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Comet Top Speed

erik

Well Known and Active Website User
VOC Member
I fitted a sprocket with two teeth more on the rearwheel.This makes driving and gear changing into 4th better.Erik
 

Bill Thomas

Well Known and Active Website User
VOC Member
We really need to go the other way, Smaller rear sprocket, 46, I have tried it ,
To get the rev's down !,
But with my size and heavy tank bag, It's a bit too much.
My next Comet, I only have a 45 !! sprocket,
So need more power !, If I ever get the 560 cc done ?.
 

vibrac

Well Known and Active Website User
VOC Member
We really need to go the other way, Smaller rear sprocket, 46, I have tried it ,
To get the rev's down !,
But with my size and heavy tank bag, It's a bit too much.
My next Comet, I only have a 45 !! sprocket,
So need more power !, If I ever get the 560 cc done ?.
Not if I cant even find a 90 bore supplier .....
 

erik

Well Known and Active Website User
VOC Member
I think a normal Comet doesn`t reach the engine revs with the most poweroutput in top gear.Therefor gearing down to get higher revs is the better way.Erik
 

Colin

Well Known and Active Website User
VOC Member
Many years ago when I got a Comet without knowing anything about them, I was very disappointed with it. It would not accelerate and would not pull top gear at all well ,in fact it was faster in third.
I eventually learned it had a (twin) 46 tooth rear sprocket. and swapping it for a 48tooth improved the position. I now run a 49 tooth on my Egli Comet which is what it came with, but I would think it would go even better on 50.
I am with Erik here. As standard it is too high geared for performance. Gear down, definitely not up.
Bill you will never be happy with a standard Comet on 45 rear sprocket
The Arbuthnot Iron ran a 60 tooth rear and would pull out tree stumps!
 

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Bill Thomas

Well Known and Active Website User
VOC Member
My idea is to keep the rev's down at 70 ish, I know how they go with a big sprocket,
As I raced it as a Black Flash, With a 2" pipe, Sounded Super,
But still only about 16 seconds for the 1/4 mile sprint,
Far too much noise for me now, Worried about the conrod !.
Tony's engine was destroyed !!.
 

erik

Well Known and Active Website User
VOC Member
A single cylinder engine lives from high revs.This the reason why the Godet Grey Flash Racers are built to rev high and for a complete race on the IoM.The power delivery is as most People know only every second turn of the crank of a four stroke.If you want to go fast with a single cylinder bike you have to rev it through the gears.changing gears more often as with a multicylinder bike.
 

vibrac

Well Known and Active Website User
VOC Member
My idea is to keep the rev's down at 70 ish, I know how they go with a big sprocket,
As I raced it as a Black Flash, With a 2" pipe, Sounded Super,
But still only about 16 seconds for the 1/4 mile sprint,
Far too much noise for me now, Worried about the conrod !.
Tony's engine was destroyed !!.
Here are the two mutes I have made up for the twin racer 'megaphones' they are in stainless and the aluminium end plug is changeable. At the moment orifices add up to around 3/4 of open pipe capacity, side holes are left unburred on the inside and backward facing faces are grooved at 45deg.it all helps
1604054646005.png
 

Bill Thomas

Well Known and Active Website User
VOC Member
Maybe I used the wrong word,, I meant rev's /Fuss, Poss' Damage !,
Anybody got the photo of Tony's Comet Engine, That went BOOM, I think it was in MPH Many years ago ?.
 

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