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DR350SE questions...

M38A1

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First Name
Scott
Well, a few months ago I broke down and purchased a 1996 DR350SE from a fellow forum member. I blasted out to New Mexico, talked a bit more on the 'project bike' and a deal was struck.

From the PO, the bike wasn't being used much, probably needed a good carb cleaning and has a charging issue with either the stator or rectifier not working properly. Good tires, not really abused, 14K miles, larger fuel tank, bark busters and some Wolfman soft luggage, SAE pigtail and BatteryTender as part of the package.

i-gXgrTSW.jpg


I got it home and shortly thereafter emptied the fuel tank/put in fresh fuel and tried to get it to start. No joy. Not even really a 'pop' so to speak. So I poked around a bit on the web and saw valve adjustments kept popping up as a possible hard start culprit. So I dove in and adjusted the valves. Still no joy in starting. :ponder:

Wondering if there were some more serious problems, I checked I had good spark and I did. I checked I had compression and that seemed good with my finger over the hole and trying to get my compression tester to work properly. And I checked that I had a good fuel supply from the tank which I did. It should at minimum fire, right?

So I tried a bit of starting fluid, and presto - it popped and sputtered! That confirmed I had a reasonably good top end for compression/spark so that just left fuel as the next thing to attack.

https://youtu.be/xLQJKnqiOYk

The little bike just sat in the garage for a while looking all sad, so Rusty offered up his experience in carb cleaning. Yesterday I pulled the carb out (an aftermarket Mukuni pumper TM33-8012) and we did a deep clean on most of it. There was one cover we didn't take off, yet apparently it was the slide access so not really necessary? Anyways, with a clean carb I got home and installed it, put the fuel tank on with a gallon of fresh fuel and hit the start button. Within a few seconds it fired up and ran! Not smooth, but it was running..... Choke was on and once it warmed up, pulled that off and it evened out. So I'm thinking I need to adjust the air/fuel screw next.

https://youtu.be/zC7VhuDN_JI

While that was going on, I had a voltmeter hooked up to the battery as the stator/rectifier issue was in the back of my head. Throughout the starting process I noticed the voltage was 12.25v, then as it was running it dropped to 12.23, then 12.21, then 12.19. ie: the battery was draining, not charging around 14 as where I would have expected it to be.

So I shut it down and thought for a minute, how do I troubleshoot these two components as I don't want to just replace the easy rectifier and have it be the stator. Gets kind of spendy at that point.

While pondering that, I remembered the headlight was 'weird' in that the low beam was pointing pretty high and the high beams when turned on went low. Hmmmm.... A quick look at the big rectangle bulb showed me it was upside down! So I swapped that orientation.

Which leaves me to my question for the moment...... Just how do I test the charging system to determine which (or both) is at fault? I have a simple voltmeter and that's about it along with a limited knowledge of how electrical stuff really works.

Any help would be much appreciated!
 
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The rectifier should be able to ohm test if I recall, and you can also test voltage before and after the rectifier and compare that to what the manual says it should be. Just remember, before the rectifier you will have AC power so make sure your meter is on the correct setting.

Lastly, you could just pull the stator and look at it. If it is the stator, chances are pretty good that one of the coils are burnt up (literally). That would be my last check as it could just be a broken wire as well, but it is a good confirmation.

Anywho, those are my thoughts on it. Just remember, I'm not much of an electrical guy.
 
Scott, have you bought a chiltons service manual for this machine? Said service book should have a step by step on how to diagnose those troubles...:sun:
 
Is the battery good ?

Signatures? We don't need no stinking signatures!
 
Ok Scott, here is what you do.
locate the regulator rectifier, squarish finned object, it will have6 wires going into it with two plugs, one plug will have three yellow wires, these are the wires from the stator.

inspect that plug for signs of over heating, melting and or corrosion.

if this plug looks good unplug it and take your meter set it to ohms and assign A,B,C to the wires. test A to B, then B to C then C to A. you are looking for a even number between all three generally around .6 ohm but it varies by bike, it is more important that the three test even.

next take ground lead and put to good ground point and then put ***+ lead to each of the three stator wires, this test for short to ground, any reading other than what you meter shows when not connected to anything indicates a short.

next test you start and idle the bike and with ground lead still on good ground test each of the three stator wires with meter set to AC voltage, you should see around 16 volts AC at idle on each leg, you then rev engine up to 5000 RPM and you should see at least 50 volts AC

if all three test pass inspect the other plug to the regulator for over heating damage and if none found it is pretty safe to say the regulator rectifier is bad.

burned plugs are a common problem on suzuki's I hope that is your issue.
 
Going to look at the rectifier in a few hours and inspect externally the stator wires for anything weird/hot/fried/broken. Got a few things I need to do first today....
 
