). 

 

 

 

Cimatti “70’s chrome” (wrap-around): From 1976-1978 some US mopeds had Domino “1970’s chrome” levers (1976-77 Cimatti City Bike, 1977-78 Rizzato Califfo, others). The lever blades are chrome, stamped from sheet metal. The cast aluminum housings are painted silver in the 1970’s. The left side control is the same, but the right side has a different type of throttle. This “wrap-around” type of throttle winds the end of the cable around part of the twist tube. There is no sliding block, and much less tendency to stick. But wrap-around throttles require a solder end piece on the cable. That makes the throttle cable not universal, since the inner wire exposed length is pre-set by the lead barrel end at the handlebar. That is in addition to the smaller in-line barrel end at the carburetor, making it a “two-ended” or “double-ended” throttle cable. Most modern motorcycles have double ended cables, while bicycles always have single ended. Mopeds can have either or both motorcycle style 2-end, and bicycle style 1-ended cables.

 

Domino “70’s chrome” (sliding block): From 1978-1984 some US mopeds had Domino “1970’s chrome” levers. The lever blades are chrome, stamped from sheet metal. The cast aluminum housings are painted black. All of these black throttles worked better thanks to the silver-dollar-sized throttle assist spring. The 1978-on housing was longer, and the metal twist tube had more “inner” length. Plus it had a flange with a spring anchor hole. You can see the extra 1/4 inch of length in the housing, just to the left of the hand grip, and just to the right of the twist tube securing screw. That is where the three-loop throttle assist spring goes. All subsequent Domino sliding block throttles had the throttle return assist spring. 

 

Domino “70’s chrome” (sliding block): These Domino DA3 and DB3 controls are identical to the previous DA2 and DB2 ones, except for the grip style. This and all subsequent Domino sliding block throttles had the throttle return assist spring. These DB4B and DA4B controls do not have M6 threads for adjusters on the brakes, nor the starting clutch cable. The DA4B right control does have M5 throttle cable adjuster threads.

 

 

 

Vespa “70’s chrome” (sliding block): Up till 1977, Vespa (Piaggio) mopeds had Domino “1970’s chrome” levers  with silver painted housings. These throttles did not have the throttle return assist spring. So they tended to stick easier, especially when they needed lubricant. Instead of a “three finger” start lever, like most other left controls have, these have a “one finger” decompression lever. It does not need to be squeezed hard like the clutch start levers do. The engine starts when the decomp lever is released.  The Vespa VA0 throttle and brake control has a bottom mount for an integrated engine stop button. Both VA0 and VB0 controls have a M6x1 threaded hole for the 6mm brake cable adjusters D29, but not for the decomp.

 

Vespa “70’s chrome” (sliding block): From 1978-1984 Vespa Grande, and from 1980-84 Vespa Si mopeds, without turn signals, had Domino “1970’s chrome” levers with plain grey painted housings. These throttles also had the helper spring, visible just left of the grip. Instead of a “three finger” start lever, Vespa moped left controls have a “one finger” decompression lever. It does not need to be squeezed hard like the clutch start levers do. The engine starts when the decomp lever is released.  Both VA1 and VB1 controls have a M6x1 threaded hole for the 6mm brake cable adjusters D29, but not for the decomp. 

 

Garelli “diamond chrome” (sliding block): From 1977-80 Garelli mopeds, for sale in the US, had Domino chrome levers. The housings were silver with a diamond shaped mount for an integrated switch. The Garelli GA2 throttle had an assist spring. Everything else was the same as the Domino diamond controls, except the Garelli start cable hole was bottomless and threaded M6x1. The grips were D21 and D22 “waffle” style. These were the first controls on mopeds with provisions for integrated switches. From 1977 to 79, Garelli made their own “Garelli oval chrome” switches. Those switches got broken easily when the knob was struck. After about 1981 Garelli mopeds had DA3M, DB3M black diamond controls with CEV “diamond” switches. 

Some important “ifs, and’s, or buts”:

With all of the various Domino controls, the question of whether the holes for the cables have a bottom, or are bottomless and threaded, has been confusing moped mechanics for decades. You need to know this when you are missing or changing cables. Now the question finally has a precise, but long answer! (the old answer was “some do and some don’t”)

 

 

Domino “diamond chrome” (sliding block): From 1978-85 some US mopeds had Domino chrome levers with a diamond shaped mount for an integrated CEV switch. Everything was the same except the black housings had molded in switch mounts. 

