'Diamond in the rough'

[bikeymikey748]

No joy .
I bolted the carbs up a few minutes ago.
Still no movement on the balls in the synchro tool. I took it off altogether,thinking it might be influencing things by allowing too much vacume leaking.The motor,still sounds ,rough popping & spitting,though its better than before. It will almost hold an idle,but I have to keep the party going with the accel pump.
Oh, and it runs real hot,real fast.
Did I mention the 'mystery' oil leak? That's right cadets, like not enough is going wrong as it is. Seems I've got small drips on the front cylinder fins ( two up from the base gasket,directly in front of # 2 & 3). For the life of me,I'll be damned if I can see where it comes from (the base,head and valve cover gaskets are dry, as are the sealed cylinder studs.).Nothing from the exhaust ports either.
I'm tossing in the towel for the evening,the 'X' has,definitely, won this round.
My head hurts....spirits low

[steve murdoch icoa #5322]

I've got a slightly weeping camchain adjustor bolt that puts oil in that area but sitting stationery it is not going to spread that far.

[cbx6ss]

Nice build... I went back thru your thread to verify if compression was checked after assembly. I did not see any reference. Could compression, or cam timing cause your idle issue?
/r
Brad

[daves79x]

I, too had to review the thread to see what all had been done. Lots, it appears. Complete engine teardown, etc. I also see that the bike ran decently when it was acquired, apparently worse now after all the work. Hard to say where to start. I'd verify cam timing also, correct cam installation, static timing and advancer operation. Then deal with the carbs. Something still not right with them, I'm sure. This is not a criticism by any means, but the speed with which you do the fabrication and 'McGyvering' is amazing, but I've found that a bit slower pace is usually required when assembling these engines and especially the carbs. Keep us posted on what you find.

Dave

[bikeymikey748]

No worries about any input being taken as criticism. I welcome any advice anyone might take the time to offer. And please, keep those comments rolling in.Besides,my skin is suitably thick
News of the day: Round two goes to the 'X',again. The 'kid' has staggered back to his corner,but has some fight left in him yet!
I post these latest results as,clean, oil drips down my,previously, pristine motor.God,I hate working this way!
Here goes:
-Base timing was off slightly,certainly not enough to account for how poorly the motor is running.
-I was really hoping it would be otherwise (it would explain a lot),but the cam timing was correct.
-A leak-down test (using my tester that 'zeros' at 100psi.,you gotta think that much pressure will push the issue),showed that with the exception of a 15% loss at cyl.#3 ( exhaust valves),the loss at the remaining cylinders was negligible.Again,not ideal,but not the 'smoking gun' I'm looking for.
-Oddly,during the course of a compression test immediately after the leak-down (with a fully charged battery,starter cranking with enthusiasm,and throttles wide open),no cylinder would go over 100psi.? Admittedly,#3 was a little lower (85psi., just under the accepted 10% allowable difference between best and worst readings). This parallels the lack of vacume I noted when trying to get a reading from my synchro unit.There's no obvious vacume leak at the carbs to account for the synchro tool's poor showing. I realise compression gauges are,generally, best for comparative results versus specific ones. But,two gauges gave the same readings.Why would the leak-down test be acceptable, and the compression reading be so low (almost 2-stroke in nature)?
The kicker is,as Dave pointed out,the bike ran better before I did all the work. This doesn't,normally,happen to me,I'm not a half-bad mechanic.The bike had issues that made you wonder why it ran as well as it did beforehand.
It should be running like new now. I just don't get it........YET.
Only bright-ish news? My oil leak just might be from a galled copper washer on the cylinder stud between #2 & 3. A bit of work on an emery cloth and plate glass should square that away.
Scotch time.You. Can't always celebrate with it,but it'll take some of the 'blahs' off ya.

[EMS]

Mike, when Dave referred to the cam installation,

correct cam installation, Dave

he probably meant the orientation of the halves relative to each other. You know, that it is possible to do this wrong. Even in the first edition of the Honda Service Manual it was shown incorrectly and later changed.

[Jeff Bennetts]

Have you rechecked your valve clearances? could be a tight valve causing the one cylinder to be leaking down.

[bikeymikey748]

First off, a big 'THANKS' to all for spending their,valuable, time thinking on my current brain-teaser, and actively contributing to its resolution. It,really, means a LOT to me.

he probably meant the orientation of the halves relative to each other. You know, that it is possible to do this wrong. Even in the first edition of the Honda Service Manual it was shown incorrectly and later changed.

