Author Topic: Plunger tranny problems  (Read 527 times)

Offline Drew Back

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Plunger tranny problems
« on: 17.05. 2015 02:00 »
My plunger seems to shift like a dream finds neutral quite easily however it tends to pop out of gear and slip all the time..Basket is tight and nuts are run in evenly friction plates are a little worn..primary chain is to specs all gears look good im just stumped I would not trust a long ride for sure..

Offline duTch

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Re: Plunger tranny problems
« Reply #1 on: 17.05. 2015 02:10 »

 Which gear(s)...? mine does it sometimes in third under load, not sure if shifting up or down or both I have a theory, but later..hows the detent(?) plunger adjustment..??
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Offline Drew Back

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Re: Plunger tranny problems
« Reply #2 on: 17.05. 2015 02:21 »
I think its mainly second to third its like it just dont catch i did not check that thank you for reminding me..

Offline Drew Back

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Re: Plunger tranny problems
« Reply #3 on: 17.05. 2015 16:54 »
Ok  got that adjusted now it slips badly do they sell wet dry plates for plunger clutch??thats why it slips because im running oil in primary since I dont have a cover..I knew it would be something stupid simple..

Offline muskrat

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Re: Plunger tranny problems
« Reply #4 on: 17.05. 2015 21:02 »
G'day Drew.
67-3242, surfex if you can get'em. They should be able to run wet, just DON'T use friction modified car oil. ATF is good or oil for modern bikes with wet clutches.
You could try soaking your plates in petrol then thinners to clean them, but I have found that once plates are contaminated with friction modifiers they are pretty much toast.
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'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Muskys Plunger A7

Offline shuswapkev

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Re: Plunger tranny problems
« Reply #5 on: 31.05. 2015 02:21 »
the jump out of gear problems I have had with other gearboxes were solved by sharpening the detent ..polishing bumps out of the cams and most important...buying new springs...plunger gearboxes have an adjustable detent spring tension thingamy
 I think the gearboxes  work by having the detent and spring push the cam into place and hold it there...of course..hope its not the gear dogs being worn...bsa dogs don't look too easy to grind

my plunger clutch works fine in oil..no cover on...I bought new springs from the local builder supply...set up pressure plate at max pressure using a dial guage.....tightened springs till it would just release enough to select neutral with engine running...
works fine for me...