GS1000G Secondary Drive Bearing Replacement

[Guest]

Since I could not find one, I am writing a how-to on replacing the bearings in the secondary drive unit of the shaft-driven models. I will be copying the text and pics from the 21 page document into hopefully three posts here. As always, this is a work in progress, so constructive criticism is welcomed. I have saved the document as a PDF, (click to download it) however it is over 4 MB in size.

Contents
Post 1 will have overall information, parts & tools required.
Post 2 will cover the process of removing the drive assembly and how to disassemble it.
Post 3 will cover removal of driven assembly, overall reassembly and clearances through final reassembly.

I am reserving the first three posts in this thread for this purpose.

***
On occasion usually due to a lack of maintenance the bearings in your secondary drive unit can fail. When this happened to my bike, I found there was no definitive how-to on the subject, so I decided to write one.

First, some terms so we're on the same page:
The GS “G” models are shaft driven.
This involves a primary drive from the crankshaft at the clutch.
The primary drive connects to a secondary drive system is located on the left rear of the engine and connects the engine to the rear wheel drive shaft.
The drive shaft connects to a final drive located next to the rear wheel and allows shaft rotation to turn the wheel.

If parts of my bike look different from yours, it is probably because this one has had a fuel injection system installed in place of the carbs. The fuel filter and feed hose for the fuel rail are visible in some pictures. There is an extensive write-up on this project on the GS Resources.

This repair paper will focus on replacing the secondary drive bearings. When these fail, the results can be catastrophic in that the rear wheel will be unable to turn freely. God blessed me by allowing this to happen at a low speed- I had just been riding at over 60 MPH and had stopped due to the fuel cutting off.

The secondary drive consists of two shafts at a 90 degree angle. One is parallel to the crankshaft and I'll call this the drive gear. The other is parallel to the drive shaft and I'll call it the driven gear. An easy way to remember this is the crankshaft drives the drive gear, when then results in the gear that connects to the shaft to the final drive so the shaft can be driven.

Repair overview:
The engine does not need to be removed on the 1981 GS1000G. The drive gear can be removed in about 15-20 minutes from the left side. The driven gear takes longer since the swing arm needs to be removed for access.

Service manual:
I downloaded the factory GS1000 service manual from BikeCliff's excellent website. It's free, so there's no excuse to not have one. This how-to is based in part on tech info from that manual, as well as firsthand experience. No special tools are required, but you need the know-how to do things such as pressing bearings on and off and removing and installing bearing races. The manual is not optional.

Parts required (with frugal commentary/sources):
Each of these two shafts has a pair of bearings, and the assembly uses one oil seal and two large o-rings. There is also a round cover on the side of the engine. As of 2015, most parts are all still available from Suzuki.
Here's a list of part numbers for the 1981 GS1000G. While other models are similar, always look up your application and/or compare your old parts to ensure you buy the correct parts.

Drive shaft bearings (2): 09265-32001. My bearings were stamped 4T 320/32X and measured (IDxODxWidth) 32x58x17 mm. These are over $50 each at the Suzuki dealer. To get an idea of the prices for this bearing & race, the same bearing can be found new on eBay from seller “locatebearings” for about $18 each plus $10 shipping for the first item and then $2 for each additional one. Amazon sells a “VXB” brand for about $9 shipped. You can buy two at Suzuki and spend $110 shipped or two on eBay for $48 shipped or two on Amazon for $18 shipped. The eBay seller has other bearings as well, so you can buy more to save more since they reduce shipping for additional items. I could not find these on Rock Auto.

Driven shaft front bearing: 09265-25012. This bearing measures 25x62x18.25 and has a stamped number of 4T 30305C. Unfortunately it can't be found online for a lot less than the $40 dealer price unless you go overseas. The 30305C number crosses over to a bearing that is usually listed as only 17mm wide. I verified mine was 18.25mm wide. I found new bearings & races from a foreign seller on eBay for $16 each plus $5 shipping. Amazon no longer sells a “VXB” brand in this size. Rock Auto sells a 30305 bearing that specs out correctly in the “National” brand for a little over $16 each.

Driven shaft rear bearing: 09265-25024. This bearing measures 25x52x16.25 and has a stamped number of 4T 30205C. It can be found online for a lot less than the $32 dealer price. I found new bearings & races from a USA seller on eBay for $5 each. Amazon sells a “VXB” brand that has good reviews for about $14 each. Rock Auto sells them in the “National” brand for a little over $12 each.

