Topic: now that the bike is running, it has NO pickup to it

[Gordon]

and on top of that i may have one bad coil, as cyl 1&2 plugs have heavy carbon deposits on them, while 3&4 are shiny as new....

One coil fires cylinders 1&4, the other fires 2&3, so what you've described is not a symptom of a bad coil.   

[martino1972]

the more i re read your posts here,the more im leaning towards a blown head gasket..
reasoning for that is
-plugs on 1 and 2 fouled
-oil leak from cylinder 1 and 2 area
-bacl fire from cylinder 1 and/or 2
-grunts but doesnt go(makes sence,3 and 4 doing all the work,1 and 2 just limp along)

i think you will end up and take the cylinder head off,that way you can
-fix the head gasket
-take a very good look at piston/cylinder 1 and 2
-take a good look at valves on 1 and 2(while your at it 3 and 4 too ofcource)

lets say head gasket blew out in 1 and 2 area,that will result in limping cylinders on that side...
also,all the oil your talking about,might be an indication that theres something wrong with the pistons or rings on 1 and/or2
while you have the head off,it wouldnt hurt(would even be smart)to take the cylinders off aswell,so that you can really inspect the pistons etc...

its really not too big of a job and that way you can really take a good look at all the components..
like,cam,rockers,pistons,rod's etc..
when you got it off,ask a friend or someone that has know how about engines to take a second look for you,just to make sure...

good luck...

[sinister902]

i know plenty about engines, just fuel-injected ones (I built a one-off turbo ford focus daily driver from the ground up and tuned it myself)...I just was trying to see what opinions are out there for this simpler motor before i tore into it not knowing what im getting into when it very well could have been something simple.

the way i am looking at it, is if it's a headgasket or bad rings/piston....then its not worth the money to repair the existing engine and i am better off trying to locally source a replacement used engine that runs properly for $150-200, rather than spend $300+ to rebuild this one....

[martino1972]

that might clear up alot of problems already......

on mine(1973 cb750) the left coil goes to 1 and 4,the right one to 2 and 3

[sinister902]

that might clear up alot of problems already......

yeah, i just went out to double check and i was mistaken on that.......

the only thing i do notice is the plug ends are not factory, the are straight-on orange rubber boots rather than the stock NGK 90* plastic plug connectors......

something tells me either the wire-ends were once replaced or the coils are crappy knock-off replacements....

[martino1972]

i remember reading about the sparkplug caps,i think they need a 5k resistor inside,not sure what it would do to the bike when you dont have that in there,seems to me you might run into some slighly preigniting plugs,but that shouldnt cause your problems,i would think..

[Gordon]

the way i am looking at it, is if it's a headgasket or bad rings/piston....then its not worth the money to repair the existing engine and i am better off trying to locally source a replacement used engine that runs properly for $150-200, rather than spend $300+ to rebuild this one....

I have to disagree on that point.  If you can find a used engine for $150-$200 you'll have no idea what kind of problems are lurking just under the surface that will spring up a few miles after installation.  If you take the time and spend a little extra money getting your current engine in good shape you'll know you have a good engine that will be reliable for another tens of thousands of miles. 

[sinister902]

i guess you are right.....I just wanted to be riding it this summer, not working on it only to put it away till next year

[martino1972]

any progress on the bike?

[sinister902]

meeting up with a friend today to borrow the carb syncronizer....tomarrow i have a day off so im spending my whole day working on the bike. Im planning to run through all the maintenance schedule and when i finish i will compression test it. any tips for timing and cam-chain tensioning? lol.

if compression is bad i already have my eye on a rings kit and top end gasket kit on ebay....and a 605 big bore kit lol.........

[sinister902]

so for those kind enough to give a crap about an update lol.......

checked points gap, perfectly in spec.

checked valve tappet clearance, approximately double the spec value, HA (adjusted obv.)

borrowed a mercury tube carb synchronizer and spent about an hour getting them synch'd.

so I narrowed down a whole bunch. I bought a compression tester but of course it only fits 18mm and 14mm spark plug holes and the cb550 uses a 12mm plug. So i ran to my favorite local fitting heaven (ferry hydraulic, they have EVERYTHING) but alas they are closed until monday for the holiday. the neighbor had this old school one that has a rubber snub on the end and you just hold it real tight in the hole to check it out, so i may try that once the bike cools down. I fiddled with the idle-air adjustment screws on the carbs figuring im either too rich or too lean but i couldn't seem to get it smoothed out.

if i get a good compression test today or next week when i can get an adaptor for my tester, then i will pull the carbs off and re-clean them, electrolysis-clean the tank, and take apart/clean the petcock followed by fresh fuel lines and in-line filters......


any other idea's guys?

[martino1972]

did you check the timing with a strobe light??
does your advance move freely???
im still leaning towards a top end teardown to find the problem,but make absolutly sure you have checked the timing/advance first..
comression test might shed furter light on a problem too...
but i bet you will end up with low psi readings on the 1 and 2 area....
(i really hope its a simple fix for you,but i doubt it)
i mean,you seem to have coverd most outer engine settings very well....
but i havent read anything of you testing/checking the advance and timing yet..
keep us posted,we're not giving up on ya,we all want you to solve the problem...

