The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: gary on 18.05. 2021 21:53
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hi. i finally got the 50 golden flash running for a little seemed like it was kicking a little hard but got it to fire. not sure what happened i went the next day to try and start and i could barely kick over i even stood on kicker and would not move.we ended up pulling the whole clutch out and everything looked ok there i took outer gear box cover off to check the teeth on kicker ratchet and on end of the main shaft looked ok. take plugs out and kicks over nice and smooth. tried doing compression test and came up with about 100 per cylinder. it is a standard bore. it does not have the original hepolite pistons i do not remember the brand but was told they are a racing piston but they are not a domed piston they are flat. any thoughts greatly appreciated. thanks
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hi. i finally got the 50 golden flash running for a little seemed like it was kicking a little hard but got it to fire. not sure what happened i went the next day to try and start and i could barely kick over i even stood on kicker and would not move.we ended up pulling the whole clutch out and everything looked ok there i took outer gear box cover off to check the teeth on kicker ratchet and on end of the main shaft looked ok. take plugs out and kicks over nice and smooth. tried doing compression test and came up with about 100 per cylinder. it is a standard bore. it does not have the original hepolite pistons i do not remember the brand but was told they are a racing piston but they are not a domed piston they are flat. any thoughts greatly appreciated. thanks
Unlikely i know but it has got the right spark plugs? Not long threaded ones used in alloy heads?
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How are things going when trying a rolling start ? Go very gently in the beginning !! in case something should really be wrong with engine internals. If a rolling start goes ok, then (imo) the starting point is to fully check the kick mechanism.
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the plugs are ngk b7hs. no i have not tried a rolling start. thanks
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Problem could be with the kick starter quadrant jamming on the ratchet.
Happens occasionally if there is wear in any or all of the following:
- quadrant teeth
- ratchet pinion (teeth)
- kickstarter shaft bush (in outer cover)
- brass bush which ratchet pinion turns on.
If it occurs again, it is easy to prove; put bike in gear and rock forward; this will re-position the quadrant and it will kick over.
Richard
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BTW, 100psi compression is low.
If the pistons are 7.25: 1, it should be in the range 140 - 150 psi.
Did you hold the throttle open when you did the compression test?
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G'day Gary.
+1 on orabanda's suggestion. Both mine do it occasionally. The main culprit for me is the pinion bush.
Cheers