DRZ400 Rear Suspension Maintenance

[2Wheels 0]

DISASSEMBLY Still working on this.

I'd like to come back to this and fill it in, but for right now I'd just like to say that when you remove the bolt that attaches the dog bone to the bell crank, lift the swingarm up about a half inch to relieve the pressure on the bolt so you don't end up with this:

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You can use a screwdriver to pry the dust seals out. Be careful not scratch the bore. Scratches can cause leaks.

To clean the old grease off the bearings, I tried diesel, engine degreaser, and gasoline; but I found that gasoline worked best. Clean the gasoline out with brake and parts cleaner and dry with compressed air. I didn't have an air source at home so I just used one of those compressed air cans for dusting off computer parts.

you may need an impact wrench to take out the screws from the chain buffer.

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I'm coming back to this at the end of March/beginning of April - finish it up then.

[2Wheels 0]

DEALING WITH STUBBORN BOLTS

PULLER FOR SWINGARM BOLT

After trying to pound out my swingarm bolt with a dowel, I ended up with this and the bolt didn't even budge.

There's got to be a better way. Make a puller for that stubborn swingarm pivot bolt!

Make sure what's left of the washers is smaller than the swingarm bolt.

At first I tightened the nut to the point where I thought the rod would almost bend or break ... and the swingarm bolt still didn't budge. (Those all-thread rods are made of soft steel.) Then I gave the other end of the rod about a dozen LIGHT taps with a hammer and I was able to tighten the nut about another 1/8 of a turn. Some more light taps and I was able to tighten the nut another 1/4 of a turn. After tapping and tightening ... and tapping and tightening for 2 or 3 complete turns, I was able to turn the nut without tapping the other end of the rod anymore.

The night before, I did squirt some WD40 on both ends of the swingarm bolt and into the spaces between the engine case and the swingarm. When the bolt finally came out, it was covered with WD40 so that must have helped to pull it out after it broke loose.

I bought this bike new 18 months ago and it hasn't seen a whole lot of water. I guess this goes to show that one of the first things you should do when you buy a DRZ is to grease the swingarm pivot bolt.

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Somewhere in the write up I said: "After trying unsuccessfully to use a larger size, I ended up using a 5/16" rod."

Well, I said that to simplify the write up. Here's the whole story:

I started the job and actually broke loose the swingarm pivot with a 3/8" rod, but I finished pulling the bolt out with a 5/16" rod.

There were a couple of issues with the 3/8" rod:

1st - With the swingarm bolt still stuck, I couldn't measure its outside diameter to see how small the two nuts had to be ground down to follow it through. Now that it's out, I know that they have to be less than 0.665" - I could have pulled the bolt through with the 3/8" rod when I gave up on it.

2nd - The inside diameter of the swingarm bolt is slightly narrower at the threads than the rest of it. A 3/8 rod fits freely through the unthreaded part of the swingarm bolt, but it's a real tight squeeze through the threaded part. Pushing it through damaged the threads on the rod slightly. You can still get a nut on it, but it's difficult to turn - you'll need a wrench.

So, yeah, you CAN use a 3/8 rod to pull the bolt out, but make sure you grind/file whatever you use as a stopper down to less than 0.665 of an inch. And you'll be working with slightly damaged threads.

The advantages of a 3/8" rod? If you need to pound hard on it, it should be a little sturdier than 5/16.

Allthread is only about a dollar per foot. Maybe get a three foot section each of 5/16 and 3/8 and save yourself a trip to the store if you destroy one of them.

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REMOVING A STUCK BELL-CRANK-TO-FRAME BOLT

There are some posts on the ThumperTalk DRZ forum about stuck bolts that attach the bell crank to the frame. This improvised clamp never got past the idea stage because mine came right out, but I think it'd work. When I do the suspension on my DR200, I'll probably get to give it a try.

[2Wheels 0]

IMPROVISED BEARING PULLERS AND PRESS

Parts List:

• A 12" section of threaded rod - available at building supply stores
  
• A 2 or 3 inch section of 1 1/2 inch diameter pipe
  
• A Deep socket small enough to fit in the inside bore of the swingarm, but bigger than the swingarm bearing
  
• 2 nuts
  
• A bunch of washers
  

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DUST SEALS

To pop off the dust seals, I filed the sharp edges off a cheap screwdriver and used that. Just stick the screwdriver between the bearing race and the dust seal and pry it off.

