Topic: Need help with my 550k motor rebuild!

[A Grove]

Well.. It's that time of the year.  Starting a build on my "spare" 550.  I am rebuilding the motor, customizing the bike, etc... But I'm engine dumb and need some input as to what to replace, etc.

Firstly, I want to keep it a stock bore. 
I plan to do some mild porting myself (machineshop in my basement..)
I am getting OEM Honda rings
And I am getting a megacycle cam w/ 126-00 grind (spikey's running one)


And beyond that... I don't know what else to do.

Valves? Guides? Retainers? Valve Springs? Camchain? Cam Tensioner?


I'm not looking to build a "race" motor, but I want a strong, reliable runner that I can get my feet wet with and hopefully in a year or two I can do a MAJOR rebuild/machine job on my current running 550k (in the cafe')

I searched around for the past two days, got "some" information, but nothing specific like I am looking for....

I really appreciate any help anyone can provide!!
Thanks!!

[mmtsquid]

Well, what needs to be done is really a function of wear - download the service manual and make sure all of the measurements are in spec.
If it's in spec - don't mess with it!

If you are porting the head, before you remove the valves dump some penetrating oil into the back side of the port and let it sit for a day.
If nothing leaks out through the valves, then they are seated correctly and need nothing other than to remove all the carbon gunk off of them.
If they do leak, you'll need to lap the valves (not difficult, just boring).
I'm not sure about your particular cam, but the website should tell you if you need stiffer springs/different retainers.

Camchain and tensioner - you can visually inspect the tensioner for wear per the manual, but the chain is a different story - depends on how many miles the engine has on it.  It's a real PITA, so if it doesn't need replacing, leave it alone!

[Spikeybike]

get the valve springs megacycle makes, they aren't totally necessary but they are very inexpensive as far as valve springs go ,  i believe mine were like 50 bucks (cheap insurance)  they aren't that much stronger then stock according to megacycle, but my springs were out of spec so i got them.   on the other hand ,the grind on that cam is not that high, so if your springs are to spec it wouldn't be a terrible idea to reuse them. and as far as retainers, that depends on how deep your pockets are, the nice ones are pricey (150+) and with the mild grind cam , in my opinion they are overkill , just reuse the stock the ones

definitely get a cam chain,  (more cheap insurance)
and seriously concider NEW rocker arms (david silver spares) , megacycle voids the warranty if you don't get new ones. megacycle used to reface rockers , not sure if they still do, many have skipped this step , i am not one of them

and from what i've read your gonna want to degree the cam in, i haven't done this yet, and plan on documenting the process this winter once my ported head is finished ,so watch for that (we might just go through it together)  but even running the cam off the stock marks , its a huge improvement so i can't wait to get it degreed in

hope that helps


oh yeah one more thing , i plan on having a pro tell me if i need new guides or not,   i know how the process is done, i just trust a pro's tools and experiance more then my own
 the modding you (we) are doing is mild by comparison, so don't go to over board with the parts

[A Grove]

I plan to tear the entire engine apart to paint it, etc anyhow.  So now is the time to do all the replacing of parts to get it like new again.

Let me rephrase... I am willing to spend the extra money to ensure that once I put this beast back together, it can run for another 35k miles without any major problems.  That being said, I know "#$%* happens" but I want to take all the precautions to make sure nothing does. 

OK.

-rings
-cam
-cam chain
-valve springs
-retainers
-rocker arms

I understand things are mild, but I just don't want to miss any steps.  If what I have above is plenty for a mild cam (and otherwise STOCK motor), then I'll leave it at that and move on.

Thanks both of you for the replies.

[psykod]

Make sure to check your primary chain...I didn't change mine when I rebuilt my 550 and now I'm regretting it.

[A Grove]

I'm sorry, not sure what a primary chain is?

