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General => General Douglas Discussion => Topic started by: Spash on 25 Nov 2015 at 08:57

Title: Douglas Dragonfly Piston Clearence
Post by: Spash on 25 Nov 2015 at 08:57

Hello all,

I am in the very final stages of getting my wife's Dragonfly back on the road.  The engine requires a re-bore.  The pistons are currently +0.030" and I have ordered +0.040 from the spares department.  I have been told that the guy who does the re-bore will need to know the clearance between the piston to bore diameter.  Is this correct and if so can anyone advice me what this should be 0.003" or 0.004" etc etc etc?

Cheers for the help

Spash

Title: Re: Douglas Dragonfly Piston Clearence
Post by: eddie on 25 Nov 2015 at 09:04

Spash,
            The barrels should be bored to 'size' - in your case, that is 60.8mm +.040" (2.394" + .040" = 2.434"). The clearance is allowed for on the pistons.
  Hope this helps,
    Regards,
                  Eddie.

Title: Re: Douglas Dragonfly Piston Clearence
Post by: Spash on 25 Nov 2015 at 09:19

Hello Eddie,

Fantastic!  Thanks for the very quick reply.

Regards

Spash