Many non-US models do not have brake lights. So their Domino housings don’t have threaded holes for CEV brake light switches. Their Domino “70’s chrome” levers do not come with the plate that pushes the button on the brake light switch. Their lever blades do not have the extra little hole punched in them to anchor the brake light switch plate.

 

Domino “diamond long chrome”: From about 1980 to 1986 Garelli Basic mopeds, and some others, had long chrome levers with a diamond shaped mounts molded into the black housing for integrated CEV switches. Everything was the same as the DA3 and DB3 controls, except the start cable had a M6 threaded adjuster, the brake lever blades were longer, 155mm instead of 140 or 145, and the grips were longer, 120mm instead of 105 or 110. People with big hands would probably like these controls better.

 

 

Vespa “diamond chrome” (sliding-block): From about 1977-80 Vespa Bravo mopeds equipped with turn signals had these controls.   Like other Vespa “V” controls, both VB2 and VA2 “diamond” controls have a M6x1 threaded hole for the 6mm brake cable adjusters D29, but not for the decomp cable.

 

 

 

 

 

Vespa “square chrome” (sliding-block): From about 1978-84 Vespa Grande mopeds equipped with turn signals had these controls. The Domino “diamond chrome” left brake and decomp control housed a CEV diamond horn button switch. The Domino “square chrome” right brake and throttle control housed a CEV square engine stop and turn signal switch. So the buttons were reachable with the thumbs without letting go of the grips. These throttles had the helper return spring, so they always snapped back when you let go. Both VA2S and VB2 controls have a M6x1 threaded hole for the 6mm brake cable adjusters D29, but not for the decomp. 

 

 

 

Vespa “diamond chrome” (sliding-block): This VB3 left control is exactly like the VB2 control, used on Vespa Bravo with turn signals and Grande with turn signals. It also has M6 threads for the brake cable. The only difference is it is silver, not dark grey. It could be for another Italian “variator” type of moped, like with a Minarelli V2 or C2 engine, or a Morini M101 engine. There are not very many of those. For now it is an “orphan”, a lonely control without a bike to go on.

 

 

 

 

Domino “diamond chrome” (sliding-block): This early 1980’s Domino DA5 black diamond right control is like a late 1970’s Domino DA3 black diamond right control, except for two things. The grip is a D21B “basketball texture”, not a D21R “ribbed”. Both the throttle and brake cables have threaded adjusters, M5 and M6. Since the early 1980’s, Domino has made all their moped controls with threads for cable adjusters, aka adjustable cable stops. This was the earliest Domino aftermarket control with threaded adjusters on all cables. The corresponding left DB5 control would have M6 adjusters on the brake and start cables, to match. No photo is available.

 

 

Dom#  pic#      description               price        applications or comments

=================================================================

D1     26  sliding block Domino 70’s        $18  aka throttle slider, new, correct and well made
D2     27  pinch bolt Domino 70’s            $3
D3     28  barrel clamp screw                $3  aka twist tube securing screw
D4     25  barrel spacer (not nec.)        n.a.  helps reduce friction from grip

——————————————————————————————————————————

 Note: D5, D5A, D5B, G5D have M5 threads for an adjuster. V5K, V5D, V5P, V5S do not have M5 threads.

D5     17  R plain housing silver              n.a  for DA0, DA1, used, shorter for no helper spring, no M6 brake threads
D5A   17  R plain housing black               n.a  for DA2, used, longer for helper spring, no M6 brake threads
D5B   18  R diamond housing black         n.a for DA3, new, longer for helper spring, no M6 brake threads

V5K        R Vespa Kill sw. housing silver    n.a. for VA, VA0, for no spr, 128585 Ciao w/sigs, M6 brake threads

V5D        R Vespa Diamond housing grey   n.a. for VA2, for spring, 163242 Bravo w/sigs, M6 brake threads

V5P        R Vespa Plain housing gray       n.a.  for VA1, used, for spring, 307154 Grande no signals, M6 brake threads
V5S        R Vespa Square housing gray    $45  for VA2S, used, for spring, 307250 Grande w/sigs, M6 brake threads

G5D       R Garelli Diamond housing silver $50  for GA2, used, for spring, for 1977-80 Garelli, no M6 brake threads

——————————————————————————————————————————

1+2 D6A spring type with flange
3+4 D6 no-spring type, no flange

1. D20 brake lever, D11 spring, D10 brake plate, and D9 tube
2. D19 start lever, D12 spring, no brake light plate, and D9A tube

In most illustrated parts lists, the Domino D6 throttle barrel, aka twist tube, is shown as the only type. The illustrations were made years earlier when the D6A spring type did not exist. This has caused confusion that perpetuated into future parts pictures. For example, in the greyscale picture above, the D6 older twist tube is shown, when it should be a D6A with a flange. A D6 has nothing to hook the D23 assist spring onto. 

