Topic: CB550 Motor Build

[calj737]

Is there a Stage 4 for a 550 head? Stage 3 has O/S valves, Serdi, and all the porting and polishing a man can muster. I was under the impression a Stage 4 job was relevant to 750 heads  Stage 2, 3 or 31 won't matter, Mike does beyond excellent work and I'm sure the motor will be very healthy for a 550.

[Retro Rocket]

OOOOOH   stage 31.....

[Camrector]

I guess we can call it "Stage 3 plus" lol. The oversize valves are recommended for the stage 3 but not included.

[SOHC4 Cafe Racer Fan]

As I understand it:

Stage 1: Includes the following. Disassemble, inspect, hot tank, bead blast entire head, porting
and reassembly. OEM valve guide seals are extra OR can be provided by the customer.

Stage 2: Same as above but more extensive porting especially around the guide boss and intake
floor.

Stage 3: Requires removal of valve guides. Extensive reshaping of both intake and exhaust ports.
Epoxy reinforced intake spigots. This head will require new guides, guide honing and a Serdi
valve job. Basic price minus guide and valve seat work….please take note!!! This head
performs best with oversize (33.5) intake valves and cams with lifts .360 and over. A great
performing street head with 836cc and larger…..This head kicks ass…..no disappointments no
matter the displacement (400cc, 500/550cc, 750 etc.).

Stage 4: Unofficially on the menu as a Stage 3 PLUS oversize valve kit.

[calj737]

Stage 3: Requires removal of valve guides. Extensive reshaping of both intake and exhaust ports.
Epoxy reinforced intake spigots. This head will require new guides, guide honing and a Serdi
valve job. Basic price minus guide and valve seat work….please take note!!! This head
performs best with oversize (33.5) intake valves and cams with lifts .360 and over. A great
performing street head with 836cc and larger…..This head kicks ass…..no disappointments no
matter the displacement (400cc, 500/550cc, 750 etc.).

Stage 4: Unofficially on the menu as a Stage 3 PLUS oversize valve kit.

As posted above, 33.5 intakes are for the 750, 28 for the 550/500. The cam lift is much higher too.

[Camrector]

Well I'll have the lift (.363) from the cam, but not the 33.5 on the intakes lol

[MRieck]

Well I'll have the lift (.363) from the cam, but not the 33.5 on the intakes lol

That would be a tight fit.....28.5 intakes

[akabek]

Any progress on this build?  Are you going to use the Power-Barn CR26 kit or the Cycle x adapter to mount the carbs?

[Camrector]

Mike R is just finishing up on the head,rods, and jugs. So in the next few weeks I'll start building. And yes going with the cr26s carbs from Godfrey.
I did buy the cycle X adapter manifolds and sent those to Mike to port match. But we might have run into a little snafu with those. I'll post more on those once I hear from Ken at cycle X.

[FunJimmy]

Mike R is just finishing up on the head,rods, and jugs. So in the next few weeks I'll start building. And yes going with the cr26s carbs from Godfrey.
I did buy the cycle X adapter manifolds and sent those to Mike to port match. But we might have run into a little snafu with those. I'll post more on those once I hear from Ken at cycle X.

I'm sure you and Godfrey know the carb spacing is different than standard CB550 spacing. What issues are you having with the CycleX manifold?

[Camrector]

Well they do not have any o rings cut into the back where they attach to the head. So we both want to know how they seal up. Maybe they want me to use some kind of RTV? Or break out a rotary table and cut them myself? So we will see what Ken says. I'm going to send Mike my stock manifolds to port match just in case.

[akabek]

The Cycle x adapter can also use vacuum ports to sync the carbs. 

I am using a 1975 CB550F tank and with the Power-Barn setup there is a little interference between the petcock and the carbs.  I just lift the tank up slightly to open the petcock.  If the Cycle x adapter is shorter than the Power-Barn setup you may experience the petcock hitting the top of the carbs.  Something to consider.

[FunJimmy]

Well they do not have any o rings cut into the back where they attach to the head. So we both want to know how they seal up. Maybe they want me to use some kind of RTV? Or break out a rotary table and cut them myself? So we will see what Ken says. I'm going to send Mike my stock manifolds to port match just in case.

The CycleX manifold looks like a cheap copy of the FunJimmy Racing manifold. FJR manifolds have o-ring channels and are back milled to reduce weight. They also have recess socket cap fasteners. Maybe ask Ken where he got the design.

Remember that the two manifold options require different carb spacing.

[FunJimmy]

The Cycle x adapter can also use vacuum ports to sync the carbs. 

I am using a 1975 CB550F tank and with the Power-Barn setup there is a little interference between the petcock and the carbs.  I just lift the tank up slightly to open the petcock. If the Cycle x adapter is shorter than the Power-Barn setup you may experience the petcock hitting the top of the carbs.  Something to consider.

Yup. That's a valid concern. My interference problem was solved by removing the stock petcock and using an inline fuel tap. No reserve though so keep an eye on your trip meter.

Before



After

[Camrector]

Thanks guys, and yes I'm well aware of the possible clearence issues. And Fj that's exactly what these manifolds don't have, Oring channels.
I plan on using the V stacks with a sock instead of the pod filters, will clearence with the stock manifolds still have the interference?

[akabek]

I am running the Power Barn CR26 kit.  I have used stacks with ITG filters as well as pods.  I have a cb550 tank and you can see the fuel petcock lever has interference.  I can lift the tank enough to rotate the lever.

[Camrector]

Here you guys can see the concern with the intake manifolds




and this is what their eBay description states.



i guess we shall see.

[Camrector]

Akabek Why not cut off the petcock switch a bit were it interferes?

[akabek]

Akabek Why not cut off the petcock switch a bit were it interferes?

I can easily lift the tank slightly to clear the carbs. 

[Cityscapedview]

Subscribing to this one.

The work you've had done is inspiring, can't wait to see this beast of an engine when she is complete.

[Camrector]

So after speaking with Ken at cycle X he recommended Hondabond for sealing the(CycleX) intake manifolds to the head. I think though that I'll cut a oring channel instead. Also I am thinking of experimenting with a phenolic plastic spacer, between head and manifolds. That could serve two purposes. Reduce/eliminate heat transfer from head to carbs, and provide clearance room if petcock becomes an issue. Thoughts gents?

[FunJimmy]

So after speaking with Ken at cycle X he recommended Hondabond for sealing the(CycleX) intake manifolds to the head. I think though that I'll cut a oring channel instead. Also I am thinking of experimenting with a phenolic plastic spacer, between head and manifolds. That could serve two purposes. Reduce/eliminate heat transfer from head to carbs, and provide clearance room if petcock becomes an issue. Thoughts gents?

The rubber manifold boots will control the heat issues.
Petcock interference might be lessened with additional manifold length.
You'll just have to mock up and see.

[RAFster122s]

Would adding a phenolic spacer cool the intake manifolds slightly... Whereas direct connect to the motor would heat them and they would help vaporize any liquid fuel that contacts them.  I've seen phenolic spacers typically used between the carbs and the intake manifolds on cars as the higher heat of the motor is going to push the phenolic's heat range. Phenolic is often using epoxy and unless it is a high heat epoxy you are looking at what 400F being the heat range?

[Camrector]

Yes Raf I was thinking of mounting a phenolic spacer between the intake manifolds and carbs.

[schroederb2007]

Bump! Any further progress on this?