Topic: I've come so far . . . smokey engine

[Machine1]

Hello allllll - So I've rebuilding a 76 CB550F since early july of last year and I have A LOT since then about the bike and how it works and all that jazz.  Basically this bike was complete garbage when I got it - like disgusting. And missing a good number of parts.  So I basically ripped it alllll the way down to the bare frame and bones and did a complete top end rebuild - rebuilt the starter motor (which surprisingly still works after needing to be literally jump started), carbs, all new electrical wires, rebuild forks, relaced wheels with original rims, lotsa matte black powder coating so everything looks like new - new engine paint, 4 into 1 black exhaust ect.

Also all new gaskets in the top end, new spark plugs, coils, electronic ignition, new rectifier/regulator, new switches, new valves, new piston rings, cleaned like 95% of the carbon deposits off the pistons, ect.

So, after getting basically all the wiring done except for turn signals - I finally get it started up for the first time and it seems to be ok.  I did compression tests on all 4 cylinders: 1-3 are all around 135/140 but cylinder 4 is around 115/120 - I hear this is not too good to have one cylinder be that much different than the rest.

Also, I have not synced the carbs at all (I don't have the right gear to do that) - so just an FYI.

All spark plugs get spark and look good and are brand new - although after it running for a bit and me trying different things and whatnot after a while the spark plugs get black - there is quite a lot of carbon buildup on them - I cleaned them off and after more testing things and adjusting and I pull off spark plug 4 and it is pretty dang black again.  So that's issue two.

Another thing - after getting the engine a little warm - maybe running for a couple minutes and revving it up a bit to see how it sounds- I see smoke coming from where the exhaust meets the intake around cylinders 3/4 - It might only be cylinder 4 though, sorta hard to tell.  And sometimes after letting it run for a couple min and revving the engine a bit it seems to get stuck at higher rpms - like I'll rev it to 3000ish rpm and it seems to stay there unless I kill the engine.  So that is pretty weird.  I'm thinking I should rebuild the carbs again considering that was the first thing I did to the bike.

Also I did readjust the valves under the 8 tappet covers because I was pretty sure I did it wrong the first time.  That's all I can think of at this time - if anyone has any feed back or has some advice on what to do next please let me know - or they want to chat directly about it you can PM me and I can give you cell or something if its easier.

http://s1174.photobucket.com/user/chrissanchez07/library/550%20Project?sort=3&page=1

[Machine1]

I did not bench sync carbs - I used a good oem rebuild kit for the carbs - by brass/brass do you mean in the carbs?
I'll Definately look at the valve adjustment again

And what I mean with the fouled plugs: they were brand new, I let it idle for a bit - i pulled them out and found them then to be black- I cleaned them up, put them back in and let it run a bit more and a couple hours later pulled out spark plug 4 and found it black again- I'm assuming the others are black again as well-
Will def look at the carb adjustments again- although I did adjust the float bowl screws and the other brass screw on all 4 carbs to factory specs according to the manual.

I have read somewhere here I think that you could put a cup of kerosine in with the oil to clean up all the carbon? Is this something that has been known to work or is even safe to do?
I have also read that some people had smoking cylinders and they rode their bikes hard for a good 15/20 min and after it was ok-

It's very possible the piston may be out of spec -

[Don R]

 If it was me, I'd ride it normally for a while and give it a chance to run in a bit. I like the clear tube method to check float levels, a high float will cause rich running.

[Jerry Rxman Griffin aka MuthaF'er]

Assuming you honed the cylinders properly? Maybe that one cylinder's rings still need to seat if so. 

[HondaMan]

When you had the head off, did you replace the O-rings in the intake castings where they meet the head? If not, they leak now and will cause fouled plugs, frequently.

[Machine1]

I did not hone cylinders - at that point I didn't know to do that - this is my first build so there are still bits here and there that I didn't know about - But I looked it up and I guess now I know . . .

If I remember correctly I did change all the little o rings and gaskets in head.  My memory is pretty terrible so I don't remember specifically doing it, but If it was there before it was changed to a new one.  No old o-rings.

I'm contemplating removing the cylinder head cover and taking a closer look now, but I think I will definately take the carbs off and get them cleaned up again before I do any riding - And I'm not quite at the riding stage yet - No front brake yet, and I still need to get the tank painted.  And I'm waiting for these new mini controls I found.

[Machine1]

Is this clear tube method in the carb fac sheet? I cant seem to find if - would I just connect a clear tube to what exactly? I'm not familiar with that quite yet

[Machine1]

Totally figured it out - I just saw it in another recent thread - now time to get to work!