Unofficial Royal Enfield Community Forum
Royal Enfield Motorcycles => Bullet Iron Barrel => Topic started by: kylohere on May 09, 2014, 10:05:03 am
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Okay, so this might seem silly to even think of to the more initiated Bullet folk here, but I was wondering if it is possible to improve lift with a stock cam.
If we were to somehow add in a multiplying effect into the rockers, can we not achieve a larger throw?
What do you guys think? Ridiculous? Done before?
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And if indeed it is possible and has been done before, how has this been achieved?
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We've been working on a couple designs for about a year now with great results. Making adequate lift was the easy first step, preventing premature block wear was the second hurdle. Cost effective manufacturing without sacrificing our design is whats next. Here's a sneak peak at our latest prototype:
https://www.youtube.com/watch?v=pSYbmCvktaI
They should be ready in the next few months.
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I remember these!! I think :D
-Sanket
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You would be talking about high ratio rocker arms. The pushrod socket on the rocker would be closer to its fulcrum. Pretty common on v8 engines. I'd like to see some roller rockers as well.
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You would be talking about high ratio rocker arms. The pushrod socket on the rocker would be closer to its fulcrum. Pretty common on v8 engines. I'd like to see some roller rockers as well.
Okay, here you go.
First, the Ace GP Billet Roller Rocker kit with high-port head mods.
http://www.enfieldmotorcycles.com/forum/index.php/topic,17488.0.html (http://www.enfieldmotorcycles.com/forum/index.php/topic,17488.0.html)
Next, the Ace GP Roller Rocker conversion for the Bullet Big Head.
http://www.enfieldmotorcycles.com/forum/index.php/topic,16411. (http://www.enfieldmotorcycles.com/forum/index.php/topic,16411.)
Both currently available, and a street version of the Big Head GP is currently on the road, and another one currently being fitted to one of the most competitive racing Bullets on the UK Vintage Motorcycle Racing circuit.
For the Ace Billet GP package on the regular Bullet head, we have 5 in the shop here being done, and should be completed soon.
All these require head modifications for installation. they cannot "drop in" to a normal head. You can't make a Bullet valve lift this high without special valves and springs and mods. We are the only ones in the world who do it.
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Dost you were the first to see the drawings that become the prototypes in that video.
I remember these!! I think :D
-Sanket
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Good days!
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Good days!
Sanket,
The roller rockers we use on the Big Head will fit the AVL. But it requires head porting mods and new valves/springs to make it all work, so we'd need to have your head here.
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Tom - I am stocking up parts and next plan is Head and other stuff. My friends keep going to US (Pao Alto) for Business Tours so I can send it to you guys via them. I have everything in Plan but few screw ups here and there so in some time I will know how much money I will be able to invest on Motorcycling stuff. Life is a mess! and I seriously want a Hybrid of Asbo and Fireball, hope things work out good for me.
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Tom - I am stocking up parts and next plan is Head and other stuff. My friends keep going to US (Pao Alto) for Business Tours so I can send it to you guys via them. I have everything in Plan but few screw ups here and there so in some time I will know how much money I will be able to invest on Motorcycling stuff. Life is a mess! and I seriously want a Hybrid of Asbo and Fireball, hope things work out good for me.
Okay Sanket.
I hope things go well.
Probably next week I am going to post some photos of Tooseevee's AVL head work on that other thread, so you can see some of the stuff we are doing to AVL.
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Great! :D
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We've been working on a couple designs for about a year now with great results. Making adequate lift was the easy first step, preventing premature block wear was the second hurdle. Cost effective manufacturing without sacrificing our design is whats next. Here's a sneak peak at our latest prototype:
https://www.youtube.com/watch?v=pSYbmCvktaI
They should be ready in the next few months.
Your bike sounds soooo good.
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We've been working on a couple designs for about a year now with great results. Making adequate lift was the easy first step, preventing premature block wear was the second hurdle. Cost effective manufacturing without sacrificing our design is whats next. Here's a sneak peak at our latest prototype:
https://www.youtube.com/watch?v=pSYbmCvktaI
They should be ready in the next few months.
Thanks for the teaser! I can't wait!
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Thanks for the teaser! I can't wait!
Oh, you'll wait. :)
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Your bike sounds soooo good.
Thanks! I'll tell her you noticed...
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High lift cams should be on the market by June (UCE only). There are also springs, titanium retainers, non pump up lifters and several pistons.
There are several iterations. Some from Europe and some we have developed for a Factory sponsored Bonneville project. (master minded by Matt Capri if you are interested and want to google him). We are also developing some very sophisticated heads with one piece SS valves and beryllium seats. All are being made by some of the best speed merchants in Southern CA.
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Oh, you'll wait. :)
you know it!
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High lift cams should be on the market by June (UCE only). There are also springs, titanium retainers, non pump up lifters and several pistons.
There are several iterations. Some from Europe and some we have developed for a Factory sponsored Bonneville project. (master minded by Matt Capri if you are interested and want to google him). We are also developing some very sophisticated heads with one piece SS valves and beryllium seats. All are being made by some of the best speed merchants in Southern CA.
