[chef john]

Hi
Got a 96 zx-11 ninja.
valve cover gasket was blown, oil in cylinder one. had that fixed, the mechanic didnt even check the oil level which was overfilled. the psi check was
160,170, 180 & 200....my reg mechanic said thats normal....gonna have the carbs synced and adjusted.he said it sounds lie its running rich.
Does the carbs control the psi ? or the valves. the mechanic that fixed the gasket said the cams have wear them (only has 22k) and dont think he adjusted the valves
Also, is there a reason it fires up great when cold, but takes a few seconds when its hot ?

 

[christikitty]

It fires up fine when cold but takes a bit when warm is cause it's too rich. Comp looks ok but it sounds like your mechanic is a joke..

 

[e1_ZX-9r]

+1 Your mechanic should have recorded the gaps on all 16 valves. How else are you to know how the engine is aging? I would think the compression would be a little more even too, not that #1's 160 psi is bad, it's just too far off from #4 (25%, in fact).

But, if you like how the bike runs and the gaps are within tolerances, rejet and sync the carbs and enjoy the bike until the next interval.

 

[chef john]

Thanks, the regular mechanic Im bringing the bike to on Weds says too rich also.
I panicked and brought the bike to a dealer (Coyne motorsports, Indio , Ca) and got lousy treatment. Its no wonder why the 2 "mom and pop" mechanics are booked 2 weeks in advance and the dealer welcomes walk-ins !
Still cant believe they didnt check the oil level but started rooting around looking at the cams then said the bureau of automotive repair tells them to call the customer when they see stuff like that ! Guess they dont have to check the oil level though (?)

 

[nauticalmike]

If they were repairing leaking valve cover gasket like you said then noticing the cams are worn is hardly rooting around in my opinion...

 

[ninjanut]

The compression check could also give you some useful info about the valves and rings if the mechanic knows what he is looking for. I would check the valve clearances as a starting point (adjust if needed) and then worry about the carbs. No use adjusting carbs if the valves aren't set right.

 

[chef john]

My mechanic is working on her now... after multiple starts this a.m he said that the fuel is heating up in the bowls , and causing hard starting, also too rich. He suggested removing the emissions box ( which is a nightmare system, all the vapors backing up, etc...) and than adjusting the mixture, syncing the carbs, etc. The original lame mechanic never checked the valves when changing the valve cover gasket...or even suggested doing that...(?) (TEN WEST/COYNE MOTORSPORTS..INDIO,CA)
I still may need a valve adjustment but the problem seems directly tied to a fuel issue....hard starting in a.m, runs like a monster when warm, then after it sits 4 or 5 minutes takes time to restart, so we will see whats what tomorrow when hes done. Its a 5 +hr job and hes doin it for 320.00.....not bad for an $80 per hr mechanic

 

[chef john]

I have gotten lots of feedback from pros saying the rings directly affect the cylinder psi variance...good call
If the original lame dealer tech that changed the valve cover gasket had even SUGGESTED doin a valve adjustment I would have green lighted that, this being a bike from the auction with an unknown history.
FYI....they gave me the bike back saying the cams had wear on em....my mechanic says at 22k thats insane (they also didnt check oil which had almost a qt too much in the engine( prob why the gasket popped)

 

[185EZ]

Hi
Got a 96 zx-11 ninja.
valve cover gasket was blown, oil in cylinder one. had that fixed, the mechanic didnt even check the oil level which was overfilled. the psi check was
160,170, 180 & 200....my reg mechanic said thats normal....gonna have the carbs synced and adjusted.he said it sounds lie its running rich.
Does the carbs control the psi ? or the valves. the mechanic that fixed the gasket said the cams have wear them (only has 22k) and dont think he adjusted the valves
Also, is there a reason it fires up great when cold, but takes a few seconds when its hot ?

carbs need to be held wide open for a proper compression check.

+1 Your mechanic should have recorded the gaps on all 16 valves. How else are you to know how the engine is aging? I would think the compression would be a little more even too, not that #1's 160 psi is bad, it's just too far off from #4 (25%, in fact).
But, if you like how the bike runs and the gaps are within tolerances, rejet and sync the carbs and enjoy the bike until the next interval.

