SuzukiSavage.com - zero compression

Tom K

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zero compression
06/17/12 at 11:26:27

So...coming home from work yesterday. I'm cruising along at 75 and the bike cuts out for a moment (like a petcock issue). It dropped to 65 and held speed. I was right at my exit. At the stop sign I put in first and started to go and it died. Wouldn't restart.

After checking this and that I got to the compression test. zero zip nada nothing. S&%T! I poured a little oil in and that got it up to 30psi.

Any idea how bad this can be. Maybe lucky and just rings? New piston and cylinder is what I'm guessing. Maybe time for a larger bore Wink

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justin_o_guy2

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Re: zero compression
Reply #1 - 06/17/12 at 11:37:39

Okay, its an 04, how many miles? Recent work? Anything due to be done that you shoulda done?
Make sure the decomp isnt stuck.

How much oil went in to jack the compression to 30 PSI?

If you have access to an air hose, wrap tape or whatever around the end of a blower & pull the oil fill plug, blow into spark plug hole & see if its blowing out there. Set motor at TDC compression first.

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Tom K YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 37 Brighton, CO Gender:	Re: zero compression Reply #2 - 06/17/12 at 11:57:39 She's got about 16.5K miles. Oil may have been low. Looked at the cam chain tensioner andit still looks good. Decomp unplugged for test. and maybe a couple tablespoons of oil. Going out now to put some air to her.
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justin_o_guy2

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Re: zero compression
Reply #3 - 06/17/12 at 12:19:58

Ive never seen it happen, but in a No Compression moment, Id have to physically, manually, be certain the decomp isnt hung up. Go to the head & look at the spring that returns it & make sure its pushed as far in the direction the spring is ppushing it as possible. Vertical is where it goes IIRC.
Then its time for compressed air in the cylinder to see if it blows out the oil fill hole,.

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Tom K YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 37 Brighton, CO Gender:	Re: zero compression Reply #4 - 06/17/12 at 12:29:34 wanted to make sure of TDC. Pulled out timing cover. put air to it. nothing from intake or exhaust. I got a nice breeze blowing on me from the timing cover cap hole (or whatever you'd like to call it.)
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justin_o_guy2

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Re: zero compression
Reply #5 - 06/17/12 at 12:57:56

It'd be easier to pressure up on the oil fill hole. I wouldnt be that excited about trying that hard to create pressure in the case, tho, Id rather see it in the cylinder,
So far, Im not gettin it..
One thing, gotta put it in gear at TDC or the pressure in the cylinder will push the piston down. Mite even shove it off the kickstand. Be CAREful, Mite be time to enlist a friend.

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360k+ Serious Thumper Offline Savage heart of darkness Posts: 680 Cartersville, GA Gender:	Re: zero compression Reply #6 - 06/17/12 at 13:11:14 Make sure you open your throttle when testing, otherwise your intake is closed.
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Tom K

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Re: zero compression
Reply #7 - 06/17/12 at 13:26:03

To be clear. Here's what I did. Engine at TDC. Screwed in adapter into spark plug hole. Attached shop air line to adapter. Adjusted regulator on compressor to about 30 pounds. Air blows to crank case not exhaust port or intake.
Also...header is already off, and throttle was open.

I guess I'm gonna have to start tearing into it some more. Angry

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justin_o_guy2

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Re: zero compression
Reply #8 - 06/17/12 at 13:47:27

Eaux Neaux.. Yep,, youve got what is called "communication" between the cylinder & the engine case. Twisting the throttle wont open the slide w/o vacuum from the engine running.
Id drain the oil into a clean pan & see what ya find, but the answer is already known, whether or not theres anything in the oil. Id bet theres junk there, tho.
At this point, IDK if your best move is pull the engine or do it in frame, I expect youll be pulling the jug to get to the piston & thats not gonna be fun with a bike on the floor, but neither is pulling & reinstalling an engine,

This may be the time to get the bore coated & a fatter slug & a meaner cam,,
& , figuring out WHY it cratered is important.

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Tom K YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 37 Brighton, CO Gender:	Re: zero compression Reply #9 - 06/17/12 at 14:01:08 I am thinking about the 95mm. I may stick with stock cam though. trying to get good mileage. Although.... those guys with the big v-twins at work would be surprised by the power. Unfortunately I'm on a tight budget. If I could get by with just rings I would. Not like that'll happen.
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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: zero compression Reply #10 - 06/17/12 at 14:22:03 One thing is certain, youre going in & youre an odds on favorite for a fatter slug. YOu can do a cam later. The mechanical realities may not be aware of your budgetary constraints. I hope the problem is solvable inside your abilities to handle them.
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360k+

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Re: zero compression
Reply #11 - 06/17/12 at 16:19:33

360k+ wrote on 06/17/12 at 13:11:14:

Make sure you open your throttle when testing, otherwise your intake is closed.

Oops, my bad. I didn't read thoroughly, and was assuming a standard compression test with a gauge. It sounded like the classic "I didn't know I was supposed to open the throttle" test results. Undecided

Yep, and on a slider carb, you need a way to hold it open.

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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: zero compression Reply #12 - 06/17/12 at 16:30:45 Walk away & look ashamed, go stand in the corner, YOure on REport, Mister! Get your toothbrush & report to the latrine,,
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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28996 L.A. California Gender:	Re: zero compression Reply #13 - 06/17/12 at 18:34:16 might have a burnt piston.
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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: zero compression Reply #14 - 06/17/12 at 20:36:11 Sure sounds like it.,
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