Author Topic: 500/550 performance stuff? (Read 3927 times)

ponch9 · « **on:** April 17, 2006, 10:25:47 AM »

i am looking into some research ideas for the cb500 head and was reading what Hondaman's article had to say about head work to boost performance.

http://sohc4.us/tech/cb550/ta2

Towards the bottom i read that bit about getting a cam with more duration...anyone know of a place to get one (on a CB budget)?

Also what does adding a pocket mean in this quote?
"Add 4 teeth to the rear sprocket and get a cam. Don't get high lift, get longer duration - BUT: not a LOT more duration, because it is a small-bore engine. A little goes a long way. Adding 5 degrees of overlap and 10 degrees of duration should be your limit for non-racing driving: it will REALLY wake up the "mid-four". Don't bother with bigger carbs: port it in the head instead. The stock carbs can make a lot more HP than they do: make a "pocket" above the intake valve, then raise the exhaust ports about 2-3 mm and smooth 'em out. This will add up to 10 HP to this neat engine, which is a lot.."

Oh and no luck finding an aluminum rear sprocket 4 teeth up either....
lots o work to do and the weather is great....dammit i wanna ride it!! Lol

by the way here is a pic of the final product after painstakingly rebuilding the carbs....(jetting and even honed the ports as well as the cylinder heads and intake tubes).
the pics suck but i only had my phone with me but u get the idea.

TwoTired · « **Reply #1 on:** April 17, 2006, 10:34:51 AM »

http://www.megacyclecams.com/

ponch9 · « **Reply #2 on:** April 17, 2006, 10:45:14 AM »

Just found this one too....anyone try it?
http://www.dynoman.net/engine/cams/webcams_honda.html

TwoTired · « **Reply #3 on:** April 17, 2006, 12:11:46 PM »

Quote from: ponch9 on April 17, 2006, 10:45:14 AM

Just found this one too....anyone try it?
http://www.dynoman.net/engine/cams/webcams_honda.html

I'm thinkin those are gonna need high perf springs and retainers, too.

The stock cam is 220 durration and about .265 lift on my used cam.

By the way, the only way you'll get high performance on a budget is if the budget is also high.

Cheers,

bwaller · « **Reply #4 on:** April 17, 2006, 12:26:41 PM »

Did you try sprocketspecialists.com for your rear sprocket? I'm sure they would be able to help you out with an aluminum blank for the rear. You would have to bore the centre and the mounting holes or have a machine shop do it for you. The last one I bought was three years back, a 37T aluminum 520 blank, and was $38.

ponch9 · « **Reply #5 on:** April 17, 2006, 02:32:39 PM »

Just called sprocket specialists.....62.99 for the rear (37 tooth). not great but still not too bad. Does anyone know about the "pocket" mentioned in the article?

Noel · « **Reply #6 on:** April 17, 2006, 03:02:48 PM »

Quote

By the way, the only way you'll get high performance on a budget is if the budget is also high.

Heh heh. The voice of experience.

So what is the stock number of teeth on the 500 sprocket, anyway?

ponch9 · « **Reply #7 on:** April 17, 2006, 03:10:03 PM »

34 for the rear and 17 for the front.....actually i found a front with 16t and will go with a 36t rear and go with a xso chain (lasts longer).

TwoTired · « **Reply #8 on:** April 17, 2006, 03:12:31 PM »

Quote from: Noel on April 17, 2006, 03:02:48 PM

So what is the stock number of teeth on the 500 sprocket, anyway?

Stock CB500 17 front 34 rear.
Stock CB550 17 front 37 rear.

Cheers,

Noel · « **Reply #9 on:** April 17, 2006, 03:58:35 PM »

Thank you both.

The 16 front idea is a good one, I think. I live in SoCal which means freeway riding is a constant thing, so I'm not too sure about a four tooth increase at the back. Would make for buzzy freeways, methinks. A one tooth change at the front, however, may be just the ticket for my situation.

