alexp5 Posted March 30, 2012 Report Share Posted March 30, 2012 I've got this little niggle that has manifested itself over the past couple of months on the City Fly. At about 3/4 throttle I get a slight misfire almost as though it's about to run out of juice, even more so when transitioning from 3/4 to full. Throttle wide open is no problem - which is good because that's where it spends most of it's time, what with been a ickle air-cooled 125 4 stroke single an' that. I've gone through the usual suspects - new plug, cleaned out carb / tank / tap filters, checked and adjusted valve clearances etc. but I'm still getting it. The only other thing I can think of is carb icing. I use a fuel additive which is supposed to combat it (but obviously doesn't, unless the problem is something else) and the City Fly is equipped with a carb heater (which I think may not be working...) Any ideas folks..? Also - what conditions do you need for carb icing to happen, or are there that many variables it's almost impossible to predict? Cheers. Link to comment Share on other sites More sharing options...
gurninman Posted March 31, 2012 Report Share Posted March 31, 2012 In my experience (I've got a ZX-9R, so have *lots* of experience of carb icing) , it never rears it's head when your bimbling around town at varied throttle openings - it's almost always at a constant throttle at reasonable speeds.Normally when the temps are below about 15 deg C , and more so when it's a little damp.Your symptoms certainly sound like it , but if you're using a fuel additive it shouldn't happen.I use surgical spirit at 1% every fill up, and that does stop it happening. What type of carb heater do you have - is it electrickery or hot water ? if it's hot water, there may well be a filter inline that's blocked - again, common on the ZX-9R and easy to sort. Link to comment Share on other sites More sharing options...
kevin..in Posted March 31, 2012 Report Share Posted March 31, 2012 try some Silkolene Pro FST, used to get carb icing when i commuted on a nospeedfight, pro fst cured this, it was developed for the ZX9R to cure its carb icing tendancies Link to comment Share on other sites More sharing options...
alexp5 Posted March 31, 2012 Author Report Share Posted March 31, 2012 I'll have to give FST a try, but no-one seems to stock it round here. I've been using the STP stuff. @gurninman - the bike is an aircooled single so the carb heater is an element plumbed into the carb inlet. I wouldn't have though aircooled singles would ice up, what with the carb tucked in behind the cylinder. I work nights and tend to park the bike up in the workshop while I'm there. Maybe been in a relatively warm environment all night then having the bike running in the cold morning air is causing more condensation than normal? Link to comment Share on other sites More sharing options...
BudgetBoy Posted March 31, 2012 Report Share Posted March 31, 2012 Weak spark under load. Leads Battery Check main jet for blockages oh and the air filter Link to comment Share on other sites More sharing options...
alexp5 Posted March 31, 2012 Author Report Share Posted March 31, 2012 Weak spark under load. Leads Battery Check main jet for blockages oh and the air filter Carb cleaned out and blown through with air and air filter was replaced recently. Battery is good. The rest I'm not so sure about. Any feedback re: Wurth 4 stroke petrol additive? Pro FST is rare around here unless I get it online. ...actually, scrub that. The Wurth stuff is over £7 for a 150ml can and they recommend a can to a tank. Fuck that. Link to comment Share on other sites More sharing options...
kevin..in Posted March 31, 2012 Report Share Posted March 31, 2012 pro fst works, like you i work nights and this was when my aircooled single was icing up, never had a problem with the pro fst, where exactly are you? why is it hard to get near you? Link to comment Share on other sites More sharing options...
gurninman Posted March 31, 2012 Report Share Posted March 31, 2012 Surgical spirit / IPA is easier to get hold of, and cheaper.Pro FST is 95% isopropyl alcohol anyway, with a few other bits in.It's the IPA that does the job... if you buy surgical spirit it has to be pure, which will be 95% plus. Link to comment Share on other sites More sharing options...
alexp5 Posted March 31, 2012 Author Report Share Posted March 31, 2012 pro fst works, like you i work nights and this was when my aircooled single was icing up, never had a problem with the pro fst, where exactly are you? why is it hard to get near you? I'm in Telford, Shropshire. No one seems to stock it. One of the local dealers stocks Silkolene stuff and I asked about FST, his reply was "We never sell it so we don't stock it." WTF? My reply was "If you stocked it, you'd sell it." I don't use that dealer now. I can get it online from Opie Oils, or I'll try the iso alcohol. Link to comment Share on other sites More sharing options...
kevin..in Posted March 31, 2012 Report Share Posted March 31, 2012 I'm in Telford, Shropshire. No one seems to stock it. One of the local dealers stocks Silkolene stuff and I asked about FST, his reply was "We never sell it so we don't stock it." WTF? My reply was "If you stocked it, you'd sell it." I don't use that dealer now. I can get it online from Opie Oils, or I'll try the iso alcohol. i did an online search, didn't realise it was so expensive i get mine from trade when i buy it, try the alcohol then if its available your local suplier/non suplier would be wylie & holland then! Link to comment Share on other sites More sharing options...
alexp5 Posted March 31, 2012 Author Report Share Posted March 31, 2012 i did an online search, didn't realise it was so expensive i get mine from trade when i buy it, try the alcohol then if its available your local suplier/non suplier would be wylie & holland then! Yup. Wylies aren't a Kawasaki dealer. If they were they'd sell gallons of the stuff . Link to comment Share on other sites More sharing options...
gregtrx Posted March 31, 2012 Report Share Posted March 31, 2012 I never had this issue with mine, even when I dropped it in a ford. Might be something else. They do go through plugs more than bigger bikes. Link to comment Share on other sites More sharing options...
alexp5 Posted March 31, 2012 Author Report Share Posted March 31, 2012 I never had this issue with mine, even when I dropped it in a ford. Might be something else. They do go through plugs more than bigger bikes. Can't remember if you used yours through a winter, Greg? I changed the plug a few weeks ago. And the carb heater is fuckered on mine . Link to comment Share on other sites More sharing options...
gregtrx Posted March 31, 2012 Report Share Posted March 31, 2012 I rode to the Dragon on it, don't get much more winter than that! Maybe my carb heater worked though, I never knew it had one. Link to comment Share on other sites More sharing options...
alexp5 Posted March 31, 2012 Author Report Share Posted March 31, 2012 I rode to the Dragon on it, don't get much more winter than that! Maybe my carb heater worked though, I never knew it had one. Looks like a little lambda sensor screwed into the carb manifold, 2 wires tapped into it. Link to comment Share on other sites More sharing options...
alexp5 Posted April 1, 2012 Author Report Share Posted April 1, 2012 I've put half a bottle (100ml) of surgical spirit (95% IPA) in the tank. We'll see what happens next week when the weather returns to normal (i.e. shite) for this time of year. What could possibly go wrong... Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.