Story and Photos by Nick Neslon – ATV World Magazine

The Honda TRX 450R is one of the most prevalent sport quads around. The TRX 450R was released in 2004 as a kick-start only, high performance four stroke replacement for the age-old TRX 250R two stroke. The model was unchanged for 2005, and then received a new generation updated motor with more power and electric start. The 2006-2013 TRX450ER models are electric start only and there is a limited production, kick-start only version TRX450R that is popular, mostly with the racer types.

While the kick-start version is available, 95 percent of the late model TRXs floating around are electric start only. While this is definitely the most desirable option, there are a lot of us that would appreciate the security of a back up starting system. The TRX electric starter has a hard enough time starting the stock 12:1 450R motor, and anyone that has added a higher compression piston knows that it only adds to the load on the little TRX battery.

Honda does not offer the TRX with a kicker and electric starter together, nor do they actually sell a kit to add the kicker to an electric model. However, if you purchase a list of OEM Honda parts, it is possible to add a kick-starter to your electric start model, and the best part is that both starting methods work at the same time. Racers have perfected their dead engine start methods by learning to use both the kicker and electric starter to spin the motor even faster for improved starting, or the average rider can benefit from not having to worry about a dead battery leaving you stranded.

  1.  The OEM Honda parts you will need to acquire are as follows:
  2. Pinion (28T) 28211-HP1-670  x1
  3. Kick Stopper Plate 28215-HP1-670  x1
  4. Ratchet 28221-HP1-670  x1
  5. Spring 28223-HP1-670  x1
  6. Gear (31T) 28231-HP1-670  x1
  7. Collar 28232-HP1-840  x1
  8. Plate 28233-HP1-840  x1
  9. Spindle 28251-HP1-840  x1
  10. Spring 28261-HP1-840  x1
  11. Collar 28282-HP1-840  x1
  12. Bolt, Flange (6×14) 90004-GHB-620  x1
  13. Washer (14mm) 90451-PC9-000  x1
  14. Washer B (22mm) 90455-ML7-000  x1
  15. Washer (27x20x1) 90554-728-940  x2
  16. Bearing (22x29x10) 91007-HP1-671  x1
  17. Bearing, Needle 91105-KN7-671  x1
  18. Bolt, Hex (6×16) 93301-06016-0A  x2
  19. Circlip (19mm) 94510-19000  x1
  20. Gear (25T/13T) 28240-HP1-840  x1
  21. Kick Starter Arm 28300-HP1-840  x1
  22. Kick Joint Bolt 28306-MEN-670  x1

Step One.

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Starting with a clean machine, drain the transmission side oil and coolant. The transmission oil is drained from the drain bolt located under the shift shaft. This takes a 12mm socket, extension, and ratchet. The coolant can be drained via the 8mm head bolt at the bottom of water pump cover. Be sure to remove the radiator cap to release pressure and all fluid.

 Step Two.

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Lay out all necessary parts on a clean work area. Remove brake pedal pivot bolt and spring, then swing the pedal out of way. With a towel or large rag under the machine, remove water pump cover and swing it out of the way. Then remove the large clutch cover; you can lay out all the bolts you remove in order to speed up re-installation.

 Step Three

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Remove 10mm head clutch spring tension bolts and springs, and remove pressure plate to access the large (27mm) center clutch nut. Leave clutch pack in for tension to remove this nut. You will have to open up the safety bend washer with a flat head screwdriver or chisel, and then remove nut with an impact wrench. You can apply pressure to the clutch pack with a rag to hold clutch from spinning.  With large nut removed, remove entire clutch system, keeping all pieces in order.

Step Four

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Install both shaft pivot bearings. One will install in clutch cover and the other will go into the back of the case. Freezing bearings in the freezer first and a light coat of grease will help installation. It should only take a very, very light tap with a small hammer to seat bearings. They should sit flush and square. Install the kick-starter stop plate with red Loctite on the two 6mm bolts.

Step Six

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Remove the black plastic plug from the kick-starter shaft hole in the clutch cover. Use a hammer and punch (or extension) to drive out the plug from the inside of clutch cover to the outside. With the plug removed, install kick-starter shaft seal into clutch cover. A light coat of grease will ease seal installation. You should also grease the inside of clutch cover hole where the kick-starter shaft will be riding.

Step Seven


Install the collar spacer and drive gear that goes behind the clutch basket. With spacer and gear in place, install the retaining bracket with the one 8mm head bolt. Be sure to use at least blue Loctite with all the bolts you are adding to the motor.

 Step Eight


Re-install the clutch assembly. After installing basket, install the clutch fibers and steels so that you can use the rag against the fibers again to hold the shaft from spinning while tightening. Once the big 27mm nut is tight, you can use channel lock pliers to bend the tab washer against the nut, securing it to the shaft. This bend lock washer can be reused once or twice, but it is best practice to just replace it every time you remove it. Torque the clutch spying tension bolts in a star pattern for even pressure.

 Step Nine

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Assemble kick-start shaft with gear, collars, spacer, and springs. Pay attention to the two timing marks on stopper gear and shaft. They must be properly aligned for smooth operation. You can refer to an online parts fiche, or device manual for the proper order when assembling the shafts.

Step Ten

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Install kick-start stopper plate behind where the kick-start assembly will sit; use Loctite on both these bolts as well. Install kick-starter shaft assembly into the engine case. With the shaft in place, use your finger or needle nose pliers to load the spring tension and place the tip into the case recess.

Step Eleven 

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Install washers on both sides of kick-start drive gear shaft. Align the gears and mesh the teeth with the gear you installed behind the clutch basket as you install the drive gear assembly into the side case bearing that you installed in step four.

Step Twelve


Reinstall the clutch cover with new gasket, making sure to properly align water pump slot with drive shaft. The water pump drive shaft must be aligned to install the clutch cover, or you can break the case. You can clock the water pump shaft by turning the impeller with your fingers as you apply pressure to the clutch cover until it aligns and goes on easily. Reinstall clutch cover bolts and install kick-starter and brake pedal pivot bolt. You will also need to cut out a slot in your rear plastic for the kick-starter to pivot in.