oldskool Posted December 27, 2012 Report Share Posted December 27, 2012 I have a all new set up to me, with 64.50 bore,ported cylinders,+4 mill crank,34mm tm mikuni's, billet intakes with no cross over. I'm still working on jetting. 35 pilot and 260 main right now. Yesterday I fired the bike up and let it run for a few minutes, then turned the gas off to run fuel out of carb. The engine went WOT. I hit kill switch, still WOT. I then pulled both plug wires, bike is STILL RUNNING WOT, I then pulled both chokes and she died. Can someone PLEASE tell me what would allow the engine to keep running with no plug wires. Leakdown test a couple weeks ago checked out ok. Lost 1/2 lb in 10 mins. I'm pretty sure pilot is too big, but DAMN. I don't want to lose another engine over something stupid. Too many $$$ for me Quote Link to comment Share on other sites More sharing options...
Finch Posted December 27, 2012 Report Share Posted December 27, 2012 hmmm strange. but for one i wouldnt run it out of fuel to drain the carbs your creating a lean condition your better off just draining the carbs. Quote Link to comment Share on other sites More sharing options...
oldskool Posted December 27, 2012 Author Report Share Posted December 27, 2012 NOOOOO I'm not gonna run carbs out. I thought I was gonna have the big one Quote Link to comment Share on other sites More sharing options...
Finch Posted December 27, 2012 Report Share Posted December 27, 2012 . Yesterday I fired the bike up and let it run for a few minutes, then turned the gas off to run fuel out of carb. Quote Link to comment Share on other sites More sharing options...
Phelps Posted December 27, 2012 Report Share Posted December 27, 2012 it lean revved "dieseled" didn't need spark to fire the fuel only heat, compression and fuel. never turn the gas off and run the bike. Quote Link to comment Share on other sites More sharing options...
Starwriter Posted December 27, 2012 Report Share Posted December 27, 2012 You had what is commonly called a runaway. The lean condition caused by running it out of fuel heated up the spark plug and it acted like a glow plug, igniting the fuel much earlier on the compression stroke. Effectively doing the same thing as advancing the timing a whole bunch. It's happened to me on an alcohol motor. scary as shit. I yanked off the plug wires just like you. Still ran. One guy that had it happen on a single cylinder motor, yanked the carb out of the intake. Another guy said he was tempted to flip the bike upside down and dump the fuel out of it. LOL Usually you can anchor the brakes and put it in the gear and drop the clutch to kill it. Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted December 27, 2012 Report Share Posted December 27, 2012 NOOOOO I'm not gonna run carbs out. I thought I was gonna have the big one Ha, what? Quote Link to comment Share on other sites More sharing options...
Dicklez Posted December 27, 2012 Report Share Posted December 27, 2012 next time just hang on to the brakes and let the clutch out. Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted December 27, 2012 Report Share Posted December 27, 2012 You had what is commonly called a runaway. The lean condition caused by running it out of fuel heated up the spark plug and it acted like a glow plug, igniting the fuel much earlier on the compression stroke. Effectively doing the same thing as advancing the timing a whole bunch. It's happened to me on an alcohol motor. scary as shit. I yanked off the plug wires just like you. Still ran. One guy that had it happen on a single cylinder motor, yanked the carb out of the intake. Another guy said he was tempted to flip the bike upside down and dump the fuel out of it. LOL Usually you can anchor the brakes and put it in the gear and drop the clutch to kill it. Haha I remember that thread. I yanked the carb out of my blaster. The one guy wanted to flip the bike and dump all the gas. Quote Link to comment Share on other sites More sharing options...
oldskool Posted December 27, 2012 Author Report Share Posted December 27, 2012 Ok guys Thanks. Never seen anything like that before. Everytime I ran an engine out of gas, it would quit running. Not go wide open. Scary? hell yeah, It took a while checking for leaks and head scratching before I would start her again. lol Quote Link to comment Share on other sites More sharing options...
crazycracker520 Posted December 27, 2012 Report Share Posted December 27, 2012 Four strokes will just die when they run out. I know it has nothing to so with it but I have seen Detroit 8v92s(2 stroke diesel engines) runaway and you can kill feul but they will pick engine oil a burn it! It crazy scary!! crazycracker Quote Link to comment Share on other sites More sharing options...
Nightmare Posted December 27, 2012 Report Share Posted December 27, 2012 Four strokes will just die when they run out. I know it has nothing to so with it but I have seen Detroit 8v92s(2 stroke diesel engines) runaway and you can kill feul but they will pick engine oil a burn it! It crazy scary!! crazycracker Gotta love them old 2 strokes Sent from my SGH-T679 using Tapatalk 2 Quote Link to comment Share on other sites More sharing options...
crazycracker520 Posted December 27, 2012 Report Share Posted December 27, 2012 Four strokes will just die when they run out. I know it has nothing to so with it but I have seen Detroit 8v92s(2 stroke diesel engines) runaway and you can kill feul but they will pick engine oil a burn it! It crazy scary!! crazycracker Gotta love them old 2 strokes Sent from my SGH-T679 using Tapatalk 2 Oh yea!! Aint nothing like em!! Sweet music! crazycracker Quote Link to comment Share on other sites More sharing options...
2strokeshees Posted December 27, 2012 Report Share Posted December 27, 2012 Four strokes will just die when they run out. I know it has nothing to so with it but I have seen Detroit 8v92s(2 stroke diesel engines) runaway and you can kill feul but they will pick engine oil a burn it! It crazy scary!! crazycracker The company i used to work for had an old forklift with a detroit in it, while they were working on it she stuck wide open, not really much you can do when those things let loose. Quote Link to comment Share on other sites More sharing options...
dave5.0 Posted December 27, 2012 Report Share Posted December 27, 2012 Should die if you kill the air too it also. Just plug the carb with something. Just make sure it ain't a rag and you don't let it get sucked in. I'd be a little nervous about using the palm of my hand too. Maybe some cardboard or something. Had an old Zilla that would do that just sittin there idling with the fuel and everything on. Slide was worn out in the stock carb sucking too much air. First time it happened out in the middle of nowhere right after it threw the chain. Scary mofo. Slapped a new pwk on it and it ran like a top. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.