350banshee Posted August 28, 2009 Report Share Posted August 28, 2009 hey guys hope you can help? when i turn my fuel off my bike revs off its tits instead of stalling. ive had the motor apart 4 times now and replaced all seals and tried 3 diff types of gasket stuff but nothing seems to work. any ideas of what else it could be? i also put a rz350 case on it cause i smashed mine. any help would be great thanks. Quote Link to comment Share on other sites More sharing options...
Larry's Shee Posted August 28, 2009 Report Share Posted August 28, 2009 Not a good idea, your'e running it lean. If you don't have a kill switch, put it in gear, hold brake, pop clutch. Quote Link to comment Share on other sites More sharing options...
slopoke Posted August 28, 2009 Report Share Posted August 28, 2009 That is normal. Like said it is going lean wich means you are running it out of oil. That will get expensive soon. Y do you do that?????? Just turn the fuel off when you kill the bike. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted August 28, 2009 Report Share Posted August 28, 2009 Before you lean it out again and risk damage, remove the carbs and pipes and do a leak down test to make sure the multiple gaskets and seals you replaced are actually doing the job. Then...as said, use a kill switch or turn the idle so low it will stall out on you. Two strokes get all their top end and lower end lubrication from the gas. Starving the motor of that is a certain way to ruin it. Quote Link to comment Share on other sites More sharing options...
bansheesandrider Posted August 28, 2009 Report Share Posted August 28, 2009 You said you put an RZ case in, did you put in a matched upper AND lower case or just one half. If you only replaced half, that is probably where your air leak is. Pressure test your engine for air leaks before you tear it apart again, there is a thread on here to make your own presure tester. Yamaha only sells the cases as a matched set because that is what they are, a MATCHED SET. When you turn off the gas, it will naturally rev up because as it runs out of fuel, the float level goes down in the carb and the mixture goes lean. It shouldn't rev to full throttle and it should die shortly. Good luck. Quote Link to comment Share on other sites More sharing options...
350banshee Posted August 29, 2009 Author Report Share Posted August 29, 2009 yeah changed both halfs and i always turned my fuel off and it used to just die but since i put the new cases on its been stuffed. been told that its reving up because when it runs out of fuel it starts running on the gear oil? would the adjustable timing plate make it rev up? Quote Link to comment Share on other sites More sharing options...
slopoke Posted August 29, 2009 Report Share Posted August 29, 2009 Someone correct me if I'm wrong but it will rev up when it goes lean with the fuel off. Why are you doing that "test". There must be some reason behind the maddness?? Are you doing a maximum burn test??????? Quote Link to comment Share on other sites More sharing options...
dajogejr Posted August 29, 2009 Report Share Posted August 29, 2009 yeah changed both halfs and i always turned my fuel off and it used to just die but since i put the new cases on its been stuffed. been told that its reving up because when it runs out of fuel it starts running on the gear oil? would the adjustable timing plate make it rev up? Dude...just put a kill switch on. Do not run it out of gas. No, unless the case isn't sealed properly, it won't run on gear oil. No, increasing the timing won't make it rev up. Quote Link to comment Share on other sites More sharing options...
slopoke Posted August 30, 2009 Report Share Posted August 30, 2009 Dude...just put a kill switch on. Do not run it out of gas. No, unless the case isn't sealed properly, it won't run on gear oil. No, increasing the timing won't make it rev up. I cant figure out why he would do this.......why turn the gas off to kill it????? Quote Link to comment Share on other sites More sharing options...
350banshee Posted August 30, 2009 Author Report Share Posted August 30, 2009 yeah guys i do this to run the feul out of my carbs so feul doesnt sit it there for a long time thats the reason. when i use to race all the guys did it but now i thinkn its not to good.but thats not the only problem bike wont idle unless i ckrank the idle up. got no gutts down low and keeps fouling plugs. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted August 30, 2009 Report Share Posted August 30, 2009 Somewhere close to you, there is a repair shop that loves all of you guys. Regular gas will last a while sitting in your bowls. Race gas will last even longer. Personally, I'd rather take 1/2 hour to 1 hour and remove the carbs and clean them if this was an issue than run it out of gas and lean it out. Do a compression test. And it's possible your carbs are out of sync, dirt in the carbs...what jetting is currently in it? Quote Link to comment Share on other sites More sharing options...
slopoke Posted August 30, 2009 Report Share Posted August 30, 2009 I had rather leave gas in them instead o leaving them dry. They tend to get a white powder buidup. If you insist on draining them there is a screw on the bottom of the bowls that does just that. Quote Link to comment Share on other sites More sharing options...
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