 

 

 

 

 

D6     20  throttle barrel no spring type  $10  no flange, aka twist tube
D6A   35  throttle barrel spring type      $10  longer “inside”, has flange w/spring hole
D7     14  nut M6 flange                        $1  M6 x 1.0
D8     12  pivot bolt M6 for brake           $2  M6 x 1.0 x 25 slot head
D9     22  steel tube bushing brake         $8  about 6x8x12mm tube
D9A   21  steel tube bushing start          $8  about 6x8x10mm tube
D10   33  brake lite actuating plate         $5  R or L round tab snaps into small hole in lever
D11   24  spring R/L brake return          $12 can be for a long type start lever
D12   23  spring start lever return         $10 can be for a brake lever
D13   24  pivot bolt M6 for start             $3  M6 x 1.0 x 23 slot head
D14     6  cable holdfast/socket bolt        $4
D15   15  clamping bolt lock tube           $3  this cone digs into the bar move over to make tight
D16   16  R clamping bolt 6mm allen       $1  these bolts precisely fit the cone D15
D17   16  L clamping bolt 6mm allen       $1

——————————————————————————————————————————

1. L housing silver, made for Garelli  G18
2. L housing silver, for aftermarket  D18
3. L housing silver, made for Vespa  V18

Three of four possible combinations of left control styles exist in Myrons parts department. From this view you can see that some of the cable holes have slotted bottoms, and some are slotted bottomless threaded. The threaded holes require M6 threaded adjustable cable stops, aka M6 adjusters . The holes with bottoms do not need cable stops. On those the bottom of the hole is the cable stop.

With the dozens of Italian moped brands, it is likely that some will use each of these three types. There might even be a fourth type (both threaded) somewhere. So far only the Domino controls for Garelli and Vespa brands are known and documented here. More will follow…

1. L housing grey, made for Vespa  V18P
2. L housing black, for aftermarket  D18C
3. L housing black, made for Vespa? V18A

 

 

 

 

 

 

 

 

 

 

1. L diamond housing grey, for Vespa  V18DG 
2. L diamond housing black, aftermarket D18B
3. L diamond housing black, for Garelli  G18DB

 

 

 

Here are three black diamond left housings, each with different cable hole styles. They look the same from a distance. But the presence or absence of the threads for the adjustable cable stop, can make the left and right sides look the same, or be mismatched at the cable ends.

 

Left, the Vespa “V” type always has the brake hole threaded only.

Middle, the aftermarket type “D” always has neither hole threaded.

Right, the Garelli “G” type always has the start hole threaded only.  

D18B and G18DB have M8 threaded mirror holes, but not V18DG. 

 

 

D18     2  L Domino plain housing silver    $20  for DB0, DB1, no M6 brake or start cable threads

G18         L Garelli plain housing silver     $20  for GB1, pre-77 Garelli,  M6 start cable threads only

V18         L Vespa plain housing silver      $20  for VB, VB0, Vespa 147740 Ciao no sigs, M6 brake cable threads only

V18A      L Vespa plain housing black      $20  for     ??                    , M6 brake cable threads only

D18C      L plain housing black no hole     $20  for     ??                   , no M6 brake or start cable threads
D18A      L plain housing black w/hole     $20  for DB2, DB4B, no M6 brake or start cable threads
D18B 19 L diam. housing black w/hole    $20  for DB3, no M6 brake cable or start cable threads

V18P      L Vespa Plain housing gray        $30  for VB1 Vespa 307153 Grande no signals, M6 brake threads only

V18D     L Vespa Diamond housing silver $30  for VB3 left control, for Vespa  ???, M6 brake threads only            

V18DG   L Vespa Diamond housing gray  $25  for VB2, Vespa 307248 Grande w/signals, M6 brake threads only

G18D     L Garelli Diamond housing silver $25  for GB2, 77-80 Garelli , M6 start cable threads only

