thomasrolewis Posted May 19, 2012 Share Posted May 19, 2012 Yes, back again with more SR125 problems! But, I have new brakes in the post and come Tuesday, no more university. So I will finally get some time to work on it. OK, so here is what's happening. I went for a ride about 2 weeks ago to get a new helmet (although, turns out the local shops had none in my size). It was riding fine apart from the previous odd cut out when idling. Anyway, getting close to home it was getting bad, It had to have throttle or it would cut out (throttle stop screw is about 2 turns out). I put it in the garage, then checked for air leaks, didn't find any. It was weird, started then just cuts out unless it was slightly revved. Even tried to increase the throttle stop but it didn't make any difference. So anyway, I was so bogged down with work I had to leave it. When back to it a few days later and it started and idled fine. But now, went back to it and it wont start. Nothing, it turns over then every once or twice makes a pop, but other than that it wont do anything. It's sparking and has had a new plug recently. After applying some logic I have come up with some theories, just wondering if they sound right. 1. Fuel blockage/carb not filling - Fuel filter clean (my tap is stiff, don't know if that has anything to do with it)/carb overhaul. 2. Idle jet completely blocked? 3. Air filter problems. 4. Starter/spark problems (although it has been fine) I know nothing of the bikes past servies, when it was last done or anything. Only what I have done. Do you think it would be good to clean and inspect all of those areas to make sure? Reset the whole carb, take the fuel tap apart and check all the lines? I also have some noise from the engine, I'm about 90% sure it's my inlet/outlet values. Could people suggest other things to look for/do while the tank and carb is off? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 20, 2012 Moderator Share Posted May 20, 2012 for one thing i dont think you know a throttle stop screw from a mixture screw!...no one ever counts turns on a throttle stop screw hey did you run out of fuel, before you do anything pull off the fuel pipe and check you have a good flow of fuel to the carb after that...yeah maybe another carb clean Link to comment Share on other sites More sharing options...
thomasrolewis Posted May 20, 2012 Author Share Posted May 20, 2012 Yes, I do know the difference. I only counted it because that was how it was set when I got the bike, otherwise I would be guessing where to put it. Fuel? What's that? I thought it ran on pixie dust? But no, plenty of fuel. I stripped the carb and filter today, they were actually in pretty good nick. Blew out the jets, set the float height. Checked the air filter, not blocked and pretty clean. Once I put it together again it was exactly the same. I even tried to bump start it (just to see whether the battery was too flat), and it just wouldn't go. It did try to, but it never managed to get going. I'm thinking it could be a weak spark now. Although the plug was replaced about 1 1/2 months ago. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 20, 2012 Moderator Share Posted May 20, 2012 Yes, I do know the difference. I only counted it because that was how it was set when I got the bike, otherwise I would be guessing where to put it. ............. Guessing? you just turn the blighter until the correct idle speed is achieved, nothing to do with number of turns Link to comment Share on other sites More sharing options...
thomasrolewis Posted May 20, 2012 Author Share Posted May 20, 2012 The Sr125 has no rpm gauge. So i thought it was best to leave it where it was. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 20, 2012 Moderator Share Posted May 20, 2012 fair enough but you dont need a tacho to 'hear' when a good idle speed is achieved, tacho's are a fairly modern invention and setting idle in pre-tacho days certainly wasnt done by counting turns! Thats why i thought you were referring to the mixture screw which has always been a counting exercise Link to comment Share on other sites More sharing options...
thomasrolewis Posted May 20, 2012 Author Share Posted May 20, 2012 Yeah, it usually idles fine. Either way, I have no idea why its not working. I'm going to ring a local bike place and ask for a quote. What kind of price am I looking at? I mean, I know it depends what needs doing, but I have never taken anything to a garage and have no idea what prices are like. Link to comment Share on other sites More sharing options...
pyro plim Posted May 21, 2012 Share Posted May 21, 2012 Is there a breather on your fuel tank or filler cap ? My xt 125 ( same engine)used to vaccum up and act the same.Take fuel pipe off and unscrewe the filler cap to see if the flow of fuel increases. I hope this helps. Link to comment Share on other sites More sharing options...
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