Oil seal: 09283-35018. This sells for about $10 at the dealer. Mine had an NOK number of AH2068F. An online search for this seal showed this crossed over to an SKF 13947. I found one at Rock Auto for under $4, but the shipping would offset the savings unless you bought other parts at the same time.

Drive shaft o-ring: 09280-63004. It sells for about $3 at the dealer.
Driven shaft o-ring: 09280-63004. It sells for about $5 at the dealer.
Cover/plug: 09241-58001. It sells for about $11 at the dealer.

Drive shaft nut: 09159-32001. Note: Discontinued, check eBay. I measured mine and it is a 32mm x 1.5 pitch thread. This type of nut is not available, so my suggestion is to reuse the old one and use some Loctite.

Driven shaft nut: 09159-14010. This part is still available and is a dealer-only part due to the unique nature of the nut. It sells for about $8.

If you buy all this from a dealer, these will usually add up to around $210 plus shipping as of 2015. Substituting Amazon's drive shaft bearings along with Rock Auto's driven shaft bearings and oil seal and the remainder from a dealer will total about $77 plus shipping. It pays to shop.

Since you'll be pulling the swing arm, it would pay to replace the bearings there as well. The OEM bearings are part #09265-17012 and measure 17x40x13.25 mm. These sell for around $35, but since they are just regular bearings, quality replacements can be had for far less. Amazon sells a 17x40x13.25 bearing for $6.60 with free shipping. Both have the same 30203 number stamped on them.

If required, 4 x 6mm socket head bolts for the side cover.

Tools/materials required (nearly all of these can be found at Harbor Freight):

• Set of combination wrenches to include 10-17mm.
• Set of sockets to include 19mm impact socket, 21mm socket (swing arm nut), and 41mm socket
• Set of metric hex socket (side cover & swing arm bolts)
• Impact wrench to use with 19mm socket & 41mm socket if needed
• Punch, drift, or chisel
• Claw hammer
• Bench vise
• Hydraulic press or a buddy that has one
• Bearing separator for 1.2”/32mm shaft
• Phillips head driver or socket driver
• Pair of large flat blade screwdrivers
• Torque wrenches (2): At least 100 ft-lbs max & one in inch pounds (at least 2.6 minimum).
• Adapters to adapt the smaller torque wrench to the 19 and 41mm sockets
• Bearing and race driver set. Harbor Freight #95853, about $35.
• Dial indicator with clamping base that reads up to 4 decimal places- need to mount it to check backlash. Harbor Freight sells #93051 for $35 that includes a clamping base and flex arm. It is item #93051. This only goes to .001 while the manual gives a spec of .0031 to .0051. A reading of .003 to .005 yields a range of .0030 to .0059, so this allows sufficient accuracy.
• Prussian blue for marking/checking teeth backlash (some have used fingernail polish)- Amazon sells this for about $6/tube.
• Grease- such as lithium, this is for the o-rings
• SAE 90 gear oil. The manual calls for 11.5-13.5 ounces, so buying one pint will do.

[GS1000G Shopper]

Removing the drive assembly and how to disassemble it

Post 2: Removing the drive assembly and how to disassemble it. Click on thumbnails for full-size picture:
Process:
Remove the shifter using a 12 mm wrench. Put the bolt back into the shifter so you don't lose it.
Remove the left rear side cover via 4 bolts. It may have cruddy Phillips head screws or socket head bolts. I suggest using the latter, they can be obtained at a local hardware store.


Drain the gear oil from the secondary housing by removing the drain plug. You'll see the drain plug located on the side under the cover you just removed, and it takes a 21 mm socket.



Removal of drive gear assembly:
Refer to the prior photo. There are 4 x 12mm head bolts holding the drive gear to the engine. There are a number of shims under the square flange. First, a trick to save buying a $55 special tool. There is a 41mm nut under the circular cover. The cover can be removed by using a drift/punch/screwdriver on the outside edge until it can be pulled or popped off. I ended up punching a hole through mine and used the screwdriver to lever it off. All the $55 special tool does is hold the shaft from turning so you can loosen the nut. I used the engine to do so, as the nut was not on overly tight. Be sure to loosen both this 41mm nut and the 19mm driven shaft nut while the assembly is in place (see next section)!

