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Author Topic: "La Pastinaca" CB450 498cc Big Bore Engine Built By DWMS Racing!  (Read 63107 times)

Offline joeyputt

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Re: "La Pastinaca" CB450 New photos! 5mm racing valves conversion!
« Reply #50 on: Jul 27, 2011, 15:24:58 »
Yesterday I worked on getting the internals of the bottom end back togethor. I installed the new shift forks, the transmission, and the crankshaft back into the upper case and was able to seal and bolt the cases back togethor late last night.

Here is a photo of the cases back togethor.

« Last Edit: Jul 27, 2011, 15:27:48 by joeyputt »
Joe - Owner/Operator of DWMS Racing World Class Engine & Motorcycle Building www.dwmsracing.com

Cylinder Head Porting Sale! http://www.dotheton.com/forum/index.php?topic=56203.msg637024#new

Facebook https://www.facebook.com/joe.dwmsracing

Offline joeyputt

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Re: "La Pastinaca" CB450 New photos! Cases back togethor
« Reply #51 on: Jul 27, 2011, 16:39:59 »
I replaced all of the seals behind the sprocket cover including the shift drum seal, the transmission/clutch rod seal, the shifter seal, and the transmission/sprocket seal.



After all of the seals were in I installed this new 16 tooth sprocket.

Joe - Owner/Operator of DWMS Racing World Class Engine & Motorcycle Building www.dwmsracing.com

Cylinder Head Porting Sale! http://www.dotheton.com/forum/index.php?topic=56203.msg637024#new

Facebook https://www.facebook.com/joe.dwmsracing

Offline Rip-It-Up

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Re: "La Pastinaca" CB450 New photos! 5mm racing valves conversion!
« Reply #52 on: Jul 27, 2011, 18:18:03 »
Shrouding on this type of head is not necessarily what you think it is and unshrouding does not necessarily create the flow improvement you might have expected. The flow problems come from two places, general shape of the port and the small short turn radius. David Vizard and AG Bell among others have written books and articles on the subject of port shapes.

If you read the article on what Kenny Augustine did with Todd Henning's head you would have seen the raised floor in the exhausts. That improves flow and also provides anti-reversion which prevents exhaust reverse flow along the floor of the port.

I never claimed that unshrouding would unlock magical heaps of plentiful HP. Simply that it's and easy way to pick up a little. And yes I did pick up where he raised the ports in the heads thereby improving the short side radius. Pretty textbook stuff and that is where you get the greatest benefit and also where most people screw the pooch.
Now raising the ports takes alot of work and as mentioned changes the exhaust port and intake port position requiring modifications not only to the port but the exhaust pipes and intake manifold.
 
For those not in the know, the most efficent path is in a straight line and by raising the ports you take the bend out of the L giving a more direct path to the valve.
 
Most people think a 305 chevy makes no power due to poor head design or black curses or something. Truth is the smaller bore has the flow coming out of the valve and directly smack into the side of the cylinder. The heads and intake actually for the displacment flowed just as well as the 350. So again saying not to unshroud a valve is like leaving a weak link in the chain.
 
Now on the subject of springs. Cam designs greatest technological leap forward here lately is primarily due to the advent of better spring technology. Comp cam's released an entire new line of cam's with faster ramps due to just the discovery of the beehive design of spring. Why? Because they remove weight from the valve tip allowing the valves to be opened and closed faster without floating, this free's small parasitic losses, and because now a lower spring rate can be used, guess what, lower spring rate also = less wear on the cam, valves, and seats. Guess what they are in every LSx based motor and part of the reason pushrod motors now make 450 tame hp instead of just 300. All top aftermarket head manufacturers now use them. Moral is theres more to it than just a piece of spring steel.
 
The 5mm valves he's installing in this motor are a huge step in the right direction due to not only a smaller stem obstructing the intake and exhaust flow in the ports. But also being lighter enabling the valve at higher RPM's to open and close faster. Now by leaving the ancient cam in the motor from the 60's you would not be taking full advantage of that benefit, It has poor valve control with slow ramps due to the limitation of the torsion bars. Now torsion bars are linear not progressive. Do a search and find out why race engines don't run linear springs... For the same reason... better valve control and faster opening and closing ramps. No engines use torsion bars and it's not because the engineers are overlooking something.
 
