RG500 Transmission Upgrade Details

RG500 Transmission Upgrade

rg500_transmission_installation Here you have it.  This fine kit from Maranello Engineering is tailor made for addressing the shortcomings of the stock Gamma transmission.  Parts included are a new input shaft with 12t 1st gear, 28t driven gear with needle bearing pivot, new design 2nd / 6th /3rd gears with new undercut dogs and massive strength for smooth positive shifts.  Ratios are stock with the exception of a taller 1st to close the gap between 1st and 2nd.
rg500_transmission_installation02 Drain the oil from both drains.  Remove the kickstart lever and clutch actuator arm from their splines.  Pull the screws from the clutch cover (note that the 3 long screws go in the middle, 1 high and 2 low) and remove the cover to expose the clutch assembly.

Remove the clutch springs, pressure plate and plate stack.  Bend the lock tab away from the net and remove the 27 mm clutch nut.  I use a Harbor Freight electric impact and deep socket set


and here


To keep the inner hub from spinning, I use a large screwdriver held between the spring posts.  As long as you are using an impact rather than a breaker bar or ratchet this will not damage the hub.  Do not attempt to use this technique when winding up pressure with hand tools.  You WILL break the hub at the post if you do


Remove the inner clutch hub to expose the first thrust washer (the smaller diameter and thinner one)

rg500_transmission_installation05 Remove the outer clutch basket to expose the larger thrust washer.  At this stage, look for the thick washer on the kick shaft to confirm its presence
rg500_transmission_installation06 Remove the retaining clip and washer from the shift shaft (just below the c/s sprocket) and remove the shift mechanism
rg500_transmission_installation07 Bend the lock tab down on the countershaft sprocket. Remove the nut with a 32 mm socket and impact.  If the motor is in the bike, this is best done while the chain is still on the sprockets.  When it is loose, move the rear wheel forward and take the chain off the rear sprocket toward the inside of the wheel to facilitate removal of the chain and front sprocket
rg500_transmission_installation08 Bend down the lock tabs on the cassette retaining screws and remove the 6 nuts and one bolt.  Be sure to keep track of the bearing retainer tab on the bolt
rg500_transmission_installation09 It helps to have a pocket magnet for this step to capture and remove the retainers
rg500_transmission_installation10 At this point the trans cassette assembly should come right out with a light tug on the kick and input shafts.  DO NOT apply inward force on the kick shaft.  Always pull out from the cassette plate or the kickstart mechanism will unwind and require attention to re-assemble.  If this happens, give me a call and I will make a low ball offer for your bike at the opportune time…
rg500_transmission_installation11 If the trans needs a little coaxing just give the tranny output shaft a tap with a mallet
rg500_transmission_installation12 Now you've gone and done it!  You are staring at the very innards of your Gamma with no hope of ever getting it back together.  In this view, you can see the 3 shift forks and 2 support shafts.  The forks with the large mouths are for the output shaft and the one narrow mouth fork is for the input shaft.  The long support shaft handles the 2 forks and the short one the one fork.  Note the location of the neutral switch button in the end of the shift drum.  This sits on a spring to contact the neutral switch.  Also, note the thin washer on the kickstart oil pump drive tower.  Do not confuse this washer with the thick one on the kickstart shaft.  Be sure that the 2 locator dowels are either in the cassette or in the engine case where they belong.  These assure proper spacing for the primary gears
rg500_transmission_installation13 Grasp the splined end of the output shaft and wrest it free from the cassette assembly.   Note the location of the thrust washer on 1st gear
rg500_transmission_installation14 Remove the input shaft with a few taps of a mallet
rg500_transmission_installation15 Locate and remove the 1st gear thrust washer
rg500_transmission_installation16 Slide off the 1st and 5th gears, stacking them in the exact order they came off with their proper orientation preserved for review
rg500_transmission_installation17 Use a QUALITY pair of snap ring pliers with one-piece tips (not the interchangeable junk) to remove the first retainer clip.  It will be helpful to have on hand both straight and bent type pliers that are for expanding snap rings.  Snap On and Sears are your friends
rg500_transmission_installation18 Remove 4th gear and maintain your gear parts stack.  You can start another stack with 3rd gear.   Remember the proper orientation.  Here you see the star retainer system that holds 3rd gear in place.  Remove the bent tab retainer and rotate the splined washer to remove 3rd gear
rg500_transmission_installation19 Inspect these retainers and look for excessive wear or bent splines from previous transmission issues.  If they are damaged, they must be replaced
rg500_transmission_installation20 Remove the remaining snap rings and gears to strip the shaft being careful to keep the proper assembly location and orientation of each part

Once you have the output shaft stripped bare you are ready to re-assemble with the new components

