notslow Posted April 23, 2005 Report Share Posted April 23, 2005 I was getting fuel leaking out of the tube at the bottom of the carb, so i did the T piece mod. I put it back on the bike and it starts to leak out even worse then before, as soon as i turned the petrol on there was a steady flow of fuel coming out of the out let spigot at the bottom. Anyway, i take the carb back off and took the float bowl off and had ago at setting the float height. I moved the little tab that connects with the valve that shuts the fuel on and off, up a bit. Put the carb back on and found the bike wouldn't start, but on the plus side, no leak. Undid the bolt at the bottom of the float bowl and fuel came out, so i did it back up and took the carb of again to adjust the tab back a bit as i think i moved it a bit too much.Then i put the carb back on and tried to start the bike. After a few goes it sounded like it almost went, so i opened the throttle and kicked it over, it started. As soon as i let the throttle go it died. Well, theres a small screw on the side of the carb which is the idle screw control, so i opened it up a bit and the bike started up and ticked over without me opening the throttle. I turned the petrol off and before i shut the garage up i thought i'd give it one more go. I kicked it over and it started first time, i put it into gear and rode forward a bit, i tried to get the bike back into neutral. All of a sudden the engine starts to rev with out me touching the throttle, it gets louder and harder, i pressed the kill switch but nothing happened it just kept on reving. I thought it was going to blow up and i turned the idle screw right down but again this did nothing. Eventualy after a few seconds it just stopped by it's self. Why did this happen? Did the needle get caught on the carb? Quote Link to comment Share on other sites More sharing options...
notslow Posted April 23, 2005 Author Report Share Posted April 23, 2005 Also theres another screw on the carb near the idle screw, what does this do excactly? If i start the engine up again and it does this again how can i stop the engine if the kill switch doesn't work? Cheers Quote Link to comment Share on other sites More sharing options...
bob Posted April 23, 2005 Report Share Posted April 23, 2005 The larger screw in the middle of the carb os the tickover screw, this has a tapered end and when you screw it in it will push the slider up, effectively holding the throttle open for you. the smaler screw sets the tickover air/fuel mixture, if your bike was going OK before then you shouldn't need to adjust this. hope this helps, you may find that your bike will still leak fuel out when on the stand and when pointing downhill, however abit of tinkering with the route of the tube on the overflow tube should stop this. Quote Link to comment Share on other sites More sharing options...
notslow Posted April 23, 2005 Author Report Share Posted April 23, 2005 Cheers bob, i've just took the carb off again to have a look at it. I think i turned the idle screw the wrong way through panic as the engine revved. The screw is turned all the way in almost, thats got to be why the engine revved it's nuts off. I reckon the reason it didn't start first of all was because i messed about with the tick over fuel/air mixture screw earlier on today, it's almost shut. Quote Link to comment Share on other sites More sharing options...
trials lad Posted April 23, 2005 Report Share Posted April 23, 2005 Cheers bob, i've just took the carb off again to have a look at it.I think i turned the idle screw the wrong way through panic as the engine revved. The screw is turned all the way in almost, thats got to be why the engine revved it's nuts off. I reckon the reason it didn't start first of all was because i messed about with the tick over fuel/air mixture screw earlier on today, it's almost shut. Haveing the idle screw screwed right in shouldnt have made the bike rev its nuts off the idle screw should only how the throttle slide about 1/8 open at most. Quote Link to comment Share on other sites More sharing options...
bikespace Posted April 23, 2005 Report Share Posted April 23, 2005 As the bike runs out of fuel they generally tend to rev a little. I would get your kill switch sorted out as soon as poss. Not a nice position to be in. If I'm upside down with my rear wheel wearing a rut in me, I like the idea of someone being able to turn it off quickish. I've mentioned before my experiences of shooting across a field with the throttle jammed open, trying to pull my plug cap off as (soaking wet through) it electricuted me. Didn't have the heart (or the wallet) to pull the clutch in and let it scream. Quote Link to comment Share on other sites More sharing options...
clarkp Posted April 23, 2005 Report Share Posted April 23, 2005 If you're around the garage and its reving its brains out, wad up an old t-shirt and stuff it into the end of the exhaust pipe. Buy and install a good two-wire kill switch, not one that grounds to the frame to kill the bike. Quote Link to comment Share on other sites More sharing options...
stevel Posted April 24, 2005 Report Share Posted April 24, 2005 Are you sure that you had the throttle cable seated properly when you replaced the carb? This is the most common reason for a bike revving it's nuts off;And when they rev this hard the kill switch won't work as you get self ignition. If you then took the carb off again the chances are you then got the cable seated properly I've done this that many times over the years when I've had the carb off, that it is now a habit to have a final check that the cable is OK before I kick the bike over Quote Link to comment Share on other sites More sharing options...
feetupfun Posted April 24, 2005 Report Share Posted April 24, 2005 If your bike is revving its tits off and the kill switch won't stop the engine and you can't stop it by changing up gears and using the rear brake, inverting the whole bike (ie with it resting on top of handlebars and rear guard) will stop it very quickly. It works by lifting the main jet out of the fuel in the float bowl. This procedure has saved three trials bike engines that were sure to either seize or throw the rod but I was able to invert them in time. However there are a few risks: Starting a fire from any fuel that leaks out before the motor stops. Getting caught up in the chain or back wheel. Upsetting the owner by doing something unexpected to their pride and joy at a time of high stress. Quote Link to comment Share on other sites More sharing options...
g4321 Posted April 24, 2005 Report Share Posted April 24, 2005 Have you set the float hight properly? By the sounds of things you have not. Get the correct float hight setting and then set the float height as accurately as you can, then start playing around with the mixture and idle settings since if the float height is wrong the bike wont run right. Just a suggestion! Quote Link to comment Share on other sites More sharing options...
mickrayner Posted May 16, 2005 Report Share Posted May 16, 2005 I had exactly the same problem with mine, running ok, but found the air intake to the choke and pilot screw were completly blocked, cleared them out, kicked it over and the bike reved out of control for a few seconds then stopped on its own. I found the cable must have been adjusted to make it run, clearing the blockage made it rev too much. I had to get the plug lead off with a long screwdriver as I didn't have a kill switch then. Quote Link to comment Share on other sites More sharing options...
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