Rear Sprocket on 77 GS400XB

[lord1234]

So, me and Jethro spent this afternoon working on my GS400XB. We were going to clean the carbs, and change out the chain/sprockets...

Well the carb cleaning went well...the bike purrrrrs. On the other hand the chain/sprocket change was not as nice...

We got the old chain removed and the front sprocket changed out, no problems...the rear sprocket was a problem child. So, I am here to ask you some questions about how the HE!! to remove the rear wheel.

The rear frame is not slotted so the entire axle seems to have to come out of the rear wheel...however, to take out the rear axle...it seems like the pipes have to come off...

Please god, tell me there is an easier way than taking off the pipes...Anyone please? Beuller? Beuller?

edit: (no i don't have a clymer's manual yet...yes i plan to pick one up...but would love some answers before i do)

[dcb]

I am a new owner of a GS750 so not much GS experience here. However I did own another bike where I had the same problem. I had to disconnect or remove the rear shocks and push down on the back of the bike to get the axle out. Hope that helps.

David

[bwringer]

This is common. We feel your pain.

On my GS850G (not much relation to your 400, but...), I have to either remove the pipes on the right side or unbolt the shocks at the top and then drop the rear wheel an inch or so.

I also have to put the centerstand on a 2X4 or find a way to park the bike with the rear wheel hanging off a ledge of some sort so there's enough vertical clearance to pull the rear wheel out.

Would it have really been that &^%$# hard for Suzuki to sweep the pipes up another inch or so???? I know the drill pretty well by now, but it's still a big PITA.

At least I don't have to deal with aligning the wheel or getting all filthy from some nasty dirty gross primitive farm equipment chain...

[spots25]

well, there are a couple ways to do it. Traditionally, i have gone the #1 route, but last time I did #2, and it seemed a little easier

1. Unbolt the brackets holding on the muffler, and just push it out of the way enough to get the axle through

2. Unbolt the shocks, and jack up the rear wheel out of the way

[KGB]

well, there are a couple ways to do it. Traditionally, i have gone the #1 route, but last time I did #2, and it seemed a little easier

1. Unbolt the brackets holding on the muffler, and just push it out of the way enough to get the axle through

2. Unbolt the shocks, and jack up the rear wheel out of the way

If it was only that simple. I see/agree with your ideas.
Unfortunately, this bike does not have a center stand.
And the muffler brackets don't provide enough clearance.
Even where the pipes connect to the mufflers, loosening
them and dropping the mufflers out of the way, not enough.
Seems as if the pipes need to be loosened or dropped.

[Jethro]

If there is no trick to this, the pipes need to be removed. What a serious PITA. If it were my bike Leo, I'd have a metal shop slot that rear swingarm, however, it just does not make sense that Suzuki wouldn't do that themselves unless there is a reason.

[lord1234]

If it was only that simple. I see/agree with your ideas.
Unfortunately, this bike does not have a center stand.
And the muffler brackets don't provide enough clearance.
Even where the pipes connect to the mufflers, loosening
them and dropping the mufflers out of the way, not enough.
Seems as if the pipes need to be loosened or dropped.

Keith...aaah but the bike DOES have a centerstand now

[ptm]

As I recall the last time I removed the rear wheel for a new tire, the mufflers did have to come off. It's really not that bad a chore. There are two bolts that hold each muffler to the frame and then the clamp that secures it to the header pipe. 5-10 min for both. Good time to put some never-seize on those bolts so they don't rust themselves together, and do a little clean-up of parts you can't reach when they're on...

[Jethro]

As I recall the last time I removed the rear wheel for a new tire, the mufflers did have to come off. It's really not that bad a chore. There are two bolts that hold each muffler to the frame and then the clamp that secures it to the header pipe. 5-10 min for both. Good time to put some never-seize on those bolts so they don't rust themselves together, and do a little clean-up of parts you can't reach when they're on...

Yeah we pulled the mounting bolts and loosened the clamp. That is what needs to be done, but the baffles are seized onto the head pipes. They still have nice chrome on them, and I didn't have my huge rubber mallet, so I wasn't comfortable with beating the crap out of them. I think I made Leo nervous enough by yanking the carbs out and deforming the airbox boots.

That is an insane design in my opinion. There is no reason that the axle mounts can't be slotted and a retainer of some sort used.

[lord1234]

Yeah we pulled the mounting bolts and loosened the clamp. That is what needs to be done, but the baffles are seized onto the head pipes. They still have nice chrome on them, and I didn't have my huge rubber mallet, so I wasn't comfortable with beating the crap out of them. I think I made Leo nervous enough by yanking the carbs out and deforming the airbox boots.

That is an insane design in my opinion. There is no reason that the axle mounts can't be slotted and a retainer of some sort used.

i don't see why not...i figure we can slot them neatly with a dremel tool...no mechanics shop required since the metal is SWISS CHEESE. Don't even think I would have to take the tire out to do it...the only issue is what to use as a retainer...

If all we needed was a rubber mallet you shoulda said...sears hardware is down the street...

[Jethro]

i don't see why not...i figure we can slot them neatly with a dremel tool...no mechanics shop required since the metal is SWISS CHEESE. Don't even think I would have to take the tire out to do it...the only issue is what to use as a retainer...

If all we needed was a rubber mallet you shoulda said...sears hardware is down the street...

Well, you need a 12mm socket, a 14mm socket, a big rubber mallet, a can of PB Blaster or the like, and a 10" adjustable crescent wrench to get that rear wheel out. Remove the mounting bolts for the pipe, loosen the clamp between the baffle and headpipe, and spray the PB Blaster under that clamp. Wait a half hour and try to pull the pipe off while twisting it. If it doesn't come free, whack at it on the side near the clamp with the mallet, spray, wait and try again.

When you get the pipes off, remove the axle nut (you have the 24mm in the stock tool kit) and pull the axle completely out of the wheel. There will be spacers that need to go on the same way they came off, so keep track of what and where.

The sprocket should be held in by 6 12mm bolts. The whole hub may be able to come off, and there should be rubber cushion bumpers under the hub. Don't lose any of them. The sprocket bolts have safety retainers that need to be flattened before they can come off- use a screwdriver and hammer to flatten them so you can spin the bolts.

Put the wheel back in, keep the axle nut loose. Thread your chain around the sprockets and use the master link to secure the chain. The only trick is to make sure the open end of the retainer for the master link is not running forward as the chain rotates.

To adjust the rear wheel, use the threaded bolts on the back of the swingarm to pull the axle back. There should be some sort of indicators to tell you how equal each side is. If there aren't, use a ruler to measure how far out of the retainers the adjuster screws are. There should be about an inch to and inch and a half of play in the bottom run of the chain as you are sitting on the bike. Something I have started to do recently (after toasting a brand new chain and sprockets) is visually check and see that the chain is not riding one side or the other of the rear sprocket. To do this, spin the rear wheel while looking at the space between the side plates of the chain and the rear sprocket itself. I use a flashlight pointed towards me, aimed at the rear sprocket so I can see the tiny amount of light between the side plate and the sprocket. Ideally, the chain will wander from both sides of the sprocket, and not hug one side. I do this because you can't trust the hash marks indicating that the rear wheel is straight.

Make sure the front sprocket is torqued down, and bend the retainer washer over one of the flats on the large nut. Put the sprocket cover on, mount your pipes back up and hit the road!

You can't be scared of working on the bike, it's almost 29 years old. And unless your rich, you better get used to doing all your maintanence yourself! Old bikes need contant attention....

Not to mention, you've got that $1M insuarance, so what if the rear tire falls off next time you are crusing?:-D