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DRZ400SM lost power, stalled and now will not start

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Hi

I’ve got a 2008 DRZ400SM with 13,000 miles. Yesterday I was riding along at 70-80mph when there was a loss of power (felt like running out of petrol) so turned onto reserve and kept going for about half a mile (but bike still felt under powered) until I stopped at a junction where the bike stopped/stalled and would not restart. I checked there was enough fuel which there was and kept trying to start it and even bump starting but with no luck. I eventually got recovered after waiting 5 hours.

When I got home I took the tank off and removed the spark plug to check it was sparking which it was. I then put the spark plug back in and the bike fired up (without the tank on so no fuel connected) just with the fuel that was in the float bowl. When I put the tank back on (remembering to connect the small diameter hose to the tank) the bike would not start. I removed the drain screw from the bottom of the float bowl to drain out all the fuel, tried starting the bike again with no joy, then I did the float bowl drain again and fuel ran out so I know petrol is getting to the carburettor.

My concern is that when I have tried to bump start it the engine turns over easier than previously which makes me think the compression may be lower, I am not sure about this but will try to get a pressure gauge to check the compression.

I have been looking through the forum for ideas as to what the problem may be and what I should do next. Any suggestions or ideas would be much appreciated as I have had the bike from new and have never had any problems with it previously.

Many thanks

Matt

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Stator? Even though it sounds like a fuel problem, that rascally stator will get you every time.

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From what you have said I don't think there is a need to do a compression/leak down check as you have already confirmed your compression is reduced...Though here is a link if you wish to do so..

http://www.thumpertalk.com/forum/showthread.php?t=812173

IMO..You could have holed the piston or your could have a valve that is not closing correctly....

I would check your valve clearances 1st and go from there...

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From what you have said I don't think there is a need to do a compression/leak down check as you have already confirmed your compression is reduced...Though here is a link if you wish to do so..

http://www.thumpertalk.com/forum/showthread.php?t=812173

IMO..You could have holed the piston or your could have a valve that is not closing correctly....

I would check your valve clearances 1st and go from there...

Or what he said!!!

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Hi Guys

Many thanks for you very quick responses I will check the bike over using your suggestions when I get home. In answer to some of the questions raised:

I have not checked the valve clearances (and never have) so will do that.

The air filter is a K & N but I will check it is clean.

Please can someone let me know how to test the stator.

Many thanks

Matt

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From what you have said I don't think there is a need to do a compression/leak down check as you have already confirmed your compression is reduced...Though here is a link if you wish to do so..

http://www.thumpertalk.com/forum/showthread.php?t=812173

IMO..You could have holed the piston or your could have a valve that is not closing correctly....

I would check your valve clearances 1st and go from there...

+1

the valve clearances are very easy to check. make sure your frame and the area above/surrounding your valve cover is clean so it won't drop crap in the engine while checking the valves. cover it up immediately after finishing.

also, a compression test is easy to do with the cover off. i jammed a small piece of zip-tie into the auto-decomp mechanism for the compression test. don't forget about it or let it fall into the engine though.

since you have a spark, let's assume the stator is working. you can check timing with a light and the inspection plug removed from the left hand side case cover. you should see the timing line as the engine is kicking over with the starter. if you don't, you may have sheared a key on the flywheel.

speaking of timing.... don't mistake the flywheel mark as the only timing to depend on. the cam timing is very easy to check while the valve cover is off. it's in the FAQ section also.

i blamed my stator for the last failure very close to 13000 miles. it was the rings instead, and meant a couple hundred dollars and a few hours work to replace them. if you're running lean at all, my understanding is that things run warmer and wear out faster.

while you're doing things around the valves and slowly turning the engine with the back wheel and/or a ratchet, that "CLICK" you hear around TDC is likely the auto-decomp mechanism on the exhast valve, closest to the timing chain/cams. once you have it apart you'll see what i mean, and it should put you at ease that it's not something about to explode.

the fastest way to check valves is to remove the intake and exaust, and do a compression test, while listenting for leaks (psssssssst) through the intake or exhaust channels in the head.

be careful with teh spark plug torque.... it's very very little, and if you shear the threads off the end of the spark plug and need an ez out and quite a bit of patience to remove the threaded end without damaging the piston or head. ask me how i know :bonk:

... please thoroughly do the stator test before anything else....

