Author Topic: Ace assisting Bullet Whisperer racing effort  (Read 124646 times)

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AgentX

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Reply #75 on: January 17, 2014, 12:36:32 am
That race bike pictured is f'n awesome with the featherbed frame.  Would love to know more about that oiling setup if it's not top secret.

But I do have to ask--did the exhaust bracket break, or is there just some optical trickery going on?  Or is the silencer really hanging that low??


High On Octane

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Reply #76 on: January 17, 2014, 02:08:18 am
That really is a great looking bike!   :D

Tom, I know another bike that will look good with an ACE sticker when it's done.   ;)

Scottie
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Bullet Whisperer

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Reply #77 on: January 17, 2014, 09:28:08 am


But I do have to ask--did the exhaust bracket break, or is there just some optical trickery going on?  Or is the silencer really hanging that low??
That exhaust is all there is of it and it tucked right under the engine, just off the centre line, so it never touched down, although it got a dent in it once when a conrod broke while racing and leading a championship at Lydden a few years back  :o
 Here are a few incarnations of this bike, from when we first built it, the oil filter part of the timing cover was cut off so we could sit the engine lower in the frame and a remote spin on filter can be seen above the gearbox, with lines to and from the timing cover. My Brother, Ian, cut 4" out of the Manx frame cradle, to shorten it because there were big gaps everywhere when we first placed the engine in the frame. It is one of the best handling Featherbed rolling chassis around - an advantage no Norton can enjoy, due to the space those engines require  ;) Our original high level exhaust is similar to the 'Woodsman' style one to emerge from India a few years later - but we did it first !
 I will try to find and add a picture of the most recent exhaust system used on this machine as soon as I can, to bring things right up to date.
 B.W.


AVL Power!

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Reply #78 on: January 17, 2014, 11:59:36 am
BW! Please get few Gopro cams for this bike! Would love to see some onboard video of this beast nailing other vintage 500cc+ bikes! :D


High On Octane

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Reply #79 on: January 17, 2014, 12:20:53 pm
BW! Please get few Gopro cams for this bike! Would love to see some onboard video of this beast nailing other vintage 500cc+ bikes! :D

+1000  ;D
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ace.cafe

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Reply #80 on: January 17, 2014, 03:11:23 pm
Okay, so we are really pulling it all together now.
We have the technical theory working with the real world data, and we now have all the tools at our disposal to make these engines do what we want them to to.

I feel pretty confident in saying now that we can make a Bullet at virtually any range of power and rpm that is consistent with its displacement and stroke. All the way from lowly stock Bullet to something like this racer of BW's. And anything in between.

We know how to set the valve and port and lift and carb requirements to reach the flow delivery and target rpm for virtually any build. We have the data on enough cams and head flow and power output, and we have the tools and valve train parts to accurately set up any targeted outcome.

We have reached "nirvana". We are "at one" with the Bullet.
We are within it, and it is within us.
We can snatch the pebble from the master's hand, and walk across the rice paper mat without leaving a trace, Grasshopper!
 8) 8) 8)
 ;D
« Last Edit: January 17, 2014, 03:16:16 pm by ace.cafe »
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Reply #81 on: January 19, 2014, 09:48:47 pm
A little later than anticipated - but here is the most recent incarnation of our 500 racing Royal Enfield, with the latest exhaust system fitted. This gave a considerable boost of some 3 bhp to the midrange power, while nothing noticeable went from the max power at the top end of the rev range. A shorter inlet manifold was fitted and used a little later, though, and it gave a tiny increase in max power.
 B.W.
« Last Edit: January 19, 2014, 09:51:01 pm by Bullet Whisperer »


ace.cafe

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Reply #82 on: January 22, 2014, 11:21:26 pm
Okay, I got the final paperwork on the race head today.
With the carb on, and the whole inlet tract flowed in toto, the max flow recorded was 260 cfm. It took a little more loss with the carb and inlet tract than I expected, but that's what it was.

To put this in perspective, on the way the head came in from last year's season without our rockers or port work, the max flow at peak valve lift with that set-up was about 210 cfm with the carb and inlet tract on.
So, even in the worst case scenario, or you could say the most accurate scenario that will have everything on it the way it will be on the track, we picked up 50 cfm at max flow and max lift with these mods. That is calculated to be worth about 12.5 hp of flow increase.
They had 43.5 rwhp on the dyno last year, so add 12.5 hp to that, and we estimate 56 rwhp with this set-up, after it is sorted and optimized on the bike.
Attached is a pic of the inlet tract with the beryllium copper valve seats in place.
Also attached is a pic of the combustion chamber view.

