Dr Big

Full Version: Front sprocket fitting
You're currently viewing a stripped down version of our content. View the full version with proper formatting.
Pages: 1 2
The CS sprocket should be fitted with the flat side OUT (as in your 3rd photo).

Then the rubber silencer ring will sit in the recessed part of the locking plate. The outer edged of the chain will bump into it and (supposedly) quite the running a bit. Check for any spots where the chain wore on the cases....it may have done so since you were running it so close to the cases (by inverting the CS sprocket). A slight worn spot is OK...just make certain you haven't worn through the case in any spot.

A bit of play between the sprocket and the output shaft is normal....but just a bit. From the photos it looks as though the sprocket fits well onto the shaft.

Be certain that there is NO play in the output shaft itself. Remove the sprocket and try to move the output shaft up/down/forward/backward...there should be no play in the output shaft bearing. You may find just a bit of movement if you pull/push the shaft into the out of the cases...this is OK.

I usually put a bit of grease on the splines just to keep the rust away.

Hope this helps....thanks for the photos it makes things much easier to diagnose from a distance.

There were 18 other views of this post and NOBODY wanted to tell him he had his sprocket on backwards.

OK, I don't post much here but HOLY CRAP.....a little help is nice.
The raised centre part of the sprocket is there to locate and centralise the rubber ring behind the locking plate, which, as stated, is supposed to quieten down the chain action. Quite how effective it is at dampening any noise is debatable though.
As for having the flat side out on the sprocket, well, this is the first time I`ve heard of it and it just doesn`t make any sense to me, and I`ve never heard of any one else doing it this way. It`s certainly not represented in any manuals or fiches as being fitted this way so I`ll continue as I always have done unless definitive evidence is forthcoming.
As for nobody replying, well, I`ve only just seen it and maybe the others didn`t feel qualified to make comment.
As for the sprocket having a bit of free play, it`s not unusual at all, especially if it`s done quite a few thousand miles. I`ve not known of a worn engine shaft.
My advice with c&s is if you are at all unsure about them due to lots of play or tight spots in the chain then replace them with quality items immediately.
Having a chain snap, which is not uncommon with Bigs, can take out a big chunk of engine casing as I found out for a second time quite recently.
Lol as Ladder runs out to bike and pulls sprocket cover off asap Big Grin

Seriously though, i accounted for one of the 18 non responding viewers. Im on a new laptop (old one is on death row awaiting an arrow as its pissed me off too often :x ) and i didnt have my downloaded manual to hand to check if the lad was right or wrong.
I feel like I have been told off Cry
Quote:Lol as Ladder runs out to bike and pulls sprocket cover off asap

Sorry to spoil your laugh but there was no question in my mind.

Quote:The raised centre part of the sprocket is there to locate and centralise the rubber ring behind the locking plate,

......it's pretty difficult to centralize something when the sprocket raised section is about 4mm smaller in diameter than the ID of the rubber bit.

If you look at the second photo so thoughtfully provided, you will observe that the rubber ring is MUCH larger in diameter than the raised portion of the CS sprocket. Add to that the indentation provided in the locking ring....if you assemble the parts as in the second photo the rubber ring just spins and wobbles around doing absolutely nothing.

Now flip the CS sprocket around so the flat side is facing OUT. Now the rubber ring nestles nice and friendly between the locking plate and the sprocket and stays in place as the sprocket turns and actually contacts the bottom of the outer chain links with some form of support. Granted, it doesn't do much but at least it has some function.

If you have further doubts, remove the chain all together, crouch down in back of the rear sprocket and sight down the face of the rear sprocket like a gun-sight. With the CS sprocket mounted as it is in the second photo you'll easily see the chain-line is incorrect. Flip the sprocket around with the flat side outwards and everything lines up.

I think the raised part of the sprocket is there only to provide additional contact area for the splines on the output shaft. With the torque and power pulses of our machines it would make sense to maximized the contact area here.

This is the best example I could find of drawings and examples. There were no clear photos or drawings in the Suzuki manual or parts drawings for the Bigs.

Here's the JT sprockets diagram for the DR650....it has a raised section:

[Image: ScreenShot2012-07-31at60655PM.png]

Here is the cms parts drawing for the output shaft and CS sprocket....the drawing for the DR750/800 is crap

[Image: ScreenShot2012-07-31at60202PM.png]

Note that the FLAT side of the sprocket goes against the rubber ring and the locking plate.

