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DRZ won't start - very confused......


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2005 DR-Z 400S, I believe it is a CA bike

3x3 mod, jetted to match, extended range plastic tank (no vacuum petcock, and fuel flows with the petcock in the "on" position), manual CCT

Running great about six months ago. Started it about two months ago with a very low battery, ran terribly but it did run. Got a new battery recently, and it wouldn't start at all. At first it would run for about five seconds and die, but now it just doesn't start at all. Starter works fine, and it turns over, but doesn't fire.

Compression seems fine, though I haven't tested it. It pushes plenty of air through the exhaust, and it it hard to turn the motor over by hand.

New spark plug, and plug does create visible spark

New gas

Cleaned the carbs

Put a little oil in the cylinder to try and wet the seals

Sprayed carb cleaner into cylinder, no bang or anything

Bought a stock carburetor off of ebay that the seller claims was running great. It is very clean inside, so I believe him. If it was the carburetor that was the issue, I expected it to at least run with the stock jetting, though I didn't expect it to run well.

New gas again

Put old jets in new carburetor

 

I think I've tried just about everything except for the electrical system testing. I tried the voltage measurement going to the coil, but my multimeter doesn't have a peak voltage setting, so I'm not sure if it was working or not.

Any advice on where to go next? Would it be worth it to try a new coil and/or CDI? I see coils on ebay for pretty cheap, so I may try that next.

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#1 culprit would be plugged up carb....Most people don't clean the carb good enough, you need to make sure the passages aren't blocked (not just the jets). Also need to check that the vent hoses aren't pinched or blocked...same with gas cap vent. (I'd use starting fluid or gasoline in the cylinder to see if it fires (not carb cleaner)

#2  tight valve lash (which lowers compression)...check valve clearances and cam timing.

#3  be bad stator (common with the DRZ's)...best way to test is swap with a known good one.

#4  short or bad connection in wiring (check kill switch, clutch and side stand switches)

After all that then I'd start thinking about the coil or cdi but those aren't a common problem on these bikes.

 

 

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Thanks for the reply! All good thoughts.

#1 - I would have thought that the replacement carburetor would have eliminated the cleaning aspect of it. I will check the vent lines. 

#2 - I'll probably borrow a compression tester to eliminate compression as the issue. If it is the issue I'll check the valves and timing.

#3 - Good to know - I'll see if I can find one.

#4 - I thought if any of the switches weren't working, it wouldn't spark? The kill switch is working for sure. The sidestand switch has been bypassed, so I'll double check that, and I'll double check the clutch switch.

Good to know on the coil and cdi - I saw that in another thread that sounded similar to mine.

Thanks again for the reply, I appreciate it!

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On 5/1/2017 at 8:25 PM, Matt Woodruff said:

2005 DR-Z 400S, I believe it is a CA bike

3x3 mod, jetted to match, extended range plastic tank (no vacuum petcock, and fuel flows with the petcock in the "on" position), manual CCT

Running great about six months ago. Started it about two months ago with a very low battery, ran terribly but it did run. Got a new battery recently, and it wouldn't start at all. At first it would run for about five seconds and die, but now it just doesn't start at all. Starter works fine, and it turns over, but doesn't fire.

Compression seems fine, though I haven't tested it. It pushes plenty of air through the exhaust , and it it hard to turn the motor over by hand.

New spark plug, and plug does create visible spark

New gas

Cleaned the carbs

Put a little oil in the cylinder to try and wet the seals

Sprayed carb cleaner into cylinder, no bang or anything

Bought a stock carburetor off of ebay that the seller claims was running great. It is very clean inside, so I believe him. If it was the carburetor that was the issue, I expected it to at least run with the stock jetting, though I didn't expect it to run well.

New gas again

Put old jets in new carburetor

 

I think I've tried just about everything except for the electrical system testing. I tried the voltage measurement going to the coil, but my multimeter doesn't have a peak voltage setting, so I'm not sure if it was working or not.

Any advice on where to go next? Would it be worth it to try a new coil and/or CDI? I see coils on ebay for pretty cheap, so I may try that next.

frozen rings maybe....

drop some penetrant (pbblaster/kroil/similar) down the spark plug hole and let it soak. give it a couple days, install the plug and try starting again. when the rings rust they seize in their grooves, and compression drops off. 

 

the other easy thing to check (compression and spark are coverd) is the rotor key. 

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