Topic: Another project-1976 Honda CB550K

[denward17]

Thanks Mark, I'll take them if you will get rid of them.

[Mark1976]

Thanks Mark, I'll take them if you will get rid of them.

I'll get back to ya....

[denward17]

Carb rack back together after cleaning.  Not complete yet, waiting on some brass from jetsrus and from another source.

Performed a leak down test today, and as expected I was in the 40-60% range of leakage, sounds like coming from crankcase on all cylinders.

I suspect this is because of not being run for a few years and cold.

I may pull the head off anyway to address what looks like oil leaks, or may just pop off the valve cover and replace pucks, not sure yet.

I have a habit of while I'm there and the engine is out........I hate to with only 12k miles.

[calj737]

I suspect this is because of not being run for a few years and cold.

With only 12k miles, this is the most rational explanation. Given the ability to service the motor on the 550 while in the frame, I’d leave it be and get it running then, christen it with a good old fashioned Italian Break-in and see how she runs.

[Mark1976]

I suspect this is because of not being run for a few years and cold.

With only 12k miles, this is the most rational explanation. Given the ability to service the motor on the 550 while in the frame, I’d leave it be and get it running then, christen it with a good old fashioned Italian Break-in and see how she runs.

+1 !!!!!

[BenelliSEI]

+1. With that low mileage it might surprise you how well it runs after a few hundred miles and an oil change.

[denward17]

Cleaned and polished a couple of covers waiting for carb parts to come in the mail...

I still have some more work to do on polishing.


Received carb parts from Mark1976 (Thanks Mark!) and jetsrus.  Carbs back together and float heights set to ~21.5-22mm.


Engine is next....plan is to pull off head, new head gasket, new oil seals/pucks for oil leaks and check valve to make sure none are leaking, then go from there.  The current plan is to leave cylinders alone.

[Mark1976]

   Nice lookin' rack...

   Of carbs....

[BenelliSEI]

Nice work Dennis….. I seem to have left the carbs ‘till last!

[denward17]

Head is off and all cylinders have a lot of carbon it appears.

I noticed something wonky with the tensioner, id doesn't want to automatically spring back to adjust the cam chain, so it looks like I need to lift the cylinders to take out the tensioner.

I didn't really want to do that as the cylinders look pretty good, with no wear marks I can feel, but I might have at this point to make sure the tensioner is functioning correctly.

Here we go...

[BenelliSEI]

Good plan, check it now.

[Mark1976]

   A little bit of mission creep going on there, next thing ya  know you're splitting the lower half.
Do what ya gotta do, better safe than sorry.

[denward17]

Cam chain tensioner teeth are bent from previous owners not knowing how to adjust.  I tried to repair but don't feel comfortable with it, just ordered a new Honda tensioner.

So that means the cylinders had to come off.

Time for some measurements and determine if I need to rebore and go to the next size pistons.

[BenelliSEI]

Looks like some fine weather there!

[denward17]

It is pretty nice, mid 50s.....

Found out that tensioner/guide is not available anymore from Honda, argh...

[grcamna2]

It is pretty nice, mid 50s.....

Found out that tensioner/guide is not available anymore from Honda, argh...

Den,have you tried cmsnl.com ?

[denward17]

^Yes, I looked, about $200 by the time it gets here.

I may try to repair mine and see if it will work.

[Mark1976]

   Keep an eye out on Ebay,
https://www.ebay.com/itm/276182296112?hash=item404dbf6630:g:CXoAAOSwkfhlXSg4&amdata=enc%3AAQAIAAAA0FdzHZaGA0I6o8jAdIJxmsIVCxYu5YzZW0lReVtBoMz8mYT%2B5uSawmZ6ATeywUxRpVT8cqosyEYD0%2BjVdEh9IhymSUyERsepMWwXc22oJyYMat0G%2FqP%2Blz%2BEYQ5FeKkCiZADxgFN7Ca3cr%2F9F5Cq2YJ6tXEHO9xWNYgUVIodhsfWily1ey22roiosPxE6b57Qsc8Bbhm%2BkZw0%2FYqB8lzzI6qIIwaDVXdTsdABJX%2FkbE5ehPGCXn5pChYeAkiv80dPkD0c11vJxxtIuNFo2TYDxw%3D%7Ctkp%3ABk9SR7KM2o6yYw

[denward17]

^Thanks Mark....thought bout a used one and thought it could be just like the one in my hand....

I hated to do it, but just ordered a new reproduction from JTMarks.

[Mark1976]

   New is good!!!

[BenelliSEI]

You won’t be disappointed.

[Mark1976]

   So the $64,000 question is, "whatta going to do with the head?" Best bang for your buck is spent here.

[denward17]

I will just clean it up, lap the valves and check for flatness.

I thought about sending it to Mike, but he is tied up for a while.

[denward17]

EDIT to add bore measurements:
appears to be a little bigger on Y axis

#1 x=2.3035 y=2.3045
#2 x=2.3037 y=2.3040
#3 x=2.3036 y=2.3041
#4 x=2.3040 y=2.3042


Standard piston size from manual = 2.301 - 2.30 with a limit of 2.302

Pistons measure: Edit: corrected piston measurements
1=2.3034
2=2.3035
3=2.3035
4=2.3035


Standard end gap = .005-.013 with a limit of .027

Piston rings end gap: (only measured #1 and #4)
1= top ring .013 in the middle and bottom of bore; .014 in top of bore
2nd ring is .015

4= top ring .014 in the middle; .015 top and bottom of bore
2nd ring same as top ring ring

Trying to determine if I need to re-bore or just do a light hone and new rings.

[grcamna2]

Den,I imagine you're going to keep this 550?
The amount of work you're putting into it,it looks that way.

The numbers you mentioned above.. I personally would fresh re-bore it,imo.
Bring the factory service manual w/ numbers to the machinist.
I hope the condition of the valves,guides and seats are in excellent cond.,then lightly use some very fine grit lapping compound? unless the valves or seats are worn,then a light grind on them to bring it to 100% best compression for many years of enjoyable riding,imo.