Topic: DWMS RACING CB550F SUPER REVERSE PORT! NEW ENGINE COLORS AND PHOTOS!

[FunJimmy]

It surprises me that you get as much accomplished as you do, considering the amount of time you spend maintaining this and the DTT build blogs. Stop typing and start grinding. 

[joeyputt]

HEY! What gives? It says "new photo" in the title and I havent seen a pic on this page at all. Just a whole lotta words!

Brother Frankenstuff it has been pretty busy here today! Hahahaha! The newest photos are of the front frame conversion to make room for the dual carburetors up front, they are on page 11.

[joeyputt]

It surprises me that you get as much accomplished as you do, considering the amount of time you spend maintaining this and the DTT build blogs. Stop typing and start grinding.  

Brother FunJimmy you would not believe the number of hours I work if I told you! I update the forums while I am taking snack breaks! Hahahaha! I did take today off though!

I have a couple of Brothers that invited me to share this build over on DTT and I joined here as the Honda SOHC 550's are my favorite bike. Here is a photo of my Dads that we are building a sidecar for now.




That was Dads tank we used to set up my bike in this photo.

[joeyputt]

Note - I posted this in response to a member on another forum and most of you here probably already know this but I thought some of our guests may like to read it as well.

I have been cutting and testing my own race cams for over 15 years and very subtle changes to the cam make very large differences. I will also say that even two of the same engines may like different cams than each other and even further I like different cams for different racetracks.

I am however amazed at the prices that a lot of aftermarket atv and motorcycle cams are bringing in comparison to what automotive cams are available for. I feel a lot of people buy cams just for a few thousandths of extra lift, a strand of hair is roughly three thousandths thick.
 
A lot of race cams that are under lift rules at the racetrack now run a cupped profile on the opening side to launch the valve but still pass spec at lift when spun by hand. For lift on a street or playbike I would slightly cup the opening side on a stock cam before I spent $400 on an aftermarket cam.
 
The same goes for compression, I see people spending a lot of money on decking the heads and running high compression pistons because they do not know that most engines have a ramp on the cam which keeps the intake valve slightly open and only allows the piston to build full compression through one third or less of its compression stroke, reconfiguring the ramp on a stock cam allows the piston to build compression full stroke. Some aftermarket race cams will already have this removed but you can reconfigure a stock cam and make a lot of compression without ever removing the head.
 
A lot of lift and compression can be gained from reworking a stock cam.

[joeyputt]

I thought everyone wanted to talk camshafts? I have seen almost every regular visitor to this thread visit today as well as others and not one reply...what gives?

[Syscrush]

They're not so good with word learnin - they only like to look at pichers.

I would really love to see your cam grinding rig sometime, I think it's awesome that you're able to take on stuff like this.

I was engaging in a stupid thought experiment about other ways to solve the cam problem, and it occurred to me that you could gun-drill the cam, cut each of the 8 lobes into its own segment, assemble them onto a jig with the IN and EX valves swapped for each cyl, and weld the segments back together.  At first it struck me as a hilariously idiotic idea, but now I'm not so sure.  It might not be more work than building up the lobes and re-grinding followed by the chroming and/or surface hardening you'd need to do with a regrind.  So now I'm tossing out there as a thought experiment.

I know that approach would make no sense for you, Bro Joe, but I thought you might find the idea entertaining, or someone else reading this might want to give it a shot sometime.

[joeyputt]

They're not so good with word learnin - they only like to look at pichers.

I would really love to see your cam grinding rig sometime, I think it's awesome that you're able to take on stuff like this.

I was engaging in a stupid thought experiment about other ways to solve the cam problem, and it occurred to me that you could gun-drill the cam, cut each of the 8 lobes into its own segment, assemble them onto a jig with the IN and EX valves swapped for each cyl, and weld the segments back together.  At first it struck me as a hilariously idiotic idea, but now I'm not so sure.  It might not be more work than building up the lobes and re-grinding followed by the chroming and/or surface hardening you'd need to do with a regrind.  So now I'm tossing out there as a thought experiment.

I know that approach would make no sense for you, Bro Joe, but I thought you might find the idea entertaining, or someone else reading this might want to give it a shot sometime.

Brother Syscrush that makes perfectly good sense and that is actually how my Brother wanted me to do the cam when I discussed it with him but I felt it would be very difficult to keep it true.

