SeaKrait Posted August 24, 2008 Share Posted August 24, 2008 Hi, I am new to the board, and new to motorcycles. I recently received a 92 XJ600 seca II. It was working pretty good there for a few weeks, but now it dies after a few minutes of riding. It starts up pretty strong and seems to run fine, but after about 3 to 5 minutes it starts having trouble. If I am riding it at speed, it will continue to run, but barely and will little power. When I release the clutch it dies. If I pop the clutch it starts back up, but there isn't enough power being produced to accelerate much. I can start it back up with the choke out, but it will often just rev high for a sec then die again. Sometimes I can keep it going if I give it gas, put the choke in, and keep the rpms high, but as soon as I let the clutch out it dies - no real torque being produced. If I let it sit for a good while, it will start up strong again, and the process repeats itself. Any suggestions on where to look? Would it overheat that quick? I live the Monterey area, so it stays pretty cool. How can I tell if it has overheated - though I don't think this is the problem? Before I inherited it, the carb was rebuilt. It has a new battery. I checked a few of the spark plugs and they looked ok. Any help would be greatly appreciated. Thanks, Thomas Link to comment Share on other sites More sharing options...
grizzlydan Posted August 25, 2008 Share Posted August 25, 2008 Sounds like a charging problem. You said it had a new battery, I wonder why? Is it because the charging system or reg/rectifier needs to be checked. This can happen coz as soon as the bike warms up the electrics start breaking down. A quick way to check is put a voltmeter across the terminals of the battery & check the charge when running ( should read 14.5 volts) & watch what the charge is when it cuts out. A more in depth check can be done using a manual on electrics (Haynes do a good one). By the way also check the reg/rect for getting too hot (smell & feel). Link to comment Share on other sites More sharing options...
SeaKrait Posted August 25, 2008 Author Share Posted August 25, 2008 Sounds like a charging problem. You said it had a new battery, I wonder why? Is it because the charging system or reg/rectifier needs to be checked. This can happen coz as soon as the bike warms up the electrics start breaking down. A quick way to check is put a voltmeter across the terminals of the battery & check the charge when running ( should read 14.5 volts) & watch what the charge is when it cuts out. A more in depth check can be done using a manual on electrics (Haynes do a good one). By the way also check the reg/rect for getting too hot (smell & feel). When I get a hold of a volt meter I will check, but if it isn't charging the battery back up, then how come it starts up so easily after it sits for a while? Perhaps you are right and it would have enough juice to start up, at which point the turning of the generator/alternator takes over and provides enough power to run the engine and charge back up the battery - until it heats up, at which point the generator/alternator begins to fail and there is poor spark, and it dies. Is this the scenario you imagine? I can think of a lot of problems that would cause the engine to die, but I am having trouble figuring out what would work fine for a while, then go bad after a few minutes. Link to comment Share on other sites More sharing options...
pilninggas Posted August 25, 2008 Share Posted August 25, 2008 A number of posible causes spring to my mind: 1) worn main jets in the carbs. 2) Valve clearances out of adjustment. 3) Knackered plugs and/or coils 4) Sticking choke mechanism. Firstly see if from stone cold you can start it without operating the choke mechanism, if you can it is probably 1 or 4 (check choke mechanism by pulling the tank and seeing if it operates ok on the carbs), but is is likely gonna be main jets, hard to know for sure without seeing it run - is it rich when hot? does the engine bog-down when the throttle is blipped from idle whilst hot? you could get a factory pro or dynojet kit (factory pro better) or even replace with OE main jets and needles. If you have a workshop manual find the idle jet screws and check they are at the factory settings. Any number of motorcycle owners are presently grappling with the above problem! For (2), when wee the valves last done? if the bike has done more than say 20000miles and you do not know then assume they need to be done. again a workshop manual will tell you all you need to know. essentially the valves close up ove time due to 'valve seat recession' meaning the engines ability to breathe is stunted. this often exhibits itself as a quiet(ish) top end, reduced power and poor hot running. For (4) On any bike of unknown history, i would change the plugs as a minimum and the coils if it has starting problems or hot running issues (as you have) - this is because the coils beak down under cetain conditions. phew.... that is a lot of stuff, start with the plugs and give the carbs a once over. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted August 25, 2008 Moderator Share Posted August 25, 2008 Well were all coming up with different ideas Ive got three for the mix 1 ) You are developing vacuum in your tank as the fuel is used up, maybe a trapped vent line. To check for this run the bike with the fuel cap loose and if its ok check for trapped vent line. 2 ) Faulty vacuum diaphragm in fuel tap (Petcock), Try running in Prime position, if its ok sort out vacuum diaphragm, dont continue to use prime position as a fix though! 3 ) If the above dont fix it, maybe ypou fuel filter is blocked, To check remove the fuel line to the carbs, switch to prime position, there should be a good flow of fuel. (Definitely a no smoking operation) Good Luck Link to comment Share on other sites More sharing options...
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