Author Topic: StrongPerf CB550 Engine Build - Gentleman's Express Style (Read 26030 times)

StrongPerf · « **on:** December 29, 2008, 01:13:49 PM »

I've decided to rebuild my 74 CB550 engine. It is stock and has 25,000 miles on it now. It has low compression on 2 cylinders.

I intend to build a 590cc, higher compression motor with a ported head and CB650 cam. I already have the CB750 pistons and CB650 cam. I chose this route because used 750k pistons are cheap and good rings are easy to find. I will document as much as possible here.

I appreciate any help. Thanks

Here is some of the teardown.

I can already see I'll need a primary chain because it's rubbing the case. Looks like I'll be splitting it apart and doing everything.

StrongPerf · « **Reply #1 on:** December 29, 2008, 01:28:32 PM »

It looks like the cam cover is good and without wear in the cam saddles. I still need to check for rocker shaft wear in the cover.

The rockers do have a pattern of wear but light. The one on the left looks different and off to one side a little compared to the rest. I still need to check for wear on the shaft and end play.

StrongPerf · « **Reply #2 on:** December 29, 2008, 01:30:06 PM »

Some crud in the pan.

FunJimmy · « **Reply #3 on:** December 29, 2008, 01:50:40 PM »

Looks good Jens.
The newer 77 rocker cover has locks on the shafts to prevent wear.
Let me know if you need one.

Cheers
FJ

StrongPerf · « **Reply #4 on:** December 29, 2008, 01:54:46 PM »

Quote from: FunJimmy on December 29, 2008, 01:50:40 PM

Looks good Jens.
The newer 77 rocker cover has locks on the shafts to prevent wear.
Let me know if you need one.

Cheers
FJ

Will do. Should know soon...

StrongPerf · « **Reply #5 on:** January 05, 2009, 08:37:46 AM »

So I checked out the valve cover. I have no rocker wear on the shafts or shaft wear in the cover. I do have some side clearance issues.

The manual says .004"-.008" max on rocker side clearance. I have .016 on most and .032 on one.

I don't understand why they want such a small number. There is no oil pressure around the shaft. I can understand they want to keep the lash adjuster in the center of the valve stem. The problem is I think the cover is worn more than the rocker. A steel rocker rubbing on an aluminum cover doesn't seem to be good anyway. I don't want to buy new rockers because the cover is what's worn. I wonder if a new (used cover) will be any better. I think the best approach might be to shim each side of the rocker to the proper clearance which should also stop future wear into the cover. Steel shim stock is available in all thicknesses needed for much cheaper than even one rocker.

FJ, I have not seen the clips on the 77 model cover and I'm not sure they address this problem. Have you measured rocker side clearance on your available side cover? Do the clips address this issue? Do you have a pic of the clips?

Thanks

FunJimmy · « **Reply #6 on:** January 05, 2009, 10:01:06 AM »

Haven’t measured anything yet. I’ll take a good look at it tonight.
The update consists of a couple of shaft anti rotation pins.
It is intended to prevent the rocker shafts from rotating and wearing the shaft bores.

PM with your email address and I'll send you the service bulletin

FJ

FunJimmy · « **Reply #7 on:** January 06, 2009, 02:13:40 AM »

SP

Interestingly, I couldn’t find anywhere in the Honda factory manual, a service limit for rocker side play. Those numbers you give are only listed in my Clymer manual. After checking both of my rocker covers I find that 0.020” to 0.030” is quite common. Close visual inspection suggests that these tolerances are normal factory tolerances and not wear. I also discovered that my extra rocker cover is pre ’77 and not the cover with the anti-rotation pins. Sorry.

For what it's worth.
FJ

StrongPerf · « **Reply #8 on:** January 06, 2009, 07:49:55 AM »

No sweat. Thanks for trying.

That's good info to know. I don't think .004"-.008" is realistic. The rocker with .032" wear is the only one that shows any wear and it's in the aluminum. I think I'll shim it and run it.

I bet if we check 1000 covers none would have .004"-.008".

Moving on to the next issue. Intakes are ported. Will work on the exhaust this weekend. Machining pistons to follow.

turboguzzi · « **Reply #9 on:** January 23, 2009, 01:21:33 PM »

wouldnt worry about rocker side play....

will be interesting to see what shape of piston top you end up with

cheers

TG

StrongPerf · « **Reply #10 on:** February 18, 2009, 03:53:21 PM »

Time to get the machine work done for the engine. I'm live 1.5 hours from APE so I will give them a shot. I called and they quoted me $189 for a valve job +parts, $189 to bore and hone the jugs and $30 to surface the head. I plan to machine the piston crowns myself. They said it should take 4 weeks. Thoughts? Comments?

HondaMan · « **Reply #11 on:** February 18, 2009, 08:44:05 PM »

Quote from: StrongPerf on February 18, 2009, 03:53:21 PM

Time to get the machine work done for the engine. I'm live 1.5 hours from APE so I will give them a shot. I called and they quoted me $189 for a valve job +parts, $189 to bore and hone the jugs and $30 to surface the head. I plan to machine the piston crowns myself. They said it should take 4 weeks. Thoughts? Comments?

Locally, I'm told a 3-size overbore is about $200. I'd wonder what is done to the valves for $189: if it's just lapping, you could do that in an afternoon. Do you have leaking valves?