[Flying J]

I thought everyone wanted to talk camshafts? I have seen almost every regular visitor to this thread visit today as well as others and not one reply...what gives?

I would comment but your speaking way over my head. I bought my first bike 4 years ago and rebuild my first motor last year so grinding cupps to make the lifters jump, just sounds like a bad idea for somebody like me. But i try to always be learning so i keep reading. But i must say i am a visual person so when you say cups in the cam a picture is worth a thousand words.

[joeyputt]

I thought everyone wanted to talk camshafts? I have seen almost every regular visitor to this thread visit today as well as others and not one reply...what gives?

I would comment but your speaking way over my head. I bought my first bike 4 years ago and rebuild my first motor last year so grinding cupps to make the lifters jump, just sounds like a bad idea for somebody like me. But i try to always be learning so i keep reading. But i must say i am a visual person so when you say cups in the cam a picture is worth a thousand words.

I will try to take a photo of one of my cams in the daylight tomorrow but I doubt you will be able to see it. When I say cupped I mean that if you look at the lobe from the side instead of it being eggshaped to the outside it will be slightly concaved to the inside.

[BR]

Joey,

Good Stuff!   It's been many years since I messed with cams much (never had the time to grind but discussed in length the specs we wanted/needed with the manufacturers we used, Web and Megacycle) Lots more than the average builder understands. We built drag motors, and a few road race motors, changing the cams in the road race motors helped tremendously with the different tracks as well as the couple of bikes we had that used more than 1 rider from week to week. Sounds like you've got it down. Good luck with the rest of your build, looking forward to seeing it completed.

[joeyputt]

Thank You Brother BR, working with cams is fun! I really have tried to stay away from the technical side of this build but a lot of people seem to be interested so I am trying to ease into it although it is not always easy to explain.

[Syscrush]

Brother Syscrush that makes perfectly good sense and that is actually how my Brother wanted me to do the cam when I discussed it with him but I felt it would be very difficult to keep it true.

If it were gun-drilled and a keyway ground into it with a bit of an interference fit (half a thou?), soak a rod & key in liquid nitrogen and give the cam pieces an hour in the oven at 550, you might get it all back together without even having to weld anything, and it should be nice and true...

Not that I would have the means to do such a thing, nor am I suggesting that it would be better than your approach.  Just thinking out loud again.

[joeyputt]

Brother Syscrush that makes perfectly good sense and that is actually how my Brother wanted me to do the cam when I discussed it with him but I felt it would be very difficult to keep it true.

If it were gun-drilled and a keyway ground into it with a bit of an interference fit (half a thou?), soak a rod & key in liquid nitrogen and give the cam pieces an hour in the oven at 550, you might get it all back together without even having to weld anything, and it should be nice and true...

Not that I would have the means to do such a thing, nor am I suggesting that it would be better than your approach.  Just thinking out loud again.

Except I always end up in trouble with my wife when I try to use the oven for bike parts! Hahahaha!

[joeyputt]

Here is a little more about the intake valve being open during the compression stroke for those that may be skeptical about it.

Most cam cards will not show it but this one does. See on the intake side at the bottom where it says EZ - START 51.5  ABDC and EZ - STOP 85 ABDC, this is the range on a degree wheel where the intake valve is open during the compression stroke, so with this particular cam the intake valve would be open for 33.5 degrees during the compression stroke.

[Flying J]

OK, so why do they build the cam with this small opening of the valve? What is the pro to it and what is the con of removing it? Do you know if the cb550 has this ramp in the cam?

[754]

The Honda cams;
 If the journal size is at all close to the base circle size, it will be hard to bore them out and refit them.
 You dont want to key them, you want an interference fit, check them, adjust them, THEN weld them..

 I know this because a local builder (Goldammer), has done it with Harley cams, and it worked well.

[joeyputt]

Brother ffjmoore the cams are built this way for easy spinning and starting and totally removing it would be too much compression for a street engine, you would barely be able to turn the engine over and you will normally not be able to use the stock electric start. I would not recommend doing anything to it unless you have a lot of experience working with camshafts.

Brother 754 my cam is ready to go, the local builder you know cut his cams in half and welded them back togethor?

[Syscrush]

Brother 754 my cam is ready to go, the local builder you know cut his cams in half and welded them back togethor?

