how many kicks for compression test?


kawraper

Member
Mar 4, 2009
100
0
Just wondering how many for proper results? Its a 2 smoke. I can top it out at nearly 180psi but it takes quite a few kicks to get there. Its been feeling like its lacking power but maybe its just time to move up from a 125.
 

kawraper

Member
Mar 4, 2009
100
0
Ok thats what i figured just wanted to hear it from someone else. My bike kicks really easy like it has no compression but thats what the gauge reads when I hook it up. My buddies rm125 feels like it has alot more resistence when you kick it.

I just been trying to find my lack of power issue and it ended up the clutch is toast. I was suspecting top end and its suprising its still good considering its probly got like 40-50 hrs on it.
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
A 125, ridden once a week by a little old lady from Pa., at 50 hours? Its shot. I am getting the idea that by kicking it enough, almost 1000 rpm, it gets up to 185? You need to check the ring end gap and skirt clearance at least. Unless its a kdx, then just get a sleeve. You really gave it away about it feels like no compression, before admitting long on hours. You will see the difference with the top end fixed. If its a plated cylinder, the bore may be oval, it can be fixed. A compression gauge can be misleading when not used properly. You check it new, broke in, then once in a while. Any drop in your readings, its time again. Curious how worn it is, if you just kick it once, as if normal starting, how much does it read? Forget that, my luck it would shatter the piston skirt into a zillion pieces.
 

kawraper

Member
Mar 4, 2009
100
0
With one kick it only reads about 50psi if that. I pulled the exhaust off it and the Piston side/skirt still looks new. I bought the bike in may so ive just ridden it all season and havent really opened the motor up cause if it aint broke i dont fix it. Im pretty sure the topend was brand new when I got it. The thing starts like a champ pretty much first kick every time. And this bike does have the nikisil plating on the cylinder.
 

Patman

Pantless Wonder
LIFETIME SPONSOR
Dec 26, 1999
19,774
0
So you said it has 40-50 hours and you are hoping it had a new top end when that started? You have no idea what the service life of the rings or piston is do you? The idea to fix something only when it is broke is stupid. Why would you risk more extensive damage to the bike or injury to yourself because it still almost moves under it's own power? The mentality of dirt bikes being like a lawn mower just blows me away. If the mower quits the grass just grows until it's fixed. If the dirt bike quits on the face of a jump...
 

kawraper

Member
Mar 4, 2009
100
0
supposedly 10-20hrs. And with a topend with a brand new piston at the beginning of the season i figured yes ride it till it feels weak ask hell or doesnt start from lack of compression. All the catastrophic failure ive seen isnt from a bad piston or ring but from a rod bering siezing in a motor. When ive seen topends go the bike dont want to start and if it does it runs very weak.

The bike starts like its brand new....yes its feeling weak....i asked how many kicks for a compression test.

I didnt ask " hey could you guys harass me about riding the hell out of my bike?"

I want a #, 1 kick 25 kicks Thats what im asking. I was figuring it was done anyhow I just wanted a number to go off of.

My idea of fun with a dirtbike is riding the hell out of it a bunch of times every week. This bike will never be perfect its 12yrs old and every time i hit the track its pinned out the whole time. Im not gona spend twice as much time servicing a $800 bike than i am riding it. Its a throwaway. I bought it figuring at the end of the season it would only be worth its weight in scrap metal. Now Im just trying to squeeze another month or 2 out of it to finish out the season without spending more in parts on it than i paid for it.
 

Patman

Pantless Wonder
LIFETIME SPONSOR
Dec 26, 1999
19,774
0
kawraper said:
I didnt ask " hey could you guys harass me about riding the hell out of my bike?"

By posting you actually did open yourself to whatever comes your way. Too bad you are so emotionally fragile it's going to cause you a lot of problems.

Maybe you should go check out Eric Gorr's site to see what can happen to pistons run past their service life. Lost compression and hard to start is what you hope for! It's amusing when people get more info that THEY specifically were looking for and get all bent out of shape over it. Yes it is your bike but if you don't care and just want to ride it until it blows then who really cares how many kicks it takes?

Since you can't make up your mind if it's 40-50 hours of 10-20 hours let's just admit there is no idea how many hours are on the top end let alone the bottom. The overall condition of the engine has an impact on the performance not just the rings or piston & rings but hey who cares just throw it away when it's dead... (and cry about it being broken I'm sure).

Most every bike I have had didn't need more than a couple kicks to determine what the compression was. Then again I maintain my stuff and keep a factory shop manual handy so I don't have to subject myself to the mean old Internet guys. :laugh:
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
About the only thing looking in the exhaust will do, is see if the exhaust skirt is intact. The places that wear, you can not see through the exhaust. Its just the truth, I did not make it up. People have some odd habits to say the least, been there, done that, learned and moved on. The best still is tipping your bike over before starting it, works every time, I know! Here is hoping it does not let loose and hurt you, or somebody else. Ride her till it melts, its all good.
 

Patman

Pantless Wonder
LIFETIME SPONSOR
Dec 26, 1999
19,774
0
whenfoxforks-ruled said:
... learned and moved on.
Something MANY can not claim :cool:
 


Top Bottom