Viberation

Imcgyver · Full Member Joined: Jun 25, 2008 Posts: 15

I have a 1981 XS650, the problem is in any gear between 3K and 4K RPM it acts like the carbs are out of sync if i let off or throttle up lust a little it goes away then I can go up or down in that range with no problems. Do not know if it is a fuel, ignition or?
Thank you for your time and response
Ron

xsjohn · Posted: June 24, 2008, 9:15 pm Post subject: Re: Viberation

Had same problem.........right cylinder gets hotter and makes it run leaner....bad chatter that eventually made me crazy and made it useless for any more than beer runs................xsjohn

jimdi · 650Rider Supporter Joined: Oct 27, 2005 Posts: 512

vibration is usually carb sync. - so if you are getting it - you are probably out of sync. check you mix then set sync.

Imcgyver · Full Member Joined: Jun 25, 2008 Posts: 15

I checked the carbs for sync they are sync, I tried to recreate the problem with the gauges hooked up but could not do it, will try later to ride with the gauges hooked up to see what happens, on the stand carbs are sync.
any other possible ideas?

xsjohn · Posted: June 28, 2008, 8:48 pm Post subject: Re: Viberation

IF the mix screws are not set correctly for "each" cylinder then one will lead in power ..hard to explain but the guages may read right because you can advance the weaker cylinder to make it look balanced...and the screws are not always the same turns out or each side due to the possibility of slight variations in carbs and cylinder pressures.....but the stock needles will also create a gross imbalance at highway speeds when the engine is a full operating temps..........

any might disagree but since the other jets are fixed you can adjust the mix screws more closely this way............using older plugs......wipe them clean with a rag and take a easy 10-15 mile ride.....you will be on the mix screws most of the time then........stop and check the soot on the plug ring and notice how high up the ground strap the black goes should be no higher than half way...and should be just a trace of soot on the ring.......then slightly adjust each cylinder till both sides look the same......then try the balance sync.....at least at that point the mix screws will be closer to what each cylinder needs and if it is too rich both then can be moved about the same to lean or richen.......

xsjohn

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