First, use a punch to raise the flattened part of the nut.

Then put the 41mm socket on it and give it a swift pull. My broke loose right away. My 3/4” drive ratchet is about 18” long, so that helped for leverage. Be sure to loosen both this 41mm nut and the 19mm driven shaft nut while the assembly is in place (see next section)!

Remove the 4 bolts, and then loosen the case bolts that are adjacent to the gear, likely 2 x 12m head and 2 x 10mm head. It helps to remove the fill cap (17mm wrench) to access the inner 10mm head bolt.. This helps to lessen the tension on the gear assembly.


You then can work on pulling the gear out. I found that using the screwdrivers one on each side helps. It must come out straight, if it is crooked it will not come out. Once it is out far enough, you can remove it by hand.


Here is the assembly once it has been removed:


Next we want to disassemble the assembly. Once the 41mm nut is off, you can place the assembly in a hydraulic press using the flange to support it and press out the shaft. You'll be left with the shaft and one bearing plus the spacer and shims. Do not lose the shims, they are discontinued. Use the bearing separator and press off the remaining bearing. This was the tightest fit of all the press work on my assembly. Finally, use a punch to remove the bearing races from inside the housing. I did not take any pictures of this part of the job, but here is what you have left once you're done:


Now we are ready to reassemble the drive assembly. Make sure everything is clean. Assembly is basically the reverse process:

1. Install the new bearing races in the housing
2. Press on the new inner bearing
3. Install the spacer and shims
4. Press the shaft onto the new outer bearing
5. Lube the bearings with gear oil
6. Thread the nut onto the shaft
7. Note: Do not install the square shims or new o-ring until the preload has been checked
8. Install the assembly until the engine shaft engages the gear.
9. Once it is in place, torque the nut to 87-108 foot-pounds.
10. Remove the assembly for preload testing

Now we can check the preload:

1. Turn the shaft several times in both directions to seat the bearings.
2. Using the 41mm socket, the turning force (preload) should be 2.6 to 4.3 pound-inches. You'll need to adapt the socket to the proper scale torque wrench.

If the preload is not within spec, the manual calls for shims to be replaced, which requires nearly a complete disassembly. The shims appear to all be discontinued, so I'd suggest checking eBay for replacements if needed.

Once the preload is OK, then:

1. Remove the unit and install the square shims but not the new o-ring- it will be installed after we check the backlash & tooth contact.
   
2. Be sure the gear teeth are free of any oil or grease.
   
3. Reinstall the assembly making sure the drain hole lines up with the hole in the case, the manual says to have the letters “UP” facing up. You'll have to wiggle it around some, so be sure it goes in straight.
   
4. Torque the 4 bolts to 14-19 foot pounds.
   
5. Install a new 41mm nut and torque it to 87-108 foot-pounds.
   
6. Using a drift or chisel, flatten the nut where the threads are indented.

We're done with this part until we check the backlash and tooth contact.

[GS1000G Shopper]

Removal of driven assembly and clearances through final reassembly

Post 3: Removal of driven assembly, overall reassembly and clearances through final reassembly. Click the thumbnail images to view the full size picture.

Removal of driven gear assembly:
This part is more difficult to access than the drive assembly. I found it was easiest to just remove the swing arm for more room. Follow the manual's instructions, and once it is off the process is very similar to the drive assembly.

With the drive gear still in place, try to remove the flat part of the 19mm nut on the end of the shaft. I did not have any luck doing so. It took an impact wrench to loosen this nut. Once it is off, then remove the 4 x 12mm head bolts, just like the drive gear assembly.


This must also be pried out evenly. I again used two screwdrivers and then when there was enough of it out, a claw hammer on one side. Take your time and it will pop out. It may pay to have a rug or a foam mat under the bike since it may pop out quickly.

Disassembly is just like the drive assembly. The shaft and front bearing came out on their own. I then pressed out the rear bearing using the press, and then the front bearing using the bearing separator. The races came out the same way via a hammer and chisel.

Once everything is apart, you'll have a similar set of parts:



Just like the drive assembly, reassemble it in the reverse order.

