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low compression pistons

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hondauser
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Posts: 62
Joined: Fri Aug 15, 2003 3:33 pm
Location: France , poitiers ,86

low compression pistons

Post by hondauser » Tue Mar 15, 2016 11:30 am

Hello

what would be the influence of low compression pistons on the CB72 engine???
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cb 72
cb 77 ,c77 ,cl77
velocette thruxton

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G-Man
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Post by G-Man » Sat Mar 19, 2016 7:01 am

Hi Hondauser

It depends what you are looking for. The power will be less with lower compression and standard bore but if you go to a larger bore with a flatter piston, you may get a better combustion chamber shape and improve things.

I am going to experiment with a 305 engine with flat-top pistons as a project one day. I think it could be interesting.....

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G
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160
'66 Matchless 350 '67 CL77
'67 S90 '77 CB400F

hondauser
honda305.com Member
Posts: 62
Joined: Fri Aug 15, 2003 3:33 pm
Location: France , poitiers ,86

low price chinese pistons !!!

Post by hondauser » Sat Mar 19, 2016 7:50 am

chinese pistons !!!

the goal is to find in Chinese production pistons that can,be adapted, to our engines, 250 and 305 cc. there are quantities often overbore with an axis of 15 mm and modern rings, but also less compressed ,
and also , LOW PRICE !!!
cb 72
cb 77 ,c77 ,cl77
velocette thruxton

Nick
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Location: Paradise

Post by Nick » Sun Mar 20, 2016 12:23 am

Lower comp pistons will give easier starting, smoother running and a bit less power.

I built my BSA 650 with lower than stock compression and am very happy with the performance. It starts very easily, vibrates less and still has plenty of power. I also fitted taller than stock gearing to drop the rpm on the highway.

Whether it's a good idea to run "cheap Chinese pistons" in your bike is another matter altogether....
Do what you've always done and you'll get what you've always had.

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