Yup. I checked this. Unless I did something wrong;#6 TDC, IN + EX lobes pointing towards plug,sprocket punch marks aligned with surface of heads.Rotate crank 360 install LH cams with lobes pointing at plugs. I didn't remove the sprockets from the RH cams when doing the work, and all cams were tagged/bagged when removed. But, I checked the LH ones just to make certain I didn't mix the IN & EX ones.Rh are hard to screw up with the sprockets & tach drive gear.
What mistake in the manual are you referring to ( I've got an 'oficial' '82 Honda manual) ?

Have you rechecked your valve clearances? could be a tight valve causing the one cylinder to be leaking down.

I verified all my clearances, all were still in spec. It seems my pressure loss on #3 ex valves is likely that they have to seat a bit more fully. They passed my 'varsol' test ( 5 min. no leaks past either in or ex valves with the combustion chamber filled with varsol, spark plug in place). Another 'head scratcher'
That's the who;e deal with the issue....it should be running fine ( with the exception of the carbs being balanced) ?!
The points that stand out are the fact that my synchro tool wasn't receiving enough vacume to give a reading ( get the steel salls to 'float'), and the compression test, max, values seem low. Can this motor run well with only 100psi showing during a comp test? I thought the least acceptable figure would be 125, with a good motor showing 150 and up. For the life of me, new rings/bore, valves lapped in ( #3 ex. the possible exception) great leak=down test results, why won't the motor produce higher compression figures? This is why I was disappointed to see my cam/valve timing in spec. I was really hoping to see one or both sprockets off by a tooth, it would explain the low comp. figures. Though, as soon as I'm back home ( I'm on break at work just now) I'm having another look. Hey, my buddy Gord-O dropped by last night and, without any prompting from me, discerned that the cams were properly placed !!
Again, thanks for pitching ideas/info my way...I have to believe its just a matter of time....

[cbx6ss]

Back to your thread (13 pages and growing; what's the longest thread on this board by the way?). Head gasket new? Both surfaces flat? guide dowels in good shape and properly seated? I snapped a compression ring on reassembly of a rebuild (right SteveG?); fortunately I caught it at assembly. Could one have snuck through? Could any rings be upside down? Wrong order? Studs properly torqued? Sequence? Dry? Lubed?

Open season fishing expedition... Next?
/r
Brad

[daves79x]

Just some points (only from experience). I wouldn't take too much stock in compression readings just yet. These things will sound and run fine with 100psi. And even with a BURNT valve on one cylinder, you can hardly tell it's missing with everything else working right (carbs). I don't think the problem is a subtile as that. Something else big wrong.

The early shop manuals (1978) show cams installed with both 1 & 6 lobes pointing the same direction. Bad news - the infamous '25 mile rebuild'. Bike would still run OK, but sound a little lumpy, until the camchain broke. Sounds like you have that right.

Even at 100psi, your vacuum gauges should still pull 5 pounds of vacuum at idle. Easily good to sync the carbs. Drops to almost nothing at anything above idle though. Bike should run and idle smooth as silk and idle down to 600 rpm easily. Popping noise is usually valves that aren't seated, but you confirmed that. Give some more exact description of how it starts and sounds right now.

Dave

[bikeymikey748]

Brad, ,good ideas all. Funny thing is, as a small fry I snapped a ring In the course of ,yet another rebuild,on my long suffering SL125.I didn't notice until,with the SL smoking furiously under me, I realized that all was not well.Since that episode,many rebuilds ago,I am chuffed to report that no rings have been injured in the making of any of my motors. In the case of the 'X', seeing as I wasn't in the mood to order in replacements, I was extra cautious installing them. They were all clearly stamped with 'T's',indicating 'up'. Chrome top ring,black second,oil rails can go either way (expander,properly positioned.). I fit them into their bores with a good quality compressor. I, also, had the advantage (since I was doing the entire motor) of installing them into the cylinder block and then putting that in place while bolting up the rods.Afterward, I cranked them through a few revolutions,and checked for tell-tale scoring on the cylinder walls, before dropping on the head.....all ok.
Yup, all dowels in place. All fasteners got a touch of lube before torquing,even the washers under some fasteners got lubed lightly. We want to measure torque at the threads/heads, not how much we use to overcome friction between them, how am I doin' so far?
New head gasket,check. The cylinder deck was planed.The head was true, and lightly prepped with abrasives. I figure the leak-down test would have pointed out any defects regarding these. All good.

