Let's talk about cams.

[ace.cafe]

I suspect all the data collected will be used in the development of your new cams. I would figure the new cam design will eliminate any need for the 3-way pinion or the re-phasing. This thread keeps getting better. Keep it coming Ace, It's almost lunchtime!  

Blltrdr

Yes, certainly I'm using all the data that I can collect, and observing what happens even with different displacement Bullets.

And I will use all the data available to help in the new cam design.

But the cool thing about the re-phasing is that for a Bulleteer on a budget, they can get some nice results by just making some adjustment to the cams they already have.

And I might even make up some custom cams that are already pre-set to the rephased timing, to make it easy for people to do it. Just like Luoma suggested.
There's really no reason why not. It's an effective cam timing that people might like, and if they can just drop them in, then they don't have to fuss around with all the dial-indicator work.
The only downside is that they would cost as much as any cam set costs, because they'd be new custom cams. But, they'd work well, and this is now certainly a proven fact. So, that's another possible option.

The new cams that I'll make for the Mondello head will be much more specifically targeted at exactly how that head flows, so they will be somewhat different. And probably be about the same cost.

But, variety is the spice of life, and different strokes for different folks, and all that jazz.
So, perhaps I can do both. Some people won't want to spend what it takes to get the Mondello head, and I can produce something that works well for a stock head.

[Blltrdr]

 Ace, how would the re-phasing work with a stock engine whose head had been lapped to eliminate the gasket? Would there be enough compression to take advantage of the re-phasing? You have mentioned before that the re-phasing mimics the duration of the original Redditch cams; what was the compression ratio on those engines?

Blltrdr

[ace.cafe]

Ace, how would the re-phasing work with a stock engine whose head had been lapped to eliminate the gasket? Would there be enough compression to take advantage of the re-phasing? You have mentioned before that the re-phasing mimics the duration of the original Redditch cams; what was the compression ratio on those engines?

Blltrdr

Not enough static compression with a stock engine to work with that late of an intake valve closing angle.  I'm not sure about the Redditch cam which the rephased timing is derived from. It might be the "S" cams or something which went with a bike that had more compression. The Redditch cam specs are a little sketchy, and I've received some conflicting info about them, possibly relating to different cams that they produced.
But the stock Redditch Bullets had 6.5:1 compression.
And I can tell you for sure that 6.5:1 will not support this late intake valve closing timing with the 32mm Indian-made cylinder head. You need at least 8:1, and probably the 8.5:1 is the best option. Even 9:1 wouldn't be out of the question.

And the stock piston isn't really up to doing what we want to do anyway. We need a piston change, and the 8.5:1 item seems to fit the bill.

I'd like to say you could do it with a stock piston, but the numbers don't add up.

What I'd really like to do, but don't know if I will, is to make a superlight piston with a shorter height with a relocated wrist-pin hole, that has about 10:1 static  compression ratio and a good quench area, and use that with a late intake valve closing timing to produce a dynamic compression ratio of about 8:1 when running.
That would give great results and still run on 92 pump gas. But it would need the Hitchcock's crank to handle that. And the barrel would have to be shortened some.

Ya know, I did some figuring the other night, and if we de-stroked the crank down to around 3" stroke, and used the 87mm bore size, we'd have a short-stroke 350. Of course the barrel would have to be cut way down shorter to do that.
But, piston speeds would allow revving to 8000 rpms, and with proper porting and camming, it could produce over 40hp as a 350 in a configuration like that. It would be a little wild for street use, but it's interesting.

[Blltrdr]

Not enough static compression with a stock engine to work with that late of an intake valve closing angle.  I'm not sure about the Redditch cam which the rephased timing is derived from. It might be the "S" cams or something which went with a bike that had more compression. The Redditch cam specs are a little sketchy, and I've received some conflicting info about them, possibly relating to different cams that they produced.
But the stock Redditch Bullets had 6.5:1 compression.
And I can tell you for sure that 6.5:1 will not support this late intake valve closing timing with the 32mm Indian-made cylinder head. You need at least 8:1, and probably the 8.5:1 is the best option. Even 9:1 wouldn't be out of the question.

And the stock piston isn't really up to doing what we want to do anyway. We need a piston change, and the 8.5:1 item seems to fit the bill.

I'd like to say you could do it with a stock piston, but the numbers don't add up.

What I'd really like to do, but don't know if I will, is to make a superlight piston with a shorter height with a relocated wrist-pin hole, that has about 10:1 static  compression ratio and a good quench area, and use that with a late intake valve closing timing to produce a dynamic compression ratio of about 8:1 when running.
That would give great results and still run on 92 pump gas. But it would need the Hitchcock's crank to handle that. And the barrel would have to be shortened some.