[Spikeybike]

-rings
-cam
-cam chain
-valve springs
-retainers
-rocker arms

I understand things are mild, but I just don't want to miss any steps.  If what I have above is plenty for a mild cam (and otherwise STOCK motor), then I'll leave it at that and move on.

that sounds perfect (to me) for what your after .

when you get it all open post a pic of your cam chain tentioner, it may be obvious that it needs a replacement, but we can tell you for sure

actually , if your planning on a refurbishing the entire motor and money is no option, break out the parts book and replace everything made of rubber
-cam chain tentioners (there's two, one rubber one plastic, chesk DSS for those)
-oil seals .. if your tearing apart the motor you'll want to replace those anyway
-oil guides.. ther's two of those i think
-all the o-rings and gaskets (if you get a kit , they're all there)

might not be a bad idea to get  clutch plates and springs (i absolutly love my Barrnet clutch, i've heard some complain that the springs are overkill but it doesn't bother me at all)
and at that point i would do the sprokets too (front and rear) 

man your making me what to build another motor 

[bryanj]

Primary chain is what connects crank to transmission and can eat away the crankcase when worn

[BlindJoe]

You're going to hone your cylinders too right?

[MRieck]

Stock retainers are fine. You need a cut up cam cover to time the cam.

[Spikeybike]

Stock retainers are fine. You need a cut up cam cover to time the cam.

you do ?

[MRieck]

Stock retainers are fine. You need a cut up cam cover to time the cam.

you do ?

How else can you get to the cam sprocket bolts to adjust the sprocket?

[RRRToolSolutions]

AGrove, there is one component that I feel is key to efficiency. It can make day/night difference in performance and it has absolutely nothing to do with longivity, reliability, and once done becomes a simple maintenance item years down the road.

Have your head ported by someone who knows what they are doing. It's not about bigger - it is about improving flow and removing certain shapes present in 35 year-old ports. If you do it up-front, then you can go through many builds down the road and enjoy the same port work for years. Porting works with stock compression, high compression, stock bore, big bore - and anytime you get "better flow" you fill the cylinder more efficiently and that generates higher torque. I'd have to check my math, but I think I remember the cylinder trying to fill some 50 times per second at 9,000 rpm. This is as you will agree - not long.

If they are too big, then you won't get volumetric efficiency until it's near full rpm and only if all other components can support it. If you have an efficient, high velocity port flow, you get a filled cylinder and the added benefit of having that velocity continue to fill as the cam starts closing the valves and the pistons pass BDC and start positive pressure. This will translate into noticible gains in peak torque and spread over wider rpm. Torque is what moves you through the rpm range, off the corners, up hills, and adds significantly to the smile factor. You go messing around with ports without flowbench study and lots of practice in what works - you'll likely hurt filling efficiency or create something even the gods can't fix. Spend the couple hindred and have those 35 yeard-old designs turned into near modern wonders. You'll be amazed at what a vintage 2-valve engine is capable of. With the 500/550's it's easy to add cc's and cams later if the desire arrives. A good head design will support you in everything from stock to near wild with no downsides. I am absolutely convinced headwork alone is more responsible for my CB's thrilling performance. I don't own another vintage bike that can pull corners from 2,000 to 11,000 - I give credit to the ports!

Regards,
Gordon

[Spikeybike]

Stock retainers are fine. You need a cut up cam cover to time the cam.

you do ?

How else can you get to the cam sprocket bolts to adjust the sprocket?

i was thinking it would require ALOT of removal/install of the cam cover while timing,  meaning: set the cam, back off all the tappets, pull the cover, tighten the bolts, reinstall, repeat ....... i've never done this and have no idea if it's even possible 

     ...but that sounds a whole hell of alot easier , i doo have and extra cover i could cut up ,  hmmm. not sure if i have any extra rockers for it though...   i'm gonna bring that to work and slice it up tomorrow

AGrove, there is one component that I feel is key to efficiency. It can make day/night difference in performance and it has absolutely nothing to do with longivity, reliability, and once done becomes a simple maintenance item years down the road.

Have your head ported by someone who knows what they are doing. It's not about bigger - it is about improving flow and removing certain shapes present in 35 year-old ports. If you do it up-front, then you can go through many builds down the road and enjoy the same port work for years. Porting works with stock compression, high compression, stock bore, big bore - and anytime you get "better flow" you fill the cylinder more efficiently and that generates higher torque. I'd have to check my math, but I think I remember the cylinder trying to fill some 50 times per second at 9,000 rpm. This is as you will agree - not long.