Open season fishing expedition... Next?

I love it

Steve-O, much appreciated info ( there's no substitue for experience,huh ?) regarding how tough the motors are,and what conditions are needed to get them to run.It puts my mind at ease on a number of points. Sergio also pointed out that fresh rings in new bores won't provide max sealing until after break-in (still a puzzle then, regarding the leak-down results. Though some loss was heard from the cases).
I'm still wondering about the sync tool, and will plug in a vacuume gauge to one of the adaptor ports to see what sort of vacuume is,actually,there.
In looking over the bike this afternoon (thanks Serge & 'Skinny' Dave !), two points came up ,that I'll look into late tomorrow or Sunday. #1:The frame for my coils wasn't bolted down securely ( in my defense.....aw hell, no defense) . Serge asked where my harness was grounded. I showed him a fitting attached to one of the coils,and he noted that they were loose ? Not only that, but I had yet to expose the bare metal where they mount ( remember I painted the frame), they were only grounding through the threads.:O. Could it be that simple ?
#2:The remote tank I use for synching holds but 750ml., it might not have enough volume to feed the carbs with any reliability.They may have been starving for fuel. That and a small,in-line filter,I added may have been contributing factors.
In any event, I'll be bolting bits back up, shampooing off the oil & trying it again. No matter the outcome,I'll post a vid of the results.

[cbx6ss]

one point about sync from Dave "...can idle down to 600RPM); RPMs at sync are important (idle speed); anything off-idle and above reduces vacuum. You mentioned bench-syncing with wire in your thread so should have that covered.
/r
Brad

[CopperCollar]

Dayum,

This sounds like what I went through with the Travesty.

Ran okay but low manifold vacum, I had to flip the gauges upside down to measure it and then it was around 5 mmhg at best. I put some miles on her and she never really was right. Slow return to idle, missing in the 4500 range, just did not seem right.

Ran compression checks and they were 110 psi, Low in my opinion. Ran a leak down test and that was not encouraging....10-20%.

Finally I pulled the top end down and ran through the specs again. While my piston to bore clearances were in spec I noticed ring end gaps were way to big in all my bores!

This allowed a LOT of blowby into the crankcase. This I believe was cause for the poor leakdown and the sound of air in the crankcase with the leak down test.

Next I set the head on the bench and filled the intake and exhaust ports with carb cleaner, nearly every valve leaked! Originally I had checked them as you did, spark plugs in and fill the combustion chamber. I had no leak after 24 hours with this method.

However Filling the ports revealed the leakage in less than 5 min.

Rather than get oversized rings and fit them for correct end gap I went with a big bore kit. Good thing to, #1 cylinder liner was cracked up high in the compression area, this was found by Preston but not until he got to the final hone. That crack could explain the poor performance when hot.

I am slowly putting the girl back together but I am betting she will be at or close to 140 psi. and less than 5% leakdown. This should produce some good manifold vacum.

Now, I am not sure of this but have been told that poor compression and leaky valves will really affect manifold vacum on the CBX.

I'll know in a few weeks.

Mike

[bikeymikey748]

Oh man,Mike,you got bit too. Believe me when I say I feel your pain.
Curious thing...input please:
I just finished correcting the scoring on all the copper washers,under the head bolts. It seems highly likely they were the source of my 'mystery' oil weep.
I then took out the coils,and their frame & ground the main frame paint to expose the bare metal. I replaced the high tension leads,with cool braided items,and had a second look at their placement. I used p.1-9 of the service manual for reference. The thing of it is,according to that page it appears the leads go to their,respective,cylinders ( from the coils going left to right) 1-6-3-2-4-5. Thumbling ahead to the diagram on p.17-0, the order appears to be 1-6-3-4-2-5.
HUH????
Can anyone supply the,actual,high tension lead sequence (left to right) .
I have a,cautious,good feeling about this !

[bikeymikey748]

You know,the second order looks to be correct,especially given the manner in which the pairs of pistons move.
Looks like I screwed up my plug leads.
Verification? First one to chime in gets to bask in the glow of trumping my,furry, behind.