DR750 & DR800 owners thread

Hi guys, glad to be here, it's my first time here.

I recently (this week) bought a DR800 1999.
I have to make a lot of recuperation work on the bike, hope someone can help with some issues.

First, I guess the bike battery isn't the right one. (pictures below)
Its a 12V 9ah battery.




I have a broken wire at throttle side




And another loose wire under the handlebar



In doubt if those caliper are originals



Missing a protector here



The outside looks good, except the exhaust system



Thanks so much :)

Marianovale,

Welcome,

Your first photo is the wiring for the front brake light switch..easy repair

The second wiring photo is most likely for the horn.

I'll have to have a look at the brakes to see if your's are altered or not....more later. But the rubber lines look cracked and probably should be replaced.

You can also find expert advice on

www.drbig.info

Yeah! The rubber lines and a bunch of rusted screws..

Thanks so much for the info!

2021 upgrades:

Hydraulic clutch






and 3 kilograms less...

Did you felt much difference between the hydraulic clutch and the older one?

Yes. The pull is muuuch lighter!

Bump

Hello!
I bought a 750s -88 a week ago. Been standing left outside for some years. Apart from changing oil and filters, sparks and chain, and a burned out clutch, and the things broken since the crash on the right side, what should I think of? I got advice too change the cam chain tensioner spring. Anything else? I've stripped it down and removed rust and painted the frame so far. Thanks

How many km are there on the carburetors?

Regards,

Derek

Yeah, I forgot. I have cleaned carbs with breakcleaner and Ultrasound. Waiting for new o-rings and gaskets for them.

Good to know, but doesn't answer my question.

Regards,

Derek

Oh, sorry. I assume they are never changed, the odometer is at 51380km.

Hi,
You should check the chain tension of the balancer shaft. You find it under the left motor cover.
Regards Sandra

At 51.4K km, the slide guides (and therefore the emulsion tubes) are guaranteed to be worn out (unless someone has already replaced them). There are six depressions in the faces of the slide guides. Four of these are round. If any of the round ones are no longer visible, there is no need to look any further, the slide guide, and therefore the emulsion tube is worn out. There are two more depressions that look like little parallelograms concentric to the bore adjacent to where the slide bottoms. These depressions are .010" (.25 mm) deep when the slide guide is new. Emulsion tube wear sets in somewhere around when the surrounding plastic is worn flush with the floors of the depressions, and causes overly rich mixtures in the lower portion of the rpm range (see https://store.moto-lab.com/articles/bst33-slide-guide-wear-indicators).

Check the slides for vertical grooving on the downstream side, as well as for enlarged/ovaled needle holes (see https://store.moto-lab.com/articles/slide-wear-indications). Again, at 51.4K km pretty much guaranteed to be worn out.

Have the slides been drilled? You can tell if the insides of the holes are dull rather than satiny, or if the diameters are larger than 2.5 mm. Slide guide wear is pretty much proportional to lift hole area, so drilling the slide will dramatically increase slide guide, emulsion tube, and slide wear.

Replace the jet needles if they're worn. This will be evident because missing anodizing will reveal a different color underneath. This is most commonly found right in the area where they pass through the slides (see the needle on the left at https://store.moto-lab.com/articles/jet-needle-wear-example). Also replace the needle if the clip no longer fits it tightly. The clips are easy to lose, so it's worth getting spares.

Make sure that the white plastic spacers fit the needles tightly, and are not notched, d-shaped, or beveled.

Have the slide springs been clipped? You can tell by whether they have an open coil on one end. If so, they should be replaced, as a clipped spring causes low rpm richness issues. Also replace if the sides of the coils are worn (as this changes the spring rate).

Inspect the tip of the float needles with and without magnification to see if they have witness lines where they have been contacting the seats. If so, they should be replaced. Float needles with witness lines cause a higher fuel level, which in turn causes a richer mixture (and at some point overflowing).

