The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: bsapete on 08.11. 2018 01:06

Title: First ride - disappointing :(
Post by: bsapete on 08.11. 2018 01:06
Today I took the Spitfire Scrambler for a first ride around the block after a warm up. The bike starts easily and idles nicely when warm. Immediately I noticed it was very sluggish and misfired when accelerating. On a light throttle it runs smoothly but as soon as you open the throttle or put it under load going uphill the misfire and lack of power becomes apparent. I’m not by any means an expert in magneto ignition or Amal carbs or checking timing but now it’s time to learn. Any advice would be much appreciated. (I’ve ordered a parts book and workshop manual). According to the elderly PO’s son (who I contacted straight away as he sold it to me) it was started regularly but run infrequently (without issue he said). He suggested spark plugs as a starting point. I’m also wondering how old the petrol might be. Unfortunately it’s dampened my excitement a bit.

Cheers,
Pete
Title: Re: First ride - disappointing :(
Post by: bl**dydrivers on 08.11. 2018 02:15
Think they had a manual advance retard lever (like the Super Rockets) and not the auto advance for the magneto. When you go full throttle or going uphill you need to advance the ignition.

I’ll wait for others (the experts) to respond!

Title: Re: First ride - disappointing :(
Post by: coater87 on 08.11. 2018 03:30
 Hi pete,

 You should really start out with some known good things.

 Good fuel

 Good plugs

 Clean carburator, write down the jet sizes currently in there

 Clean, well adjusted points

 Timing set correctly

 And for sure clean, new oils.

 When you start out with a bunch of known, good stuff it starts to narrow down the things that could be wrong.

 Lee
Title: Re: First ride - disappointing :(
Post by: bsapete on 08.11. 2018 04:37
Thanks fellas,
I’ve just had another close look and discovered the advance/retard cable was sticking and not releasing, therefore not allowing any adjustment. ie it was pulled on (retarded) all the time. Instantly sounded better when I started it and I’ve had another quick ride around the block and totally different result. It goes like a rocket (or a Spitfire at least). Now I need to make it stop. Brakes are a bit ordinary -
rear is grabbing and front pretty vague.
Title: Re: First ride - disappointing :(
Post by: bsapete on 08.11. 2018 06:02
Bill - agreed, good advice. I will, as a matter of course, do all you suggested but am relieved it turned out to be simply a binding cable.
Regards.
Title: Re: First ride - disappointing :(
Post by: duTch on 08.11. 2018 08:29

 
Quote
........ Now I need to make it stop. Brakes are a bit ordinary - rear is grabbing and front pretty vague.....

 Depending how 'infrequently' it was 'run', maybe there's some light surface rust on the drum...a couple of ways you can address that..... good it's running better now, smile on the dial kinda stuff hey.... *smile*
Title: Re: First ride - disappointing :(
Post by: bsapete on 08.11. 2018 10:06
Too right duTch. I pulled the baffles out of the shotgun pipes this arvo and holy shizzle Batman it pulls like a train and sounds awesome. Put a big smile on my dial. Don’t know that the neighbours are as happy...
Hopefully you’re right re the brakes being rusty or glazed but I guess machining and new shoes shouldn’t be too much trouble. I’m aware that over-tightening of the spokes can distort the hub too.
Title: Re: First ride - disappointing :(
Post by: TimK on 08.11. 2018 21:44
bsapete

I had similar issues with my brakes (but reversed - grabbing front, useless back) and following advice from the wise gurus on the forum I put a 45 degree chamfer on the leading edge of the front brake liners which cured the grabbing straight away.

The back brake was a only a little bit more difficult. With the wheel spindle held in a vice, I stuck some 180 grit emery inside the brake drum and held the brake on whilst I rotated the wheel. The first check showed that only about 5% of the shoe was contacting the drum but a couple of minutes work had this up to 95% + and the braking was transformed.

cheers

Tim
Title: Re: First ride - disappointing :(
Post by: Swarfcut on 09.11. 2018 10:47
 Have a close look at the fixed pivot for the shoes.  Sometimes this is actually sitting in a slot rather than a round hole. Loosen the pivot retaining nut and apply the brake. The pivot may move in the slot to centre the shoes. This allows both shoes to contact the drum at the same time and compensates for a small difference in lining thickness.  Well worth doing and often overlooked.

  Swarfy.
Title: Re: First ride - disappointing :(
Post by: BSARGS650 on 09.11. 2018 12:00
bsapete....Forgive please, I know this doesn't help, but, in your original post, word for word, I had a girlfriend like that......
Title: Re: First ride - disappointing :(
Post by: bsapete on 10.11. 2018 01:07
Tim & Swarfcut, thanks and good tips there. I’m sure that these brakes operating at their optimum will be adequate for my riding style/ability/bravery.

BSARGS650, I have a wife like that! 😂
Title: Re: First ride - disappointing :(
Post by: muskrat on 10.11. 2018 10:38
G'day Pete.
It's a scrambler mate. They don't need brakes. Just throw it back one or two gears, get it sideways and gun it. *eek*
Funny how people ask how fast will it go, never how quick it will stop! I don't call them brakes but speed retarders.
Cheers
Title: Re: First ride - disappointing :(
Post by: bsapete on 10.11. 2018 22:03
Haha, tried that Musky but a bit tricky on the tar with knobbies!😬