CaferacerMO
Been Around the Block
Compression meter may never lie but listen to it.. Honda C70 passport..
https://m.youtube.com/watch?v=SL63nUovQy4
https://m.youtube.com/watch?v=SL63nUovQy4
Does this motor need a rebuild?
- Thread starter CaferacerMO
- Start date
barnett468
Coast to Coast
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confirm reading with another gauge or try the gauge on your car just to double check it.
confirm reading with another gauge or try the gauge on your car just to double check it.
CaferacerMO
Been Around the Block
teazer said:
It's actually a brand new guage, first time I've used it..
barnett468
Coast to Coast
CaferacerMO said:
well who knows, things happen and i guess you can either do as i suggested or just start taking it apart.
also, if it says china on the back i would take it back . . one time might have been one time too many for it . . reliable gauges cost around $100.00.
Also, you didn't answer teazers question.
DohcBikes
Fuck You.
Jesus christ you guys are jumping to conclusions. Not everybody can afford a 100 dollar guage at least he fuckin has one. How bout actually talking about the test and possibly considering that the guage isnt malfunctioning before going off on a rhetorical debate about cheap guages.
They're pretty f'n simple tools, an air hose a coupling a schrader valve and a psi guage and if you haven't dropped it, it's probably just f'n fine man.
Have you checked your valve clearance?
How many times are you kicking it? You need to watch the guage if it is still going up keep kicking.
Easiest way to check your guage without wasting your time going to autozone to check with THEIR chinese guage, is to simply hook it up to an air compressor that has a guage you trust and compare the readings.
You can also spray soapy water anywhere that you think air might be escaping, including but not limited to the plug hole, the swivel connection, the coupling, the crimp at the guage, the guage itself, and the pop-off button, WHILE you are kicking the engine over, or after the guage has built the 30 psi you are getting now.
Those engine are notorious for tightening valves.
They're pretty f'n simple tools, an air hose a coupling a schrader valve and a psi guage and if you haven't dropped it, it's probably just f'n fine man.
Have you checked your valve clearance?
How many times are you kicking it? You need to watch the guage if it is still going up keep kicking.
Easiest way to check your guage without wasting your time going to autozone to check with THEIR chinese guage, is to simply hook it up to an air compressor that has a guage you trust and compare the readings.
You can also spray soapy water anywhere that you think air might be escaping, including but not limited to the plug hole, the swivel connection, the coupling, the crimp at the guage, the guage itself, and the pop-off button, WHILE you are kicking the engine over, or after the guage has built the 30 psi you are getting now.
Those engine are notorious for tightening valves.
No one is suggesting that he go out and buy a $100 gauge for one project, but the ones used by the Auto stores are usually not HF and are usually accurate enough. The one that the OP has came in a red plastic box just like the ebay/HF POS we tried. In fact we tried 3 of them and only 1 worked for more than a couple of times. We have two good gauges here and the most accurate is one from Motion Pro. http://www.motionpro.com/product/08-0188
For one time use, I would just borrow one for the auto store.
As a matter of approach, the first thing to check when you have an out of spec reading is the gauge. Ask any old pilot and they will tell you that. Checking against a known high pressure source is a good way to at least see if it's in the ballpark as you suggested.
For one time use, I would just borrow one for the auto store.
As a matter of approach, the first thing to check when you have an out of spec reading is the gauge. Ask any old pilot and they will tell you that. Checking against a known high pressure source is a good way to at least see if it's in the ballpark as you suggested.
DohcBikes
Fuck You.
I agree teazer that the motion pro gauge (hey look i finally spelled it correctly) is a good one.
Another tip or caution for ANY compression or leakdown gauge is to never disconnect the coupling until you have released the pressure from the gauge via the popoff. It will wreck the calibration on nearly any gauge in short order.
Another tip or caution for ANY compression or leakdown gauge is to never disconnect the coupling until you have released the pressure from the gauge via the popoff. It will wreck the calibration on nearly any gauge in short order.
barnett468
Coast to Coast
you're jumping to conclusions by assuming we are jumping to conclusions.
yes the valve adjustment should be checked anyway, however, it should not be assumed that the gauge is good, and if he has an adapter that will fit another engine he has that is in good running condition, he can do a test on that as i suggested and if that also reads extremely low it seems reasonable to deduce that his gauge is in fact bad . . in contrast, if it reads above 120 psi, it would then seem reasonable to deduce that the gauge is in fact good which in turn would prove that there is in fact something wrong with his engine.
since the test i proposed "should" only take around five minutes and doesn't require any special tools, it seemed like one of a few different reasonable options to resolving the question of why the gauge is reading low
Also, since the engine turns over several times with one kick, the amount of times he kicked it over is irrelevant.
there are sometimes more than one road that will eventually lead to the same place.
yes the valve adjustment should be checked anyway, however, it should not be assumed that the gauge is good, and if he has an adapter that will fit another engine he has that is in good running condition, he can do a test on that as i suggested and if that also reads extremely low it seems reasonable to deduce that his gauge is in fact bad . . in contrast, if it reads above 120 psi, it would then seem reasonable to deduce that the gauge is in fact good which in turn would prove that there is in fact something wrong with his engine.
since the test i proposed "should" only take around five minutes and doesn't require any special tools, it seemed like one of a few different reasonable options to resolving the question of why the gauge is reading low
Also, since the engine turns over several times with one kick, the amount of times he kicked it over is irrelevant.
there are sometimes more than one road that will eventually lead to the same place.