TwoTired · « **Reply #10 on:** April 17, 2006, 06:17:24 PM »

Quote from: ponch9 on April 17, 2006, 03:10:03 PM

34 for the rear and 17 for the front.....actually i found a front with 16t and will go with a 36t rear and go with a xso chain (lasts longer).

X ring chains and well as oring chains are wider than the standard 530 to accommodate the orings or seal at each end of the link. There is not enough space in the CB500/550 sprocket area to accommodate this extra width. The front sprocket floats on the splines and as the sprocket teeth wear, the lateral drift of the chain chews into the engine case, and particularly a rubber shaft seal near in that area. I last tried an oring chain and found it to be about 1/4 inch wider than a standard. The extra 1/8 inch on the case side left marks on my cases after just a short drive around the block.
If you must have an o ring or x ring chain on the 500/550, a 520 type will fit. Of course, new sprockets will be required to match as well.

Also note that a smaller front sprocket makes the chain wrap tighter, it bends more, and less teeth are engaged with the chain under load. This results in faster chain and sprocket wear.

Cheers,

ponch9 · « **Reply #11 on:** April 18, 2006, 03:05:29 PM »

thanks twotired!! that is really cool to know ahead of time. That is why i am on the site, lol. any idea about the whole head thing from hondaman at the top of the string?

TwoTired · « **Reply #12 on:** April 18, 2006, 06:39:59 PM »

Yes, I know what he is talking about. But, the short verbal description alone is not enough to go on for replicating the modification. Between the intake port and the valve opening in the head is an intake runner. The modification described relates to changing the shape of this runner that is currently cast into the head by removing metal in strategic areas along the runner. The "pocket" is likely to be behind the intake valve. However, the amount of material to be removed is in question. Too much and you punch through the wall of the runner rendering it junk. Unless you know where to grind or how thick the material is where you are grinding, it might take a few cylinder heads to get it right. Unless of course, there are detailed pictures on just where and how much metal is to removed...

There is also the question of what RPM ranges this porting makes a difference. Okay, it makes 10 HP more. At what RPM? Are we reving 2k past standard redline to get this? And, how often will we need to replace pistons and rings while achieving this power? Engine specifications and changes always involve some kind of trade-off. Generally speaking, engines changed to make more power don't usually last as long. Some don't care about this. It's an individual decision.

Cheers,

ponch9 · « **Reply #13 on:** April 19, 2006, 08:57:47 AM »

yeah i know about the life cycle of a modded engine (I currently race CCS on a 2004 GSXR600 &750 and have since 1995). I am one who believes too much power is never enough.....

this pic is of the intake that i have started to grind & polish and is the arrow indicating what you are talking about? the lining that holds the sleeve? that i am assuming is to allow more airflow into the chamber. so what about raising the exhaust ports? still not sure where he is going with that?

TwoTired · « **Reply #14 on:** April 19, 2006, 10:55:08 AM »

I'm uncomfortable making recommendations about removing metal from the CB550 head as I've never done it. And, I'm not sure of my skills as Hondaman's interpreter. It's probably best to PM Hondaman for clarification.

On other port jobs I've seen, the valve guide support post was narrowed and smoothed into an oval shape parallel with the gas flow. The support post and valve stem behave as a restriction in the runner tube, So, it would make sense that the runner walls on either side of the post have a "pocket" to increase the cross sectional area of that part of the runner. I would also expect the pockets have ramps going into and out of them in the direction of gas flow. Fluid dynamically speaking, the pocket depth on each side would be half the valve stem and remaining guidepost width. But, I don't know if there is enough metal to accomplish that. Then there is the skill of making each runner have the same pocket depth and shape so they flow evenly.

Unfortunately (for this thread anyway) , I don't have one of these heads off right now for a better examination.

Oh, and forget about that most fuzzy picture award. I've taken worse.