We also saved a lot of weight in the valve train with the titanium valves and lightweight spring stack parts.
Saved 18.1 grams on the inlet valve, and we used a bigger valve there.
Saved 23.3 grams on the exhaust valve.
Saved 7.8 grams on the valve spring.
Saved 3.2 grams on each spring retainer.
Total savings in valves and spring stack parts was 63.4 grams of moving mass in the valve train.
To put this into perspective, our new exhaust valve weighs 61.1 grams, so we saved as much weight in all these parts as our whole exhaust valve weighs!

We also adjusted the shape of the combustion chamber to modify the squish area and reduce chamber volume, and at the same time the chamber walls were sculpted to be advantageous to flow after the valve.
The surfaces of the port are done with a rough finish to assist re-atomization of any fuel drop-out that may occur on the way into the engine. Valve seat angles are also cut to have these same effects.

Estimates are estimates, and we can't really say exactly what hp this engine is going to wind up with.
However, we can very confidently say that when you add almost .200" to the valve lift, and flow this much more air into the engine, and add about 1000 rpm to the rpm range, that it is going to have a very big positive effect on power. It's going to be much more powerful than what it was. We will see exactly how much it gets when it's sorted and on the dyno, and how it does on the track.
« Last Edit: January 23, 2014, 12:18:58 am by ace.cafe »
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High On Octane

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Reply #83 on: January 23, 2014, 12:00:10 am
Beautiful Work!   8)
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da punds

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Reply #84 on: January 23, 2014, 11:38:45 am
Hi I was looking at the combustion chamber shape and see that it is no longer round. I was curious, as to whether pockets had been cut around the valves or the other area had been filled in ?. I have seen pictures of squish zones, (and I am assuming this is one), how efficient would one this small be ?.

Great commentary and insight as per usual Tom, and I wish BW lots of success.
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cycleicons

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Reply #85 on: January 23, 2014, 12:58:52 pm
Great stuff! Best of luck to all involved! Knockem' dead Tom and BW!

Cheers,
Leon


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Reply #86 on: January 23, 2014, 01:34:40 pm
Hi I was looking at the combustion chamber shape and see that it is no longer round. I was curious, as to whether pockets had been cut around the valves or the other area had been filled in ?. I have seen pictures of squish zones, (and I am assuming this is one), how efficient would one this small be ?.

Great commentary and insight as per usual Tom, and I wish BW lots of success.
First of all, let me just say that this is all looking very promising, Ace and thanks for all your input with this project!
 There will also be other mods to compliment the cylinder head modifications and hopefully contribute to an increase in power, such as a much lighter custom made piston, for one.
 Now to the squish areas - I have added these to several Bullet cylinder heads, both 350 and 500 size, with success. I get them welded in locally and in the past, have matched them and the crown profile of the piston to be used with each one to become a matched pair of features working in harmony. This time around, we have no piston as of yet, so the head and squish area have been 'optimised' as best as possible by Ace and his team and we will try and match a custom made piston to what there is above it.
 Here is an idea of what I have done in the past [and still do, for lesser machines] ;)
 B.W.
« Last Edit: January 23, 2014, 01:37:24 pm by Bullet Whisperer »


ace.cafe

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Reply #87 on: January 23, 2014, 01:50:40 pm
Hi I was looking at the combustion chamber shape and see that it is no longer round. I was curious, as to whether pockets had been cut around the valves or the other area had been filled in ?. I have seen pictures of squish zones, (and I am assuming this is one), how efficient would one this small
Hi Kevin,
It's a little bit of both. The chamber was welded up with aluminum and then re-shaped. B.W. had already done much of this process, and we just filled a little more and did some shaping. The chamber now has a lot of 3 - dimensional contouring.
The squish is small, but it does reduce the chamber volume, to allow a smaller and lighter piston dome for high rpm use.
So, it gets some of everything we wanted, but of course it still is much too deep from the valve angles in these heads. This is just part of the vintage design, and we can only do some things without designing a whole new cylinder head. There are limits to what is financially feasible and also still fit the vintage rules. This result should be enough to reach the goals they set. If it does what we estimate, it should be enough to win the championship.
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cyrusb

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Reply #88 on: January 23, 2014, 09:27:10 pm
Where is that racing happening? I see that there is no safety wire, anywhere. Have the rules changed?
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ace.cafe

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Reply #89 on: January 23, 2014, 09:45:55 pm
It's in the U.K.
I don't know the rules for the vintage classes there. B.W. would know.
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