bodgley Posted June 12, 2008 Share Posted June 12, 2008 After 17,000 miles of running well, my TRX850 has started to run rich on both cylinders. It is rich enough to foul the plugs and cause misfiring at low revs. I believe the ignition is ok as it appears fine at higer revs I have changed the plugs and air filter, checked that the chokes are not sticking, renewed the choke mechanisms, cleaned the carbs several times, but they look spotless anyway, checked the diaphragms and throttle position sensor and checked for a blocked carb breather. I suspect that the bike has been dynojetted but as it was running fine before this problem this should not be part of the problem. I have run out of ideas, any suggestions would be more than welcome. Thanks, Mark. Link to comment Share on other sites More sharing options...
Southerner oop north Posted June 12, 2008 Share Posted June 12, 2008 Have you checked the air filter isn't blocked? Link to comment Share on other sites More sharing options...
bodgley Posted June 15, 2008 Author Share Posted June 15, 2008 Have you checked the air filter isn't blocked? It has a new air filter and I have tried running it without an air filter. It still gives the same symptoms. Thanks for the suggestion Mark. Link to comment Share on other sites More sharing options...
WiCkY Posted June 25, 2008 Share Posted June 25, 2008 After 17,000 miles of running well, my TRX850 has started to run rich on both cylinders. It is rich enough to foul the plugs and cause misfiring at low revs. I believe the ignition is ok as it appears fine at higer revs I have changed the plugs and air filter, checked that the chokes are not sticking, renewed the choke mechanisms, cleaned the carbs several times, but they look spotless anyway, checked the diaphragms and throttle position sensor and checked for a blocked carb breather. I suspect that the bike has been dynojetted but as it was running fine before this problem this should not be part of the problem. I have run out of ideas, any suggestions would be more than welcome. Thanks, Mark. Hi it more than likely worn 'emulsion tubes' as they fail on TRX's and TDM's alot. Link to comment Share on other sites More sharing options...
mr benn Posted June 26, 2008 Share Posted June 26, 2008 like wicky says, emulsion tubes for sure. not a major job or expense. Link to comment Share on other sites More sharing options...
bodgley Posted July 1, 2008 Author Share Posted July 1, 2008 Success, well sort of. I have changed the emulsion tubes for a pair from an old set of carbs and it solved the problem. However, at higher speeds the bike now cuts just like fuel starvation when reserve is needed. Anyone know if standard or dynojet emulsion tubes are used and what else is changed when a dynojet kit is used? Regards Mark [ quote name='mr benn' date='Jun 26 2008, 10:48 PM' post='57575'] like wicky says, emulsion tubes for sure. not a major job or expense. Link to comment Share on other sites More sharing options...
evilHR Posted July 2, 2008 Share Posted July 2, 2008 ATTENTION!! Dear friend be careful. I had the same problem with mine. It ran rich and you could even smell the gasoline when you drove behind my bike. Then after a while it was really hard to keep it running under 1500 rpm. It seemed like the carburator was not ok... - smels gasoline, and runs rich - does not run at all under 1500rpm, later not under 3000rpm - problems with starting These problemes occures even when, new spark plugs, new air filter, fresh gasoline. Then I took my bike to Yamaha Center in Finland (aúthorized dealer) for valve adjustment and carburator check. The outcome was that my head is broken and the valves cannot be adjusted anymore. And the head cannot be fixed. Now I need to find me a totally new engine... I sincerely hope that this is not the case with your bike. So, first check that the oil is going to the head!!! There is a small screw on the side of the head. Loosen it and start the engine. After a minute it should leak a littlebit oil from that loosen bolt (do not remove the bolt). Check Haynes manual for this! I recommend you to check also the valve adjustement. Best of luck! Kristian Link to comment Share on other sites More sharing options...
bodgley Posted July 2, 2008 Author Share Posted July 2, 2008 I have adjusted the valve clearances and they were well overdue. Two valves had almost no clearance at all, but no damage has been caused. If I had left them any longer the valve seats would have been damaged. t is a very tedious job, almost as bad as the last Ducati I worked on. Thanks for your input Regards Mark. ATTENTION!! Dear friend be careful. I had the same problem with mine. It ran rich and you could even smell the gasoline when you drove behind my bike. Then after a while it was really hard to keep it running under 1500 rpm. It seemed like the carburator was not ok... - smels gasoline, and runs rich - does not run at all under 1500rpm, later not under 3000rpm - problems with starting These problemes occures even when, new spark plugs, new air filter, fresh gasoline. Then I took my bike to Yamaha Center in Finland (aúthorized dealer) for valve adjustment and carburator check. The outcome was that my head is broken and the valves cannot be adjusted anymore. And the head cannot be fixed. Now I need to find me a totally new engine... I sincerely hope that this is not the case with your bike. So, first check that the oil is going to the head!!! There is a small screw on the side of the head. Loosen it and start the engine. After a minute it should leak a littlebit oil from that loosen bolt (do not remove the bolt). Check Haynes manual for this! I recommend you to check also the valve adjustement. Best of luck! Kristian Link to comment Share on other sites More sharing options...
mr benn Posted July 2, 2008 Share Posted July 2, 2008 almost no clearance is not good but when you get zero clearance you will have problems starting. DJ kit has no emulsion tubes in it. It contains needles and main jets. you can buy emulsion tubes from Kedo in Germany for about £10 each. Sounds like you may have created a problem while changing the emulsion tubes if it's not fuelling correctly at higher revs. Rich running can cause bore washing, where the fuel washes the oil away and leads to lubrication failure. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 2, 2008 Moderator Share Posted July 2, 2008 Have you changed or cleaned the fuel filter? Link to comment Share on other sites More sharing options...
mr benn Posted July 2, 2008 Share Posted July 2, 2008 is it possible you've disturbed the float height when changing the emulsion tubes? this could cause fuelling issues. is the TPS properly connected? could it be old fuel? This website is pretty good for TRX info: http://trx850.motomaniac.net/forum/index.php Link to comment Share on other sites More sharing options...
Recommended Posts