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By Wheaters
#94291
Drag increases as the square of an increase in airspeed, which is why aerodynamics are important for more powerful machines.

I think I first read in Motorcycle Mechanics that the drag caused by a motorcycle and rider was significantly higher than a flat plate of the same cross sectional area.

I broke the handlebar screen of my 350 Electra so I dispensed with it. I rode without it for a year and did a few mods to the bike to increase the power, including a bigger carb and free flowing exhaust and it “nips along” a bit better than standard, but wasn’t able to compare like with like, as in with and without a screen. However, a couple of months ago I found an identical screen at a bargain price so bearing in mind that winter was coming I bought it. Having fitted it I immediately noticed the bike is a few mph faster than without it.
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By Nitrowing
#94292
Wheaters wrote:
Wed Dec 02, 2020 1:44 pm
Drag increases as the square of an increase in airspeed, which is why aerodynamics are important for more powerful machines.
This is actually my argument for the necessity of aerodynamics on low powered machines - making the most of what you've got!
Car eco-modders have worked out that removing wing mirrors was worth 5mpg, which has been borne out by electric car manufacturers fitting cameras instead.
A simple screen is what? £50 + 30 minutes fitting? Compared to engine modifications...
By Marko
#94395
Hi,

I've only just seen this post & can tell you that a Meteor Minor Spots piston works wonders. FWIW Paul "the Bullet Whisperer" recently did the bottom end of my engine ,a Model G, making it Asbo 39, whilst I did the top end : ported head etc Amal concentric carburetter. It certainly goes like the clappers! I still have to run it in but i'm sure you'll get an extra 4mph!
A small (apologies for the filming!) clip of the engine running ;)

https://www.youtube.com/watch?v=xNc--tKldCQ
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By stinkwheel
#94397
If you can't find one on here, Burtons have some NOS heppolite ones in stock.

I fitted one to my 350. Can't say as I noticed a massive difference in pulling power, I'm just hoping the crown doesn't collapse on this one like the Indian ones do for fun (shouldn't because it's not already half sawn-through behind the oil control ring).

That said, I also fitted trials gearing at the same time so there may have been an increase in top speed.

You'll need to heat the piston to get the gudgeon pin through, which tells you a lot about their relative tolerances compared to the indian parts. I've always fitted indian bullet pistons by pushing the pin through with my thumb.
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By windmill john
#96139
Well, tested today. Not only the meteor piston, new rings, honed bore, but a decent decoke.

The ride..... trying to ignore the placebo effect, the most noticeable change was compression. Definitely more effort needed kicking him into life.

Not sure about change to top speed, more testing needed. But I did feel there was ‘pull’ in my arms when accelerating 2nd to 3rd and 3rd to 4th, rather than the normal slight increase in speed over time.

Perfectionists, look away now. The right hand cylinder head fixing bolt in the barrel has turned since I got him. The PO had helicoiled but it had pulled out.
A few months back I removed that helicoil and I used a longer one. I’m sure you know that the right hand bolt just goes through the fins and the hole protudes at the bottom.
My helicoil didn’t take, so had a hole approx 10mm. With the exception of taking the barrel to an engineers, having the hole filled and re-tapped, I fitted a longer 8mm bolt though and fitted a nut at the bottom. I only had Allen head bolts of the required length, so the sad part of me drilled out a hex nut to fit over the top. Just for effect. Yes I. Know, Barney Bodgit, but hey....
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