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Old problem, new owner....


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Purchased a 84 Venture that sat for two summers with sta-bil in the tank. The bike ran really rough, smoked, and wouldn't stay running unless the choke was on. I drained the carbs, ran some new gas through, put in new plugs, changed the and filter, and sync'd the carbs. The bike runs great... but its still smoking a little. It looks more white but it looks to have a blue tint also. I've only been up the street(1st, 2nd gear) and back so I havent ridden the bike anywhere. Where do I go from here? Thanks for any help.

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Get it good and hot, with fresh gas ... White smoke is usually water vapor but can be water and antifreeze mix.

 

Whitish blue smoke is oil burning, and you can smell it ... Water/Antifreeze has a sweetish smell, quite different.

 

It may clear up completely when you have run it nice and hot ... If it doesn't then a compression and/or leakdown test will pinpoint the problem. Leakdown is better, and do it at TDC, BDC and halfway to check bore wear.

 

If it's antifreeze then you are getting coolant in the cylinder, that would normally mean headgasket.

 

If it's oil then it's valves, valve guides or piston rings, and the leakdown will identify which.

 

A small amount of oil burning is not a cause for immediate alarm, but burning anti-freeze is, and would need fixing pretty quickly.

 

Leakdown, if you have never done one, is brilliant.

 

You basically set each cylinder in turn at TDC, compression, and pressurise it to about 100psi. The differential on the gauges should be less than 10%, often much less.

 

If air gets by the rings you can hear it through the oil filler. If it gets by the valves you can hear it in the exhaust. If it's valve guides you can hear it under the cam covers and if it's headgasket there will be bubbles in the coolant.

 

The reason for testing at three positions is that bore wear could be minimised at TDC and BDC, but apparent mid-cylinder. At mid cylinder use much lower pressure or you will spin the engine and that wrench you have on the crank nut will smack you somewhere painful. Remove it.

 

A leakdown tester can be made for about $30, you need a compressor.

 

Hope this helps.

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