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How-To: Fix slow clunky shifting - shift star, detent arm and spring replacement

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22K views 7 replies 6 participants last post by  6doublefive321  
T
#1 ·
Annoyed by the clunky shifts and long throw of the gear shifter on your F4i (or other bikes too)?? Hate it when you get one of those 'missed shifts'?? This fairly simple mod aims to correct these issues! This involves the replacement of the shift star, detent arm, and detent spring. The replacement parts are made by Factory Pro, and uses a slightly modified shift star, micro roller bearing detent arm, and a heavier detent spring over stock. This mod makes a very noticeable difference in shift feel, making for nice clean, crisp, and faster shifts

I made this as detailed as I could, although I left out a few things in the pics but I'll explain as best I can

Cost
* $180 for the kit. I got mine from Solo Moto Parts they were about $20 cheaper than getting from Factory Pro, and free shipping on orders over $99

Bikes

* Any 01-06 F4i specifically. Probably very similar for others


Tools and Materials Required

* 30mm impact socket (1/2" drive)
* Impact gun STRONGLY recommended (electric or air, doesn't matter)
* 1/2" drive breaker bar if no impact gun is available
* 5mm and 6mm HEX head sockets (also called allen head)
* 8mm and 10mm sockets (1/4" drive)
* 10mm, 12mm, and 14mm sockets (3/8" drive)
* Short 1/2" drive extension
* 6 inch 3/8" extension
* 6 inch 1/4" extension
* 1/4" and 3/8" hand ratchets
* in-Lb torque wrench (3/8" drive) capable of 108 in-lbs
* ft-Lb torque wrench (1/2" drive) capable of 94 ft-lbs
* Medium sized flathead screwdriver
* 3+ lb hammer
* Rubber mallet (or rubber or wooden handle from regular hammer works too)
* Hondabond or equivalent GREY silicone gasket maker (must have high oil resistance!!)
* Brake parts cleaner
* Silicone gasket remover (not completely necessary, but helps)
* Blue loc-tite
* Digital caliper or micrometer (optional for measuring clutch discs and springs)
* Oil drain pan
* Clean engine oil (and oil filter too... might as well)
* Lots of shop rags
* Clutch center holder tool (optional special tool). Honda P/N 07724-0050002

Time Required: Depends on skill level, but for most mechanically inclined people, and especially those that are very anal and picky about everything, I'd allow a good part of an afternoon to complete

The Kit

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Step 1

Drain the engine oil. Make sure the bike is in neutral
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Step 2

Remove the right side fairing
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Step 3

-Remove the 8mm bolt and remove the clutch cable from the release arm
-Unplug the red 2P crankshaft position sensor connector
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Step 4

-Remove the remaining 8mm bolts from the clutch cover
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-Then it may be necessary to gently tap the cover with the mallet from the backside to break the seal, then remove the clutch cover
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Now here's what you'll see next
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Step 5

*** IMPORTANT *** Place shop rags over openings to oil pan... parts WILL drop!!!

-Remove the (5) 10mm bolts and springs from the clutch pressure plate
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-Remove the pressure plate
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Step 6

-Inspect the lifter release bearings for wear or damage. Make sure all roller balls are present and move freely and smoothly
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-Inspect the lifter piece for wear or damage
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Step 7

-One by one, remove each clutch friction disc and steel disc. Place in a pile (somewhere clean) face down in the order that you take them out. After the last friction disc is removed, remove the friction spring and spring seat that will be in the back of the basket. Be sure and check the pressure plate when you take it out, that the first couple discs don't stick to it. Clutch discs and steel plates have already been removed in picture. You should have: eight clutch discs (friction), seven clutch plates (steels), one spring seat, and one friction spring
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-This is how your pile should look
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Step 8