G18DB   L Garelli Diamond housing black $25  for GB3, 80-84 Garelli , M6 start cable threads only

——————————————————————————————————————————

D19     7  lever start/clutch blade only   $15

V19         lever blade only Vespa decomp $20  good used
D20A   5  lever R/L blade only no ball      $25  good used
D20   5A  lever R/L blade only w/ball      $12  

D20M      lever R/L long blade w/ball      n.a. for DA3M, DB3M “long chrome” 

Dlev        lever  assy D20+D9+D10+D11  $25  or $15-20 for used

——————————————————————————————————————————

D21         R grip 25mm ID “waffle” style   $15  original vintage Domino grip

D21R  3  R grip 25mm ID “ribbed” style   n.a.  original vintage Domino grip

D21A       R grip 25mm ID “knobby” style  n.a. original vintage Domino grip

D21B       R grip 25mm ID “texture” style $15  used orig. vintage Domino grip

D21M      R grip 25mm ID 120 mm long    n.a.  for DA3M “long chrome” 

——————————————————————————————————————————

D22          L grip 22mm ID “waffle” style    $8  original vintage Domino grip

D22R  4  L grip 22mm ID “ribbed” style  $6  original vintage Domino grip

D22A       L grip 22mm ID “knobby” style  n.a. original vintage Domino grip

D22B       L grip 22mm ID “texture” style  n.a.  original vintage Domino grip

D22M      L grip 22mm ID 120 mm long    n.a.  for DB3M “long chrome” 

——————————————————————————————————————————

D23   34  throttle return spring 3-loop     $4
D24   11  adjuster M5  w/nut                 $2  for all Domino controls throttle cables
D25        cover                                    see Switches
D26        cover screws (2)                    see Switches

D29       cable adjuster M6  w/nut      see Cable Parts–A3a   for Vespa brake cables, and Garelli start cables

 =================================================================

Complete control assemblies, not including switch, maybe with grips, new and used:

——————————————————————————————————————————

VA      R control assy,  Vespa  plain, silver, for kill switch, brk/throttle, no balls, no spring   n.a.

VB      L control assy,  Vespa  plain, silver, “70’s chrome” brk/decomp, no balls on levers  n.a.

DA0    R control assy, Domino plain, silver, sliding-block, brake/throttle, no assist spring   n.a.  

DB0    L control assy, Domino plain, silver, “70’s chrome” rear brake and starting clutch  $50  or $30-40 used

CA0    R control assy, Cimatti plain, silver, wrap-around, brake/throttle, no assist spring  $75  good used

VA0    R control assy,  Vespa  plain, silver, for kill switch, brake/throttle, no assist spring   n.a.  

VB0    L control assy,  Vespa  plain, silver, “70’s chrome” brake and decompression lever $65  or $45-50 used

DA1    R control assy, Domino plain, silver, sliding-block, brake/throttle, w/assist spring   n.a.  

DB1    L control assy, Domino plain, silver, “70’s chrome” brake and starting clutch lever $45  or $30-40 used

GB1    L control assy, Garelli plain, silver, “70’s chrome” brake and starting clutch lever $45  or $30-40 used

DA2    R control assy, Domino plain, black, sliding-block, brake/throttle, w/assist spring    n.a.

DB2    L control assy, Domino plain, black, “70’s chrome” brake and starting clutch lever $45  new

DA4B  R control assy, Domino plain, black, sliding-block, brake/throttle, w/assist spring    $80  new

DB4B  L control assy, Domino plain, black, “70’s chrome” brake and starting clutch lever $45   new

VA1    R control assy,  Vespa  plain,  grey, sliding-block, brake/throttle, w/assist spring     n.a.

VB1    L control assy,  Vespa  plain,  grey, “70’s chrome” brake and decompression lever $60  or $40-50 used

DA3    R control assy Dom diamond black, sliding-block, brake/throttle, w/assist spring    n.a.  

