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post #21 of 135 (permalink) Old Nov 27th, 2009, 6:23 am Thread Starter
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I'll probably try again today with some oil and see if that makes a difference. I have a couple of friends here who have testers that I can borrow. I'll post my results later. There isn't anything else to do on the bike until this is fixed.

This is the compression tester that I have:
http://www.actron.com/product_detail.php?pid=16171
I had to special order the smaller connector for the small spark plug holes in our bikes. It seems like a good quality product to me.

I listened to some Ducati engines on youtube last night and it was clear that my engine has a problem, and it's always had this problem. Those engines don't misfire unless coming off of WOT at high engine speed, typically. They sure sound nice compared to mine.

Last edited by dirkwrong; Nov 27th, 2009 at 7:15 am.
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post #22 of 135 (permalink) Old Nov 27th, 2009, 8:32 am
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I would consider using a different instrument to double check your number. A mechanic quality compression tester is about a $200 item. Not that yours isn't a useful tool, it is. In my opinion, the best way to utilize a lower end tester is to test the compression drop of an engine over time. For example, I ride a 2 stroke snowmobile, and I tend to go pretty hard on it. It had its first set of rings (and pistons) at less than 2000 miles. When it was new, I set a baseline for compression, then monitored it, with the same compression gauge, over time as it slowly went down. When it got too low, I knew it was time for a change.

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post #23 of 135 (permalink) Old Nov 27th, 2009, 8:59 am
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missfire

start by addressing the known problems. install the correct plug wires and caps. caps must have 5000 ohms of resistance and the correct resistor plugs.Also get the afr correct. have you checked the coils for primary and secondary resistance and a peak voltage test.The electronics on the newer efi bike are very sensitive any change you make can have a serious impact on the bike.If this is starting to get beyond your abilities go to a dealer I know for a fact that donnie at duck pond can fix your bike
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post #24 of 135 (permalink) Old Nov 27th, 2009, 10:25 am Thread Starter
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I figured out that I have all the parts I need to make my own leak down tester, so that's what I'm going to do next. I'll report back when I have some more data. I need to listen for the hissing...

I'm also going to test the engine temperature sensor, since Richard was kind enough to send me the proper graph. I went out and bought a good oven thermometer. Time to boil some water!
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post #25 of 135 (permalink) Old Nov 27th, 2009, 1:44 pm Thread Starter
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Compression test results:
Cold, dry: 110 both cylinders
cold, oiled: 135 both cylinders.

Doing leak down is hard because I have to install the chain in order to hold the engine still. The air pressure pushes the piston down really fast and hard. I destroyed an engine turning tool today trying to hold it still. crap!

I give up. It's too hard to turn the engine without that tool, and I broke my nice carbon fiber brake rod too getting the wheel on and off. I don't think God wants me to ride motorcycles.

Last edited by dirkwrong; Nov 27th, 2009 at 2:22 pm.
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post #26 of 135 (permalink) Old Nov 27th, 2009, 2:48 pm
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Originally Posted by dirkwright View Post
I figured out that I have all the parts I need to make my own leak down tester, so that's what I'm going to do next. I'll report back when I have some more data. I need to listen for the hissing...

I'm also going to test the engine temperature sensor, since Richard was kind enough to send me the proper graph. I went out and bought a good oven thermometer. Time to boil some water!
I bought one from Harbor Freight for $50 or so, much cheaper than building your own.

135 wet is really low. Try a known good gauge, could be yours is bad.

Tom

P.S. Mine is a Craftsman I got at Sears in the early '80s, still works fine.

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post #27 of 135 (permalink) Old Nov 27th, 2009, 3:11 pm Thread Starter
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I bought one from Harbor Freight for $50 or so, much cheaper than building your own.

135 wet is really low. Try a known good gauge, could be yours is bad.

Tom

P.S. Mine is a Craftsman I got at Sears in the early '80s, still works fine.
I believe the one I have is equivalent to a Craftsman. I don't think it's the gauge. I need a clutch holding tool as well as an engine turning tool. I have broken both of them.
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post #28 of 135 (permalink) Old Nov 27th, 2009, 3:27 pm
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the fact they are pretty even on both cylinders is also another sign that the are probably ok, seems really strange for them BOTH to go at the same time and read just as low as each other.

the cold test is good with oil but also do it hot, you want the expansion etc in the cylinders as well, incase you have a sticking ring or something, again with and with out oil.

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post #29 of 135 (permalink) Old Nov 27th, 2009, 3:28 pm
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I believe the one I have is equivalent to a Craftsman. I don't think it's the gauge. I need a clutch holding tool as well as an engine turning tool. I have broken both of them.
Build one:



or



Tom

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1998 ST2
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post #30 of 135 (permalink) Old Nov 27th, 2009, 3:42 pm Thread Starter
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Thanks Tom! I have the remains of my old one. I can make something from that also.
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