OK, so I got to the wire bundle and found only FIVE, not SIX wires coming out of the rectifier. Three yellows from the rectifier that go to a plug that appears to run into a harness which runs down to the stator, and two additional wires (a black/white stripe and a red) and a plug that go into a harness and disappear.

I got down to the bundle and the three yellow stator wires and plug all look good. I couldn't see any discoloration, burn, melt, loose wires. It looks good albeit dusty.

I took my little cheapie meter (granted, it's CHEAP) and identified the three yellow wires in the plug and from the Stator side did the ABC test. A to B read 1.1, B to C read 1.1 and C to A read .6/.7 (it couldn't make up it's mind)

i-bKfgxk6-XL.jpg


I then ran the second test for ground shorts by placing the "-" lead on a good frame point, then using the "+" lead in each of A, B and C on the Stator side of the plug. My meter was showing 1.0000 with nothing connected and on ohms, and when I tested A, B and C, it remained 1.0000 for each of them individually.

That's as far as I am right now. I'll go start it and see about the ground wire/stator output for each of the three leads next and report back. (I'm running out of hands to do this!)

Am I on the right track so far?

.
 
...and now it won't start. Not even a putter or pop. Got spark, but the plug seems dry for all I've hammered it.

Carb fuel delivery issue again? It was running fairly well when last started.
 
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Fuel bowl drained when the screw was turned/opened... So it's got fuel in the bowl
 
Took off the air filter, sprayed some starter fluid and it popped/sputtered. Looked inside the fuel tank and could see the two feel tubes were under the fuel level, but I added some more to the tank. Started and ran. Maybe an optic illusion on where that feed tube was and it was out of fuel? I dunno, but it's frustrating for sure.
 
OK, so I got to the wire bundle and found only FIVE, not SIX wires coming out of the rectifier. Three yellows from the rectifier that go to a plug that appears to run into a harness which runs down to the stator, and two additional wires (a black/white stripe and a red) and a plug that go into a harness and disappear. I got down to the bundle and the three yellow stator wires and plug all look good. I couldn't see any discoloration, burn, melt, loose wires. It looks good albeit dusty. I took my little cheapie meter (granted, it's CHEAP) and identified the three yellow wires in the plug and from the Stator side did the ABC test. A to B read 1.1, B to C read 1.1 and C to A read .6/.7 (it couldn't make up it's mind) I then ran the second test for ground shorts by placing the "-" lead on a good frame point, then using the "+" lead in each of A, B and C on the Stator side of the plug. My meter was showing 1.0000 with nothing connected and on ohms, and when I tested A, B and C, it remained 1.0000 for each of them individually. That's as far as I am right now. I'll go start it and see about the ground wire/stator output for each of the three leads next and report back. (I'm running out of hands to do this!) Am I on the right track so far? .

Yes right track, the .6/7 is a bid disturbing but not terribly.

Waiting patiently for out put from stator legs.
What they put out at idle and 5000rpm is most important test
 
1000rpm (idle)
A = 1.6v
B = 1.5v
C = No consistent readings, bounced .5 to 2.2

2500rpm
A = 1.7v
B = 1.3v
C = 2.2v

5000rpm
A = 1.6v
B = 2.1v
C = 3.1v

I wondered if there was a conversion or something with my cheapie multi-meter so I stuck it in the wall on AC and got 120.2. I think it's safe to assume there's no factoring with the reading so the voltages above are what they indicate in AC.

So I think it's safe to say the Stator is bad?

Idle
i-Gd5nWKv-XL.jpg


5000rpm
i-2Cwxscm-XL.jpg

.
 
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Ooo stick leads in the A-B , B-C , C-A and see what you get.
 
Ooo stick leads in the A-B , B-C , C-A and see what you get.

Running or while turned off? Ohms or VoltsAC?

I did the A to B, B to C and C to A test with the ohm meter above in post #11
 
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Not shorting it using meter and when they run normally the regulator shunts excess power to ground.
You are looking at the ac out put of stator.
 
You're not shorting them out, you're just reading the voltage between them. Won't hurt anything, and it's an important test.

/sigh. Right there, seconds behind Focus...
 
OK, here goes with the VoltsAC test across the pins...

i-S3CKL4C-XL.jpg


Idle (1000rpm)
A (+) to B (-) = 1.26v
B (+) to C (-) = 2.10v
C (+) to A (-) = 2.86v

5000rpm
A (+) to B (-) = 1.18v
B (+) to C (-) = 1.96v
C (+) to A (-) = 2.69v
 
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That would be a bad stator, you should see 50 volts minimum at 5000

Or a rotor issue
 
For future reference, never plug in the VRR with the engine running (or even ignition turned on). That will blow easily enough. DAMHIK. Although they're not the most expensive thing on the bike, they ain't cheap, either.
 
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