DB3    L control assy Dom diamond black, “70’s chrome” brake and starting clutch lever $45  new

DA3M R control assy Dom diamond black, sliding-block, brake/throttle, w/assist spring     n.a. long lever/grip

DB3M L control assy Dom diamond black, “70’s chrome” brake and starting clutch lever  n.a. long lever/grip

GA2   R control assy Garelli diamond silver sliding-block, brake/throttle, w/assist spring  n.a.  good used

GB2   L control assy Garelli diamond silver “70’s chrome” brake and starting clutch        $50  good used

VA2    R control assy Vespa square,  grey, sliding-block, brake/throttle, w/assist spring    $70  good used only

VB2    L control assy Vespa diamond grey “70’s chrome” brake and decompression lever $55  or $35-45 used

 

Domino “80’s black” moped controls:

 

Domino “mid-80’s black” (sliding block): From about 1985-88 some mopeds had Domino “80’s black” controls. The lever blades are black plastic. The cast aluminum housings are black, and have a large space for integrated CEV switches. The sliding block (throttle slide) and steel twist tube (throttle barrel) with flange for the helper spring, are the same as the earlier “70’s chrome”. The Domino grips are the smooth octagon style of the mid-1980’s. 

Garelli mopeds 1985-88 had DA7K, DB7K, “octagon” grips.

Tomos mopeds 1986-91 had DA7K, DB8K, “octagon” grips.

Trac mopeds 1985-1989 had DA7K, DB7K, “octagon” grips.

 

Domino “late-80’s black” (sliding block): From about 1987-early 1990’s some mopeds had Domino “90’s black” controls. The lever blades are black plastic. The cast aluminum housings are black, and have a large space for integrated CEV switches. The twist tube (throttle barrel) is black plastic, for less friction. The D1L  sliding block is different than the previous Domino D1 sliding blocks. The Domino grips are the “texture” style of the early 1990’s.

Derbi mopeds 1987-89 had a DA8K right, and like a DB8K left but with a small decomp lever, and “texture” grips.

 

 

Dom#  pic#      description                  price        applications or comments

=================================================================

D21K   3  R grip “octagon” style                $15  black vinyl squarish-octagon smooth

D21L       R grip “texture” style                  $15  black vinyl like a basketball texture
D6A         throttle twist tube metal            $10  early 80’s type, uses D1 sliding block
D6L         throttle twist tube plastic                   late 80’s type, uses D1L sliding block
D22K   4  L grip “octagon” style                $10  black vinyl squarish-octagon smooth

D22L       L grip “texture” style                  $10  black vinyl like a basketball texture
D5K     5  R housing brake/throttle                    for DA7K 85-91 Tomos 85-on Garelli
D5L         R hous. brk/throt/choke                     for DA8K 84-88 Derbi 84-88 Trac
D18L   6  L housing brake only                          for DB8K 85-91 Tomos
D18K       L housing brake/start                        for DB7K 85-on Garelli 86-89 Derbi 84-88 Trac
D20KR 7  R lever black plastic                   $14  smooth black plastic
D20KL  8  L lever black plastic                   $14  says Domino underside of lever
D1       9  sliding block for metal twist tube see above  mid-80’s type, uses D1 sliding block
D1L     9  sliding block for plastic twist tube  $12  late-80’s type, uses D1L sliding block
D3     10  screw that holds twist tube      see above
D23   11  throttle helper spring 3-loop      see above
D2L   12  pinch bolt for sliding block            $7
D15   13  cone that wedges into bar        see above
D16   14  clamp bolt M6                        see above
D8     15  pivot bolt                              see above
D11K  16  brake helper spring R&L               $4
D7     17  nut for pivot bolt M6-flange      see above
D29   18  adjuster M6 for brake cables         $4
D24   19  adjuster M5 for throt&choke    see above
D14K  20  brake cable socket bolt               $3
D35    21  choke lever                               $10
D36          choke lever holdfast                   $3  has a step, 7-to-8 mm, unlike all others
D37          choke lever retaining rivet          n.a.  must drill and tap
D19K  22  start lever                                $20
…             start parts same as brake lever

 

 

Here are the two different Domino sliding blocks, shown with two different views. At left is the 1970’s to mid-80’s Domino type, part number D1. At right is the late-80’s and 90’s Domino type, part number D1L. The older D1 kind is wider, and the “tongue” that slides in the spiral groove of the twist tube is narrower than the D1L kind. Currently the D1 is scarce at Myrons, and elsewhere. The D1L is available, but not many US mopeds had that. You can’t substitute a D1L for a D1, even grinding the tongue, because it is narrower, and will cock sideways and stick. When a sliding block throttle sticks, of course, you first put oil on it. When the “tongue” wears down, one side gets rubbed, and it gets thinner, causing the throttle to stick.