Motorcycle Repair: low vacuum, vacuum leak, head gasket

Question
1984 goldwing 1200 only has 6 in. of vacuum on right cylinders,left cylinders have about 17 in. runs good except at idle. compression is between 150 and 152 on all four. can find vacuum leak. have cleaned carbs. at a loss ,could it be a head gasket? have changed slow air valve. thanks

Answer
Hi John,

Question:
1984 goldwing 1200 only has 6 in. of vacuum on right cylinders,left cylinders have about 17 in. runs good except at idle. compression is between 150 and 152 on all four. can find vacuum leak. have cleaned carbs. at a loss ,could it be a head gasket? have changed slow air valve. thanks


Q:  "...1984 goldwing 1200 only has 6 in. of vacuum on right cylinders,left cylinders have about 17 in..."

A:  What are you using to measure vacuum? Where are you measuring vacuum (connection)?


Q:  "...runs good except at idle..."

A:  Could be carburetors are out of synchronization and/or fuel in carbs has varnished and is obstructing pilot enrichment circuits.


Q:  "...compression is between 150 and 152 on all four..."

A: Cylinder compression is adequate.


Q:  "...can find vacuum leak..."

A:  Do you mean can't find vacuum leak?


Q:  "...have cleaned carbs..."

A:  Describe how the carbs were cleaned.


Q:  "..at a loss ,could it be a head gasket?

A:  I doubt that head gaskets are defective. Cylinder compression is good and there's no mention of any cooling system problems.


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Respectfully,
Mark Shively