1. Install the new bearing races in the housing
2. Press on the new inner bearing
3. Install the spacer and shims
4. Press the shaft onto the new outer bearing
5. Lube the bearings with gear oil
6. Thread the nut onto the shaft
7. Note: Do not install the large shims or new o-ring until the preload has been checked
8. Install the assembly until the engine shaft engages the gear.
9. Once it is in place, torque the nut to 65-79 foot-pounds.

Now we can check the preload:

1. Turn the shaft several times in both directions to seat the bearings.
2. Using the 41mm socket, the turning force (preload) should be 3.4 to 6 pound-inches. You'll need to adapt the socket to the proper scale torque wrench.

If the preload is not within spec, the manual calls for shims to be replaced, which requires nearly a complete disassembly. The shims appear to all be discontinued, so I'd suggest checking eBay for replacements if needed.

Once the preload is OK, then:

1. Remove the unit and install the large shims but not the new o-ring- it will be installed after we check the tooth contact.
   
2. Install a new oil seal. It should be flush with the housing so as to offer better contact on the flange.
   
3. Reinstall the flange and a new nut. Torque to 65-79 foot-pounds. Use a drift or chisel to flatten the nut by the indent in the threads.
   
4. Reinstall the assembly making sure the drain hole lines up with the hole in the case, the manual says to have the letters “UP” facing up. You'll have to wiggle it around some, so be sure it goes in straight.
   
5. Torque the 4 bolts to 14-19 foot pounds.

We're done with this part until we check the backlash via tooth contact.

Checking backlash

At this point, both assemblies are installed and are

• Properly preloaded, have had
• Large shims installed, and the
• O-rings are NOT installed

Backlash is adjusted by changing the large shims on the driven gear housing.

To check backlash of the driven gear, install the dial indicator so the tip touches the flange of the driven gear. Now turn the flange in both directions until it stops and check the measurement. The manual's picture is poor quality, so I have rejected it and substituted my own:


The specification here is .0031 to .0051 inches. The Harbor Freight gauge will register .003 to .005, so if it is under or over these numbers it is out of spec. As with bearing preload, if it is out of spec you'll need to source some shims on eBay or elsewhere. The manual has the sizes and part numbers.

Checking tooth contact
Leave the driven gear assembly in place. As a reminder, it is:

• Properly preloaded, has had
• Large shims installed, and the
• O-rings are NOT installed

Tooth contact is adjusted by changing the large shims on the drive gear housing.

To check tooth contact of the gears:

1. Be sure the driven gear teeth are clean and free of any oil.
2. Apply the marking material such as Prussian Blue to several teeth.
3. Reinstall the driven gear assembly and torque the 4 bolts to 14-19 foot pounds.
4. Turn the driven gear flange several times in both directions.
5. Remove the driven gear assembly and check the contact pattern.

I will copy the illustrations from the manual here for easier reference:
Correct pattern (middle of tooth), full size image:




Incorrect pattern (contact at tooth top), full size image:




Incorrect pattern (contact at tooth roof), full size image:




As with bearing preload, if it is out of spec you'll need to source some shims on eBay or elsewhere. The manual has the sizes and part numbers. I did not need to change any shims for this part. Here's a pic of the tooth pattern:


After this is complete, be sure both sets of teeth are clean and remove any marking dye that may be on them. Double check the inside of the housing for any debris. Having to do this again is worse than a trip to the dentist, so clean teeth are important.

Final reassembly
This is the easy part. Now that everything is properly dialed in, all you need do is:

1. Install the new o-rings and reinstall the assemblies. Use a light amount of grease on them.
2. Apply thread locker and torque the 12mm head bolts to 14-19 foot pounds.
3. Reinstall the swing arm.
4. Install the new cap on the drive assembly.
5. Torque the case bolts loosened earlier, 12mm head to 9-16 ft-lbs, 10mm head to 4-7 ft-lbs.
6. Reinstall the side cover and shifter.
7. Refill with proper gear oil- the manual calls for SAE 90, 11.5 to 13.5 ounces.

[gordinho80]

Thanks for this!! I'm in need of replacing bearings on my driveshaft.

[GS1000G Shopper]

You're welcome. I'm still not done with the repair. Had to wait on some parts, and then another car broke down and I had to put the swing arm & rear wheel on the bike to move it. I hope to get back to work on it in a month or so.

