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Vintage Speed 43mm on a 1915?
paslow22 - September 23rd, 2021 at 07:21 PM

Hello,
Thinking of a 38mm Super Sport (quiet ) or a 42mm full system for my 1915, but think the 42mm may be may be to big and noisy, currently have a Fatboy it's noisy.
Anyone running 38 or 42 on theirs and what are the downfalls if any?
Any information would be a great help.
Thanks
Darryl


vw54 - September 24th, 2021 at 08:33 AM

I ran 38 mm pipes more than big enough for 1916 engine

Also made the front pipes fit inside heater boxes to keep warm in winter


vw54 - September 24th, 2021 at 07:13 PM

pm sent


Bizarre - September 25th, 2021 at 07:05 PM

Are you running heater boxes?

No point running a 42mm system if you are.

What sort of HP are you getting.

I ran 38mm (stock) on my 1916 with heater boxes and that made ~75 HP at the wheels.

Unless you are going for 100+ ponies I would stay with the38 mm system


paslow22 - September 26th, 2021 at 08:25 PM

Quote:
Originally posted by Bizarre
Are you running heater boxes?

No point running a 42mm system if you are.

What sort of HP are you getting.

I ran 38mm (stock) on my 1916 with heater boxes and that made ~75 HP at the wheels.

Unless you are going for 100+ ponies I would stay with the38 mm system


HI,
Standard crank, twin 40 carbs, stock heads, 12 lb flywheel, 1.25/1 rockers, magna spark dist, and it goes quiet well.
I noticed more torque after fitting the rockers.

No Heater boxes, unknown horsepower, So I ordered a 38mm, should be a lot quieter, I'm half deaf and it's still to noisy.

Thanks for the input.