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There are two bearings in each of the two big bell crank bores. They'd be the bores where it attaches to the dog bones and to the frame. You can press them both out the same side at the same time.

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IMPROVISED BEARING PRESS

I tried putting the new bearings in the freezer overnight, but that still wasn't enough for them to drop in easily. They were starting to go in crooked. This improvised bearing press worked well for me and I was able to get the bearings to go in evenly by lining everything up before starting.

Side View of Improvised Bearing Press

How deep should you press in the bearing?

So I used those three washers as a depth gauge.

[2Wheels 0]

REPAIRING SWINGARM DAMAGE

Here's the swingarm after welding:

I ended up getting it welded at Form Fab 619-562-6054 located at 11478 N Woodside Ave in Santee. The guy welded some steel tubes for me a couple years ago and did a really good job, but I wasn't sure whether he also welded aluminum. It turned out he works with all metals including aluminum. He even works exotic metals. He had some kind of titanium alloy tubing in his shop when I picked up the swingarm. Rides motorcycles too - street bikes.

What I liked most was that both times when I went to to him, he wanted to know what the part was and how it worked before he started welding on it. I've run into welders who just want to grab the part and start welding on it.

Here's the swingarm after machining:

I had it machined at E-Z Spring 619-336-1307 on 231 11th Street in National City. To work on that part of a swingarm, the shop needs a special tool to hold it level and in place. E-Z Spring has one. They wanted to know what the part was, how it worked, and how close the tolerances had to be before working on it. I've never run into a machinist who just wanted to grab a part and start cutting on it.

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AN OUNCE OF PREVENTION

The scratches on the swingarm are from the chain rubbing on it. It happens when you bottom out. To prevent it, keep an eye on the rubber bumper on the left front of the swingarm ... especially after a ride when you've bottomed out the suspension. On the Suzuki parts fiche, it's called a buffer, chain touch defense. It's a $40 part, but replacing it is cheaper and easier than repairing a $1000 swingarm.

I first noticed the damage on the swingarm when I saw the rubber bumper dangling. Upon closer inspection, I saw the scratches on the swingarm. The dealer, South Bay Motorsports, said they see that all the time and not to worry about it, but when I took the swingarm out I noticed the scratches had gone all the way through. Water and dust could get into the bearing through the hole. I also asked one of the mechanics at work and he said to get it welded since cracks can start forming at the scratch.

[2Wheels 0]

REASSEMBLY

Putting these 26 needle bearings back into the bell crank is a good place to start.

Hold them in place with grease.

Next come the dust seals. I was able to push them in by hand.

I put them in with the U-Groove facing out. That's how they were originally installed, but I seem to remeber a post somewhere where the guy said the factory installed them backwards. Hope I got it right.

This is a cross section of a U-Ring that I drew by hand. If a U-Ring is used in a hydraulic system like a brake, the U faces towards the high pressure. But since the purpose of the seals is to keep dust and water out, it seems like the U should face out. The lips of the ring will press against the bushing on the inside and on the bearing bore on the outside and form a seal. Someone correct me if I'm wrong. I'd hate to be responsible for ruining other people's bearings by spreading bad information.

I did a web search for correct installation dust seal lip and found some links. According to everything I found, the lips face out. Below are two examples.

Installation of dust seal on electric motor - lips face out - see paragraph K: http://www.whitedriveproducts.com/pdf/serv...200_service.pdf

Installation of dust seals in general - lips face out - see the paragraph just below figure 1: http://www.machinerylubrication.com/articl...p?articleid=838

This thread is about dust seals on wheel bearings. The groove faces out.

http://www.thumpertalk.com/forum/showthrea...581#post8083581

But the dust seals on the wheel hubs of a 70 something honda had the groove facing in. Don't know which way is right.

Here's the rest of what goes into the bell crank: 4 more dust seals, 3 bushings, and 6 washers. Put it all together and hold the washers in place with grease.

Make sure you work the grease into the bearings. I stuck my finger on the needles and kept going around until no more grease would go in. I also got as much grease as possible into the bore between the bearings to help keep water out.

Now take out the brake light switch. A 10 mm hex nut holds it in place. It's easy to remove and replace with the swingarm out. You'll need the clearance to torque down the nut that holds the bell crank to the frame.

Attach the bell crank to the frame. The bolt goes in from left to right. Torque it down to 72.5 foot pounds.