Replace the float seat o-rings if they do not fit snugly or are hardened/deformed/shrunken/cracked/otherwise damaged. Leaky float seat o-ring cause a higher fuel level (and at some point overflowing), which in turn causes a richer mixture.

If both the float needles and needle seat o-rings are in need of replacement, it's probably best to just get rebuild kits, as the rest of the rubber parts are likely to also be in poor condition (for example it's certain that the slide guide o-rings and fuel screw o-rings will be smashed flat).

Selecting o-rings that are made from, or kits that contain FKM (aka "Viton") o-rings will significantly extend the service life.

Inspect the float hinges for wear (pivots should not be loose, pins should be round instead of lozenge shaped, bores should be round instead of oval).

Make sure the floats are not fuel logged (should weigh 6.1g or fewer when separated from the cage).

I recommend replacing the pilot jets with a fresh stock sized ones as a matter of course. It's otherwise difficult to be sure that they're clean and they're cheap. The problem on an '88 is that they're pressed in.

You will need to set the float height before the float bowls go back on. Use a float height setting tool (ideally itself set with the tail of a caliper) to accomplish this accurately. The stock setting is 14.6 mm. Instructions with pictures: https://store.moto-lab.com/articles/float-height-setting-tool-instructions-bst33-carburetors.

You can replace the easy to strip and prone to corrosion JIS float bowl, diaphragm cover and throttle cable bracket screws with stainless steel socket heads.

You can add an the inlet fuel filter inside the inlet hose barb (like the DR650SE has).

Adjust the idle mixture via the following procedure:

Start the engine, let it warm up and ride the bike around until it's hot. Using the idle speed screw, adjust the idle speed to 1300 rpm (for accuracy, use an aftermarket electronic tachometer - you don't have to mount/permanently install it if you don't want to). Set the CO to 3-3.5 %. If gas analysis is not available: coming from the lean side, adjust the fuel screws so that the strongest idle is achieved. You will notice there is a threshold where it becomes rich enough (enough turns out) to run strongest, beyond which no change is noticed. Adjust the idle mixture screw ~1/8-1/4 turn out from this threshold. Adjust the idle speed back to 1300 rpm (as it is likely to have changed). Leave the mixture to the leaner side of these settings if the bike will be seeing altitudes much higher than the one it was set at. Set to the richer side if you would like the engine to idle well earlier during warm up. Extended/remote fuel screws simplify the process and allow adjustments on the fly if you will be riding at extremes of altitude. For diagnostic purposes, report back with the resultant settings.

Regards,

Derek

Howdy Ladder,

Does your offer still stand?

Regards,

Derek

Sure does. Although, my shop is awash with boxes for the holidays. If you have a time sensitive project, I can look through my spares but if not, sorting through stuff would be best after Christmas.

Let me know

Thank you very much for the detailed explanation. I'll report back on how it goes. Atm I'm going to change the cam chain tensioner spring so it's still some time away before I can tune in the carbs, but excellent info when I get there! The circles are still visible. Many o-rings are stiff so I ordered gaskets and o-rings some time ago to replace them. Big thanks again / Marcus

S

Thanks. Will check that too when I loosen the left cover :)

Zaijdan,

To ad to your "to - do" list.
..Remove the swingarm and all suspension pivots. Clean, re-grease, or replace as necessary.
..The rear shock is likely done. It was never great even when new. Replace it with a better unit and the correct spring for your weight and riding load. (Don't bother with this unless you do the step above. A great shock with binding suspension pivots will still feel terrible)
..Remove and disassemble the forks. Replace fork bushings and seals. Renew fork oil.
..While the forks are off, remove the triple clamps and re-grease or replace the steering head bearings (use tapered rollers if possible).
..Inspect all wheel bearings. I'f it were me, I'd replace them all.

Putting an old abused bike back on the road is always a labor of love. It's expensive and time consuming.

The DR750 is worth every bit of it. It's one of the most well balance bikes I've had the pleasure to own and has great character.

Plenty of help here with info and service manual photos, etc...feel free to ask. Also good advice can be had at drbig.info (a UK web site)