Author Topic: Do I need head? (Read 4531 times)

FunJimmy · « **on:** February 12, 2009, 12:52:28 AM »

Pardon the pun but that's a bit of a loaded question. Har har har. Of course I need head. What normal functioning male doesn’t? Dam, there goes the politically correct content too.

Anyway, we’ve all read it in the manual. The statement about camshaft bearing inspection.
If you haven’t it reads: Inspect the camshaft bearing surfaces. Camshaft bearing surfaces should be smooth and shiny. If it is scratched or excessively worn, it should be replaced.

Clymers says: The surfaces of the camshaft bearings should be smooth and shiny. If the surfaces are scratched or worn, the head must be replaced.

Now I’ve gotta believe that these guys are in cahoots with each other to sell more heads. Take a look at the pictures of my camshaft bearing surfaces. Do I need head?

fuzzybutt · « **Reply #1 on:** February 12, 2009, 01:00:09 AM »

those look better than the ones in my k4. i wonder if they can be bored out and have bushings put in.

bryanj · « **Reply #2 on:** February 12, 2009, 01:50:29 AM »

If thats a 550 No you dont thats normal "polish" marks

bwaller · « **Reply #3 on:** February 12, 2009, 03:21:31 AM »

Rare to see them without those marks.

tygrant · « **Reply #4 on:** February 12, 2009, 04:38:52 AM »

we all need head! sorry i had to

MRieck · « **Reply #5 on:** February 12, 2009, 04:42:18 AM »

Normal wear

Soos · « **Reply #6 on:** February 12, 2009, 08:41:47 AM »

Plastiguage would be the definitive answer for you.

Looks no better or worst than the running cb's i've been into.
You got what, 20k+ miles on it?
You should see what my stock '79 cb650 head.
It had about 50k on it when removed.
Doesn't look that much different from a 10k cb650 head.

It ran, what more do I want.

A dedicated setup would be needed to bore the bearing diameter.
Then you gonna bush them, or deck a part to be able to re-bore to size?
not impossible, just wouldn't be anywhere cheap... unless you were doing lots of them.

You worried about too big of gaps? Run a heavier weight oil.
(noo, really , i didn't just mention oil, people move along, nothing to see.)

l8r

mystic_1 · « **Reply #7 on:** February 12, 2009, 08:53:44 AM »

I'm curious, would it be a good idea to polish out those marks, or is this unnecessary and/or a bad idea?

mystic_1

crazypj · « **Reply #8 on:** February 12, 2009, 09:04:32 AM »

I would polish them out using 1000 grit.
Clearance may be slightly tight allowing cam to contact head during cold starts (when the bearings 'shrink')

PJ

goon 1492 · « **Reply #9 on:** February 12, 2009, 09:24:36 AM »

That's very interesting as to I am new to the 500's, and also +1 on what Tygrant said. Women need it too though

fastbroshi · « **Reply #10 on:** February 12, 2009, 10:03:08 AM »

Everybody needs it really. But good to know about the scratches. I asked my machinist. I do trust the wily old fart as he still drag races mini versions of Top Fuel cars (don't know what they're called, but they run aluminum block, half V8 pontiac motors) and he's an aluminum wizard. He said it's normal as well.

FunJimmy · « **Reply #11 on:** February 12, 2009, 03:52:36 PM »

Good to know.
I thought it seemed overkill to throw away a good head just for scratching.
Maybe the scratched will hold the oil better. LOL

Thanks for all the input.
Jimmy

Jerry Rxman Griffin aka MuthaF'er · « **Reply #12 on:** February 12, 2009, 06:51:09 PM »

I wouldn't even attempt to polish them without the proper piece of expensive equipment! I'd like to think that round is MUCH better than out of round.

Besides, where are you going to find a new or even better replacement?! Use it.

Soos · « **Reply #13 on:** February 13, 2009, 01:06:55 PM »

Quote from: Jerry Griffin aka Rxman on February 12, 2009, 06:51:09 PM

I wouldn't even attempt to polish them without the proper piece of expensive equipment! I'd like to think that round is MUCH better than out of round.

Besides, where are you going to find a new or even better replacement?! Use it.

+1

Round with a few blemishes are WAY better for longevity of a motor than polished and a un-true surface.(out of round, taper, high and low spots)

Unless changing a cam I wouldn't even think of it.
Even then with trepidation.