Ya know, I did some figuring the other night, and if we de-stroked the crank down to around 3" stroke, and used the 87mm bore size, we'd have a short-stroke 350. Of course the barrel would have to be cut way down shorter to do that.
But, piston speeds would allow revving to 8000 rpms, and with proper porting and camming, it could produce over 40hp as a 350 in a configuration like that. It would be a little wild for street use, but it's interesting.

 I guess i am trying to visualize the best route to go for someone not wanting to pony up for the crank & rod and split the case scenario. Someone who just needs to replace there stock barrel & piston with say, the upgraded alloy barrel w/ 8.5:1 piston. Is the re-phasing feasible or is it just to much for the bottom end to handle? It would be great to fill the need for every price point out there, from the budget minded to the guy with the wheelbarrow full of cash. It would be fun to start the discussion from mild to wild and see just how far it goes.

Blltrdr

[ace.cafe]

Not enough static compression with a stock engine to work with that late of an intake valve closing angle.  I'm not sure about the Redditch cam which the rephased timing is derived from. It might be the "S" cams or something which went with a bike that had more compression. The Redditch cam specs are a little sketchy, and I've received some conflicting info about them, possibly relating to different cams that they produced.
But the stock Redditch Bullets had 6.5:1 compression.
And I can tell you for sure that 6.5:1 will not support this late intake valve closing timing with the 32mm Indian-made cylinder head. You need at least 8:1, and probably the 8.5:1 is the best option. Even 9:1 wouldn't be out of the question.

And the stock piston isn't really up to doing what we want to do anyway. We need a piston change, and the 8.5:1 item seems to fit the bill.

I'd like to say you could do it with a stock piston, but the numbers don't add up.

What I'd really like to do, but don't know if I will, is to make a superlight piston with a shorter height with a relocated wrist-pin hole, that has about 10:1 static  compression ratio and a good quench area, and use that with a late intake valve closing timing to produce a dynamic compression ratio of about 8:1 when running.
That would give great results and still run on 92 pump gas. But it would need the Hitchcock's crank to handle that. And the barrel would have to be shortened some.

Ya know, I did some figuring the other night, and if we de-stroked the crank down to around 3" stroke, and used the 87mm bore size, we'd have a short-stroke 350. Of course the barrel would have to be cut way down shorter to do that.
But, piston speeds would allow revving to 8000 rpms, and with proper porting and camming, it could produce over 40hp as a 350 in a configuration like that. It would be a little wild for street use, but it's interesting.

 I guess i am trying to visualize the best route to go for someone not wanting to pony up for the crank & rod and split the case scenario. Someone who just needs to replace there stock barrel & piston with say, the upgraded alloy barrel w/ 8.5:1 piston. Is the re-phasing feasible or is it just to much for the bottom end to handle? It would be great to fill the need for every price point out there, from the budget minded to the guy with the wheelbarrow full of cash. It would be fun to start the discussion from mild to wild and see just how far it goes.

Blltrdr

Ok, I hear ya.

Do the 8.5:1 piston and alloy barrel in 84mm bore(500cc) to keep the weight of the piston down. The 535 can give a couple horses more, but the piston is alot heavier and will stress the stock rod more when you use the higher revs. So the 84 bore is easier on the stock rod.
Rephase the stock cams as discussed. Or wait for my cams.
Get the Mondello head and the carb that I finally decide on, which is very likely to be the 32mm Mikuni flat-slide, but not certain yet. Or use a stock head with a good valve job, and a 30mm flat slide from CMW(for ease of installation and jetting).
Upgrade your clutch to the 5 plate, or get the strong springs, cuz you'll need it.
Use the Power Arc ignition., and set up a way to switch in the retarded curve when you need to.
Get a tach, and limit your revs to 5500 rpm.

What's it gonna produce? Don't know yet, because I have to see the data from Mondello on the breathing of the head.
But, with a stock head that has some smoothed ports and a good 3-angle or 5-angle valve job, and rephased cams, and the 8.5:1 piston and a 30mm flat-slide and good exhaust system, you should be good for around 30 ft/lbs of torque, and about 30hp at the rear wheel.

Expect to have a somewhat reduced lifetime of the bottom end, especially the main bearings. So plan a rebuild to beef up the bottom end, as soon as it is feasible for you to do that.

If you can't get the Mondello head, but want some lower cost headwork, contact me and I can work something out for your stock head improvement.