Do this, put your arm in front of you and move it up and down as fast as you can. Now hold a 5lb weight in your hand and do it again. Thats the best way to understand how reducing these inertia's helps in the valvetrain.
 
Cam's have to comprimise with letting the valve down gently enough not to destroy the valve and the seat yet fast enough to open and close the valve precise enough for optimal valve timing events.
 
« Last Edit: Jul 27, 2011, 19:16:41 by Rip-It-Up »

Offline Habanero52

  • Posts: 547
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Re: "La Pastinaca" CB450 New photos! Cases back togethor
« Reply #53 on: Jul 28, 2011, 10:01:30 »
I thank you very much for your comments!!!!!
Much appreciated Glenn.

When I asked Joey to take on this project, thru ought our conversations, it was obvious to me, that he is an indisputable subject matter expert.
I have such faith in his knowledge that I have subscribed to all of his recommendations. To top it all, he is gentleman and a top notch human being!!!!!!

As I have stated, and you have reiterated, this thread if for the purpose of sharing with all this build you all and to be enjoyed by all!

I have no doubt that Joey is doing an outstanding job and I am greatful to him and all of the other that have chimed in support.

 :D ;) Thank you all!!!!
Habanero52
Speed cost....How fast do you want to spend?
Follow the dream.
Why does life get in the way?

Offline Habanero52

  • Posts: 547
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Re: "La Pastinaca" CB450 New photos! Cases back togethor
« Reply #54 on: Jul 28, 2011, 11:42:27 »
I know that will be the case! 8)
Habanero52
Speed cost....How fast do you want to spend?
Follow the dream.
Why does life get in the way?

Offline Swagger

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Re: "La Pastinaca" CB450 New photos! Cases back togethor
« Reply #55 on: Jul 28, 2011, 12:06:55 »
Since my posts seemed to kick this over, I ask that we please keep it friendly here. Let me reiterate that I think this will be a helluva lump when Joey gets it buttoned up. There's obviously lots of kats here with engine building experience...perhaps we could pool our knowledge rather than just with it?
.....there's no way that little rice cooker is going 100m/h when the work need to get up to those speeds includes a big fuck off fairing shaped like a giant cock. ~Staffy

Weiner tetanus is nothing to scoff at. ~JustinLonghorn

Offline Rip-It-Up

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    • My project
Re: "La Pastinaca" CB450 New photos! Cases back togethor
« Reply #56 on: Jul 28, 2011, 15:58:56 »
Swagger,

You did not cause this response.

A buffoon did, all good!

Alright, I was going to post and appoligize if I came off the wrong way until I was called names. I re-read my own post and see where I coud have come off as being arguementative. It was never any of my intentions to start an arguement or disrespect Habenero's build thread. I offered to start a new thread out of respect. Joey welcomed the discussion or else I would have left it alone. I had the complete intention to be informative and create a good discussion as other less experienced people also read the forum. Apparently some are too sensitive and closed minded.
 
Teazer, I'm sure we could both learn from each other. I admit I'm new with bikes, And I mean you no disrespect either man. I have been building race engines albeit in car's not bikes along time and also am far from an amatuer at it.
 
To Revhead, Nobody is the end all, All knowing guru. There's always someone faster, And even the pro's learn new tricks from each other all the time. I guess it's just a crazy "theory" (In your words) of mine that reduced spring pressure, weight at the valve, and improved cam geometry is beneficial. Guess I should have included my resume before posting as you also have no clue who I am or what my experience is. Guess we will let my post count give you the assumption I was born yesterday.
 
If my FACTS where incorrect at any point then please let's have an adult discussion and show me the errors in my thinking. I am a very receptive person. I have already seen that Joey knows his stuff and at no point doubted his abilities. If you reread my post I paid him much credit to his knowledge. I would say that Habenero's build IS in very capable hands. I never once tried to discredit that or Joey... I have read several posts from Swagger and see that he also produces some awesome stuff and is an obvious asset to the forum. My intention was to shed light to the advantages that newer springs have over the torsion bars. You mentioned you didn't know why people where selling the kits.
 
Teazer, I welcome you to further digress your theory of these motors needing the valves to be shrouded to prevent crossflow. I didn't doubt your knowledge of this or the benefit of doing so. My point was that theres a cause and effect to any issue. In other words... If you blow a fuse, the fuse isn't the issue, there's a short in the wiring that needs fixed. To further digress on my part I was trying to provide info that the ramp's could be profiled faster to negate alot of overlap using beehives, 5mm valves, and titanium retainers.
 