I was able to fit a torque wrench with a 3/8" drive into that space after taking out the brake light switch, but I still couldn't fit a 1/2" drive torque wrench in there.

Put the brake light switch back in.

Now attach the dog bones to the swingarm.

The side of the dog bones with the inserts sticking out goes on the inside. That's the side that's facing up in this picture.

Dust seals go in first, bushing comes next, then washers, then dog bones. Just hand tighten for now.

Next assemble the stuff that goes into the swingarm pivots.

This is one side only. A dust seal and the bushing with a collar go in the inside. On the outside goes the outside bearing, a dust seal, and the stepped washer. The inside and outside parts have different diameters so you can't mix them up.

These three things are the outside bearing. The washer with the needle bearings is sandwiched between the other washers.

Here's the swingarm assembled and ready to go back into place.

Don't forget the rubber chain touch defense. You could put it on with the swingarm in place, but why not do it now when it'll be a little easier.

Put grease on the metal inserts in the engine case so the swingarm pivot bolt doesn't get rust welded in place again.

In goes the swingarm. I used tie downs to help hold it in place and line up the holes. I was able to push the pivot bolt through by hand.

Next attach the bell crank to the shock absorber. Torque it down to 40 ft. lbs. before attaching the dog bone to the bell crank.

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At this point, I'd like to ask a question. As you can see in the above picture, there's grease on the threads after I pushed it through. It happened on all the bolts because I put grease in the bushings to keep them from getting rust welded to the bolts. Now, the torque settings given in the factory service manual are for clean dry threads or at least I think they are. So I cleaned off the threads with a tooth brush and brake parts cleaner as shown in the picture below.

But cleaning them off this way was a real PITA. Next time I do this, I may just wipe the threads down and reduce the torque a little. What do you think?

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Next attach the dog bones to the bell crank. Line up the holes by moving the swingarm up and down so you don't end up with a broken bearing.

Torque down the three remaining nuts.

Both dog bone nuts: 72.5 ft. lbs.

Swingarm Pivot Bolt Nut: 55.5 ft. lbs.

You're done with the linkage!

Put the chain guard, chain guide, brake, and rear wheel back on.

THAT'S IT!

[blind_in_1_ear 0]

un-freaking believeable...how did you do the things AND get pics...amazing detail.

dude A++ on that....as a fellow DRZ guy i am floored.

i bow to you.

Blind ...all he saw was banana banana picture....banana.... :air_kiss:

[sandiegoland 0]

When did you first notice the damage on the swingarm? What caused that to happen prematurely?

[Spaugh 1]

nice work! :air_kiss:

thank god for PDS.

[paulmbowers 236]

I'll answer your question, but I'm shamed by your expertise anyway.

I'd use brake cleaner on the greasy threads, being careful not the get the liquid into the nicely greased bearings. Then I'd use blue locktite. I use either locktite or anti-seize on every bolt, but never grease.

But I'm no expert.

[2Wheels 0]

When did you first notice the damage on the swingarm? What caused that to happen prematurely?

An ounce of prevention... The scratches on the swingarm are from the chain rubbing on it. It happens when you bottom out. To prevent it, keep an eye on the rubber bumper on the left front of the swingarm ... especially after a ride when you've bottomed out the suspension. On the Suzuki parts fiche, it's called a buffer, chain touch defense. It's a $40 part, but replacing it is cheaper and easier than repairing a $1000 swingarm.

I first noticed the damage on the swingarm when I saw the rubber bumper dangling. Upon closer inspection, I saw the scratches on the swingarm. The dealer, South Bay Motorsports, said they see that all the time and not to worry about it, but when I took the swingarm out I noticed the scratches had gone all the way through. Water and dust could get into the bearing through the hole. I also asked one of the mechanics at work and he said to get it welded since cracks can start forming at the scratch.

Thanks for asking. I've gone back and edited the original post to include this info.

[TrophyHunter 15]

Your avatar tag line....."are you impressed?"

YES!!!! Great detailed explaination!

[2Wheels 0]

Thanks for the props guys. But no way am I an expert at this. This was the first time I took apart and lubed the suspension on any bike. Just trying to make a step-by-step pictorial guide for anyone else to follow and to help me remember for the next time I do it.

[bikeslut 1]

great post Gene... If you weren't an expert before, you are now. I especially like the custom made tools!

I have had to replace the chain buffer on my bike already, and I had some swingarm damage too... Good reason to replace my spring, too... $100 spring