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Re: The what if A65 67hp challenge. [Re: Mark Parker] #791228 11/25/19 2:00 am
Joined: Apr 2005
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Mark Parker Offline OP
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A rough measure on volumes, the stock Lightning port 65cc, with a flow tested with a bell on the port of 112cfm, the head for the sidecar racer filled to the same length from the valve 73cc, (about +45% flow, from an increased volume of 12.3%) my T/bolt head which was seeping water between head and manifold about 79cc (about + 52% flow + 21.5% volume) (If I use flow readings through the carbs for this one, it's an increase of around 60%, stock being 100cfm OKO 34s being 160cfm, this represents an increase in gas speed of 31.68%). 38mm round port with 44.5mm valve 95cc (about +41% flow + 46% volume) Nothing precise about these measurements. 38mm oval port with 44.5mm valve about 95cc (+79% flow) + 46% volume

Dividing flow by volume gives a figure to represent relative speed. The worst being the big round port at 1.66, next worst stock with 1.72 then the big oval port 2.1, my T/Bolt at 2.15 and the sidecar head at 2.19. The last three are pretty close and much more efficient.

The + 46% volume will work on a 654cc engine, or a 750, however with enlarged headers usable power below 5,000rpm can be compromised by reversion, obviously to a lesser extent on a 750, stock headers lessen this greatly but also limit to a degree top end. + 46% volume on an 883cc engine is uncompromised by reversion with enlarged headers, but the poor flowing round port limits power which falls off around 6500rpm. The same 46% bigger oval port with 79% more flow extends available power to 8,000rpm + adding hp.

The volume percentage increases on the smaller oval port T/bolt heads should cause no problem on smaller engines.


Last edited by Mark Parker; 11/25/19 1:04 pm.

mark
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Re: The what if A65 67hp challenge. [Re: Mark Parker] #791255 11/25/19 12:30 pm
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koncretekid Offline
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Mark,
You have achieved some fantastic flow numbers with your improvements to the A65 heads.

Am I the only one here who would like to see you bolt one of your motors into a stock frame and head to Lake Gairdner in March? You'd have to run in the 750 class unless you de-bore or de-stroke the 654. Surely one of your cronies would give you a hand. I'm quite sure that PrTom would lend you a hand as I would if we could get there. You could take one of your beautiful road bikes, but there is salt.......

Tom


Life's uncertain - go fast now!
Re: The what if A65 67hp challenge. [Re: Mark Parker] #791440 11/27/19 2:56 am
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Mark Parker Offline OP
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Working on almost zero $ allows me to carve heads that I have, and test them on the vacs, but I haven't got the money to do a race bike though I have sons who'd like me to, but they are paying for houses and raising kids. I ride my bike all the time so don't want to use it. If Tom wanted to try a head then we'd get a measure on how it worked on dyno and track, but even then posting one to the US from here isn't cheap.

My next project is a Lightning head hopefully welded in the pushrod tunnel where it has free area to be wider. I'll try 34mm to start, squashed oval entering the head aimed where I want the port to go, to try to get just one curve that tightens onto the valve as smoothly as possible and see what is possible through that little 42mm valve. An 'optimal' port should have a taper at the entry so I might add some bigger pipe to the 34mm manifold and use a 36 or 38mm carb. Theoretically it should be possible to get 100hp or more from a hot rod 750 that flows 175/180cfm. The smaller the port the more flexible the power delivery. It would also probably need 11.5 or 12-1 compression and very good complementing tuned exhaust. I know I can get the flow with bigger valves, which may be necessary, but maybe it can be done without the high speed section of port needing to go over 34mm if the shape is good enough.

[Linked Image from i.postimg.cc]

I need the manifold a little low so the whole port can curve over and down, even if it's straight and turns is fine but if it's high to start and has to go down then up that heavy air has to change direction and it doesn't like it, one turn is enough.

[Linked Image from i.postimg.cc]

If I use countersunk screws in the manifolds it aligns them correctly every time.

Last edited by Mark Parker; 11/28/19 12:06 pm.

mark
Re: The what if A65 67hp challenge. [Re: Hillbilly bike] #791450 11/27/19 6:34 am
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NickL Offline
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Originally Posted by Hillbilly bike
That's what i like about the early 90's 900 2 valve belt cam drive Ducaits...They will rev freely to 9000 but theres that abundent hydraulic torque from 4000 on up so 7500 rpm is good enough...They have about 75 RWHP in stock tune but it puches like 100 HP
If I had 3000 bucks to throw around I would do a 76 degree crank in my T140...


Tony, my older brother converted several t140's to 76 deg norton cranks. It's much easier than doing the beezer a65.
The main cost is camshafts and getting a decent set of norton rods or aftermarket ones.
The flywheel is a turning job.

Re: The what if A65 67hp challenge. [Re: Mark Parker] #791454 11/27/19 8:48 am
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Mark Parker Offline OP
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MAP do rods for Norton cranks in Triumphs. But you can cut the std Triumph crank and bolt it up on a new flywheel.


mark
Re: The what if A65 67hp challenge. [Re: NickL] #791455 11/27/19 11:19 am
Joined: Oct 2012
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Hillbilly bike Offline
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Originally Posted by NickL
Originally Posted by Hillbilly bike
That's what i like about the early 90's 900 2 valve belt cam drive Ducaits...They will rev freely to 9000 but theres that abundent hydraulic torque from 4000 on up so 7500 rpm is good enough...They have about 75 RWHP in stock tune but it puches like 100 HP
If I had 3000 bucks to throw around I would do a 76 degree crank in my T140...


Tony, my older brother converted several t140's to 76 deg norton cranks. It's much easier than doing the beezer a65.
The main cost is camshafts and getting a decent set of norton rods or aftermarket ones.
The flywheel is a turning job.


Nick, MAP Cycle in in the USA does sell forged billet 76 degree cranks, Triumph stroke, for about $2200 and use the Triumph rods.Finding a good Norton crank, rods, and having the machine work done would cost north of 1000 bucks around here..I sold the Sportster so I do have the money.....But I am on the look out for an old 544 Volvo project.... crazy


79 T140D, 96 900M Ducati ....On a bike you can out run the demons..
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