Cheers,

VitaminCB550 · « **Reply #15 on:** April 19, 2006, 12:58:33 PM »

I believe it would make more power @ every RMP. A smoother bore is more efficent leading to a faster smoother flow. The only downside, I believe, is that the walls are thinner: worse cooling, weaker metal. Consider Extrudehone. They push an abrasive mixture through the port under high pressure. It comes out very nicely with a minimum amount of material used for the desired effect.

http://www.extrudehone.com/ <------Dramatic.

dusterdude · « **Reply #16 on:** April 19, 2006, 01:07:54 PM »

now thats an idea!

ponch9 · « **Reply #17 on:** April 19, 2006, 02:08:42 PM »

thanks. I have a million more things to ask...haha

so far things have gone well and fairly easy (bleeding knuckles aside). Now i have to figure out where to send my head and cylinder case to be machined. Most automotive shops' machines are too big. any idea as to what they usually charge for that?

I also found that i can have the cam reground but need to find a shop to do it. I called Megacycle and it is a 3-4wk lead time because they do them in cycles. plus i like to find local shops only because i like to support local buisnesses and talk person to person with peeps. I was hoping someone else has an idea.

cb650 · « **Reply #18 on:** April 19, 2006, 04:34:43 PM »

Hey guys Thanks to Paul he brought over a 550 cam today and we compared it to a 650 cam. Identical except for the lift. 650 had .030 more. What kind of gain would that be in hp? Not much but maybe a cheap substitution when rebuilding. I was wondering as one of the cam co's has a performance 550 cam that has .030 more that the 650. So who ever has a desk top dyno lets see some #'s.

Terry

TwoTired · « **Reply #19 on:** April 19, 2006, 05:32:14 PM »

Does the 650 have the same rocker arrangment? Is the distance between cam follower and pivot the same? What about rocker pivot to valve masher? If the rocker ratio is different, the cam lift is only part of the valve opening equation. Or, are you thinking of simply putting a 650 cam in a CB550?

Anyway, when you increase lift, you usually put stiffer valve springs on too, in order to get them to close at high RPM. There is also the valve spring compression height to verify.

You guys have me eyeballin' that spare 550 motor in my back yard. I wonder what's making that clunking/rattling sound from the trans when it runs?

Cheers,

ponch9 · « **Reply #20 on:** April 19, 2006, 05:37:42 PM »

crack it open....I am sure another project won't hurt....as for the noise, get louder pipes. lol. I am sure i would not try to switch a cam without a matching crank. I read that the crank would work and has for other in some past posts. have an idea what machining the heads cost?

cb650 · « **Reply #21 on:** April 19, 2006, 05:41:09 PM »

Well he didnt bring the whole head but i bet if the cams were put side by side no one could tell the diff. I am thinkin the web cam, cam for the 550 in a 650. Or a stock 650 cam in a 550. Would only be 1 mm more lift so we dont need all the extra fancy #$%*.

Terry

ChevelleSSLS6 · « **Reply #22 on:** March 21, 2008, 10:14:30 AM »

Quote from: ponch9 on April 17, 2006, 10:25:47 AM

http://sohc4.us/tech/cb550/ta2

dead link

Gordon · « **Reply #23 on:** March 21, 2008, 11:06:22 AM »

That post is two years old.

The item in the link has either been deleted or moved. Considering it was from Hondaman, chances are it was just moved and saved somewhere else.

hymodyne · « **Reply #24 on:** March 22, 2008, 12:54:47 PM »

slight hijack..
Would a 650 cam fit a 500/550K head or offer the performance benefits that have been discussed here? I have a 605 overbore kit installed on a 500K case. Mrieck is working on a valve job and porting the head.

hym

turboguzzi · « **Reply #25 on:** March 22, 2008, 03:27:10 PM »

ponch

I have put quite a lot of material in the forum about my 500 racer tuning, look at my posts from about a year ago.

Much to say about 500 tuning but its getting real late here in italy.

Soryy if I missed this but are you going to race in a certain vintage class or is it a road bike?

Cheers
TG

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Author Topic: 500/550 performance stuff? (Read 3927 times)

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