Do you know of Goldammer?  Guy is an internationally-renowned superstar genius:

[joeyputt]

Brother 754 my cam is ready to go, the local builder you know cut his cams in half and welded them back togethor?

Do you know of Goldammer?  Guy is an internationally-renowned superstar genius:

With all respect I have never heard of him?

[754]

Roger G is one of the few people in the world who got 6 pages or so of an H-D based bike in Cycle World.
 He builds huge single cylinders on H-D lower ends (165 mph single), raced one at Bonneville.. he is building a twin for the salt right now..

 Just search Goldammer  (no H )and see what you find..

 Syscrush, he used to live a mile from here,now lives across town.. I ride out there a few weeks ago.. cool stuff happening there..

[joeyputt]

Brother I did a search and I have seen one of his bikes before. It looks like he does nice work.

[paulages]

Joey,

Well now you sound like you ARE concerned with performance.   Are you familiar with engines like these inline fours that like to spin up high? You're right that the intake valve is still open during part of the compression stroke, which is why determining a true compression ratio is difficult. I could be wrong, but your approach here seems to be very car or big twin- oriented... Why do you think the cams are designed so that there is overlap on the intake and compression stroke? They didn't do it just so that the lobes look nice.   A nice port design will allow for a strong intake charge at high RPMs, which will overcome the compressing gasses and force more mixture in. YAt some RPMs compression suffers, others it benefits greatly. At certain points reversion is terrible. It's a wild cycle that can be described in many more than "four" strokes... but you seem to know the combustion cycle well. You gotta remember, it's all about getting that gas in there. Get good intake velocity, and those 30-something degrees past BDC aren't going to do anything but let more air and fuel in.

In any case, shortening the duration is not necessarily going to yield a higher compression. You seemed to give off the impression that port design and valve size, etc isn't all that important to your build, and now you're talking about cam profiles to get more compression. Anyway, don't let me be the Debby Downer... you have lots of fans here, so I'll keep quiet. I just like the go fast tech stuff. You know, what 754 said...

[joeyputt]

Brother paulages I respectfully think you have misunderstood what I wrote as I was not writing in referance to valve overlap which occurs when the exhaust valve is closing and the intake valve is opening which occurs at the end of the exhaust and beginning of the intake strokes not the compression stroke, valve overlap is however important for scavenging which I have not wrote about yet.

I was writing in referance to cam ez-spins and their affect on the compression stroke.

[paulages]

Brother paulages I respectfully think you have misunderstood what I wrote as I was not writing in referance to valve overlap which occurs when the exhaust valve is closing and the intake valve is opening which occurs at the end of the exhaust and beginning of the intake strokes not the compression stroke, valve overlap is however important for scavenging which I have not wrote about yet.

I was writing in referance to cam ez-spins and their affect on the compression stroke.

Re-read what I wrote, Joey... I said "...cams are designed so that there is overlap on the intake and compression stroke." I am talking about the grey area that is between the intake stroke and the compression stroke. I was not referring to intake/exhaust valve overlap. We call them "four stroke" engines, but in reality each "stroke" is not a cleanly between TDC and BDC. The point at which the intake stoke ends and the compression stroke begins is not necessarily decided by the closing of the intake valve or the rising of the piston. There is an overlap of these two cycles (not confusing with valve overlap) which intake velocity RULES. The intake valve overlaps the compression stroke to get as much combustible mixture into the cylinder as possible, by having the velocity of the intake charge overcome the compression caused my the rising piston, ideally until the moment the valve closes. There is certainly an argument to be made regarding high lift vs. valve duration, but do you really think that no one has ever considered duration vs. lift on these engines? 

For your consideration, for example, try this article from 1971: http://cb750k2.tripod.com/Technical/porting/Porting_the_Honda_Head.htm

I was just pointing out the simplicity of your description of the fact that the intake valve closes after BDC, as if Honda and every performance aftermarket company did this on accident or something. Bear in mind, the intake valve is relatively cool on the intake stroke and doesn't need to be closed as gently as the exhaust valve... If the cycle were as simple as you describe, why wouldn't cams close the valve at BDC? Why would you need to make this "EZ spinning" cam to get more compression?



Ok, I just realized that you're talking Briggs stuff here. Eh, I give up.

[paulages]

By the way, in case I wasn't clear... really pretty work.