[Blltrdr]

 If the piston weight puts to much unneeded stress on the bottom end then why not have it machined to shed some weight or have a piston made by Aria with correct specs to alleviate those problems. They have an easy to fill out order form: www.ariaspistons.com/products/orderform.pdf. I would think that one could put together a top end that would give a sufficient power band and be easy on the bottom end too. I think your suggestion to use the PWK is a good one; a simple affordable carb with reasonable performance. Save the big gun for your Four-Aces motor!

Blltrdr

[ace.cafe]

If the piston weight puts to much unneeded stress on the bottom end then why not have it machined to shed some weight or have a piston made by Aria with correct specs to alleviate those problems. They have an easy to fill out order form: www.ariaspistons.com/products/orderform.pdf. I would think that one could put together a top end that would give a sufficient power band and be easy on the bottom end too. I think your suggestion to use the PWK is a good one; a simple affordable carb with reasonable performance. Save the big gun for your Four-Aces motor!

Blltrdr

Yes, there have been various piston makers try to do the 87mm piston.
The lightest one is the forged one from CMW, as far as the high compression pistons are concerned. It's a very good piston, and as light as any maker has been able to do, considering the design it has to conform to.
Unfortunately when it gets bigger to the diameter of 87mm, it gets 25% heavier than we'd really like it to be. That's why I suggest the 84mm piston. when using the stock rod.

Believe me, I am aware of the issues involved with this piston thing.
I will by trying to get something done in that area. It's not as easy as it might seem.
But, it's on the list, and we'll see what we can do.
I've had initial discussion with Joe Mondello about it, and he says he can get something special done by his vendor that supplies the pistons for his Pro-Stock racing engines. We'd like to raise the pin location, so we can make the piston shorter, and also reduce the piston rock that we currently have to deal with. But this would mean shortening the barrel height, which we can do. But, it complicates matters, because it's no longer just a "drop-in" modification when you have to shorten the barrel.
But that could kill a few birds with one stone.

[ace.cafe]

Check out these hp and torque curves from the guy in the UK who re-phased his cams on his 350 Bullet.
The green lines are the baseline when he brought the bike in to the dyno shop.
The blue line is what they got on the dyno tune, with adjustments of the carb jetting and the ignition timing.
This also really shows how important it is to have your bike tuned right. There was a huge increase in power seen after they get the jetting and the ign timing tuned in.
The top chart is hp, and the bottom chart is torque.

Can you believe how broad and flat these power curves are??!!
This little 350 has alot of power at almost every rpm that you'd ride at. Those curves come right up high real early, and they stay there. It's pretty awesome!
This 350 would whip most 500 Bullets. It has as much hp at 2500 rpm as a 500 Bullet with free-flow exhaust and filter has at 4000 rpm. And it has more hp than the 500 at peak too, by a small amount. But this 350 gets it so much earlier and hangs onto it for so long, that it's pretty amazing. It would eat a stock 500 Bullet alive, and give a kitted 500 a fit too.

Horsepower


Torque



And here's a chart of hp curves for a stock and modded 500 for comparison.

[Blltrdr]

 So Ace, I would suspect that each grid to the right is 1k RPM increments. If that is so then these are some very impressive results. The HP stays consistent for about 3500 RPM's and the torque is in the same ballpark. What is that RPM range on the dyno sheet.

 These results have got to put a smile on your face, they're quite incredible. How about the guy with the 612 is he going to dyno his bike? That would be very interesting to see.
#'s #'s #'s we can't get enough #'s!

Blltrdr

[Blltrdr]

 Well, even in 500 RPM increments the smoothness the power is developed is awesome. Like you said, the power is developed at the perfect operating RPM range. Should be a blast to ride! What mods have been done to this 350 Ace?

Blltrdr

[Blltrdr]

 Well keep up the posts on all these re-phasers you are working with. If the results of this dyno could be had on a consistent basis for all the different displacements then the re-phasing should be standard procedure when installing a high compression piston.

 Kind of getting off the subject I saw a picture of a CB 450 engine in a Rickman frame and thought it looked like a good candidate to put in a Bullet frame. What do you think?

Blltrdr

[ace.cafe]

Well keep up the posts on all these re-phasers you are working with. If the results of this dyno could be had on a consistent basis for all the different displacements then the re-phasing should be standard procedure when installing a high compression piston.

 Kind of getting off the subject I saw a picture of a CB 450 engine in a Rickman frame and thought it looked like a good candidate to put in a Bullet frame. What do you think?

Blltrdr

Well, the rephasing would normally be possible along with the intstallation of the hi-comp piston. But I'm not sure that everyone wants to play with cam timing. However, I'm contemplating a making cam sets with re-phased timing on new cams for people to drop in. With maybe a couple of other needed improvements, like ramp change to deal with the excessive tappet strike when hot.

