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Yamaha XS500 issues

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A couple of weeks ago I acquired a '78 XS500 cafe racer....I was wondering if anyone has any experience with bikes. I can't seem to get it to start at all. The bike was some kid's project and he started on it and then let it sit for a couple of years. I charged the battery(I'm going to go get the battery tested tomorrow). The clutch cable seems loose, like really loose, it doesn't seem loose enough to affect it, or so I think. I can't get even a noise from the electric start. I tried to kick start it. Nothing. Anyone have some ideas?

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drain the gas out of the tank, replace the fuel filter, if the tanks not rusty count your blessings, add fresh gas.

 

replace the spark plugs, probably the battery.

 

 

I'd soak the carb in cleaner, after a few years you're gonna have some nasty varnish buildup, take the carbs apart and make sure the jets are clear.

 

spin the motor over by hand, change the oil and filter, maybe put a squirt of oil in the cylinders and turn it over a couple of times till it all spurts out the spark plug hole.

 

good luck.

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Normally once I've got an engine turning over and it won't start I check:

 

Fuel, make sure the carby has fuel in its float bowl, have a look in the throat and see if its is wet with fuel.

 

Spark, pull a plug lead off, stick a screw driver in it and hold the screw driver near (2mm to 4mm) the engine and try to start, it should spark.

 

Air, make sure the air filter and passage ways are clean. Or take the air filter off while trying to start it.

 

If it still doesn't start after all that is correct I find how to set the motor to TDC, then set the points (if it has points, was working on a cafe racer Kawasaki the other week that had points) so they just open at TDC.

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Start with the basics always which are Spark present on both cylinders,Fuel system which will include fuel tank cap venting fuel tap which if original will have 3 positions On---Res---Pri

Pri means Prime On and Res are operated by vacuum moving a diaphragm in the fuel tap which can stick especially if not used for some time,Prime however will bypass the vacuum feature of the tap and should flow fuel constantly in this setting.

And last but not least compression,as some have alluded to a light grade of oil can help to free up sticky rings if these are an issue and should be tried before dismantling an engine.

Compression can quite often be a cause of hard starting with bikes because the valve clearances are too tight especially on the inlet valves,whereas too tight on the exhaust valves can not only burn the valve and valve seat but affect how well the vacuum style Cv carbs work as well as affect compression,If this is a later XS500 with what is refered to as the One Piece head they are not a bad bike to have a play with only the early TX 500 and early XS models were two piece heads and leaked oil profusely.

Qualified Car and Bike Mechanic and Machinist for 35 years which is why I know this model. Hope this helps you out Cheers Steve

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Update: Worked with the bike a bit... got a few "coughs" out of the bike on thursday trying to kick start it on the only nice day this week. Unfortunately had to go to work...going to put a space heater in the garage if I can finagle one off someone.

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chances are if the bike sat for an extended period without being properly prepared for storage the carb(s) are all gummed up & will need to be torn down, cleaned thoroughly - lots of tiny passages that can get completely blocked, possible kit installed and re-installed on the bike.

it is a time consuming process, but not all that difficult. had to pull the carbs on my KZ550 apart twice and it has 4 carbs! (didnt have the kit the first time)

Once i got the carbs properly cleaned, rebuild kit installed, and everything put back together the bike runs GREAT! when i got it, it would only "run" on a shot of starting fluid...

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I have experience with this motorcycle, Theres alittle window on the top of the cylinder. Wait until the mark is there then kick it over. Should work then.

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