Well Kevin, that's interesting news!
We shall see what they present, and perhaps we can find ways to apply those parts to good use.
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We will see. As you know it always takes more time than you think. We have the cams, piston and heads ready for testing but I am sure we are going to have to tweak the cams. Then we will see what the cost ends up being. At any rate I expect that there will be lots of speed parts from many different vendors within the next year.
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.....As you know it always takes more time than you think....
Aint that the truth ...
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We've been working on a couple designs for about a year now with great results. Making adequate lift was the easy first step, preventing premature block wear was the second hurdle. Cost effective manufacturing without sacrificing our design is whats next. Here's a sneak peak at our latest prototype:
https://www.youtube.com/watch?v=pSYbmCvktaI
They should be ready in the next few months.
Hey, its great to see this! How much do these affect the jetting of the mikuni?
My Bike should be nicely run-in by the time these are ready ;)
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Hey, its great to see this! How much do these affect the jetting of the mikuni?
My Bike should be nicely run-in by the time these are ready ;)
Hasn't had any effects on jetting on the test bike.
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Thanks Ace, I presumed there would be. So its just bolt in and go!
Chris
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Yes.
You'll need to re-adjust your tappet clearance, of course.
Possibly some idle speed adjustment might be needed.
The general effects are a bit more torque all through the range, especially at the higher rpms, and some additional top rpm extension.
Basically, at allows you to access the extra 7 cfrm(202 cfm) that the Fireball port flows at the new higher peak lift(.410" lift), and also gives more open time at all the lifts beneath that, so that the area under the lift curve gets a nice overall increase.
Chumma has been running these prototypes on his bike for more than a year. They work great. The only reason that are not out on the market yet is because of difficulty getting them produced at a cost low enough for the Enfield market.
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I've ridden Chumma's bike with these rockers in and let me tell you, it's pretty friggin' awesome. And I already have a Fireball.
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Well so far the cost of the fireball has been worth it to me, As I said I've yet to complete the run-in, but once these are ready, It will be nice to have another boost :)
Chris
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I would like to expound a little bit on the lift vs port flow subject.
Best results from higher lift come when the port is capable to flow more air at the higher valve lifts. If the port flow has flattened-off, and doesn't gain much(or anything) at higher valve lifts, then it is a much smaller kind of gain. In that circumstance, the flow is really only improved by more time open at the valve lifts that it can flow well at.
So, when we port a head, we ensure that it can flow well at all the lifts which we anticipate using on that head.
For the record, virtually all the stock Enfield heads flatten-off their flow at a lift of .350" or lower. At lifts higher than .350", it would be strongly advised to have a ported head which has been flow bench tested to show that the ports can make best use of that higher lift height. All Ace heads will do that.
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Ace what do you mean by readjusting tappet clearance. Do you still adjust them for almost tight or do you give them a little looser adjustment. ERC
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Ace what do you mean by readjusting tappet clearance. Do you still adjust them for almost tight or do you give them a little looser adjustment. ERC
This is a very perceptive question!
There are two answers.
My comment to re-adjust tappet clearances was a simple answer that since there are changes to the rockers, the previous pushrod length would probably not be right, and would need to be adjusted to fit the new rockers.
However, the rocker ratio does affect the behavior of the valves, and the lash ramp of the cam must be considered. In order to maintain the same lash ramp timing for take-up of the valve lash, and to avoid changes to the timing at the .012" points, the general rule-of-thumb is to increase the lash adjustment by about .001" per tenth of rocker ratio. So, in this case with 1.15:1 ratio, it would be appropriate to add about a thou to a thou-and-a-half of cold lash when using these rockers. If not, the valves will begin to open while the cam is still on the lash ramp.
But, this is such a small ratio increase that if a person used the same "zero lash cold" adjustment as before, he'd simply add a degree or so to the duration, and probably not even have any notable effect at all on the lash ramp effectiveness.
When we go to higher rocker ratios, we do recommend that the lash be increased, and we also let the owners know that they can do some "fine-tuning" by using less or more lash in their final adjustment.
In the case of these Shotgun Rockers, it really isn't critical, but as long as you asked, I gave you the technical answer. ;D
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Hi,
although not using the shotgun rockers, I have roller ratio rockers in my big head, I run mine on the loose side, I can just detect a bit of vertical movement. This seems to be a good balance and is not really noticeable over other engine noises.
Kevin
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Kevin,
Loose is good for your rockers.
.0045" cold lash would be the "neutral setting" for your rocker ratio.
Regarding noise, rockers just like ours are routinely run in racing cars and hot rods at .020" lash, so no real worries about beating anything up from lash.
But, if you prefer it where you have it, by all means, use that setting.
BTW, have you checked your compression to see how much it was with these rockers? I remember one comment about low rpm torque when you were setting up your SuperTrapp exhaust. This rocker ratio can lower dynamic compression, and your torque may benefit from removing some of the gasket thickness under the barrel.