Saturday, August 27, 2011

Changing the drive sprockets on Yoshie

Though I am still waiting on the Type 530 Chain with the 16,000 lb tensile strength from sidewinder sprockets.  The stock chain that came with Yoshie, is an EK525 SRX chain with a tensile strength of 8800 lbs and it had already started exhibiting signs of "stretching" under sidecar loads.

The "performance" replacement sprockets from Supersprox had arrived earlier this week and I decided to install them while waiting for the chain to arrive, probably early this coming week.  I hope.

I'd done my research online, asked question of fellow V-Strom riders on advrider, stromtroopers and vrsi discussion forums and had a fellow named Chris aka Bluebye on advrider who lives in Castle Rock just a phone call away.  Thanks Chris!

Took me a few hours, as I was documenting with pictures as I went, being very methodical and cleaning things as they became available to me.  I also ran into a stuck mounting nut on the rear sprocket that caused me to invoke the Oscar factor, more on that later.

First thing you have to do is remove the Slave Clutch Cylinder that is held on 
by two 6mm Allen Head Screw

 The clutch cylinder screws are not the same length, the one to the left goes in the 
upper mounting hole and goes inside a metal tube insert

 Above is the inside portion of the clutch cylinder, I would of course be cleaning it 
up before re-installing it

 Above you can see the circular cavity where the clutch cylinder was mounted.
That's the clutch actuator rod in the middle, note the donut shape tube end at 11 O'clock

 Here's the clutch cylinder moved out of the way of things,
I would end up zip tying it into this position

 Above I am removing the tube insert for the upper mounting screw 
for the clutch cylinder

 Removing the clutch actuator rod, it was quite longer than what
I remembered from when the same type rod broke on Vikki

 Above, the sprocket cover housing is removed and zip tied out of the way
revealing the front sprocket and chain

 It was a bit "gunky" above, with accumulations of flung off chain lube and dirt

 Here's the area again, after some initial cleanup work

 Now, for a 6mm Allen Head wrench to remove the speed sensor 
mounting screw.

 Before you can remove the speed sensor mounting screw, you have to have the transmission
in Neutral.  You then block forward movement by the rear wheel by either using a 2x4 block of wood
or what I found easier, I used a really long flat tip screwdriver resting on
top of the swing arms.

 With the rear wheel blocked, the chain then held the front sprocket in position and
I was able to apply the loosening torque against the sensor mounting screw and remove it.

 Here's the speed sensor plate coming off, revealing the 32mm nut which
secures the front sprocket to the transmission spline hub.

 The nut above comes from the factory with red Loctite.  I worried that it would be a bugger 
to remove but apparently the previous owner had changed sprockets at least once 
before, and I didn't have to struggle much with the cheater bar I used.

 Front sprocket nut removed, the front sprocket can now be removed
from the transmission splines but first I must remove tension on the chain.

 Here's the right side swing arm tension adjuster screw before I loosened them up.

 The tension adjuster screws fully retracted, did the same on both sides.
At this point, with the axle nut loosened beforehand, I was able to push the rear 
tire forward, releasing tension on the old drive chain.

 As you can see below, I took the chain off the rear sprocket, which allowed me
to take the chain off the teeth on the front sprocket above.


 The old front sprocket came off easy enough at this point
you can see the washer below which makes contact with both the sprocket
and the sprocket nut.


 Above is a shot of the transmission input spline hub on which the sprocket rides.

 Above is a comparison shot of the old front sprocket (left) and the new
front sprocket from Supersprox.  Note, the new one is a type
530 sprocket.

 I placed the two sprockets together, note how the teeth on the old
sprocket were starting to "hook" due to chain wear.

 A top down view of the sprockets, note how much bigger the new sprocket teeth
are and how thicker the sprocket itself is.  Note, the old front sprocket comes from
Suzuki with a rubber "damper" to lessen noise.  It's not necessary for the new sprocket.

 Here I am starting on the 14mm mounting nuts (five of them) that hold the rear sprocket 
onto the rear carrier assembly of the rear wheel.  I used the cheater bar again and thought I had
easily loosened all five screws.  Turns out, I missed one.

 At this point it was time to remove the rear wheel to get at the rear sprocket.  
Above is a view of the mounting hardware for the axle on the right side swing arm.

 I gently tapped the axle out towards the left side swing arm, above you can
see it start to come out, displaying the tension adjuster metal block.

 Above is the wheel spacer that goes between the left side swing arm and the wheel.
Below is a view of the spacer between the right side of the wheel and the 
right swing arm.


 Above is a view of the wheel, free of the tug, sitting on top of the new car tire
that I will be mounting later on this summer.  This way, the brake disk on the underside is
protected from contact with the floor.  It was at this point that I realized one of the five 
mounting nuts was "stuck" and the edges starting to "wear".

Before I caused more damage, I took a break from removing the old rear sprocket from the carrier and instead lifted the sprocket and the carrier off of the wheel to reveal the cush drive.

 Above is a view of the spacer which sits under the rear sprocket carrier assembly
which at this point has been pulled off the cush drive rubber pieces which "hold" 
the carrier in place.  The fact that the carrier assembly came off easy told me the old cush drive
pieces were worn and needed replacing.

 Above is a view of the old cush drive rubber pieces, note the worn spots
on top of each.  The underside of the sprocket carrier assembly also showed 
spots where the rubber had rubbed off onto the carrier assembly.