+1
And the fact that it's gradually increasing across the bank is odd. Still thinking on that one.:tard

I have gotten lots of feedback from pros saying the rings directly affect the cylinder psi variance...good callIf the original lame dealer tech that changed the valve cover gasket had even SUGGESTED doin a valve adjustment I would have green lighted that, this being a bike from the auction with an unknown history.
FYI....they gave me the bike back saying the cams had wear on em....my mechanic says at 22k thats insane (they also didnt check oil which had almost a qt too much in the engine( prob why the gasket popped)

I just find it odd that the variance is gradual from one side to the other. Why would one cylinder have weak rings and the other side has good rings? If the motor was worn out, they would all be fairly equal.
I'm thinking bad valve adjustment or even bad head gasket.
Only way to tell for sure is a cylinder leak down test.

 

[e1_ZX-9r]

My mechanic is working on her now... after multiple starts this a.m he said that the fuel is heating up in the bowls , and causing hard starting, also too rich. He suggested removing the emissions box...

True to some extent. It's easy to imagine what's going on inside your carbs as they sit full of expansive fuel on top of a hot engine. After shutdown all that heat percolates upwards heating the carbs, causing the gasoline to expand. The caveat is that the emissions equipment will have no baring on it, good or bad. Removing it, is unnecessary.

If you're getting hard starting, begin by recording the number of turns on each of the four pilot air screws. Let's say they're somewhere around 2 1/2 turns out from a gentle seating. You might want to try them at 2 or 2 1/4 turns for a while and synching the carbs at that point to return the best results possible. Less turns lower the amount of fuel delivered by the pilot fuel circuit, more turns increases.

On a similar note, it's quite common for our downdraft CV carbs to seep gasoline out into the combustion chamber right after engine shutdown (as above). The expanding gasoline has nowhere to go but out, especially if the bike sits parked on its side-stand, due to the diagonal fuel level in the bowls. To mitigate/eliminate seepage flooding, turn the fuel tap off prior to engine shutdown, as much as 1/4 mile (more or less) from when you're considering parking the bike for an extended period of time. And if you can center the bike on a wheel stand, that will also help out greatly...from what I've experienced anyway.

:thumbup

 

[rileydeed]

Good info here, I just wanted to add some other possible explanations for the uneven compression. If the oil level was overfull when they checked the compression there could easily have been some oil build up in one or more of the cylinders which would increase the compression and if the carbs were rich or flooding the extra gas could have rinsed all the oil off the cylinder walls on one or more of the cylinders which would decrease the compression. Also if it has been running rich for a while it could have carbon buildup in some, which would again bump it up.

Anyways, I thought I would mention all this because it is very possible that once you get all your carb issues resolved and run it for a little while, you may find that another compression test will come out a lot more even:dunno

Oh yeah and E1 and EZ are both right:smile

 

[chef john]

very interesting theory on the full oil thing
Finally got her done. My mechanic found vacuum lines off, one tank vent neded a wire to unclog it, # 2 pilot screws was almost a 1/4 turn from falling out, air box joint had bolt on wrong side causing air leak,
rerouted and capped emissions system vacuum hose.
NOW in the a.m when I choke her it fires instantly,and when hot it fires up fast too.
My mechanic spent 7 hrs and only charged me for 4 (he also quoted me that prior and couldnt go back on it....it is a very complicated system)

 

[e1_ZX-9r]

That bike was pretty bad off. Your new mechanic sounds like he has a customer for life! Congrats!

So when do we get to see the bike?

