Hydro'd C10 rebuilt and running smoothly... but no power underload!

[Brad Baerwald]

Hi Guys,

Yup, I'm one of those guy's that didn't know "Hydro-ing" was something that ever happened to a C10... mine happened 100 miles from home as it sat in a parkinglot overnight.  I knew I had a stuck float but had to park it and get to work (new years at the church I work sound at... and yes it's that far away)  went to start it in the rain for the long cold ride home and BANG! all over!

2 weeks later in a shed at the church I checked for a bent con rod... (using the Tech. one of your guys suggested on a post at this site) and sure enough!

Year and a half later I finally started putting it back together last couple of days and its together and running!  It actually starts better than it EVER has (as I went thru the carbs carefully and made sure the choke valves / diaphams are working)

BUT very little power!  it will free rev but you get the sense it's not happy... On the road it has very little torque  and "Boggs" very hard if you open the throttle both too far and / or too fast.  If I "milk it" I can get the rev's aound 7 or 8 K but even then if I slam the throttle full open...BOGG.and it's almost like I imagine a "Jake Brake" acts

HELP!  I've had the bike appart so many times my hands are bleeding from every knuckle!  Anybody know what my bike's issue is??

right now I'm waiting for the bike to cool so i can go see if I have the Cams swapped??!? but I don't even know if thats possible anyway?  I've pulled the carbs twice checked my foalts, then the vacuum diaprhams (if they are properly seated)... but nothing seems to fix the problem

brad b Studio51

[Daytona_Mike]

have you done a compression check. I think that might tell you your cam timing is off one tooth.
That is my best guess

[MAN OF BLUES]

I have to ask if you are trying to run it on the 7 month old fuel that was in the tank, especially if you shook the tank like when it was removed and reinstalled a couple times.... when you clean and repair carbs, always ditch all of the fuel, rinse the tank with fresh fuel from a new gascan, and start fresh.

methinks you will need to drain and reclean those carbs again now...

[Brad Baerwald]

Thanks Guys!  for the responses!

I'm trying desperately not to fall into a deep state of depression...  I went in and re-timed the cams to the crank, but it doesn't look like anything is different from before!  I even went as far as trying everything one tooth each way to look if it could be "fudged" one way or the other but allas no... only one way works and I must have counted the cam chain pins to "35" about 40 times!

Is there a (bad) chance that there is more damage than the connecting rod and bearing that I replaced?  when I put the cylinder block on I did a "good looking" at it (and the pistons) to see if there was any twisting but I didn't "mic' it out or nothing.  Have you folks ever heard of a "hydro'd Conny that wasn't fixable??

Daytona Mike; I did a compression test (only on cylinder 1) and only got about 85PSI... the book says 128-180ish...WTH??   also I noticed that (when I crank the motor with the starter motor) I get a wierd preasure pulse from the vacume hose that feeds the Petcock... that seems wierd to me (like a cam timing issue!!?!)  but Ive checked and re-checked! and then checked again.  the pistons and rings all look great cause this is a pretty low milage bike (it just turn 37,000) and when I had her apart she looked amazing  (my 93 ZX11D looked way worse and she goes like a bat outa hell  (yeah she did the "3rd bearing spinned thing" so I had her all apart too)

I didn't think I was this bad of a mech.  but I'm getting my ass kicked

[jettawreck]

Compression test on the other three cylinders to compare. 85# wont do it.
Sparkplugs all out, throttle wide open, battery fully charged.
Given various inaccuracies in gauges, the amount of difference between cylinders is more important to me than the actual number, but that's not even a start there.

[MAN OF BLUES]

a lot of things may have occurred during reassembly, like the ring gaps not being staggered, and the low compression may also just due to a dry cylinder.
I assume you checked and double checked the valve clearances during the assembly, you may be wanting to  pour about a teaspoon of light weight oil in thru the the sparkplug holes and turn the engine over a bunch to wet the cylinders.
and do hold the throttle wide open when cranking it during the compression test, very important.

[Deziner]

Ignition timing?

[Brad Baerwald]

Bare in mind gentelmen, that even though it has very little power it's runnig very smoothly (like a sewing machine) when I get it back together again I will do a small video clip with sound.  It doesn't sound any different than it ever has and it isn't backfiring.  It now starts very easy and very evenly (it NEVER did that before it used to only start on 2 cylinders and was very sensitive to choke postion) 

I had it out on the highway this morning doing 70 MPH... but it just doesn't have any get up and go. and will not rev but boggs and quickly slows down if I open the throttle wide open, pulling a tall gear

I agree that it seems like some kind of timing issue ... but I can't find anything with the cams and I wasn't aware you could do ANYTHING to the ignition timing...like I don't even uderstand how they accomplish timing advance on this bike?? maybe that isn't working?

but keep it coming guys cause I obviously can't find it!!