If they are too big, then you won't get volumetric efficiency until it's near full rpm and only if all other components can support it. If you have an efficient, high velocity port flow, you get a filled cylinder and the added benefit of having that velocity continue to fill as the cam starts closing the valves and the pistons pass BDC and start positive pressure. This will translate into noticible gains in peak torque and spread over wider rpm. Torque is what moves you through the rpm range, off the corners, up hills, and adds significantly to the smile factor. You go messing around with ports without flowbench study and lots of practice in what works - you'll likely hurt filling efficiency or create something even the gods can't fix. Spend the couple hindred and have those 35 yeard-old designs turned into near modern wonders. You'll be amazed at what a vintage 2-valve engine is capable of. With the 500/550's it's easy to add cc's and cams later if the desire arrives. A good head design will support you in everything from stock to near wild with no downsides. I am absolutely convinced headwork alone is more responsible for my CB's thrilling performance. I don't own another vintage bike that can pull corners from 2,000 to 11,000 - I give credit to the ports!

Regards,
Gordon

man i can wait 

[paulages]

Stock retainers are fine. You need a cut up cam cover to time the cam.

you do ?

How else can you get to the cam sprocket bolts to adjust the sprocket?

air-ratchet and a 10mm socket...  almost cut a spare cover up to time the 718, but it wasn't that difficult to R&R the cover in between adjustments.

[paulages]

I'm sorry, not sure what a primary chain is?

really don't mean to sound snide, but if you don't know what the primary chain is, you've got your work cut out for you. the good news is, anyone with half a brain, a decent repair manual, and this wonderful site can rebuild your engine. you'll want your cylinder bores measured well with a dial-bore gauge, and want to make sure the piston skirts don't have wear on their sides. overheating can cause this, and can cause failure if run too long damaged. before you buy rings, have a reputable shop measure your bores against your pistons and verify that your clearances will allow you to keep the stock bore.

unless the engine was run really hard or really mistreated, the main and rod bearings will probably be fine. if you want to be sure, plastigauge them. replace: cam and primary chains, all cam chain tensioner parts available, all gaskets and seals, and o-rings. lap or recut valve seats, and re-ring. should have a great engine if you do all this.

[A Grove]

paulages... I understand exactly what you're saying, but to be honest, I am wanting to rebuild the motor to LEARN about these things more.  In my opinion, half the fun of learning about things is getting your hands dirty and learning by experience (with help... is always a good thing) 

I appreciate all the input, got most all my information.  I'll be refering back here and posting as I start the build process, I'm sure.

Thanks!

[A Grove]

Spikey, where did you source the barnett clutch/springs specific to the 550?  Also, do they offer any big gains over stock?  for future modifictaion/ longevity, etc.  Thanks

[A Grove]

...DURR.  the one time I post before searching...
http://www.barnettclutches.com/products/clutch_plates_springs.aspx?type=clutches_other&clutch_make=Honda&clutch_cc=550

[Spikeybike]

 



it does shift smoother , the springs are more heavy duty , the main thing i noticed was having to pull the lever ALOT less (meaning, lever travel distance)    i could pull it a quarter of the way and shift

[ieism]

Read Hondaman's posts in the FAQ section.

I agree that a professional portjob makes a huge difference. You can pick up a lot more flow in these heads without removing much if you're know what you're doing.

My ports measured 9% more flow, but didn't look like they had much work done.

[A Grove]

Welp, I am digging back into my bikes from a crazy busy winter... Dug this thread back up to read, re-read, and now I've got MORE questions.. hey whats new

After talking with StrongPerf and following his thread, I've decided to copy the gentlemans express/strongperfs ideas and machine my motor to run stock cb750 pistons.  When all said and done, the goal is to aim for higher compression, a tad bit added to the CC's (590cc), and also have the ability to run more readily available rings.

I'm wanting to build up a pretty hot motor, so instead of running the 126-00, im planning to run the 126-20 grind instead.  Megacycle claims you will need modified pistons and new springs.  I was planning to re-do practically the whole motor anyhow, so not a huge deal there.  But I do have a few questions..

1. what is meant by "modified pistons?"  Higher compression?
2. I am assuming megacycle springs will work great for my given application, opinions?

I'm sure there will be more, but that does it for now..

[Spikeybike]

if you need the 750 pistons i have some i could sell ya real cheap

[A Grove]

PM'd you....

[A Grove]

OK. so pistons are now accounted for, thanks spikey!

Anyone have input on the 126-20 cam?