 

[chef john]

OK....new problems....up until today the bike fired up great after the mechanic tuned the carbs,etc....today i filled the gas tank and ever since it has been very hard starting after shut off...it sat in garage after i got home after filling tank and the garage smelled of gas ...BAD ! there is a sticker on tank not to overfill due to expanding fumes (which causes hard start) took off seat,pulled tank vent hose and a squirt of gas came out for a second...weird?
Can this bike possibly only take only, say, like 3 gallons, anything more causing hard start? it smells rich and mechanic spent 7 hours adjusting that.
The emission vacuum hose has been rerouted and capped. .
just weird how this started after I put fuel in it.... HELP !
**SPOKE TO A LOCAL TECH WHO FIXES BIKES...HE SAID RIGHT OFF THAT THE FLOAT NEEDLES ON THE CARBS ARE WORN...THAT EXPLAINS THE GAS AMOUNT FLOODING THE BIKE WHILE ITS OFF, REEKING OF GAS...AND WHY GETTING BIKE BACK WITH 1/4 TANK "GOT BY" THE MECHANIC AND WHY THE BIKE RAN TITS TILL I FILLED HER UP TODAY....***
what do you guys think about that??

 

[e1_ZX-9r]

Not surprised by all the witch hunting. If your float needles are "worn," then so too are the eight I have on both of my 9Rs and they must have been "worn" after 4,000 miles on each bike. Nah, I'm not buying that. My main 9R has almost 54,000 miles on it and it acts the same as it has for the previous 40,000 miles.

I know what worked for mine and it should work for yours too from my Feb 4 response. Only thing I might add would be to raise the float height 1 or 2 mm from where they are now. BTW, what are their heights now?

 

[Masta Squidge]

Actually from what I have read, stock brass needles will wear after 4k easily.

That being said, the difference is god damn near trivial. I have seen totally stock bikes with 20+ that run just fine. A little rich never killed anyone.

 

[chef john]

my old mechanic says that it is definitely a venting problem....thats why when the bike was running great till I filled it up. The work done by my tech did a pressure test on a the carbs and they are all fine....needles included.
When the bike was worked on my mechanic,he capped off the emission system vacuum line, and also didnt check the bike with a full tank.when I was trouble shooting it when full, opening the gas tank made a hissing sound, so its not venting properly, backing up and causing " hydraulic lock" is it possible that capping off the emission line is causing this? one last thing. while the bike was running, we took seat off, and pulled the tank vent line off....a tiny squirt of gas came out 2 xs...

 

[chef john]

this D (U.S) model has a record for cams pitting after 16-20 k, but as far as this issue with the bike very hard starting after fill-up...it reeking of gas in garage and very hard starting till it gets down to 1/2 tank sounds like a fuel delivery/venting problem.
also,with full tank, when it as running and we pulled the tank vent hose off a bit of gas squirted out....2 xs !

 

[e1_ZX-9r]

The two emissions tank vents will capture overflow whether there is a recovery system or not, when fuel flows passed the gasoline cap's seal. I can't say what affect that would have on how your bike smells or runs, however in the past when I've accidentally tipped my CA model 9R over, fuel filled these tubes and probably the vapor emissions recovery plumbing. The result was that the bike ran a little differently until the fuel level ran below the fuel tank's ON fuel tube, while the tap was in the ON position. I think that when there is fuel filling either the tank's emissions plumbing or in the vapor recovery system, it will clear through normal riding, since any fuel in this system would be scavenged as fuel level falls below the tap's ON position tube. Once clear, the bike will sputter as it should until the tap is turned to the REServe position. Most people will not even know there was additional fuel in the system, unless they're recording their MPG, in which case they'll see a noticeable bump in the bike's range. int Like where when I ride with this one 49 state ZX-9R. It needs fueling around 150 miles, whereas my CA model 9Rs will go 250 miles before they are in the same situation. :lol

Others have reported odd/phantom running symptoms too if they've overfilled their tanks and let the bike sit for extended periods in direct summer sunlight, but the recovery system always clears itself and we all go on about our business.

The fact that your tank's emissions plumbing is capped, may in fact be creating the condition your mechanic is hypothesizing. But it also runs contrary to the conventional wisdom of those who've capped their systems. Or at least there's the perception that there isn't a problem with capping these tank tubes, since nobody is coming out saying it creates other problems. So your dilemma is to figure out a way to vent the emissions recovery tank tubes or give up and reattach it.

 

[Bobflyer]

this D (U.S) model has a record for cams pitting after 16-20 k, !

Probably lack of ZDDP in the oil, not bike specific.