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Thread Like Summary
Allan G, Dave Lid, Hillbilly bike, slofut
Total Likes: 5
Original Post (Thread Starter)
#837082 01/17/2021 6:10 PM
by Dave Lid
Dave Lid
Would unbalanced down pipes have an effect on the performance etc for my T140v "74" Mk1 carbs i'm running it with balanced at moment but thinking of changing to unbalanced your thoughts would be appreciated

Many thanks Dave
Liked Replies
#837803 Jan 23rd a 09:27 PM
by Hillbilly bike
Hillbilly bike
There is no doubt a properly placed balance pipe can increase mid range power.However 4 inches from the head might not be the proper place.....
1 member likes this
#837795 Jan 23rd a 08:22 PM
by Tridentman
If noise is not a problem then IMHO there is no downside in not using the unbalanced pipes.
Bear in mind that the noise tests back in the day were carried out in a fixed manner---well removed from everyday life.
If your MOT man approves it then great.
We dont have that concern over here in New Jersey--there is no testing of motorcycles.
The only constraint on noise is the opinion of the cops.
But most bikes here are Harleys and a lot of them are unsilenced and many of them owned by cops-- so no problem!
i have not heard of a motorcyclist in NJ getting a ticket for excessive noise.

However judging your carburation from the coloring of the pipes is a bit of a blunderbuss approach---it would for example not discriminate as to what stage of the carburation was causing what coloration.
Best of luck with the bike!
1 member likes this
#838025 Jan 25th a 04:01 PM
by Hillbilly bike
Hillbilly bike
About 5 years ago, a 70 Triumph with a 750 kit...I fabricated the cross over with a slip joint for disassembly. No comparison test but the engine ran very nicely...
Attached Images
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#838039 Jan 25th a 07:27 PM
by Dave Lid
Dave Lid
That' a very nice job Hillbilly that it allows the very hot gases to move away quicker from the head in theory putting the cross over joining pipe a lot lower it also increases the air flow around the fins.Using stainless steel could cool the gases better than stock mild steel chromed headers too.
Very bloody nice indeed sir
1 member likes this
#838107 Jan 26th a 08:33 AM
by Morrisey
Dave Lid at 7:27
Stainless steel has a significantly worse thermal conductivity than steel so the gases would stay hotter. As gases cool, their specific volume drops, so stainless exhaust pipes would have a higher velocity at their end than the equivalent steel ones would. That means a tuned exhaust for stainless would have to be different dimensions to a steel one, but the difference probably isn't that significant up the top end.
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