rg500_transmission_installation22 Slide the new 2nd gear onto the shaft
rg500_transmission_installation23 Replace the splined washer from the old 2nd gear
24 All snap rings are replaced with new ones supplied with the kit.  Secure 2nd gear in place with the snap ring
rg500_transmission_installation25 Place the new 6th gear onto the shaft as shown
rg500_transmission_installation26 Install the next retaining snap ring
rg500_transmission_installation27 Install the new splined washer supplied with the kit
rg500_transmission_installation28 Install the new splined support bushing supplied with the kit
rg500_transmission_installation29 Both of these parts go on either way.  There is no specific orientation other than washer first, then bushing
rg500_transmission_installation30 Install the new 3rd gear as shown
rg500_transmission_installation31 Re-install the lock ring and rotate into the proper position. Re-install the star retainer, engaging the tabs with the outer splines
rg500_transmission_installation32 Re-install 4th gear with splined thrust washer (note that some 4th gears came with splined inner bushings like what are supplied with the new 3rd gear.  Either system is fine) and install new retaining snap ring
rg500_transmission_installation33 Re-install 5th gear
rg500_transmission_installation34 Install new washer and needle bearing supplied in the kit
rg500_transmission_installation35 Install the new 1st gear and original thrust washer.  The output shaft is now ready for re-assembly of the cassette
rg500_transmission_installation36 Let's move on to the input shaft.  Locate the first snap ring on the shaft (NO, it is not under the 2nd gear and inaccessible) and move it inboard toward the 3 / 4 gear
rg500_transmission_installation37 Here is a better angle of what I am referring to. Note the type of pliers end used for this operation.
rg500_transmission_installation38 NOW, you can slide 2nd gear down the shaft to expose the hidden clip wire holding it in place.  Remove it with a small screwdriver
rg500_transmission_installation39 This often distorts the profile which can be corrected
rg500_transmission_installation40 I use a slightly out of focus pair of pliers to squeeze the clip back into shape
rg500_transmission_installation39 It should look like this when you are done
rg500_transmission_installation42 Remove 2nd and 6th gears and the inner bushing for 6th, remembering to reproduce the stacking order of all parts as they come off the shaft
rg500_transmission_installation43 Remove the next snap ring (the one you first moved aside to begin dismantling the shaft) and remove the 3 / 4 gear
rg500_transmission_installation44 Remove the last snap ring and 5th gear with bushing taking note which way the bushing shoulder faces against the gear
rg500_transmission_installation45 You are now ready to replace the old shaft with the new one and re-assemble the gear stack with new snap rings
rg500_transmission_installation46 Replace 5th gear as shown
rg500_transmission_installation47 Time for the first snap ring
rg500_transmission_installation48 Install the 3 / 4 gear as shown
rg500_transmission_installation49 Place the next snap ring on past the groove to prepare for the installation of the end wire
rg500_transmission_installation50 Install the 6th gear and bushing as shown
rg500_transmission_installation51 Install 2nd gear and the retaining wire
rg500_transmission_installation52 The retaining wire should be securely in place and out of focus just like this…
rg500_transmission_installation53 Slide the 6th gear and bushing toward the end of the shaft and drop the snap ring into its groove to lock things in place
rg500_transmission_installation54 Things should look like this when you are done.  If this shot still looks out of focus, you may want to forgo any more celebratory beer until you are done with the job
rg500_transmission_installation55 Do you want to come back to this when you are feeling better?
rg500_transmission_installation56 Re-insert the input shaft assembly into the cassette
rg500_transmission_installation57 Work the output shaft into place by separating the 1st gear a little and jostling into position being careful not to displace the 1st gear thrust washer
rg500_transmission_installation58 Things may look something like this when you are getting close.  If you think this is tough, try holding a camera while you are doing it…
rg500_transmission_installation59 On occasion this process will dislodge the dreaded kickstart gear assembly.  No big deal
rg500_transmission_installation60 Make sure the parts underneath look like this before refitting the gear assemble and you are good to go.  If things got sprung, you may have to remove the spring and plastic guide from the other side of the shaft and start over.  Having trouble, call me and I will talk you down from the ledge…
rg500_transmission_installation61 There, that's better
rg500_transmission_installation62 Confirm that the thin washer is where it should be
rg500_transmission_installation63 I have found it helpful to grease the plunger for the neutral switch to keep it from falling out when coaxing the transmission into place.  You can thank me now or later
rg500_transmission_installation64 To recap, long shaft with big forks, short shaft with lone fork
rg500_transmission_installation65 Assemble the shift forks as shown here
rg500_transmission_installation66 And here
rg500_transmission_installation67 And here
rg500_transmission_installation68 Position the oil pump drive tab to point toward the corner cassette stud
rg500_transmission_installation69 Position the oil pump drive slot to match.  When you guide the cassette assembly input the case, grip by the kickstart shaft and input shafts.  Remember not to allow inward movement of the kickstart shaft or you will soon become an expert on how to reassemble EVERYTHING.  You were warned.  Do not rotate the input shaft as you will change the orientation of the oil pump drive.  A little wiggle is fine.  When you are trying to get the trans to seat, be aware that sometimes the shift fork support shafts or the far side of the shift drum don't quite want to drop into place.  If the cassette studs are showing a few threads, you can lightly tap on the center of the cassette place with the end of a mallet to help things along.  It can also be helpful to gently rotate the shift drum with a T-handle 10 mm wrench to get it to drop into place.  Be sure that you can still get the chain over the end of the output shaft before seating the transmission.  If things don't feel right, start over.  It is easier to do so now than to blindly tighten things down and damage who knows what.  When the trans is in to stay and all retaining nuts and screws are affixed it is time for the shift shaft assembly to go back in.  Remember the washer and retainer on the other end.  You should have a plastic bushing in the case just before the washer.  Make sure it is present
rg500_transmission_installation70 This thin O-ring goes between the countershaft bearing and the steel collar that rides on the c/s seal.  If you didn't see it when taking things apart, it is probably stuck to the outside face of the c/s bearing.  It may be wise to find it early on and set it aside for when the c/s collar and sprocket go back on.  Speaking of which, do not wail on the c/s nut with a powerful impact.  A few good squirts of the trigger will do.  I have actually broken a shaft with excessive torque