Topic: The snowball effect...or, how to maximize a stock 550

[Lostboy Steve]

A stock head gasket is +-0.043" so aim for piston top at deck height and the gasket thickness equals your squish clearance. Just remove the least amount possible from the head to straighten. As I mentioned Cometic offers viton coated steel base gaskets in 0.010, 0.014, 0.020" thicknesses, (which give you options) plus MLS head gaskets in a few thicknesses as well, one at 0.040" which would be perfect is your piston crowns end up @ 0 deck.

I've never seen stock pistons as far down the bore as Cal experienced.

I would suggest whatever your pistons are below deck you remove from the top surface of the cylinder.

Don't forget you still need to measure all clearances, before you start, and after each time something is machined before you do another step. It's a process, so leave nothing to chance. 

Is using the thickest base gasket to achieve the 0 deck height recommended to give you options in case another skim on cylinder or head is required?

It's damn tough asking a machinist to remove exactly "X" and get it! So I like to use a gasket in the middle of the thickness range when measuring, then go thicker or thinner as needed afterward. OEM base gaskets are good but I really like these viton coated steel gaskets. In my last race engine effort I stacked two different thickness gaskets and they never leaked. (now use 1 x 0.014") So really the minimum thickness with these is 0.010", then 0.014, 0.020", then stacking offers 0.024" 0.028, etc.

With freshly machined surfaces aim to use an MLS head gasket, they are great too.

A lot of Honda car guys stack headgaskets in their boosted projects with success. I didn't use a mls on my 550 and am now regretting it as my fiber one may (or may not) have a slight oil leak. It could be coming from above but I'm not sure and haven't looked too hard.

On a separate note this is a great thread.


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[Lostboy Steve]

Steve - pull the valve cover and re-torque the head. I'll wager a dollar to a donut this will probably solve your seep...

Will do! Maybe I should put a cam in it while I'm there. Think it's worth it on a stock bottom end, ported head w/ stock valves?

I should add I followed the specs given to me with the dynoman studs.

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[BomberMann650]

Steve - pull the valve cover and re-torque the head. I'll wager a dollar to a donut this will probably solve your seep...

Will do! Maybe I should put a cam in it while I'm there. Think it's worth it on a stock bottom end, ported head w/ stock valves?

I should add I followed the specs given to me with the dynoman studs.

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Cam upgrade?!  Does a bear sh!t in the woods?!  Get one while they're still on ebay.  Could be a while before the next crop harvest comes to market.

[SOHC4 Cafe Racer Fan]

Another way to maximize the 550 is to reduce as much weight as reasonably possible.  Strip unneeded parts, shave off unneeded mounts etc. on the frame, simplify the wire harness and electrical, use Aluminum wheels, replace steel bodywork with aluminum, etc.

Another way: pop in a 650 engine, with a mild port job and increase compression.

[RAFster122s]

When plentiful the prices can be lower...when not many are available they tend to go high...  Yes, a 650 cam in a stock bike with no changes perks things up and only requires a valve cover gasket.
Have to sort the tach drive as well to use a 650 or 750 tach if going mechanical or blank port after removing drive gear and using an electronic tach.

[BomberMann650]

Another way to maximize the 550 is to reduce as much weight as reasonably possible.  Strip unneeded parts, shave off unneeded mounts etc. on the frame, simplify the wire harness and electrical, use Aluminum wheels, replace steel bodywork with aluminum, etc.

I read somewhere the ratio for weight reduction to gain.  Iirc it was 14lb to free up 1 pony with static weight.
Reducing rotating weight had a better gain ratio

I lost 30 lbs before my dune trip and that was the best weight reduction gain ever.

[Lostboy Steve]

Another way to maximize the 550 is to reduce as much weight as reasonably possible.  Strip unneeded parts, shave off unneeded mounts etc. on the frame, simplify the wire harness and electrical, use Aluminum wheels, replace steel bodywork with aluminum, etc.

I read somewhere the ratio for weight reduction to gain.  Iirc it was 14lb to free up 1 pony with static weight.
Reducing rotating weight had a better gain ratio

I lost 30 lbs before my dune trip and that was the best weight reduction gain ever.

I was thinking of getting a dynoman 358a and new springs. Idk. I might just leave it. It runs good and (for what it is)has great power even with the bags and everything.


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[joeyvans]

Kinda got my feelers out for a 650 cam ( I KNEW I should have held on to the one I had....), and I've been reviewing my notes and pics on head porting.

And a fine 650 cam it is, Scott.   

I threw it in when I replaced my valve cover with the updated pinned rocker shaft cover I acquired from Cal.

Sorry.... couldn't resist.

All jabbing aside... great thread and definitely curious to see what you end up doing.  I also have 2 spare 550 motors (one locked and one good) that I would like to "wake up" some day for a potential custom build of the '74 roller I have.

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Kyle

[Scott S]

 You know what? I'm glad you replied. I just spent another $100 to replace it. At the time, my plans had changed. Today....or, over the next year or so....I plan on "maximizing" it.
 Yeah.....I could do better but...


 Just left  the Bonneville Bobber release party. Beautiful new Thruxton... 70 Something TQ....and $15K!!!
 The Bobber wasn't that pretty, to me. New Scrambler was gorgeous.
 Give me a high end $~4K CB 550, though...