You cam has worn to your head, as well as your head wearing in to your cam.
change things now, and you will get even more wear in a shorter time, because the head will again have to wear into for the cam.

l8r

FunJimmy · « **Reply #14 on:** February 13, 2009, 04:06:00 PM »

Quote from: Soos on February 13, 2009, 01:06:55 PM

Your cam has worn to your head, as well as your head wearing in to your cam.
change things now, and you will get even more wear in a shorter time, because the head will again have to wear into for the cam.

Different cam this time around. Probably a 650 cam or maybe a Webcam, but either way I'll leave things well enough.

FJ

Terry in Australia · « **Reply #15 on:** February 13, 2009, 04:20:07 PM »

I'm in the process of rebuilding a 550 engine and installing a "605" kit (actually a 591.75cc kit, but that doesn't sound as cool) for Al, the wear in his cam bearings is about the same as those, and I'm thinking of using some "Pro-Ma" grease as a re-assembly lube, it contains particles of lead and copper that fill and polish scratches in damage like this.

I've used it in my Suzuki GS1000S engine when I did a top end rebuild and last time I pulled the cams out to do the valve shim adjustments those areas were as smooth as butter, and you could see the copper had filled the scratches. The only down side is that this stuff can make the clutch slip, so I'll just use a small amount. Cheers, Terry.

Spanner 1 · « **Reply #16 on:** February 13, 2009, 04:41:21 PM »

No hijack...just to tell Terry in Aus. how sorry we are for the major tragedy due to the wild fires this week. So sorry, mate.

Terry in Australia · « **Reply #17 on:** February 14, 2009, 05:07:48 AM »

Quote from: Spanner 1 on February 13, 2009, 04:41:21 PM

No hijack...just to tell Terry in Aus. how sorry we are for the major tragedy due to the wild fires this week. So sorry, mate.

Thanks for that mate, I appreciate your taking the time to express your concern. Cheers, Terry.

moham · « **Reply #18 on:** February 14, 2009, 07:26:39 AM »

So, FunJimmy, looks like no head for you , pal...

MRieck · « **Reply #19 on:** February 14, 2009, 07:52:43 AM »

Quote from: moham on February 14, 2009, 07:26:39 AM

So, FunJimmy, looks like no head for you , pal...

He's married too??

FunJimmy · « **Reply #20 on:** February 14, 2009, 07:59:03 AM »

Quote from: moham on February 14, 2009, 07:26:39 AM

So, FunJimmy, looks like no head for you , pal...

Quote from: MRieck on February 14, 2009, 07:52:43 AM

He's married too??

Thanks for stating the obvious guys! LOL

Jimmy

masonryman · « **Reply #21 on:** March 21, 2009, 03:36:52 PM »

I just bought a head, no really a 1976 cb 550 ss head with cam but not the valve cover/ rocker assembly. I think the wear in the bearing area is fine but the cam has some pitting right on the end of the lobes, the 1st and 3rd from left to right.

The cam was just thrown in so no biggie one way or another. from the marks on the cam journals it looks like the bike had been sitting is it possible these pits are from rust or is this a common find in these old bike. does any one do regrinds on these cams to get more lift

Mark

City Boy · « **Reply #22 on:** March 21, 2009, 03:55:05 PM »

Hi Terry.Tell us more about that Pro-ma stuff.Sounds neato.Is it widely available.I would sure add it to my tool chest if I can. Rock On Jim

FunJimmy · « **Reply #23 on:** March 21, 2009, 09:16:38 PM »

Mark

Both Webcam and Megacycle do regrinds on OEM cams.

FJ

masonryman · « **Reply #24 on:** March 21, 2009, 09:53:50 PM »

mega cycle is a little pricey but it seems they would give better results for what I am looking for. I am not that concern about it's manners, I am looking for a little obnoxious.

Mark

FunJimmy · « **Reply #25 on:** March 22, 2009, 11:13:03 AM »

Mark

I agree. The Megacycle cam specs looks the best to me too, but others are convinced that the Webcam profile is right.
It's all a matter of preference I guess.

MegaCycle - 126-20

lift dur. lobe ctr Description Timing
.363" 259° 104.5° Must use modified piston and springs. Road 25 btc/54 abc .004"
.333" 259° 104.5° race or street/strip. Great throttle response. 54 bbc/25 atc .005"

This spec is very close to the Yoshimura Cam of the 70's

FJ

News:

Author Topic: Do I need head? (Read 4531 times)

fuzzybutt

masonryman

masonryman