BergDonk's DR650s and the Odd Tangent

Yeh, the cracking swingarm is a worry. My thinking at this stage is that I'm not doing big air, and with a properly controlled movement with the Ohlins, which was put in the mail yesterday, so maybe arrives today, will result in a more controlled movement and reduced shock (sic) loadings on the swingarm. We shall see, but it doesn't seem to be that many, ie other than Snowy, reporting it as a problem AFAIK.

Chronic issues I've become aware of apart from the upper chain roller is the cush drive bearing, which could have killed me when it failed, derailing the chain and locking the rear wheel, and I'm told the kill switch is an issue when exposed to bulldust and fine sand. The supposed fix which I've implemented is to remove the detent spring so it doesn't stay 'killed'.

I know of a couple of other DR650s locally with failed cush drive bearings, which the owners assumed to be one offs at the time. The training and tour company I'm associated with, Stay Upright, used to carry the cush drive bearings with them and often changed tham at the end of day maintenance.

My original cush drive bearing failed at 14,000 kms. Having a close look reveals that it is not centred on the sprocket, so there is twisting moment applied that possibly contributes to premature failure. I plan change it out at say every +/- 10,000 kms, or each new chain, or something, but failure is catastrophic, and painfull, and they only cost about $6 and take about 10 mins to change. It may also be that the original not having double seals didn't help.

Steve

Now you've got me worried. I haven't heard of the cush bearing failure before but I don't doubt (especially with the Stay Upright experience), that there could be an issue there. I would be interested to know how many other DR owners might have had the same problem but perhaps think that theirs was an isolated case.

I changed mine out, including wheel bearings, as a matter of routine service at around 15,000kms. They were all looking pretty 'ordinary' by then, but were only the single sided seal type (OEM), and having only been checked and lubed once previously. I did upgrade to quality CBC bearings (blue double sided seals) but can't remember how much they were, but do know they weren't cheepies. I don't understand how the bearing could be off centre in the carrier however. That is really strange.

I had a cush drive bearing fail on my last DR. Locked at 115kmh :eek1 just cresting a rise, the released and locked again. I kept it upright. The bearing wasnt that old but I think something damaged the seal and we had been riding in sand that day. I had been hearing a strange noise but couldnt trace it.
Trashed the cush drive an bent a new chain

You'll start to notice the play in the cush drive long before it fails.

Mine was so loose that when I started to slip the clutch, if I looked down and back at the sprocket I could see the sideways movement of about 10mm at the rear.

The standard bearing has a seal in only one side. So it fills with dust and crud every time you ride/wash it.

The bearings I got from Suzuki as replacements were off the shelf SKS bearings with 2 seals. I repacked them with a mixture of Moly grease, Nulon grease and added Graphite. My own concoction that is aimed at being both a grease and an anti seize.

I think the standard bearing gave out at around the 18000km mark. Bear in mind that I do around 50/50 trail/tar commuting. After I fitted the new bearing the bike has been used for trips and trail riding only. No commuting.



Pulling the DR up is an interesting exercise. I used the RMZ front end complete, and the brake disc is smaller - 265mm - so brake force decreases. In the dirt I can still lock it up, but tyre selection is crucial to getting it to stop.

At the Tallanganda ride I used the Mitas E09 front and rear, and the biggest thing I noticed was the front will not hook up on single track. Great on dirt roads, tar roads etc, but forget it on single track. I also had the RMZ rear shock working through a modified DR linkage to the standard DR swingarm. The spring rate was too soft if being pushed hard. "Trail riding" the 5.6 spring was good. But the minute you start pushing harder, like chasing the guys on the 250s and 450s, then you have to have the compression damping up a little harder and it tends to hop in the back end, which in turn affects the way it brakes and steers coming into tight turns.

I did a lot of tyre testing after that because I didn't like the excursions into the trees. I think Steve was right behind me when I hit some greasy clay going hard in third gear. The track dog legged, and when I went to brake it just let go. So I stood it up straight aimed for the gap between the trees and tried to just bull ride it to a stop.

Dunlop 952 front, Mitas Stoneking C02 rear. That combo works best on the dry rocky trails around here. The rear can feel very skatey, but it's predictable. The Mitas will drive and turn, the Dunlop steers and stops really well.

At the moment I'm running a 2006 RMZ front end. The 2007 RMZ front end is off being rebuilt. They are nothing alike as far as fitment issues go. But as far as they work, very similar. The 2006 is a single chamber design, and the 2007 is twin chamber. I prefer working on the single chamber after having both sets stripped down.

A scratched fork leg has chewed up the seal on the brake side of the 2007. So keep an eye on the condition of the lower legs. I knew it was scratched, and I used 2000 grade wet and dry to polish most of it out, but it still chewed out the seal.

Keep me posted and drop me a PM if you want a riding partner over the break.

You're a hater.

Where's my steering damper?

And my CB1300?