-Using a flathead screwdriver or chisel, and a hammer, unstake the nut as much as possible
-Using the 30mm socket, and either an impact gun or breaker bar, remove the clutch center nut. If you don't have the clutch center holder tool, the easiest way to hold the clutch center from turning is to shift into 5th or 6th gear (you'll have to use one hand to turn the clutch center as you shift through the gears to make them mesh). Once you get in gear, use your foot to step down hard on the rear brake pedal as you remove the nut. It's easy with an impact gun, much harder with a breaker bar. After the nut is removed before removing the clutch center, shift the transmission back to neutral. Again it will be necessary to spin the clutch center back and forth as you shift through the gears. It will spin freely once you get to neutral

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Once again... highly recommended!!
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-Once the nut is off, the clutch center will slide right off. Take care not to lose the lock washer that is behind the nut, or the large washer that's on the back side of the clutch center that may come off with it when you pull it off
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Clutch center
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Step 9

-Remove the clutch outer basket. This is kind of tricky and hard to describe... there's 2 gears on the crankshaft that mesh with the gear on the outer shell, called 'scissor gears'. They are not aligned with each other and make the clutch outer rather tight to get out and back in. You need to turn the crank until you see a small hole in the gear on the crank, and stick a screwdriver in the hole and then hold tension on the crank to make the 'scissor gears' align with each other, so that you can remove and install the clutch outer

This is what you'll now see
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Step 10

-Remove the 10mm bolt on the gearshift linkage and remove from the gearshift spindle
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-Remove the gearshift spindle and thrust washer from the crankcase
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Now here's the parts that will be changed
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Step 11

-Remove the 5mm hex bolt from the detent arm and remove the arm, spring, and washer
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-Remove the 6mm hex bolt from the shift star (also referred to as the gearshift cam), and remove the shift star

Parts comparison -- Factory Pro EVO shift star kit on left, OEM on right

Front
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Rear
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Step 12

-Install the new detent arm, spring, and washer. Torque the bolt to 108 in-lbs (9 ft-lbs)
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Step 13

-Apply blue loc-tite to the 6mm bolt for the shift star
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-Using a flathead screwdriver, hold the detent arm up while you install the shift star. I forgot to take a picture, but there is a dowel on the shaft that the shift star bolts to. Align the hole on the back of the shift star with the dowel on the shaft. This can take several tries and can be a little tricky... just be patient and keep trying, and you must push it in firmly for it to seat properly. You can tell when the dowel is in the hole when you rotate it back and forth you can feel the shift forks moving around

-Once in place, tighten the bolt to 204 in-lbs (17 ft-lbs)
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Step 14

-Install the gearshift spindle, making sure the thrust washer is in place. When it feels like it's in as far as it will go, you need to lift up on the part that goes over the shift star. It's spring loaded and fits 'over' the dowels on the shift star. When you get it lifted up enough, the spindle will slide in just a little bit further
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T
#2 ·
Step 15

-Hold the spindle to keep from pushing it back out, and re-attach the gearshift linkage to the spindle. Align the punch mark on the spindle with slit in the linkage
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-Tighten the 10mm pinch bolt to 7 lb-ft
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***** STOP HERE!!!!! VERY IMPORTANT!!! *****

Before going any further with reassembly, verify that all the gear change correctly. CYCLE THROUGH ALL THE GEARS, UP AND DOWN!! Start in neutral, and make sure you have all 6 gears in the correct pattern. If it doesn't seem right, IT ISN'T!! If it doesn't shift normally, something is off with the shift star. Go back and recheck your work, and repeat until it's right. Remember you'll need to turn the transmission input shaft (the one that the clutch inner splines onto) as you shift through the gears to allow them to mesh. If everything feels good, proceed to step 16


Step 16

-Inspect these needle bearings on the clutch outer basket for missing, worn, or damaged needle bearings
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-If everything looks good and operates smoothly, install the clutch outer. This is where it's kind of tricky again... you need to put a screwdriver into the 5mm hole in the gear on the crankshaft, then turn the 14mm bolt on the crank to make the scissor gears align. While holding tension on that, you'll be able to slide the clutch outer into place

-Rotate the oil pump driven gear (the one with the little chain) as you push the clutch outer basket back. The 3 dowels from the oil pump drive gear need to go into the 3 holes in the back of the clutch outer to drive the gear. Once in place, the drive gear on the crank and the driven gear on the clutch outer should sit flush with each other
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Step 17