Looks to me like that CB450 would fit.
I'm not a big fan of doing stuff like that.  It just makes me cringe. But it's one way to get cheap horsepower.

[Blltrdr]

Well, the rephasing would normally be possible along with the intstallation of the hi-comp piston. But I'm not sure that everyone wants to play with cam timing. However, I'm contemplating a making cam sets with re-phased timing on new cams for people to drop in. With maybe a couple of other needed improvements, like ramp change to deal with the excessive tappet strike when hot.

Looks to me like that CB450 would fit.
I'm not a big fan of doing stuff like that.  It just makes me cringe. But it's one way to get cheap horsepower.

 Well a new streetable re-phased camset will be optimal. I myself would never stuff a Japanese twin into a Bullet frame, just saw a few posts a while back about that SX650 engine in a Bullet and ran across this picture and thought it could be done quite easily if someone was wanting and willing. There seems to be a lot of interest in putting a vertical twin in the Bullet, I've read about it often. Some people are hoping & praying that one day soon RE is going to produce a new twin; I say wishful thinking at best. Think about all those diehard's waiting for the new GTO and look what the factory came up with, talk about cringing!

Blltrdr

[ace.cafe]

Well, the rephasing would normally be possible along with the intstallation of the hi-comp piston. But I'm not sure that everyone wants to play with cam timing. However, I'm contemplating a making cam sets with re-phased timing on new cams for people to drop in. With maybe a couple of other needed improvements, like ramp change to deal with the excessive tappet strike when hot.

Looks to me like that CB450 would fit.
I'm not a big fan of doing stuff like that.  It just makes me cringe. But it's one way to get cheap horsepower.

 Well a new streetable re-phased camset will be optimal. I myself would never stuff a Japanese twin into a Bullet frame, just saw a few posts a while back about that SX650 engine in a Bullet and ran across this picture and thought it could be done quite easily if someone was wanting and willing. There seems to be a lot of interest in putting a vertical twin in the Bullet, I've read about it often. Some people are hoping & praying that one day soon RE is going to produce a new twin; I say wishful thinking at best. Think about all those diehard's waiting for the new GTO and look what the factory came up with, talk about cringing!

Blltrdr

I've noticed the discussions about twins too.
There's a few different ways to skin the cat.

Let's look at an Interceptor twin engine, which was known "in the day" to have plenty of power for a 750 twin, and fits right in our Bullet frame.
Alright, it has about 52hp, or somewhat less as a Super Meteor or Constellation.
But, let's take the 52hp.

It weighs about 90 pounds more than a Bullet at 450 lbs. And it's wider and more top-heavy than a Bullet, and it costs more to work on than a Bullet.
It's weight-to-power ratio is about 8.65:1.

The Bullet can be made to have about 40hp at the rear wheel as a 612(dynoed and proven), and I'm shooting at doing that similar power level with the 535 in streetable form, and I think I can do it.
At 350 pounds, a Bullet with 40rwhp has 8.75 weight-to-power ratio.
Very close to an Interceptor twin.

Yes, the Interceptor will be a touch more powerful, and just a touch faster, but will be less nimble and more "weighty" to move around.

In the Cycle Magazine test of the Interceptor, it managed 106mph as a top speed, even though it claimed top speed of 117 mph.
A Bullet can do that with a 19T gear on it, or do 102mph with an 18T at 6k rpm, if it is modded to around the 40hp level. So, top speeds are also in the same ballpark.

Essentially, it's within spittin' distance of an Interceptor, with  the nimbleness and low weight advantages of the Bullet.

I thought about putting an Interceptor engine in my Bullet at one time, but after cranking those numbers, I just didn't think it was worth the effort.
I think a properly modded Bullet would be just as good, or better.

[Blltrdr]

 Well Ace I am glad you decided to develop the single. I think a lot is determined from the sounds an engine makes that draw it's faithful to it.
 I don't know if you watched the youtube vid of CJay's 612 start up and idle but it makes the desire for a 612 conversion seem necessary. But I will bide my time and see what excellence you bring to the table. I like everything you have discussed and believe you have thought everything through and are on the right track to developing a high performance Bullet that is very streetable and dependable.
 I like your idea of destroking the motor some. How much? You said that the barrel will have to be shortened; can you make up some of the difference in machining the case? I have read that some problems develop because of the way the barrel sits on the case. Now if you machine this surface true you would eliminate this potential problem. I think this could be part of your process of building a very bulletproof motor. What you say?

Blltrdr