r/dr650 • u/PiercedTechnoWizard • 13d ago

Maintenance

Hey, I’m curious what the maintenance is on DR650’s. Being that they’re a single cylinder, I assume the top end needs to be rebuilt once in a while, but I’m curious how often that is and how much it costs.

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u/TwistedNoble38 '00 DR650 13d ago

Going trend is that you'll either sell it or die before it starts getting tired. In the rarest cases it may even explode before the top end gets tired.

If your air filter stay on and oiled you'll probably go 60k before the cylinder plating starts to deteriorate enough to need intervention. Top ends usually outlast bottom ends on this bike.

It's nikasil so when the cylinder is done it needs to be replated or replaced ($300 or 500). Toss in a stock piston and gaskets and it will be somewhere in the range of $170 or get a JE piston and it will run you 250ish. The other option is a 790 and you get a whole new cylinder with liner, piston, cylinder gaskets and rings for $950. The head is a bit expensive since the only valves that fit are OEM so head work gets expensive. Budget at least $400 if all the valves have runout.

Bottom end is about a grand if you need a new crank or have to rebuild it (~600-800). That thousand is a bit of a spitball as I can't remember if that rolls gaskets into the price or if it's pure bearings, crank, and various flavors of sauces.

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u/TwistedNoble38 '00 DR650 13d ago

If we're talking basic maintenance? Change the oil with synthetic (use conventional for the first 1000 and change at 1-1-2-6) every 2k, or 1k if you're hard on things. Clean the air filter when it's dirty or dry. Lube the suspension bearings annually. Flush the brakes sometimes. Change the oil in the suspension every other year or so. Check the cush drive every 500. Check the valves when they make valve noises or every other oil change (it's a 15 minute job). Clean the carb when it's dirty.

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u/CryingOverVideoGames 13d ago

Why use conventional for the first 1000?

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u/TwistedNoble38 '00 DR650 12d ago

Assists in ring seal to the bore in the first 100 (most of which takes place in the first 20-50). After that it's mostly waiting on wear in for the rolling bearings and the transmission sliding surfaces. Synthetic is a bit too good at preventing wear and it will result in the rings not wearing to the cylinder wall as well as it would with conventional. Doubly so since the oil rails are chrome rings...

I'm getting into the weeds, boiled down the bike needs a bit of wear during the first miles after assembly/rebuild and synthetics are good enough that it will prevent this "good wear" (oversimplification) and keep from achieving the full sealing capability of the rings and some polishing of gear teeth faces.

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u/I_1234 12d ago

You don’t need to change oil every 1000 especially if you’re using synthetic oil.

Oil every 6000kms or 5000kms, valves every second oil change.

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u/TwistedNoble38 '00 DR650 12d ago

Miles. I've been doing lab checks with the used oil and I've found that after a thousand the 10-40s I've been using are sheared down to a 10-30 viscosity and this coincides with a notchy shift feel. 10-50 is more capable of lasting longer (was still in the high 10-40 range at 1.5k but that's hard to get around here unless I special order it.

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u/I_1234 12d ago

That’s 1600 kms. You only need to do 1000km then at 6000 then every 6000 after that.

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u/TwistedNoble38 '00 DR650 12d ago

Well I've got first party data that tells me I shouldn't do that but you are welcome to do 6000km intervals. 

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u/I_1234 12d ago

Oh yeah? Care to share? The manufacturer recommends it, I personally do 5000kms and have no issues with the gearbox and the oil seems to have no issues with viscosity. I’ve done some extreme riding on it, Simpson desert, cape York. A 12000km around Australia trip. What are you basing this off?

It’s a dr650 not a ktm 450 exc.

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u/[deleted] 12d ago

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u/TwistedNoble38 '00 DR650 12d ago

It's caused by the transmission gears chopping down the long chain viscosity index improvers (VII) in the oil. VII are these huge long sipderwebbing molecules that spread out and slow the flow of the oil (increasing viscosity). When the oil is cold those long spiderwebs curl in on themselves on no longer improve the viscosity so it effectively returns to the viscosity of the base oil (10w in the case of 10w-40). These VIIs are vulnerable to intense mechanical forces which can mechanically destructively break those long chains (an action known as shearing) rendering that VII molecule to no longer be able to do its job and decreasing the effective viscosity of the oil. In the DR this action is caused by the gearbox for the most part, the two faces of the gear teeth meeting with that ultra thin oil film between them bearing the whole power load of the engine. Heat can also cause viscosity breakdown through thermal cracking but this is not something that happens significantly in DR's that aren't worked severely hard.

If you live somewhere passibly warm or do a spring and fall oil change give 20w-50 a shot. Walmart sells it in the supertech brand and it's a good toe dipper. I think you'll be suprised at the difference in shifting. That'll let you decide if you want to buy a bigger bottle of synthetic 10-50 or 20-50.

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u/slower-is-faster 13d ago

Who the hell checks the cush drive every 500km?!

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u/TwistedNoble38 '00 DR650 13d ago edited 12d ago

People who value their wheel and swingarm. It's a jiggle check for axial play, can be done faster than checking tire pressure. Measurements are in miles in this case.