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D1 Engine losing power in top gear
La Poste
Maintenon, France
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July 22, 2020
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July 22, 2020 - 8:44 pm
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apologies if this has been asked before and have searched the site to see if the question has been asked before, however not beimg technical has made the search difficult.  Recently when riding the bike, 125cc bantham 1962, when I go into the top gear, 3rd, it starts to lose power and eventually conks out. The other day I had to ride it using only 1st and 2nd gear.  Has anyone encountered this and or could guide me where I could seek assistance.

thanks in advance for your help, much appreciated.


Lancashire (A chip shop somewhere near Preston)
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July 27, 2020 - 9:10 am
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The D1 Bantam does not have a lot of power but a healthy bike ought to be able to hold its own in 3rd gear without too much trouble.  In order to advise we (this forum of Bantamites) would need a bit more information about this loss of power etc 

Has it always been like this or is it something new ??

Does it happen on the flat, or uphill etc ??

Has any work been done on the bike recently ?

What sort of condition is the fuel and exhaust systems in ??

More information about the bike - perhaps a photograph  

Sorry to ask a load of questions but - happy to help but need some info to go forward.  


La Poste
Maintenon, France
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July 27, 2020 - 8:35 pm
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Hi Sponge

thanks for the response, here's the answers:

it is a recent thing

it happens on the flat, I daren't go up hills

the only work was to clean the spark plug and fill it with fuel, as basic as that, but 1st and 2nd gears run fine

fuel was fresh and to my very basic knowledge the exhaust is fine

Not sure how to add photos  this site as nothing happens when I press photo in the tool bar. 


Let me know if I need to check something, like the exhaust, but please be descriptive.




Up north
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July 27, 2020 - 10:06 pm
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The fact that it pulls ok in 1st and second would suggest to me maybe something is binding when you put it in third.After all if the engine runs ok it should run ok regardless of which gear it's in?the engine doesnt know which gear it's in.

Just a thought.

If you put it in 3rd gear and pulled the clutch in would it start if you kicked it?(with the kickstarter obviously)

Hope that makes some sense.

What's 7/16 in mm again?

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