SuzukiSavage.com - Rear Pulley Wobble Fix

DragBikeMike

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Rear Pulley Wobble Fix
07/01/19 at 00:00:30

The drive pulley wobble issue has received a bit of attention on the forum. Over time, the ball bearing that supports the pulley hub wears and allows the pulley to skew. This causes the belt to rub on the vertical rails on the pulley, and you end up with this screwy belt whine. Dave came up with a nice fix where you machine the inner boss on the drive hub to accept a bushing. The bushing provides additional support for the hub and pulley, which mitigates the cocking.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1428436529/4#4

The stock setup utilizes a single-row deep-groove ball bearing in the cushion drive hub. The single-row bearing is OK for the radial load but doesn’t provide a lot of support for side loads or cocking loads. I have fixed this problem on several metric sport bikes that had cushion drives. Double-row angular-contact ball bearings worked great on those sport bikes, but I had to machine entirely new drive hubs to accommodate the wider double row bearing.

I decided to see if I could modify the LS650 drive hub, or fabricate an entirely new hub that would accommodate a double row bearing. As it turns out, the stock hub will accept the wider bearing just fine. I utilized a sealed bearing and simply left out the stock hub seal. I think it will work just fine. Probably not good if you are constantly riding in the pouring rain, or if you intend to race the Baja peninsula, but for simple street cruizin it should fit the bill.

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DragBikeMike

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Re: Rear Pulley Wobble Fix
Reply #1 - 07/01/19 at 00:02:57

I found a suitable bearing on eBay for $16 (delivered). The vendor is Quality Bearings Belts & Chains, Lexington, KY 40509 (www.qualitybearingsbeltsandchain.com). The bearing is a 5305-2RS, item number 111730106826. This is an extremely inexpensive, Chinese bearing. A similar SKF bearing costs about $112. Generally, I wouldn’t bite on a deal like this. I would be skeptical of the quality (you get what you pay for). But I figured it would be worth $16 to try the mod out. If it works good, I might consider springing for the gold standard bearing. What the heck, I’ll keep an eye on it. I may end up just leaving the Chinese bearing in place as long as it doesn’t misbehave.

The only machining that must be accomplished is to turn down a shoulder on the left side wheel spacer. Very easy to do. I did the entire job in three hours this afternoon.

I started by measuring how much side play/wobble I had on the pulley rim. Set up a dial indicator and use your hands to wobble the pulley right and left. Mine had .070” wobble. Boy, that’s a lot considering the bike only has 3500 miles on it

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DragBikeMike

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Re: Rear Pulley Wobble Fix
Reply #2 - 07/01/19 at 00:04:09

I removed the rear wheel assembly. The pulley and hub just pull off by hand. In anticipation of doing this mod I had previously purchased a used hub on eBay. I removed the bearing seal and took a look. There’s plenty of room for the duplex bearing if you leave the stock grease seal out. I’m using a sealed bearing so I don’t think I will need the stock seal.

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DragBikeMike Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 4411 Honolulu	Re: Rear Pulley Wobble Fix Reply #3 - 07/01/19 at 00:05:01 Here’s a look at the single row bearing next to the double row bearing. You can get a feel for how much wider the double row bearing is. The stock inner spacer fits perfectly into the new bearing.
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DragBikeMike Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 4411 Honolulu	Re: Rear Pulley Wobble Fix Reply #4 - 07/01/19 at 00:05:59 I cleaned up the new hub and put it in the BBQ. Fired it up and toasted the hub for 1 hour at 250°F. Pulled it out of the oven and quickly installed the new bearing (gotta move fast, don’t want the hub to cool off) The new bearing dropped right into the hub, “clunk”.
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DragBikeMike Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 4411 Honolulu	Re: Rear Pulley Wobble Fix Reply #5 - 07/01/19 at 00:06:54 As I mentioned, the only machining that has to be accomplished is to turn down a shoulder on the existing left side wheel spacer. The shoulder fits snug in the new bearing and maintains the proper pinch on the inner race. This is a shot of the left side wheel spacer after machining.
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DragBikeMike Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 4411 Honolulu	Re: Rear Pulley Wobble Fix Reply #6 - 07/01/19 at 00:07:39 This is a sketch of the modified spacer.
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DragBikeMike Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 4411 Honolulu	Re: Rear Pulley Wobble Fix Reply #7 - 07/01/19 at 00:08:27 I assembled the rear wheel and checked the wobble. You can’t feel any wobble when you try to rock the pulley right and left but dial indicators don’t lie. The pulley now moves .007” when you rock it right and left by hand. Pretty good. Here’s the finished product.
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Re: Rear Pulley Wobble Fix
Reply #8 - 07/01/19 at 00:09:53

