Guoseph Posted December 30, 2017 Share Posted December 30, 2017 I know this has been discussed many times. I have a 98 bone stock 5th gen that smells like gas when I stop at a stop light. Fuel economy is mid 35’s city / low 40’s Highway. i thought it was the thermostat, but just ran 40 miles of highway at 80mph and ambient 46F. Temp gauge was 168 on the nose. That seems to be in the “normal” range everyone talks about, maybe. Air filter is clean. What else could it be? thanks! alex Link to comment Share on other sites More sharing options...
Member Contributer Terry Posted December 30, 2017 Member Contributer Share Posted December 30, 2017 Maybe a fuel pressure regulator failure; there is a vacuum line and diaphragm that keeps the fuel rail pressure constant relative to the manifold air pressure. If the vacuum line leaks, the fuel pressure can be higher and send more fuel. Or the diaphragm can rupture and allow fuel to be sucked straight into the inlet. Check the vacuum line for any liquid fuel. I'd also check the starter valves are correctly synchronised. Link to comment Share on other sites More sharing options...
bigbadbass Posted December 31, 2017 Share Posted December 31, 2017 My '98 exhibited similar stinky fuel symptoms accompanied by slow warmup ....at 19 years old and 40,000 miles its getting up there.....I predetermined I would automatically replace (factory original?) thermostat and in doing so, while disassembled and accessible.. ...additionally replace the (no doubt original) fuel pressure regulator and injector seals. Upon disassembly, I found all 4 upper clamps on the throttle body rubber manifolds loose...and 1 manifold was visibly "misting" as a result. There was the source of my fuel stink. Went ahead pulling the throttle body...and all parts replacement mentioned. A bath...aggressively cleaned inside the "V" and the radiator cooling fins...both sides while there too. New coolant, of course. Double checked all vacuum, vent hoses, sensor and electrical connectors related to the throttle body re installation. Admittedly, a bitchy phase. Tightened and double checked ALL the throttle body clamps to my satisfaction.... finished with a starter valve synch. Upon completion..no more stink, warms up quicker, very stable, smooth idle, quick smooth revving..and cooler running temps and possibly better mileage to boot . As I've got multiple bikes, I haven't accurately nailed down mileage as yet. Clearly worth the effort and expense. Would encourage you to tear into yours! I'd source whatever parts you choose to replace in advance... Link to comment Share on other sites More sharing options...
JoelF Posted January 3, 2018 Share Posted January 3, 2018 If you are smelling raw gas you have a fuel leak out the bike, and it's between your legs. That might not end well. Injectors can drip or hose through to the intake and fuel pressure regulator diaphragms can leak as suggested but that but that fuel goes into the engine and causes the bike to run pig rich: black plugs, black smoke, etc. Different problem. Also bad, but less burny. If you are smelling raw gas the leak needs to be repaired before it burns up. The other condition should be fixed also as it is bad for the oil, cylinder walls, plugs, carbons up the valves, etc. 168F sounds cold, your thermostat is probably leaking. If the oil does not get up above the boiling point of water it will get sludged up. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.