Topic: CB550 Motor Build

[Camrector]

Hello all
To help cure some winter boredom and to further my knowledge, i have decided to do a bottom up 550 engine build. But lets not just take a motor apart and put it back together, where is the fun in that. Lets give this all the bells and whistles! This will be a first for me digging this deep in a motor, so expect alot of bone head mistakes, and newb questions. Hell the whole venture could be a bone head mistake. I promise though to do my research before asking "where does this go?", to be diligent in my work, and listen to the communities wisdom. Hopefully this might help someone as well modify a 550.

Remember this is engine only. This motor does not have a home as of yet. My current build (which ill share shortly) is receiving Hondamans Gentlemen's Express motor (which there is a thread on). So i guess we could think of this as a compare and contrast as well.
So first of thank you and lets build a beast.

Plans: cruzinimage 61.5 pistons, megacycle 126-00 cam, MRieck 2.5/3 port job, all new valves, springs, etc etc, shot peen rods, send the crank to APE to lighten, and Fast by Gast gets the tranny. Carbs will be CR26s and exhaust TBD. Nothing though is really set in stone so if you guys have better ideas im all ears. The piston kit is already in my possesion, and i have dropped of the gears to Paul Gast to be race cut.


Our Motor: 77 cb550f


i picked this guy up from member Nicks2319 for $100. Nick is an awesome and solid dude, but not much was known about the engines previous life, except it had a tick. As soon as i got home i quickly began to tear it down, split the cases, bagged and labeled everything, then boxed it up to have Nils work his Vapor blasting magic on everything. Oh and like i said before dropped of the trans gears to Gast.























I have a ton more pictures but figured id start with these. Besides the exterior dirt, a chewed up cam chain tensioner, and a missing cam chain guide,(think we found the cause of our ticking) everything looked pretty good inside. Especially the bottom end. But if you guys see something please let me know.

So there we are so far.

[calj737]

Personally, if i were going to 61.5 and the crank work, I'd not muck around with stock rods but jump straight to Carrillos. And I'd definitely use HD studs. Hopefully you're getting new guides and +1mm intakes from Mike too?

[Stev-o]

Nice project, subscribed. Seems
Ike you are going all out but bought cheap Pistons.   I would have suggested forged Wisecos (I just bought a set for my H2)

[flatlander]

i'll be watching...
take plenty of photos as you take things apart, it will help when you put it back together.
if you want an all-out beast, why not a 126-20 cam?

[Camrector]

Cal: I'm not opposed to carillos. Could you explain further. And Yes the plan is to send it to Mike with a note that says "the works" lol. HD studs of course.

Steve o : It does seem that way and I don't want to beat a dead horse again with a forged vs cast conversation. These Pistons have gotten good results from others and were sourced locally. (Thanks Gv1390!). I guess the extra 9cc these provide was the determining factor

Flatlander : that cam was my first choice . But I think I read somewhere about clearance issues. Maybe someone can further provide info if that's the case.

[SOHC4 Cafe Racer Fan]

If you are going with MR headwork and a performance cam, I too would recommend the Wiseco high compression kit. The cruzinimage kit is fine for a mild hp and torque gain but the higher compression kit will give you better gains with all of the other go fast parts you are spending money on.

Carrillos are very very nice but spendy.

[flatlander]

for the pistons, the fan is spot on. also, you'll keep more of your piston sleeves with the wisecos which makes a sturdier, longer lived motor.

126-20 needs the valve reliefs in the pistons cut out. also the head needs to be clearanced.
126-00 should not need any mod to the pistons but you do need to check if it has enough clearance in the head and cover. mine fit but that's not guaranteed.

i was torn between these two but went for the -00 as i wanted to have the most possible torque for use on the road. still gained some topend due to the port job and because the cam is still better than a stock or 650 cam.
if you care about the top of your rpm range mostly than -20 would be the way to go.

[Camrector]

Excellent thanks guys. I was suspecting that maybe the cast Pistons might not be able to handle the extra compression.
Spot on Flatlander! Modifying Pistons is not something I'd like to really get into. Also seeing that it's better than the 650 cam is enough for me.

Duly noted on the Wisecos I'll order those.

[calj737]

you're not really changing the compression in a way the cast pistons you bought can't handle. But the Wisecos are a much higher quality piston. "Modifying the pistons" is simple enough. Just mill a relief pocket for the intake valve (I assume you're ordering +1mm intakes?) and there you go-

http://forums.sohc4.net/index.php?action=dlattach;topic=132935.0;attach=287334;image

I did the same recipe on my 500 build: 59mm, +1 intakes, Stage 2.5, CR-26s, 126-20, etc.

[flatlander]

yeah, are you building for a purpose or because you're lazy? what do you want from your motor?
i used that cam because it makes sense for my application. with the lightened crank and all, it seems like you're building for performance at high rpm range. combined with a an nicely flowing exhaust, the 126-20 would maximise the benefit.