The pulley is solid as a rock now. A short ride was music to my ears. The howling belt is a thing of the past.

Hope this post proves useful to some of you. It’s a very simple fix and looks like it should work well. I will be checking it periodically to make sure that the bearing is holding up. I’ll keep you posted.

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Best regards, Mike

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Dave

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Re: Rear Pulley Wobble Fix
Reply #9 - 07/01/19 at 03:33:27

Good fix DBM......and I would think the seal on that bearing is just as good as the stock seal and will keep everything but water from a pressure washer from getting inside the bearing.

It you wanted to improve the seals ability....maybe you could install a small shield (flange) on the spacer to prevent a direct splash at the edge of the seal.

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Hiko

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Re: Rear Pulley Wobble Fix
Reply #10 - 07/01/19 at 21:51:00

Great fix Mike The last time I got a warrant of fitness the tester remarked on the pulley wobble and the bike had only done 6000 Kms at that stage
I managed to talk him round that it is Ok and he passed it but it does seem
a weakness with the savage but you have solved it!
A neoprene disc tight on the spacer would help the seal but not that necessary I feel I have had experience with sealed bearings in worse environments than that with no problems
Thanks for sharing I have another project now!

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RocketScienceSmurf

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Re: Rear Pulley Wobble Fix
Reply #11 - 07/02/19 at 06:55:06

Beautiful work! Since I live in Sweden I will probably try to get a SKF bearing, but I was wondering if a dual row ball bearing is better that a single row roller bearing. When I compare load ratings between two similar bearings, one roller and dual row ball, the roller bearing seem to handle a lot more:

https://www.skf.com/group/products/bearings-units-housings/roller-bearings/cy...

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DragBikeMike

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Re: Rear Pulley Wobble Fix
Reply #12 - 07/03/19 at 00:46:04

I think the roller bearing would probably work fine but I'm not sure how well it deals with the skew. I imagine the offset load on the pulley just shifts the contact point on the double row ball bearing since the balls and races are arced. On the roller bearing I'm not sure how things will behave. Will the skew edge load the rollers? I never considered a roller but it might be better than the duplex ball. IMO, load isn't the issue. Either bearing is rated for more than the savage can produce. I think its the skew that causes the problem.

Got a little over 50 miles on the Chinese bearing and it's still solid as a rock. I checked it a few times to see if it gets hot. I can place my hand on it and its barely warm. I think its gonna be OK.

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Re: Rear Pulley Wobble Fix
Reply #13 - 07/03/19 at 04:01:19

I have no doubt the double ball bearing is going to work great. If the single row bearing is "adequate" with the eccentric load that is putting a "skew" pressure on the bearing .....the double row bearing is going to be far superior as the load is now converted to load that is concentrated in the centerline of the races (where it belongs).

The stock single row bearing doesn't wear on the centerline of the races.....it wears on the sides and allows the wobble to set in with very low mileage.

The majority of Savage riders don't realize how much pulley wobble they have, as the chrome cover makes it somewhat difficult to grab the pulley and wobble it back and forth.

I will check the wobble that I have on the pulley with the bushing installed.

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philthymike

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Re: Rear Pulley Wobble Fix
Reply #14 - 07/05/19 at 07:38:31

My 07 doesn't have wobble yet at 18K miles.
For that matter the OEM petcock still works as it should.

However, I have good proof of how bad the wobble can get. The used driven pulley I recently purchased has extreme wear on the teeth for the belt. Each tooth is gets skinnier from one side of the pulley to the other.
Or is that just a sign of unequal tension adjustment?

I'd be mad about it but I only wanted the hub anyway.

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