DohcBikes
Fuck You.
Tests are good, all im saying is that maybe we need to look at the procedure as well before instantly blaming the gauge. It is certainly a possibility that this is the first time he has ever attempted a compression test.
It DOES matter how many times he kicks it. Out of the approximately 137.4 times I have done a compression test on a kick bike, max pressure is NEVER achieved with one kick. Or 2. Or even 3.
Point being, irregardless as you would say, always turn the engine until max pressure is achieved. If the pressure is still rising, keep kicking.
It DOES matter how many times he kicks it. Out of the approximately 137.4 times I have done a compression test on a kick bike, max pressure is NEVER achieved with one kick. Or 2. Or even 3.
Point being, irregardless as you would say, always turn the engine until max pressure is achieved. If the pressure is still rising, keep kicking.
barnett468
Coast to Coast
DohcBikes said:
It only matters how many times he kicks it per test if his compression is over maybe 60 - 70 lbs on the first kick because it spun at least three revolutions . . Since there was only thirty lbs, AND he did it more than once, he could kick it until Nico turns honest and it would still never, ever, have enough compression to consider it to be acceptable which is why in his particular case i said that.
In normal cases, where the first kick shows enough compression to suggest there may still be hope for it, it does warrant additional kicks.
If you watch a compression gauge as an engine turns over, you will clearly see that the first or first two revolutions generate the most pressure after which the gain will be progressively less with each revolution until, ultimately it will no longer gain compression . . Also, this initial pressure level will ALWAYS be at least 50% of the total amount of compression an engine has if the test is done properly, therefore, since he only had 30 psi after 3 revolutions of the engine, he would only have a possibility of having round 60 if he kicked it until he passed out.
I ain't that old or forgetful yet and i ain't that sleepy today so you'll have keep tryin.
PS - By the way, there is no such word as "irregardless".
CaferacerMO
Been Around the Block
I am going to rent a different gauge from o'riellys whenever I get the chance, I did kick it over until the meter stopped as I have run multiple other compression tests, just this is the first time on this gauge. I just was shocked to only see 30 pounds as it sounds a lot better then 30 pounds as you can hear in the video.. And id previously run the old finger test on it before I had a gauge and it blew my finger off which is by no means a reliable test...
barnett468
Coast to Coast
CaferacerMO said:
yeah i listened to the video, and of course its hard to tell just how much compression an engine has just by listening to it, but from what i did hear, it just didn't seem like it was incredibly low which is one of the things that made me question the gauge, but in the interim, you can check the valves as DOHC suggested.
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CaferacerMO
Been Around the Block
barnett468 said:
Just make sure the gaps are all up to spec and all that good stuff?
barnett468
Coast to Coast
CaferacerMO said:
Yup.
Did you buy it like that or did something happen to it?
CaferacerMO
Been Around the Block
barnett468 said:
Long funny story actually.
I started giving it a "rat" type job whenever I first owned it like two years ago whenever I had first kind of started getting into working on bikes.. Did a lot of ugly, sloppy work to it. Needless to say I got in a money pinch, and sold it.
Fast forward two or so years and I'm really getting into bikes, motor work, learning to weld etc.. Getting serious about the hobby and what not.. And the guy I sold it to is like "hey I don't want this do you wanna buy it back? I'll let it go for 50 bucks" so of course I had to jump on that deal. So now it's back in my possession.. A little rustier and grosser than when I had it (he kept it outside I believe) but this will be my summer daily since I have to sell my baby (my custom brat kz200 money pit) to find my next semester of college.
Plans for this are to fab up a proper steering mount for some tracker bars, stretch the tube on the frame a couple inches, maybe stretch the swing arm, lower it a bit.. Maybe throw an old super trap on and follow the rat rod theme, and then hopefully try my best to do one of the patina imitation paint jobs.
I just wanna have something I can scoot around on this summer after I ditch my brat and wait for a cheap cb750 to pop up.
barnett468
Coast to Coast
.
well it sounds like it already has a patina and maybe just one more winter outside should finish it off nicely, plus save you same money on painting fake rust on it.
well it sounds like it already has a patina and maybe just one more winter outside should finish it off nicely, plus save you same money on painting fake rust on it.
CaferacerMO
Been Around the Block
datadavid said:
Yes. As far as I know I followed the correct procedure, as I've done it before.
I didn't open the throttle up, I had the carb intake completely off when I tested.