[sinister902]

well, i have a timing light....i guess im not familiar enough with the bike yet to understand what you mean by the advance......

i thought simple timing was to make sure that the valve is opening/closing at the proper time while the timing park in the window for the points meets the index mark and that when the points should be open(start opening at mark "f")

am i wrong or is that just not enough to determine if its in time?

[sinister902]

ok, so WOW at compression numbers......the neighbors tester is very short, so i cant get it into 2 and 3, but siting on the bike, the left most cyl (! i think?) has 6.25lbs, and the farthest right (4 i think) has 150lbs which is excellent.....#$%*. time to order rings and a gasket kit.

[martino1972]

6.25 lbs..? yeah,thats no good...i bet if you could check #2 it would be simular...
i wouldnt doubt it that the edge of the piston is melted out on #1...
you might wanne take the head off,before you start ordering stuff..

[martino1972]

also,come to think of it,you really want to check up on your timing advance..
the way that works,is that the more rpm's the engine gets,the earlier it gives a spark..
its a mechanicly controlled unit,that sits behind your points..
just search here  for advance and it will give you lots of info..
if the advance is stuck,that will give the spark way to late on higher rpm's and could cause a melt down of all sorts of things,pistons,mostly valves etc..

[sinister902]

damn, really hoping i dont have a melted piston........what i THINK is most possible....

previous owner had some electircal woes with the bike and gave up on it and let it sit 8months in a garage over winter.

when i got the bike, the pistons were hung up, but i was able to get them moving......betting that in this process i bent or broke the rings in at least that one cylinder. betting the headgasket dried out over this time and is what is leaking, but most of the issues being contributed to bad rings.

Thats my best guess. If i have a melted piston, im doing a 605 big bore kit.

[martino1972]

******If i have a melted piston, im doing a 605 big bore kit.*******

see,at the end of things your even gaining..

[Patrick]

If this was my bike, I would probably double check that compression before I started tearing down the top end. If I understood the compression tester you borrowed. you just hold a rubber fitting on real tight to run the test. That leaves a bit of room for operator error. I would get the right fitting for the screw in tester and try it again.

If you are looking for a reason to tear it down, go for it. If I were trying to ride it this year, I would double check my own work. Just rebuilding the top end might not solve the problem.

Patrick

[sinister902]

i tried it a few times to double check for the reasons you mentioned, and DO plan on getting the proper fitting monday or tuesday to verify and also get the two inner cylinders as well. another issue i noticed is that the rocker arm for the left-most cylinder while sitting on the bike seemed to have been lightly tapping the valve cover and the tappet-cover-bolt thing(sorry i dont know the terminology)......wondering if the valve spring is beat or something.

[sinister902]

another question I had is that in the owner's manual and the shop manual, they say to adjust the cam chain tension and where the adjuster bolt is, but do not explain how to acheive/measure proper tension......

can someone enlighten me?

[MCRider]

another question I had is that in the owner's manual and the shop manual, they say to adjust the cam chain tension and where the adjuster bolt is, but do not explain how to acheive/measure proper tension......

can someone enlighten me?

For a 550, the adjuster is automatic. Simply loosen the bolt, count to 2, and retighten it.  The spring loaded adjuster will jump forward taking up any slack, then the adjuster bolt holds it there. There is not constant pressure on the chain, but a static position of the adjuster slide. It was intended to be a fool proof operation.

Some say, and I agree, that the most advantageous postion to set the engine is about 25 degrees past TDC on the 1-3 cylinders. This seems to put the most slack at the back of the engine, allowing the adjuster to move forward the most. I don't think any manual mentions this. Maybe so.

[TwoTired]

On a 550?

  There is a shoe that follows the contour of the chain.  When the cam and crank are positioned where the slack in the chain is on the backside, a spring in the tensioner is able s to place that shoe up against the chain.  The spring is defeated by the lock down nut on that stud.  Release the stud and the internal spring can do it's job.

With the stud nut loose, you can turn the post with the screw slot and feel the spring tension (one way).


Cheers,

[sinister902]

thanks guys, now to sort out the no compression issue.....I was looking at the 555cc kit but it doesnt seem to come with the oil rings, and that worries me.....

[sinister902]

well, now i know for sure two cylinders are dead at the moment. I started tearing down the bike today so i can inspect the carnage and then decipher if im going to order parts or store it until winter/spring when i have more time and more money (i finish my degree in december)......I am shying away from the 555cc kit because it has no oil rings, unless someone here has a source for replacement oil rings for them, and then ill buy the kit lol. If i had an extra few hundred i would just spring for the 605 and some uni filters and new jets......ah well. I get myself too deep, im trying really hard to go as mild as possible on this bike, i have a history of getting in over my head.......