Apologies for jumping into this thread with a bunch of bitchy criticism. Please....nobody get their nickers in a twist...I'm a NICE guy.......honest.
No one is getting their knickers in a twist over this one Ray, and certainly not me. And yes, we know you are a nice guy. In fact, we only have nice guys on this site.
This topic has never arisen before to my knowledge, whether with the DrBig or any other model, and to be honest, I really don`t think anyone has thought about it at all.
I`ve always assumed that the flat side went engine side just like everyone else, and always have done, but as they say "assumption is the mother of all fukk-ups".
I`m now thinking that there is certainly merit in what you say so will spend my day off in conducting empirical research into this.
As I have a scientific background I`ve learned not to take anyone`s word at face value, but to check things out for myself so don`t take it personally Wink .
I could start by turning the sprocket around as you say and see if there`s a reduction in vibration which would very good evidential data
I`ll also have a word with the head of Technical at Suzuki GB who I`ve known for over 30 odd years, though I bet he doesn`t know the answer to this one!
Slightly digressing but still in the same area, the V-Strom 1000 boys suffer a lot with chain vibration and a guy on your side of the pond sells a 3mm spacer that sits behind the rear sprocket which apparently transforms it into a big smoothie. A couple of friends of mine have used this mod and say it`s the best $25 they`ve ever spent. I`m wondering now that if they reversed the front sprocket, they would get the same effect for free.
Will report later
Woo hoo another SR41 bermuda triangle mystery :D . This will be added to the weird front rhs wheel bearing of doom and mystery starter gear washer, where des it go? Nobody knows :D

Ray, tis kinda irrelevant to me as ive a 530 chain with a flat section gt380 sprocket, but all the same il throw in me tuppence mate, my case had no chain wear marks and had god knows how many miles on it with the front sprocket raised lip pointing out when i got it.

[Image: lhsrearmount-1.jpg]
So no worries there. There was no wear on output shaft bearing or spline either mate. The sprocket carrier bearing was oem and aok too.

Just on that topic, ever notice how the rear sprocket carrier is seated in its cush drive? Its loose to the tune of a couple mm in any plane and i have brand new bearings and cush drive fitted! So its kinda sekf centering. Also have you ever noticed how close the chain runs to the frame with the lip out?

I remember ages back Robmoto had this dealio discussed with blue and stefan over on advrider ages back and its done to death with two camps each happy theyre right Big Grin
Would be nice to put it to bed once and for all though so i watch with interest!

Btw i have a cheapo one of these http://www.motorcycle-superstore.com/3/1...-Tool.aspx and i recommend it, takes any guess work out and you would be surprised how often the adjusters on a swinger can be off, even on a new bike.

You mean I've inadvertently started another oil thread....accckkkkk.

Never paid much attention to this since from the first time I replaced the CS sprocket it just seems like it should work flat-side-out since the rubber ring only makes sense to me when assembled in this manner.

The V-Strom uses a center nut to hold the CS sprocket on so with their mounting system it appears that flipping the sprocket around doesn't change anything.

I see your point about the cush drive having a bit of play and the rear wheel alignment making a difference in chainline...I'll have a look at my rear alignment again. (I usually do this with string lines...a bit tedious but cheap)

Didn't read the ADV thread on this but will do so and, yes, I realize that the stamped numbers are on the "raised" section of the CS sprockt and usually face outward.

RichJ....if you're reading this....I think the answer is....there IS no answer but thanks for sticking your finger into the hornets nest.......

OK - so - now.....since you brought up the cush drive....whick way do the thicker part of the rubber cushions face....toward the front (power) side of the hub or toward the rear (deceleration/overrun) side of the hub Confusedhh:
I'm on holiday at the California left coast...so no motorcycles for 8 more days....not that I'm counting....
[Image: DSCN0110.jpg]

Therefore a "leisurly" re-read over at ADVrider on the CS sprocket debate starts by Stefan (post #11228) rolling this little bomb into the room:

"hi rob
your sprocket is wrong mounted
the flat side should be in front .."
<!-- w --><a class="postlink" href="http://www.hessler-motorsport.de">www.hessler-motorsport.de</a><!-- w -->

So it would seem the Germans (Stefan Hessler and Bluesman) are of the opinion that the flat side faces out.

Robmoto (Aus.) sez the raised section should be out ....BUT (and yes it's a big BUTT) he's only using sprockets with about a 1mm raised section. Dunno where he got these but the CS sprockets from the early DR650s are built like this:

[Image: ScreenShot2012-08-01at83540AM.png]

...and will bolt right up to the SR41s

The "correct" CS sprocket for the SR41 looks like this:

[Image: ScreenShot2012-08-01at83641AM.png]

...so as you can see the sprocket is thicker at the base due only to the increase in the thickness of the "raised shoulder" area.

Now, the question is, whether this fairly small change in position of the centerline of the CS sprocket is really important given the movement of the rear cush drive, the length and tension of the chain run and the fact that applying power will tend to pull the rear sprocket inward toward the centerline of the machine.

When I finally get my hands back on my machine I'll take a much closer look......for now I'm still in the "flatside-out" camp just because it makes the silencer ring make sense in a functional way (and I think Stefan knows what he's talking about)
Pages: 1 2