If you're coming down you'll have to hurry, there's 4 cartons of premium beers and 10kg of King Prawns in the fridge. They wont be there this time Boxing day.

Hey Snowy, where abouts did the stock swingarm crack or break ?

seems the cush drive bearing is a common thing...
mine went at 12,000

If you look where the bearing is in the hub, you can see that it isn't centred on the sprocket, and there is only one bearing, so the chain pull is trying to constantly 'twist' the bearing, which they are not really designed to do. A second bearing, like a non cush hub wheel, counteracts the load. Just me speculating, but I suspect the major issue is that stock they are unsealed. Ball bearings certainly do handle lateral loads, but IMHO it'd be better if it wasn't designed into the hub.

After I got my DR I did a fair bit of research on the net to decide what needed attention, and I have not found any reference to this as an issue. I haven't gone through all of the 'big one' aka http://www.advrider.com/forums/showthread.php?t=135295

This thread does however seem to have identified a few others.

I also acknowledge Snowy's assertion that you'll feel slop long before it fails, however in my case, I'd not long had the wheel off after lacing up the 18" rim and I always check these things, wheel bearings etc when wheel are off and when lubing chains. This is why it really surprised me, the suddenness of it, and that I'd not long checked it. It also twisted the chain, effectively destroying it. I was lucky I wasn't far from the shed, just playing with jetting, and testing. I was in 1st gear at the time. 10 mins before I was up my hill and doing 110 kph on the bitumen doing more jetting tests.

The bearings are a pretty common 6205 and the seal is a 12522, and can be obtained easily, mostly off the shelf from autoparts, ag supplies, bearing places, etc. $10 should get you a bearing and seal. The seals can be recycled though, and bearing places normally stock the double sealed bearings and allow the customer to remove any they don't want to reduce stock. I reckon leave the seals in place.

Fully repacking wheel bearings can be a mistake. When they heat up, the grease oozes out, and they can run hotter too. I tried it once years ago and wondered why I had no brakes, bearing grease on the disc was the issue.

I'll add my experiences here when I get a moment:
http://www.advrider.com/forums/showthread.php?t=135295

Tyres?
My Dr came delivered with worn E09s. I swapped them to the current MT21 E07 combo when I put the 18" rim on. I've never really felt confident on it until test riding the new forks last week.

I have a C02 on the back of my Berg at the moment. They are not a bad compromise around here, lasting extremely well on the rocks, but they never really hook up either. Great trail tyre, but not for racing. I like the 952 up back as it lasts nearly as well and maintains traction as it wears fairly well. Never liked the 952s up front though, vague feeling when transitioning. Always liked BS 201s and Dunlop 773s up front though, intermediate to soft seems to be the answer for the rocks here, and these 2 don't shed knobs like many others. Both superceded though, and I haven't tested the replacements yet. I've still got a few in the shed to work through yet.

My thinking is that in between the rocks we have lots of soft powdery stuff which is why they are the best compromise for me. I haven't tested on the DR yet, but I got the DR to cruise on, not to go flat out....

A ride later this week would be good Snowy, I'll pm you.

Steve

<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <woNotOptimizeForBrowser/> </w:WordDocument> </xml><![endif]-->OK, so the Ohlins turned up Friday afternoon in the mail, so out to the shed.

Having got frustrated with 2 aspects of my upgraded stock shock, ie lack of external adjustability, and its propensity to fade and start pogoing I needed more. The Racetech and Cogent upgrades keep the standard shock body and I suspect that the fading issue would also stay. I talked to my mate Frank Pons and he made a few suggestions, one of which, as is often the case, was an Ohlins solution. He is an Ohlins dealer after all, but he also deals with lots of other stuff too and is very conscious of trying to deliver a cost effective solution to customers.

As noted previously, the Ohlins I got is from a 96 KTM 2 stroke. It seems that the last of the linkage KTMs of the time have suitable shocks with respect to the general dimensions. I got it on ebay for $188 Au delivered.

Mezo posted some really useful stuff here, including pics, which helped me decide to go this way:
http://www.advrider.com/forums/showthread.php?t=468946
The price on the day was right too, and it'd supposedly just bolt in.

Frank did a little checking for me and found that the 95,96,97,98 KTM shocks were 461.5mm long with 134mm of shaft travel. The DR shock is 455mm long with 128mm travel. The DR650 linkage ratio is also nominally 2.8:1

The numbers mean that the extra 6.5 mm length is almost all shaft travel, ie 6 mm difference there. So should be OK.

When it first arrived, I did a test assembly and found that the axle only went down 12 mm, so the ratio of 2.8:1 isn't at full travel.

The spring supplied was 5.? so I didn't bother riding it as I knew it wouldn't be much good, as currently using an 8.5 Kings with the upgraded stock shock.

I also noted that with the extra length the link was almost binding up on the swingarm, and reservoir barely cleared the exhaust. I spoke to Frank and he said to drop it off and he'd fix it. Ohlins are a bit like a Lego kit, and lots of bits can be swapped out.

