My friend has a ds650 and he went riding the other day and it died on him. He thought maybe it was low on gas so he flipped it to reserve but it still wouldnt start back up. We checked it over to see why it's not starting its getting gas, its got good spark and the motor turns over. i was wondering if any of you knew what else we could check. If you have any ideas we could use some. thanks.

 

Spark + gas = go time

Youve got me stumped...

 

I agree spark + gas =run but have you checked to make sure the valves are opening/closing =compression(?) = the last of the three things needed?

 

we havent checked the compression because my compression tester fitting is too big for the spark plug hole on his quad. we were going to pull the plug and put our thumb over it to see if it has some compression atleast but havent had a chance to do it yet. His warranty just ran up not a couple weeks ago too so we're hopping its nothing to big.

 

You actually need 4 things for an engien to run. Gas, Spark, Compression, and Ignition at the correct time. Start eliminating these and you will find your problem

 

Mine did the same thing last month. Had spark, but after changing out the plugs, I was back in business. Hope this is all that is needed for you friend.

 

Things I've heard of or experienced when it dies then won't start:
Bad fuse
Broken valve springs - Loss in compresssion. This is going to be more common on bikes with aftermarket cams
Plugs. . . well, actually had one work loose and pop out. . . so that was kind of a compression loss thing too [img]i/expressions/face-icon-small-blush.gif[/img]
Fuel vent line became pinched so, I would have fuel for a little while then after enough fuel had been sucked out of the tank the air vol. inside the tank would go under a negative differential pressure compared to atmosphere. . . result, no fuel to carbs.

Other than that. . . like others have said. . .
Fuel + Spark + compression = Fire