If I'm perceived as being too much of an asshat by this point by group concensus, I will respect who was posting here first and respectfully leave...
« Last Edit: Jul 28, 2011, 16:28:31 by Rip-It-Up »

Offline teazer

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Re: "La Pastinaca" CB450 New photos! Cases back togethor
« Reply #57 on: Jul 28, 2011, 22:03:40 »
No worries rip it up.  I'm still learning.  Only 4 decades of modifying bikes and still learning something new everyday.

My comment about shrouding alludes to the fact that in a Hemi head there is zero shrouding as designed.  Pulling valves back slightly often improves flow and reduces the short circuit effect.  What looks like shrouding that needs to be dealt with, is often beneficial.  A lot of car head design issues don't translate on bike motors for many reasons. 

That's one reason why people with an auto background have a hard time making power with bike motors.  The design constraints are different and so are the solutions.

In both cases we are looking for certain things that are the same such as critical port diameters relative to other parts of the port, the relative sizes of taper, bowl and parallel sections for example.

Agree that Ti caps and light valve help to reduce stresses and allow a motor to rev higher.  Beehive springs are an interesting subject that I think the jury is still out on.  Shorter duration higher lift cams are a trick I have used for years. Matching cams to port flow is a whole other area that can be explored. Agreed.  The cause of short circuit is valve geometry basically.  That hemi head design is great in terms of having the lowest ratio of surface area to volume but wide valve angles and deep chambers lead to being able to look down the intake and right out the exhaust when the valves are out.

All engines are a compromise in design.  It's easy for example to look inside a Honda 6 and see areas that they could have improved - because technology has marched on and the pool of knowledge is deeper. 

There was great article on the web a while ago that I should have grabbed showing different Renault F1 engine power curves and compared their effect on lap times.  F 1 fuel is (or at least was) mixed specifically for a certain motor at a certain circuit and changed from one to another. Simply amazing technology. 

You don't have a Cam Doctor or swirl meter by any chance do you?  I really need to spend the big bucks (when I work out where to get them) over at Audie Technologies.

FYI I'm trying to get a test program going on LPG fueled motors to see the effects on emissions and power etc of different "clean" fuels and I really want to see what differences we can make with liquid phase versus gaseous phase direct injection. My theory is that the effect will depend upon the motor's responsiveness to the cooling effects of liquid phase injection in the same way that some motors work best with very fine fuel atomization and some respond well to larger droplets. Now I have to line up funding to work with a mixture control specialist at a university engine lab.

BTW, I missed whatever it was that might have upset someone, so stick around.  I'm sure Joey won't mind too much if we go off at tangents from time to time. He's capable of politely telling us to keep down the noise while he works. 

Offline teazer

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Re: "La Pastinaca" CB450 New photos! Cases back togethor
« Reply #58 on: Jul 28, 2011, 22:08:15 »
Joey, Nice looking clean engine there.

BTW all valve springs work in torsion so that's not an issue and we totally understand the logic for the change to work with the new valves.  Kibblewhite have been around for ages.  The company that Mr K's father IIRC founded was called something like Precision Machining and they put together a really fast CB77 Superhawk back in the sixties. 

Offline Habanero52

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Re: "La Pastinaca" CB450 New photos! Cases back togethor
« Reply #59 on: Jul 29, 2011, 10:05:42 »
I am sorry if anything I commented on the blog was a direct contributor to the upsetting of the people chiming in and giving their opinions.

I am a firm believer that everyone has the right to their opinion. Everyone must also realize that an opinion is just that, one personís personal view on a matter/subject.
When it comes to a respected Subject Matter Expert, then that opinion carries knowledge and experience and has the pillars to support it. When a person is not a Subject Matter Expert, they should clearly state that they are just providing an opinion and are open to being educated and obtain new knowledge on the matter at hand.
It is also Ok to agree to disagree. That is acceptable in my book.
I have lived my life this way and I am convinced that it has provided me with the tools to be educated and learn on a diversity of matters.

This is what I believe in!
All I wanted to do with my comments was to be further educated, that is all. I am sorry if I upset anyone!
Habanero52
Speed cost....How fast do you want to spend?
Follow the dream.
Why does life get in the way?