Frank was able to find a slightly shorter reservoir, an Ohlins 8.5 kg spring, and got some bushes for the top eye that meant no spacer washers would be needed. He offered to change the stroke too, to match the stock length, but I reckoned the extra length would be OK, we shall see. He also stripped, service and revalved it to suit, and got it back to me on Christmas Eve

Its in now, and here are some pics. Gotta do some test riding now as soon as I change the fork seals.

Steve


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The old and new, although the new is actually older than the new

Up the top is the new top eye bushes. The Suzi is 30 mm and the stock KTM is 24 mm. The alternative is to put in some washers, which needs smaller and more hands than I have to fit. Changing the bushes is easier.

The bottom fork is 30 vs 32 mm so a couple of 1 mm washers are easy enough to fit here.

The top is bolted up and I trimmed the side cover and the seat base to make accessing the compression adjustment simpler. Just peeled back the seat cover and took 10 mm or so off and then stapled it back.

Heaps of clearance for the exhaust now too with the different reservoir.

The extra length causes the link to bind on the swingarm, so I just trimmed it a bit.

And results in about 2 mm clearance, although not real obvious in the pic. The shock will extend further too when it tops out, about 2 mm according to Frank, so a bit of clearance is good. Its also why shorter link arms aren't really a solution to getting the ride height up.

Good to go, although I may now have to lengthen the sidestand.

Steve

Thanks for the very informative write-up, Berg Donk. Could you give a klutz a bit of info about this carb mod: is it just adding a breather tube (upwards) to the float bowl overflow tube (downwards)?

For a klutz, you've got it nailed

I ran the top tube from the T fitting up to the steering head and added a small fuel filter I had lying about at that end. Seat base, or airbox top level water crossings have been negotiated to date OK.

At the bottom ends of any vent lines, the idea is to cut the end diagonally and split them for say 15 mm. This reduces the possibility of them clogging up with stuff.

Does the T eventing make a difference? Dunno, but its easy to do, and has worked for me on other bikes, albeit with different carbs.

Steve

Ah-ha. Think I ran myself into problems recently by running the overflow tube upwards to the airbox, which kept it dry but of course didn't allow it to drain properly. With the lower end: is the split to act as a valve of sorts (ie. sucks itself closed under vacuum) thus "inhaling" through the top arm instead? And why the diagonal cut?

The split and the diagonal cut just makes it harder for 'stuff' to clog it up and block it. Either on their own helps, both is better. The diagonal cut increases the area, and the split makes the ends loose and they flap a bit which dislodges shit trying to get itself in there. Not a perfect solution, but better than the square cut they all come with stock.

Standard stuff for breather and overflow hoses.

Steve

On the chain side. The vertical weld that is about 80mm rear of the pivot. It cracks straight down the middle of the weld. Had it ground out and rewelded with TIG. Chasing KTMatt to Wanaaring broke it again.

I met a couple of guys who'd changed out the rear shock for something that worked, and they said the same thing. The bike starts to handle like a trail bike. So you ride it like one. Then things start to break.

I was warned by 3 different people over about 4 months that they crack the swingarm exactly where mine cracked. KTMatt was just itching for it to break so he could slag it off....again.

Which is why I went the RMZ option.

Down side is it's a bit radical and required a lot of cutting and welding. The up side is that the entire rear end is exactly the same as a 2007 RMZ 450. The parts, the geometry, everything.

So once you spring for the weight, it's a matter of adjusting the shock until it works right.

I wind off the compression and rebound until it feels like it's floating and skating when riding across a paddock filled with tussock grass (the local park near my place). Basically the suspension is working like it does over cobblestones or a rocky track. I take the adjustment off so that it floats so I can identify the point where the damping isn't working. It's too fast so it doesn't keep the tyres on the ground.

Once I have it at the floating stage I take the rebound off until I can feel the front and rear slapping when crossing errosion ruts.

Then I adjust compression and rebound firmer by 4 clicks. Front and rear.

Seems to work ok.

But my shock is stock RMZ. No valving changes or anything. There's a ton of after market stuff available for them. I have a spare that I'm going to have rebuilt and tinkered with.

I also modded the fuel inlet on the carb so all the Safari litres get into the carb via gravity. It seems it actually holds about 38 l.

bergdonk
i recently test rode a DR650 with a 30 L safari tank, during the test ride the bike died. there was still some fuel in the tank but it couldnt get to the carb. i managed to sloch the fuel to one side and turn off the other side fuel tap and got the bike to fire and back to the shop. i have since purchased the bike and would like to know how you altered the fuel lines so all the fuel gets to the carb. the carb fuel inlet pipe is a steel pipe that is bent up the way, did you remove this pipe? i am no sure how it is inserted into the carb looks to be pressed and not removeable. how did you mod this pipe?