1977XS360 Posted April 24, 2010 Share Posted April 24, 2010 My '77 xs360 idles normally when i first get it started but has very little torque/power when I ride. After about 20 mins of riding something happens, usually sounds like a large backfire, and the bike starts running very well with a lot more torque. However, when this happens the bike idles at about 3500 rpm. Any ideas what's going on here? I am a complete n00b, this is my first bike. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted April 24, 2010 Moderator Share Posted April 24, 2010 My '77 xs360 idles normally when i first get it started but has very little torque/power when I ride. After about 20 mins of riding something happens, usually sounds like a large backfire, and the bike starts running very well with a lot more torque. However, when this happens the bike idles at about 3500 rpm. Any ideas what's going on here? I am a complete n00b, this is my first bike. could be only firing one one cylinder and the backfire is unburned fuel igniting and then working. I suggest a tune up of ignition/timing drewps Link to comment Share on other sites More sharing options...
1977XS360 Posted April 24, 2010 Author Share Posted April 24, 2010 could be only firing one one cylinder and the backfire is unburned fuel igniting and then working. I suggest a tune up of ignition/timing drewps Thanks for the response. When it first starts and rides poorly, there is still exhaust coming out of both pipes with equal strength. Would that happen if only one cylinder is firing? Link to comment Share on other sites More sharing options...
Moderator drewpy Posted April 24, 2010 Moderator Share Posted April 24, 2010 Thanks for the response. When it first starts and rides poorly, there is still exhaust coming out of both pipes with equal strength. Would that happen if only one cylinder is firing? yes, but to check; feel the exhaust and they should both be the same (hot) temperature Link to comment Share on other sites More sharing options...
troj4nm4n Posted April 25, 2010 Share Posted April 25, 2010 how long of a warm-up do you try ? older 1s need a few minutes Link to comment Share on other sites More sharing options...
1977XS360 Posted April 26, 2010 Author Share Posted April 26, 2010 yes, but to check; feel the exhaust and they should both be the same (hot) temperature You were right, the air is cooler out of one pipe until the engine starts idling at 3500 rpm, ie. the other cylinder starts firing. Any idea what could explain the high rpm while idling? I left the bike running for about 20 minutes thinking it might eventually go down but it didn't Link to comment Share on other sites More sharing options...
Moderator drewpy Posted April 26, 2010 Moderator Share Posted April 26, 2010 sounds like a big air leak! is the rubber manifold capped off/secure? spray th inlets with carb spray and see if the engine fires on that side Link to comment Share on other sites More sharing options...
1977XS360 Posted April 26, 2010 Author Share Posted April 26, 2010 sounds like a big air leak! is the rubber manifold capped off/secure? spray th inlets with carb spray and see if the engine fires on that side Looks like an air leak might be the problem...how do I spray the inlets? Does that involve removing the carburetor? Link to comment Share on other sites More sharing options...
Moderator drewpy Posted April 26, 2010 Moderator Share Posted April 26, 2010 Looks like an air leak might be the problem...how do I spray the inlets? Does that involve removing the carburetor? no you start the engine and spray around the carb inlet and listen for it firing Link to comment Share on other sites More sharing options...
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