The last head I had surfaced was far too expensive, at $40. The one before that was $10. But, these are Colorado prices....

StrongPerf · « **Reply #12 on:** February 19, 2009, 06:18:52 AM »

Lapping the valves surely won't do the trick. I hit the seats with the cutter in a couple of places when porting. Plus they look pretty pitted to begin with.

So these prices don't look far off the mark (especially for APE/California work...) it seems.

Thanks for the input.

Well I'll be dropping off the parts tomorrow. It feels good to make some progress!

A Grove · « **Reply #13 on:** February 19, 2009, 09:58:13 AM »

Super-newb here...

I am going to be cracking into my '77 550k engine here and doing a overhaul/giving 'er some balls. I have been searching for an overbore kit for our 550's that is reliable, etc for a while now with no luck. What all is required to run 750 pistons in a 550? I'd love to up compression while at it as well..

Beyond that, going for a mild street cam, port job, and lots of new bits here n there. You seem to have a very good idea of what you are doing, I'd love to hear more details on what is involved to make these pistons run in the 550. Thanks!!

StrongPerf · « **Reply #14 on:** February 19, 2009, 11:43:25 AM »

Quote from: A Grove on February 19, 2009, 09:58:13 AM

Super-newb here...

I am going to be cracking into my '77 550k engine here and doing a overhaul/giving 'er some balls. I have been searching for an overbore kit for our 550's that is reliable, etc for a while now with no luck. What all is required to run 750 pistons in a 550? I'd love to up compression while at it as well..

Beyond that, going for a mild street cam, port job, and lots of new bits here n there. You seem to have a very good idea of what you are doing, I'd love to hear more details on what is involved to make these pistons run in the 550. Thanks!!

Stay tuned and you will find out. If I get some time I'll send some info your way via PM. You can PM me your e-mail address and I can send you an article that will explain it all.

A Grove · « **Reply #15 on:** February 19, 2009, 01:49:31 PM »

You, sir, have a PM

turboguzzi · « **Reply #16 on:** February 23, 2009, 11:18:29 PM »

a bit late here, but

at that kind of money I'd consider buying new valves from david silver and a hand seat cutter form those guys in australia, (cant remeber their name)

And next time, dont touch your seats when porting!..... re-cutting the seats deeper is never good for flow and you might also need to re-shim the valve springs for correct spring length.

TG

StrongPerf · « **Reply #17 on:** February 24, 2009, 07:50:17 AM »

I need to find out the stock rocker ratio. I'm using a CB650 cam which I measure at .300" lobe lift on the intake and .290" on the exhaust. To decide which valve spings to run I need to figure total valve lift...

Also, which rings should I run. I know that OEM Honda are available for the std CB750 piston. Also Hastings makes a package for this piston in std diameter. Others? Can anyone tell me what the best ring value is for the std CB750 piston?

Thanks for the help!

FunJimmy · « **Reply #18 on:** February 24, 2009, 09:39:51 AM »

Markus

I'm planning on checking the cam timing and lift of my 650 cam and will post the results when available.

FJ

A Grove · « **Reply #19 on:** February 24, 2009, 09:51:27 AM »

I am curious, are you running/using used 750 pistons? If so, is there anything I have to watch out for when tracking down pistons to use? I am pretty dumb with engines, trying to learn tho, so sorry for the stupid questions.

StrongPerf · « **Reply #20 on:** February 24, 2009, 09:53:56 AM »

Quote from: A Grove on February 24, 2009, 09:51:27 AM

I am curious, are you running/using used 750 pistons? If so, is there anything I have to watch out for when tracking down pistons to use? I am pretty dumb with engines, trying to learn tho, so sorry for the stupid questions.

Yes and Yes. There are 2 types. F and K. F is higher compression. You want to use the K. You want to make sure that the skirt barrel shape has not worn away. APE checked (with a micrometer) mine and they were fine.

A Grove · « **Reply #21 on:** February 24, 2009, 10:26:04 AM »

Awesome, thanks. What compression are you going to be running when all said and done?

StrongPerf · « **Reply #22 on:** February 24, 2009, 10:30:53 AM »

Quote from: A Grove on February 24, 2009, 10:26:04 AM

Awesome, thanks. What compression are you going to be running when all said and done?

I don't know yet. More than stock. Stay tuned... Dig around in that article page I sent you. I think it says it. Maybe 10.25? Not sure...

A Grove · « **Reply #23 on:** February 24, 2009, 10:36:40 AM »

I read through and was un-able to find it. No biggy, you'll be done with yours before I even get mine started

Can't wait to see some pics of the machining, etc.

moham · « **Reply #24 on:** February 28, 2009, 07:21:13 AM »

Quote from: A Grove on February 24, 2009, 10:36:40 AM

I read through and was un-able to find it. No biggy, you'll be done with yours before I even get mine started Can't wait to see some pics of the machining, etc.

In the last paragraph of that article it says the engine was "a point higher than stock". Stock CR for the 550 is 9.0:1. When they say a point, do they mean a tenth or a full point? So, it's either 10.0:1 or 9.1:1. Probably 10:1...

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Author Topic: StrongPerf CB550 Engine Build - Gentleman's Express Style (Read 26030 times)