[MAN OF BLUES]

I'm going to repeat, this is a fuel issue.
you did not respond to my comment, so I have to assume what I expect to be true.
dump that fuel, flush and dump again, and flush the carbs. I have been seeing this issue for over ten years here. and can say without a doubt if everything else was unchanged, you have a fuel issue, and stuff migrated back to the carbs again.

pour the gas into your lawnmower.

[Brad Baerwald]

well I agree there is nothing like experience (thats why I'm here)  and that gas would have been more like 18-19 months old if I had used it LOL! 

While I'll admit I wasn't super "thorough" about empting the tank ... the first thing I did was went and filled up with fresh gas.  I also installed an "outboard motor fuel filter) to keep the super fine rust particals I found (when I did the first carb cleaning) from making it back into the carbs.  BTW I used a filter that is quite large (barely fits under the tank) and is designed to work without a fuel pump.  The filter seems to stay full so I can't imagine it's starving the carbs... but who knows

[Bikenagain]

Just a wild thought. could it be getting to much air when opening up the throttle, hence running to lean when opening up. I had similar symptoms when I left the air filter out of my GPZ750 by accident while test riding it when diagnosing another problem. It idled and started beautifully and only lacked power and bogged down when opening up the throttle fully.

[Brad Baerwald]

Bikenagain,  Yeah man! and that's kinda the "other side' of Man Of Blues point right? too much air is like not enough gas... and I would agree with you (specially since the airbox is an ABSOLUTE pain in the *^$#%@)(*!!!! to deal with but... It's been fully installed all the time (but not the first time I took it out) and I (like you) figured that the air box needed to be on (with the filter) in order not to run too lean
... I'm going to go with Man Of Blues thing next, but this will be the 4th time those carbs have been pulled and opened up  and I'm running out of skin on my hands that isn't bleeding... also the wife is hoping I will stop obsessing and find some time to do some work around here!

I REALLY want this bike back again.  As it is the bike that makes me ride more "civilly"  and now because it isn't running right (and is almost down right dangerous in traffic) its hard to "choose" to ride it when the ZX11 is looking at me and saying softly "let's go kick some ass"... The world doesn't need me out there (at my age) looking like another crazy crotch rocket guy... but DAMN its fun!

[jettawreck]

After you are done with the fueling/carb issue(s), address the compression issue against the other three cylinders. I would be very interested to see what they all come in at in comparison to the "low" one.

[Cholla]

Remove the fuel filter. It's full because gas flows freely to the filter. That doesn't mean gas is getting through it.

[RFH87_Connie]

About the only fuel filter that works remotely right is the FRAM 3006.  It is 5/16" inlet and outlet with a 90d bend - most people incorrectly select a filter with 1/4" because they are easy to find.  The majority of riders later decide not to use it because it can restrict fuel flow at higher rpm (like it sounds like you are getting) and even just idling.  Remove it temporarily at least for the testing until the bike runs right.

[Brad Baerwald]

OK, so I KNEW everyone was going to give me **** about the filter so I removed it before anyone said anything.

In a word I would say "better" and it's basically ride-able.. BUT it's still VERY wrong!  It's so wierd, it purrs like a kitten, it starts way easier, it rev's nicely (no appearent miss firings)  yet the bogging and the lack of pull (torque) are madding!

all the advice I believe has helped but there is still something fundementally wrong!  I'm now certain that s(hort of something being bent)... the timing is perfect and I'm not opening it again!   It has to be Carbs! but I can't get them any cleaner (that I know of)

If we ever get this right it will be one for the record books... even if it can't be fixed I need to know what is wrong (for my own sanity)

[SteveJ.]

Repeat. Compression on all four?

[T Cro ®]

Repeat. Compression on all four?

Yes... Until you confirm that you have solid 128 - 196 PSI per cylinder you are pissing up a rope.... I'd go with a cylinder leak-down test too.... Confirm that you have or have not an engine issue then move on to the carbs etc....

[Steve in Sunny Fla]

1) a compression test with the throttle closed will yield results like this;

2) remove the crank bolt holding the timing plate on and make sure the locating pins isn't sheared. it's common to try to rotate the engine with the "big nut" and shear the pin. the plate then moves out of time, and then all the cam timing and ignition timing is off a few degrees. this will yield slow throttle response and low compression.

 3) one last thought is if the intake cam is times with the wrong timing mark vs the location of the cam. in other words the cam is bolted into the square holes, but timed with the mark for the round holes. Steve

[angelo]

Brad, obviously some knowledgeable folks have given you areas to address. 

Here's an additional thought.  In my limited experience, in the late 80's, my incredibly cool KZ1000 once acted this way.  Weekend in the garage.  Frustrated.  My girlfriend / now wife came out with a beer for me, looked it over, and said, "what is this off of?'   Fricken vacuum.   Idled fine, crap at speed.