[GS1000G Shopper]

Job was finally completed today! Other more urgent projects arose, and a lot of the time was waiting for shims. After my last round of testing with the .50 and .40 OEM driven shims, I knew I needed a thinner one. I could not find a .35 shim reasonably priced, so I ended up buying two .30 mm shims from England. The seller sent me 3 by accident, and didn't want the extra one back. I was just outside of spec with the .50 and .30 (too much backlash) as well as the .40 and .30 (not enough), so I figured a .35 would work. I couldn't find one, so I did some reading here and found where a member suggested sanding to the proper thickness. Since I had 3 of them, I then figured out a way to make a .30 shim thinner, so I could use it with the .50 shim.

Here's what I did:
I used a 6" x 6" x 3" thick block of aluminum (any flat surface metal will work) and applied a thin coat of RTV. I then set the .30 shim in the RTV and pressed it flat. I let it dry overnight, then used an orbital sander with 100 grit paper- about 5 discs. I ended up about .27, which put me in the middle of the specification.

I have updated the related thread and I'll update the PDF for the entire job.

[Uncamitzi]

Interestingly enough, I'm in the middle of this kind of fix on my GS850gl....... however, it looks like I will have to, at least lift the back of the engine up to get the secondary drive out.... I will post some pictures here as I work on this.. My first mistake was thinking that the driveshaft from a GS1000 would fit.... (oh well) I'll let you know my further mistakes as I move along.. the secondary is about half way out...now I need to move the engine a bit...

[Uncamitzi]

When I took the swing arm off and went to pull the driveshaft off.. I found this. IMAG0184.jpg The nut on the end of the drive gear was sheared off and rolling around inside the flange,
I have a hard time with how this could have happened and when... I think maybe a PO has over torqued the thing... ?

Oh..and I didn't have to move the engine.. the Secondary drive slides out after loosening the engine casing bolts near the back of the engine and some gentle tapping with a wooden dowel and rubber mallet.

[GS1000G Shopper]

Ouch!

I think a few members here are selling the complete gear set. You are not supposed to replace one w/o the other.

I have updated the how-to, I realized I left out the oil seal installation for the driven housing. I have updated the PDF link as well. Let me know if I have missed anything else and I can correct it.

[azr]

Excellent write up, thanks a million. Are you thinking of having this added to Cliffs site?

[GS1000G Shopper]

Excellent write up, thanks a million. Are you thinking of having this added to Cliffs site?

You're welcome. That had not occurred to me... great idea, I will PM Cliff.

[Nessism]

There is an article on Basscliff's website about repairing the broken fastener. http://members.dslextreme.com/users/...pair_zooks.pdf

[GS1000G Shopper]

Good find. I looked that over & you can probably drill & tap it yourself. I found torque specs for a 12mm x 1.75 (coarse) pitch class 12.9 socket head bolt here:

http://www.cncexpo.com/MetricBoltTorque.aspx

Dry is 108 foot-pounds, and lubed is 81. That's above what is called for on the OEM nut, so it should work well as an alternative.

Boltdepot.com sells the 12x40 class 12.9 in both 1.75 and 1.25 pitch. Lowes or Home Depot may carry them as well, but you'd need to verify they were class 10.9 or 12.9.

You can usually find metric taps either at McMaster.com or on eBay. McMaster sells taps specifically for closed-end hole threading, but they are pricey ($18-$40 plus shipping). I saw some 12mm cobalt taps on eBay for about $8 shipped (not in 1.75 pitch though), those would work well in hardened steel which I'm presuming the shaft is composed from. Since you're drilling into steel the recommended bit is a 27/64:

http://www.littlemachineshop.com/reference/tapdrillsizes.pdf

Cobalt 27/64" bits go for about $6 shipped on eBay.

If you use a different thread pitch (1.50 fine or 1.25 extra fine), the above torque & drill specs vary.

You'll need to evaluate your capabilities & the cost / time of the tools vs the cost of a machine shop doing this.

[Uncamitzi]

The seals were leaking quite a bit.. the unbalance of that sheared nut must have done some damage to the bearing as there was a lot of slop in the gear. I found a secondary drive on Ebay...but now that I see that post about replacing the broken fastener you've sent.. I'm going to revisit replacing the bearings and seals on that gear. Thanks!

[Uncamitzi]

Hi folks, Any word on the best place to get the o rings for the Driven Gear and Secondary gear? Bike Bandit ok?