-Install the large washer
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-Then install the clutch center
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Step 18

-Take special note of which way you install the lock washer. Make sure the OUT marking is facing you, and install the washer
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-Place transmission in 5th gear just as you did to remove the clutch center nut above. Install the 30mm clutch center nut (a new nut is recommended). Using the 1/2" torque wrench and the short extension, hold down on the rear brake pedal and torque nut to 94 ft-lbs. Using the flathead screwdriver and a hammer, stake the nut into the slot on the input shaft
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-Place the transmission back into neutral. This is now a good time to turn the 14mm bolt on the crankshaft and spin the engine over by hand several times to make sure everything turns smoothly without any problems

Step 19

** Skip if you're installing a new clutch **
-Using a digital caliper or micrometer, measure the thickness of the clutch friction discs. Service limit: 2.6mm (hey mine are still in spec after 115k miles... not bad!)
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-Also a good idea to check the clutch plates (steels) for warpage, using a surface plate and a feeler gauge. Service limit: 0.30mm (no picture, sorry)

-Using a digital caliper or micrometer, measure the clutch springs. Service limit: 43.4mm (uh oh... looks like I'm gonna need new springs)
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Step 20

-Install the spring seat first and then the friction spring onto the clutch center. The friction spring is angled, and when installed the outer edge of the spring should be pointing outwards, and inner edge of the spring pointing inwards

-If the clutch discs and plates are OK and being re-used, or if installing a new clutch, generously coat or soak each clutch disc and plate with clean engine oil
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Step 21

-One by one, install the clutch discs and plates from the pile in the order in which they were removed. If installing a new clutch, follow the instructions provided for which clutch plates to put where (the rear disc, the center discs, and the front disc are all different and must be placed in the correct order). Install all the clutch discs except the last one into the deep slots of the clutch outer
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-Take special note... the last clutch friction disc to go in (the outer one) goes in the shallow slots on the clutch outer
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Step 22

-Install the pressure plate and lifter piece
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-Install the (5) springs and bolts, and snug tight in a criss cross pattern

-Continue to tighten in a criss cross pattern in 2-3 steps, and then tighten to the final torque: 108 in-lbs (9 ft-lbs)
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Step 23

-Using brake parts cleaner and/or silicone gasket remover, remove any residual silicone from both crankcase mating surface and clutch cover mating surface. Use a plastic scraper if necessary. Clean throughly with brake parts cleaner to make sure both surfaces are free of dirt, grease, and oil

-Using Hondabond or equivelant grey oil resistant gasket sealant, apply a bead around the diameter of the clutch cover
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^^^ I probably used a little too much... I always go a lil overboard with the sealant, haha

Step 24

-Install the clutch cover. This can take several tried due to the dowels and the clutch release arm, which you may have to play with a little bit to get the cover on all the way. Use the rubber mallet if necessary to 'gently' tap on the cover and make it pop into place

-Install the clutch cable onto the release arm

-Install and snug all of the 8mm bolts. Tighten the right upper corner first, then left upper corner, then right lower, then left lower. After those 4, tighten the remaining in a criss cross pattern until all bolts are tight. For some reason, the manual does not give a torque spec for these bolts, so use your own judgement on how tight to tighten them
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Step 25

-Reattach the crankshaft position sensor connector
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Step 26

-Re-install the right side fairing

-Fill the crankcase with 3.5 qts of a quality oil of your choice

-Change the oil filter
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-Always double check the oil level after letting it run for a min or so and then shut off
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Step 27

-After letting it run for a little bit and double checking everything and making sure there are no oil leaks (clutch cover, gearshift spindle on the left side near the linkage, ect), go for a test ride
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-If everything feels good, enjoy your nice new shift feel with smooth fast shifts
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#4 ·
Replacing the clutch plates and springs looks easy, but digging all the way to the shift star looks like a lot of work! Nice job with the photos!
 
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