[Camrector]

Food for thought Cal thanks. And yes the recipe is looking a lot like yours. Seeing that I'm into the bottom end of this thing, did you also use carillo rods? Interested to hear what's really different that shot peening the stock rods. I was under the impression that these beefy little stock guys could handle quite a bit of power? Carillos I assume are lighter and stronger?

[Camrector]

Flatlander Why would building a motor myself denote laziness? Purpose of this motor is to build a motor. Might as well make it better/faster/stronger while doing so. We could go more top end power band or make it more hot street. But we have plenty of time to decide on top end changes.

[flatlander]

well if the only reason for not using the 126-20 cam boils down to not wanting to make a small modification to the pistons... then i just want to give you a nudge to come up with some better excuses, or even an idea of what "better faster stronger" means to you, and a logical plan to get there

i understand that you're experimenting to some degree (i guess we all are...) but having a goal will help you make better choices overall.

[calj737]

Lighter, stronger and better bolts.

[bwaller]

550 rods are quite good, but definitely change to 750F3 bolts & nuts. If you want to be absolutely sure and sleep like a baby at night Carrillo is only one call away!

I designed 60mm pistons and Mike Rieck has a set he'd likely be happy to move. They're very light weight, tapered pins, thin rings and a skirt coating. CR can be as high as 1:12, but with different gasket thickness drop that to a decent level for the street.

[SOHC4 Cafe Racer Fan]

550 rods are quite good, but definitely change to 750F3 bolts & nuts. If you want to be absolutely sure and sleep like a baby at night Carrillo is only one call away!

I designed 60mm pistons and Mike Rieck has a set he'd likely be happy to move. They're very light weight, tapered pins, thin rings and a skirt coating. CR can be as high as 1:12, but with different gasket thickness drop that to a decent level for the street.

Hah! Now the cat's out of the bag on your new pistons!!  If you could get away with mating them with a 650 head . . .   

Brent, out of curiosity, what engine mods are allowed/not allowed in your race class?

[GV1390]

If you could get away with mating them with a 650 head . . .

Sigh...

[Camrector]

I'm not opposed either to that idea Brent! But would it be fair to build a track bike and get out there with you, only to have you stomp the bejesus out of me on parts you built for my motor 
I'll promise to tell you how good your butt looks. But I'd need probably some type of telescope mod because you'd be that far in front.
Does anyone know if the wiseco 592 61Rs have a big enough valve pocket already for the Megacycle 126-20?

I'll ask Mike about those Pistons, cause it looks like you guys might want to see a race build.

[SOHC4 Cafe Racer Fan]

Does anyone know if the wiseco 592 61Rs have a big enough valve pocket already for the Megacycle 126-20?

Dunno, but the Megacycle 126-20 produces no clearance issues with a Dynoman 674cc kit for a CB650!

[bwaller]

I doubt those pistons have deep enough valve pockets for the extra lift of the 126-20. Aren't these the pistons Cal used? If so he had to address this issue. The pistons I mentioned will work fine in a street bike and the pockets are already deep enough. Bare piston is 119 grams. I think Mike still has them. If you do go racing, good for you!

Don, re allowable engine mods, we are allowed a 5% bore increase (over 550) hence 60mm. Any cam/head work/valves your heart desires plus gearbox/ignition are without restriction. Exhaust and carbs are supposed to be "period" although guys are now getting away with modern CR's. Basically if the engine's exterior looks stock, the only restriction is that 5% ovebore rule.

[SOHC4 Cafe Racer Fan]

I doubt those pistons have deep enough valve pockets for the extra lift of the 126-20. Aren't these the pistons Cal used? If so he had to address this issue. The pistons I mentioned will work fine in a street bike and the pockets are already deep enough. Bare piston is 119 grams. I think Mike still has them. If you do go racing, good for you!

Don, re allowable engine mods, we are allowed a 5% bore increase (over 550) hence 60mm. Any cam/head work/valves your heart desires plus gearbox/ignition are without restriction. Exhaust and carbs are supposed to be "period" although guys are now getting away with modern CR's. Basically if the engine's exterior looks stock, the only restriction is that 5% ovebore rule.

I believe Cal did some relief pockets on the domes for the combo of his pistons and cam.

[calj737]

Yup, link to image is above.

[SOHC4 Cafe Racer Fan]

Yup, link to image is above.

Cal,

You went with the Megacycle 126-20 on that engine, right?

I wonder if the pistons need to be notched for the 126-00.

[flatlander]

i use the wiseco 59mm pistons with the 126-00 cam. no notching necessary with that combo.
and i remember cal used the 126-20 and did need to notch. not sure what pistons he's got, though.

[SOHC4 Cafe Racer Fan]

i use the wiseco 59mm pistons with the 126-00 cam. no notching necessary with that combo.
and i remember cal used the 126-20 and did need to notch. not sure what pistons he's got, though.

I'm pretty sure Cal is using the Wiseco kit.