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DRZ400SM died on me

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I was riding to a cruise the other day and just before I got there, my bike broke down next to a service station, no weird noises, no clunks, it just died, so don't think there is any engine damage.

 

Starting the bike sounds normal, it just doesn't start.

 

At first, I thought it was the fuel, so I turned it to reserve and tried starting the bike, still no good. I then opened the tank and it was half full so I turned it back to the normal ON position.

 

I then proceeded to try and start the bike until the battery died. I finally managed to get the bike started using the kick starter but had to keep the throttle open a little to keep it alive, as soon as I let go of the throttle it just died, never have been able to get it started since.

 

As it being a 1 cylinder, its possible that the spark plug could be shot, so I replaced the spark plug, but still no good. There is definitely spark, checked that already.

 

I have removed the carburetor, pulled it apart, seemed pretty clean, no gunk anywhere, removed the main jet and I could clearly see through it.

 

I checked the fuel source, with the tank disconnected, petrol flows when its set to ON or RESERVE so the tank isn't blocked/clogged.

 

After removing the carburetor, I placed my hand on the inlet hole and cranked the engine, there was good suction so this tells me there is good compression and the piston is intact and in good health.

 

So now I'm thinking that the timing is out. I'm hoping you can shed more light on my situation so I can get it resolved without spending much money.

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Hil al , make sure the pilot circuit is clean . That is usually what gets clogged and a lot of the time you cannot see it . Use compressed air to clear the passageways , by the sounds of it , it is just a blocked pilot circuit . Also make sure the vacuum hose on the fuel tap is good and not leaking or perished , greg

Edited by hinksy

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I put the engine on TDC and checked the timing and it all seems ok, nothing has been skipped.

 

I am going to buy new jets for the carburetor and reinstall it. Let see how this goes lol

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I had this happen to me before...my fuel/air screw fell out.  Not quite sure how it vibrated loose but it did.  I was able to get the drz open but I could not let off throttle at all.  Luckily I had my stock screw at home.   :foul:  mikuni carb.

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I had this happen to me before...my fuel/air screw fell out.  Not quite sure how it vibrated loose but it did.  I was able to get the drz open but I could not let off throttle at all.  Luckily I had my stock screw at home.   :foul:  mikuni carb.

 

Where is the fuel/air screw located on the carb?

Edited by Hil Al

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I dont have the tools to check valve clearance but have ordered them from fleabay. I'm going to put the bike back together today, pour a cap full of 20w50 in. Drain the carb and blast the air box with carb cleaner.

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Where is the fuel/air screw located on the carb?

If you are looking at the carb, on the bottom side like back left....if my memory serves me right.  I had the extend fuel screw so I knew it fell out...I just put the stock one back in.  I'd prefer not to invest money into the mikuni.  I just need to be willing to part with 560$ for a fcr.

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Hi guys, believe it or not, but I have got the bike started. I put the carburetor back on without connecting the air filter pipe, its only got the vacuum pipe and fuel pipe connected to it and still it started. I used some oil in the spark plug hole, it definitely helped. A few people on the forums said that the piston rings run dry, drops the compression then it has trouble sucking the fuel into the chamber, the oil definitely helped, I will be doing an oil change on the bike this weekend, while I'm working on the bike I will get the valves adjusted as soon as my valve lash tool arrives.

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well I did clean the jets with carburetor cleaner so maybe thats what it was lol

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Hi guys, believe it or not, but I have got the bike started. I put the carburetor back on without connecting the air filter pipe, its only got the vacuum pipe and fuel pipe connected to it and still it started. I used some oil in the spark plug hole, it definitely helped. A few people on the forums said that the piston rings run dry, drops the compression then it has trouble sucking the fuel into the chamber, the oil definitely helped, I will be doing an oil change on the bike this weekend, while I'm working on the bike I will get the valves adjusted as soon as my valve lash tool arrives.

 

 

your rings may be sticking from wear and/or over heating. are you jetted correctly ? does the bike run lean ? 

 

 

an indicator of low compression is adding oil to the cyilnder and the bike shows better compression. you really cannot check compression by hand, or at all, without disabling the auto-decomp mechanism. 

 

let us know what definite cause you find. 

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if it was the piston rings then when the oil dries my bike would die and not start again, after cleaning the jets it seems to be ok so maybe thats what it was..

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Where buy a remote air/fuel screw from? I also want to buy the jets new just incase I have the problem again.

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