Vulcha Posted December 9, 2008 Share Posted December 9, 2008 Well, I figured that his would be the place to get info on Yamaha's, so, here goes. I have a 1989 FZR400RR, which, for some reason, doesn't start. When you hit the starter, you can hear it trying to tick over, but it doesn't. I took it to a garage and they said there was nothing wrong with the battery (which I knew anyway as it would charge and hold charge) and nothing wrong with the charging circuits. They said that it was running rich and the reason it wasn't starting was due to the engine flooding when the choke was opened. I started it up without the choke and it was fine for a little while, and recently its stopped starting and I've had to bump it. It was starting without the choke whe it was real cold out. Round about 2 degrees. So, I'd like to pick your brains and see if any of you guys could help. My knowledge of bike maintenence goes as far as changing oil, spark plugs, brake pads and bulbs, so hopefully its not going to be something really hard I'm going to have to pay someone to do! Any help with this would be very much appreciated. Link to comment Share on other sites More sharing options...
Ttaskmaster Posted December 9, 2008 Share Posted December 9, 2008 Simple - Change the mixture. You'll need a copy of the service manual or the Haynes, simply because I don't know where the various bits are on your particular bike. Somewhere there will be a screw (very close, or actually on the carbs). Turning it wil adjust the air/fuel mixture. Get a Colortune kit (it's usually American, hence odd spelling) and make use of that to get a fairly accurate adjustment. Instructions are included and a decent one'll cost you about £40 including VAT, postage and all that crap. Once done, air/fuel mixture will be as good as you can get on a DIY job without lots of fancy kit. Plus, your fuel economy will go up as you use less fuel!!!! Link to comment Share on other sites More sharing options...
Vulcha Posted December 9, 2008 Author Share Posted December 9, 2008 You reckon that'll stop the whole battery charing issue aswell? Where can I get this colortune from? Are they easy to find or will it take a bit of looking to find one? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted December 9, 2008 Moderator Share Posted December 9, 2008 As TTaskmaster said the mixture is way too rich, theres no way you should be starting without choke, before you go adjusting the mixture screws though, check the air fiter, it hay be crappy and need blowing out, or even replacing, i think you should also have a look at your choke mechanism, try to see if its working correctly, after youve done this is the time to play with mixture screws Link to comment Share on other sites More sharing options...
olivers Posted December 10, 2008 Share Posted December 10, 2008 As TTaskmaster said the mixture is way too rich, theres no way you should be starting without choke, before you go adjusting the mixture screws though, check the air fiter, it hay be crappy and need blowing out, or even replacing, i think you should also have a look at your choke mechanism, try to see if its working correctly, after youve done this is the time to play with mixture screws sorry.. dont want to take over your thread.. but when you say it shouldn't start without choke.. you got me worried i'm running rich as well.. is this a general rule of thumb.. my xs400rj starts without choke and in a 0deg garage in ~1/4 second. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted December 10, 2008 Moderator Share Posted December 10, 2008 sorry.. dont want to take over your thread.. but when you say it shouldn't start without choke.. you got me worried i'm running rich as well.. is this a general rule of thumb.. my xs400rj starts without choke and in a 0deg garage in ~1/4 second. No, the only time they should start without choke is when the engine is warm, it must be rich at idle, however its not something to worry over...worry when its lean Link to comment Share on other sites More sharing options...
Ttaskmaster Posted December 10, 2008 Share Posted December 10, 2008 You reckon that'll stop the whole battery charing issue aswell? Where can I get this colortune from? Are they easy to find or will it take a bit of looking to find one? What charging issue? You said that you and your garage blokie have both confirmed that battery and charging circuits are fine. Colourtune/colortune can be had from many different places that sell bike parts and stuff. Google them up or even phone your local parts shops. Easy as!! No, the only time they should start without choke is when the engine is warm, Which mine does on a warm day. IIRC, the mixture will be ever so slightly lean at idle and rich when you open the choke? Opening the throttle adds more air into the mix, which is why you start a flooded engine with throttle open and choke shut? Right or wrong? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted December 10, 2008 Moderator Share Posted December 10, 2008 Which mine does on a warm day. IIRC, the mixture will be ever so slightly lean at idle and rich when you open the choke? Opening the throttle adds more air into the mix, which is why you start a flooded engine with throttle open and choke shut? Right or wrong? IIRC?? the mixture should be slightly rich at idle to enable smooth pick up when throttle opened, but not that rich it starts with a 2 degree ambient temperature without choke...With choke it will be very rich. As for a flooded endine, the reason for opening the throttle fully has more to do with expelling unburned fuel out of the exhaust that it does to actually start the engine, engines are difficut to start with wide open throttle. Link to comment Share on other sites More sharing options...
Ttaskmaster Posted December 10, 2008 Share Posted December 10, 2008 IIRC?? If I Recall Correctly. Think I get it now. Ta!! Link to comment Share on other sites More sharing options...
Vulcha Posted December 12, 2008 Author Share Posted December 12, 2008 What charging issue? You said that you and your garage blokie have both confirmed that battery and charging circuits are fine. Well, thats what they said, but the battery still keeps going flat, which makes me think its some kind of intermittent fault. I know the battery is fine, so its something electrical. But, I have no idea where to start looking! Cheers for all the advice guys, I'll have a look at the bike this weekend and attempt to sort it. Link to comment Share on other sites More sharing options...
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