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UPDATE:

Before I did anything to the bike I tried to start it and it fired up first press of the button, I let it run for about 30 seconds and then turned it off as the engine sounded quite rattly. I then briefly tried to restart it but it would not start presumably as it was warm. From this I am assuming that the stator is ok and that the problem is somewhere in the engine. Could it still be the valve clearances or something more serious? Any suggestions as to what to do next would be much appreciated.

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Cold start, but no warm restart points to three common items.

Gas in oil.

Closed up valves.

Failing sensor in the stator

Those are in order of likely hood to be found.

There are other things that can be at issue, but often it’s the most simple, so start there.

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Checked the oil level and found that I was not getting a reading on the dip stick, so drained out the oil from the sump (only a small amount of oil came out, maybe 100-200ml) replaced the filter but forgot to drain oil from frame put back in about 1.7litres of oil, started bike which sounded a lot better once oil had pumped round, I then realised that I had not drained the oil from frame so drained sump and frame and got just over 2litres which I presume means that the bike only had 400-500ml of oil originally. I have now put 1.7l of new oil in and initially got a reading on the dip stick but after running for about 1 minute could not get a reading so put a bit more in till I got a reading on the dip stick. The bike will still only start when its cold and seems to run fine initially but after about 30 seconds it will not tick over even with full choke and requires use of the throttle and starts to sound a bit rattly. The bike will not then start until it has completely cooled down.

I have just put this video of it on youtube

http://youtu.be/ntW32LtlXoI

I started the bike will full choke from cold and after just less than 30 seconds it stops. It doesn’t sound too bad but the video makes it sound a bit more rattly probably because the sound is echoing in the garage. I checked the dip stick after running it and am not getting a reading. The oil is not leaking out of the engine and does not seem to be being burnt as there is no smoke from the exhaust. I am thinking I need to drain oil again from sump and frame to find out how much is in it. Any suggestions would be much appreciated and thank you for the comments already received.

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Instead of checking oil level for the fourth time you should start the actual troubleshooting in the order suggested.

My bike did something similar, started looking for a clogged carb, ended up needing a new piston and rings.

I'm not saying you need a piston and rings, just that until you start tearing the motor apart and looking for the cause of the failure you won't get any real answers, just suggestions of what to look for and those have already been given.

Not meaning to sound rude and I apollogize if it came that way, but people in the forum are really trying to help and you need to follow the suggestions and post the results in order to move forward with the diagnosis.

:bonk:

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one thing: go buy a graduated cylinder that holds 1 liter. if you add oil from a gallon jug, for example, uses the cylinder to measure the oil so you aren't guessing. they can be purchased online for a few bucks.

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1.) Check valve clearence.

2.)You sure its not your petcock? Put it to prime pull off fuel line and see if fuel comes out if so hook it back up and start it.

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Have done all the things suggested and have found the following:

Stator coil resistance were within the range of those given in the service manual.

Valve clearence were all within those stated in the sevice manual

Did compression test which service manual states should be 135psi and got reading of 60psi, then poured 15cc of engine oil through spark plug hole into cylinder rechecked compression and got reading of 135psi. put spark plug back in and bike ran for about 90 seconds before stopping (obviously with lots of smoke due to oil put into cylinder) then checked compression again and got reading of 60psi.

From this I am presuming that piston rings are worn or damaged and require replacing along with checking condition of cylinder when engine is stripped to ensure it is not damaged.

Any comments on this diagnosis would be appreciated along with any other advice.

Many thanks

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I think it's the rings too but better wait for the engine experts. Did you disable the auto decompression mechanism to do the compression test?

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