Author Topic: timing and idle  (Read 845 times)

Offline mike667

  • A's Best Friend
  • ***
  • Join Date: Nov 2008
  • Posts: 213
  • Karma: 0
timing and idle
« on: 01.11. 2011 01:20 »
hey gang -  ok a while ago went on about my friends BSA A10 bobber thing and carb problems that we eventually got figured out w/ different pilot jet. The bike always seemed a bit to advanced as it would kickback most times but he just kind of dealt with it. This weekend after yet again more kicking back we decided to "retime" it and set it however many parts of an inch it says in the manual (forgot now - but same amount that i used to time my A10). Bike starts first kick - no kickback - nice! runs/accelerates up and down the street quite nice but damn if the engine doesn't race with a blip of the throttle and refuses to come back down to reason idle unless one blocks the carb orifice -  and then with another blip it will be off again. I don't think the cables are sticking - check em all, etc - at first i thought too lean carbs  - but needle up or down makes no difference (on the racing idle), neither does changing does pilot jets (except making it idle shitty) - nothing  - WTF. sprayed WD40 all over the manifolds thinking leak w/ nothing. Is excessive retarding a cause - and would this still allow the bike to run/accelerate OK and start first kick?? weird thing is the bike ran good besides the seemingly constant kickback before retiming.... 
thx!

Offline muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 8237
  • Karma: 106
  • Lake Conjola NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: timing and idle
« Reply #1 on: 01.11. 2011 09:43 »
 G'day Mike,
                sounds like an air leak or a worn slide or lean mixture. Does it have a choke? Try giving it a bit of choke, if it gets better we're on the right track.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline mike667

  • A's Best Friend
  • ***
  • Join Date: Nov 2008
  • Posts: 213
  • Karma: 0
Re: timing and idle
« Reply #2 on: 01.11. 2011 13:43 »
Hi Jim
 that's what i initially thought  too - if you give it choke it dies. I thought about it most of the night (pathetic i'll agree) - i'm going to help/suggest to retighten all the manifold bolts and carb  mounting stuff.  amazing how his bike is a temperamental bastard and my A10 chugs along quite happy, pissis off pal to no end-haha  - its reincarnation as a bobby must of ***** off what ever god there is that watches over A10's

thx!
m

Offline muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 8237
  • Karma: 106
  • Lake Conjola NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: timing and idle
« Reply #3 on: 01.11. 2011 19:15 »
Yep that god ain't happy with me either. Bent 2 valves on the A65 and the cafe is blowing blue out the left.
Next step is advance the timing a tad. Just open the points a thou" at a time, 1 thou" = 2 degrees I think.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Online bsa-bill

  • Wise & Enlightened
  • *
  • Join Date: Mar 2006
  • Posts: 5440
  • Karma: 62
Re: timing and idle
« Reply #4 on: 01.11. 2011 19:21 »
Quote
Yep that god ain't happy with me either

Sorry guys, looks like he's moved on since he pestered me with the RGF.

Strangely I had that fast idle (running on ?) thing going on, but lots of other stuff as well so it kind of got ignored and went away, wondered at times if it was pre-ignition related
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline mike667

  • A's Best Friend
  • ***
  • Join Date: Nov 2008
  • Posts: 213
  • Karma: 0
Re: timing and idle
« Reply #5 on: 02.11. 2011 01:37 »
well the culprit appears to have been the o-ring on the carb was squished out of its groove and letting air in. weird thing is my buddy had some extra supposedly new o-rings, all of which seemed a bit bigger than the ones i had. WE replaced it with what seemed like the correct sized one and the bike idled well - didn't get a chance to really adjust it etc as we were working in the dark - but he drove it around the block (aka to the local for a pint)and it seemed to run well

thx all - maybe the BSA a10 god wasn't ***** afterall, and it was the amal god - i find he is usually a much more vengeful sort who strikes at us mere mortals with regularity!