The BSA A7-A10 Forum

Technical (topic titles must be descriptive) => A7 & A10 Engine => Topic started by: beezalex on 09.03. 2009 21:46

Title: Thoughts on slipping timing
Post by: beezalex on 09.03. 2009 21:46
So, yesterday I go for a longer ride (60 miles) on the '53 Golden Flash for the first time since back surgery in December.  I'm having a generally great time with it with the bike running well and the weather bright and sunny with temps in the upper 70's (That's about 25 degrees for you eurotrash  *smile*).  Just as I've forgotten all my troubles and get out on a four-lane highway and gleefully decide to chase down a speeding convertible at around 80 mph, I start to lose power...then "pop...pop..."  My heart sinks.  "Ah crap, sounds serious"... I get off the bike and she's hotter than sorority girl at a party with an open bar.  Lick finger, touch cylinder head - SIZZLE!  I let her cool off for a little bit and she starts again, but has NO power.  I fact, it's hard to get away.  So now I'm 10 miles from home and I've gone from speed racer to roadblock in the right lane at 30 mph going up the hills.  She keeps getting slower and slower and pops like crazy anytime I twist the throttle.  I manage to nurse her to withing three miles of home and then there's the big hill...  No dice.  I wait for her to cool off again and then I try to start her, but all she does is either kick back or spit back through the carb, so I'm thinking "aha, must be timing".  So I stick a screwdriver in the spark plug hole, set the piston about 1/4" BTDC and then look at the points, which are probably 45 degrees past opening even at full retard.  I call the girlfriend and go home to get some more tools, like a feeler gauge and big, fat screwdriver to get the timing cover off then come back and crudely set the timing.  Bike starts first kick.

So, here's my question: what should I look for that could have caused the timing to slip?  I already have a nice grade 8 "C" washer to hold the AAU down, but Loctite?  Can the tapers be lapped in?  I'd really like to take some precautions to keep this from happening again.  Any suggestions?
Title: Re: Thoughts on slipping timing
Post by: Triton Thrasher on 09.03. 2009 22:54
Yes, lapping in of tapers is sometimes needed. So's tightening the nut!