 Here's the cush drive housing, after it was cleaned up.

I now returned to the stuck mounting nut on the rear sprocket carrier.   I tried for quite some time to free it, using lubricating oil, wrenches, sockets and even a propane torch.  All I succeeded in doing was stripping the edges of the nut even further.  Dammit.

I now invoked the Oscar factor.  He was out with his family but we arranged for me to go to his place later where he'd take a crack at things.  In the meantime, I went and secured some nylon self locking nuts  (M10 x 1.25) which would have to do until the replacement mounting nuts with metal self locking tabs I ordered through the dealer arrived sometime this coming week.

I got to Oscar's place and he tried something called a Gator Socket and some specialized sockets designed for stripped nuts.  No luck.  We just succeeded in rounding things off even further!  At this point, Oscar broke out his die grinder and introduced me to the grinding wonders of this tool.  He made it look easy though a bit dangerous as he ground two flat edges back onto the sides of the stuck nut.

 A midway shot of the grinding down of the stuck mounting nut.
Oscar kept saying "Dude, I've never seen 
anything like this before".  I always bring Oscar "interesting" problems.

So, once he got the two flat sides ground into place, he got this big pipe wrench and while I held the sprocket carrier in place with a different socket wrench, he applied his considerable strength at the stuck nut.  
Pretty soon we heard a "crack" and the stupid stuck nut finally came off!  See below.

 Above is a closeup view of the destroyed mounting nut, we suspect the previous owner or whomever
did the last sprocket replacement used red loctite on the damn thing
causing us to go through the struggle we did.

 Here's the sprocket carrier, free of the old sprocket, yay!

 Above is the cleaned up sprocket carrier, mounted onto the newly installed cush
drive rubber pieces.  Below is the new rear sprocket ( 43 Tooth Type 530)
mounted onto the carrier assembly.


So, some more cleanup work here and there, now I get to wait for the new chain's arrival.  This posting is both a record for me as to how things came apart so I can put them back together.  Hope it helps someone else take on what was really a pretty simple task, the replacement of the drive sprockets.  I hope swapping out the chain is as easy.

10 comments:

Canajun said...

One of the best documented u-fix-it pieces I've seen in a long time. I'll likely never own a V-Strom, let alone a sidecar rig, but I did learn a good new trick with the angle grinder solution to the frozen nut problem. Thanks for that.

Charlie6 said...

Thanks Canajun

re the frozen nut tool though, its was a die grinder...my angle grinder would not have been able to get at the nut I think due to the angles involved. The die grinder is smaller, air-driven, and the bits are correspondingly smaller in order to get at those "ackward" spots.

I will say though, all my pictures aside, one should rely on the service manual and the wisdom of certain known gurus in the respective v-Strom forums instead of my postings. : )

RichardM said...

Nice write-up with all of the pictures. What is the purpose of the rubber pieces on the cush drive? Dampen out engine pulses to reduce stress on the chain? It seems as if they would allow the rear sprocket to flex.

Charlie6 said...

Thanks RichardM...as to your question re the cush drive:

The rear sprocket is bolted not directly to the hub, but rather to a second plate with tabs on the opposite side as the sprocket. The sprocket and its plate fit in to the actual hub which has openings for the tabs on the sprocket assembly. There are rubber isolators between the two assemblies to absorb the shock form acceleration.

got the above from another member of stromtrooper.com site.

Ecceentric Rogue said...

Great write up, but I have a question. It seems that you went up a chain and sprocket size. Doesn't the Yoshie use a 525? What is the advantage or disadvantage of moving up in size?

Charlie6 said...

Eccentric Rogue

yep, the DL1000 comes stock with a 525 sized chain and sprockets (17 tooth front, 41 tooth rear).

went to 530s in sprockets (17 front and 43 rear) for more lower end torque in first/second gear (supposedly) and beefier construction of the 530s vice the 525s.

sidecars are apparently "brutal" on chains.

Ecceentric Rogue said...

Does changing the sprocket change the speedometer in anyway?

Charlie6 said...

Rogue

yes, it will, once I get a chain and mount it that is. A speedo-healer type device is in my future I am sure.

dom

Jack Riepe said...

Dear Charlie6 (Dom):

This is way too much work for me. While I deeply appreciate the education I am getting here, I am even more greatful for the fact that you are on the receiving end of this project.

A noted mehanic friend of mine has repeatedly pointed out that few, if any, motorcycle manufacturers reccommend adding a sidecar to a motorcycle frame. The fact that your already toughened chain is yielding to the sidecar pressures tells me that the tougher chain (still to come) might just be adequate.

I had no idea tha a sidecar could deliver such a beating to a tug.

Great maintenance report. Good luck with this.

Fondest regards,
Jack/reep
Twisted Rads

Charlie6 said...

Jack, trust me, its an education I could have done without....still, this has been quite the eye-opener. The stock chain, at 8800 lbs, may have been damaged by the previous owner by running it too tight. It had made klunking noises BEFORE I put the sidecar on, the sidecar just made things worse. : )

If the almost twice as strong chain fails to handle the load, then the strom will go back to being a two-wheeled moto and I will revisit another type of sidecar rig.

Yes, most manufacturers don't recommend attaching sidecars, I think it's as much liability dodging on their part as anything else. I believe a proper subframe deals with the sidecar-induced stresses but then again, what do I know.

It's all good....

dom


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