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Discussion Starter #1
So I finished the rebuild late last month.Did the normal break in , run-cool down three times. Last weekend I took the kids out riding with me to do a little shake down run. I will be honest the bike ran well but I did expect a little more from the drag porting but wrote it off as I only had my 23cc dome in. After cleaning the bikes up when I got home I decided to do a compression test ......125psi I was floored, I thought my new snap on tester was FU so I went and got my buddies that I used to use all the time 125psi also. wtf
1. the bike was cooled off
2. the cylinder looked awsome as I stated to you earlier
3. no problems when putting piston, rings, etc... back together

I have heard peaple on this site talking about a leak down test. what is this and how do you do it ?
Is this the way to tell if the crank seals are good? This is my only thing I can come up with as the reason for having low compression. When I dissasembled the bike before I sent the jug to you It had 108psi with the same gauge if you remember the rings had a flat spot on each one from the exhaust port I believe, you smoothed the port out so I dont see that as a problem. Any Ideas?
thanks for the help
Danny
 

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doing a leak down test will not tell you anything really. UNLESS there was a enormous leak, but you would know that. check your ring end gap, your piston to cyl clearence, and your squish clearence.....23cc dome is a pretty low comp dome to be honest!
 

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Possibly the 23cc dome & drag portings not working together.
Because the cylinder is drag ported, that means the exhaust port roof is higher now than it was before so you cant trap as much substance as you could before.
Compression building in the cylinder starts just as the piston is covering the exhaust port & from the point up to TDC.
You may need to go to an 18 or 16cc dome to pull the compression back up.
Even though the cylinder now is drag ported, compression went from 108 up to 125 compression, so at least some part of the build is right.
Need to do a squish test as well to make sure thats set up right. Anything over 0.040 is to wide & compression will be low.
Neil
 

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Discussion Starter #4
Possibly the 23cc dome & drag portings not working together.
Because the cylinder is drag ported, that means the exhaust port roof is higher now than it was before so you cant trap as much substance as you could before.
Compression building in the cylinder starts just as the piston is covering the exhaust port & from the point up to TDC.
You may need to go to an 18 or 16cc dome to pull the compression back up.
Even though the cylinder now is drag ported, compression went from 108 up to 125 compression, so at least some part of the build is right.
Need to do a squish test as well to make sure thats set up right. Anything over 0.040 is to wide & compression will be low.
Neil
uote]

thanks for the info the new dome is on the way! when you do a compression test is the engine supposed to be at opperating temp or cold or does it really matter?
 

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Discussion Starter #5
Itried calling your shop phone and get the answering machine and your pm is full. Please call me at 816-289-2558. I need to talk to you about a 16-18cc dome.. I talked to CT today and they thought I was an idiot until I told them you were the guy that I have been talking to , Then there tone changed to "you should listen to him"!!!!!!! They somewhat pissed me off.
 

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Itried calling your shop phone and get the answering machine and your pm is full. Please call me at 816-289-2558. I need to talk to you about a 16-18cc dome.. I talked to CT today and they thought I was an idiot until I told them you were the guy that I have been talking to , Then there tone changed to "you should listen to him"!!!!!!! They somewhat pissed me off.
Who did you talk to at CT ??.
Allen most of the time is real quick with people on the phone. I just talk junk right back to him & we get along fine.
I like dealing with miss Roxann though, but you can tell some of Allens rubbed off on her as well.
What did he say about the small dome.
Neil
 

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Discussion Starter #7
It was a lady and she was very short, she claimed there was no way the bike would even run it would be over 300psi. she asked where I got this information and when I told her it was you she started back pedaling.
 

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Yeah, Allen has really good information and is very helpful, but its his way or no way. He is very short and abrupt, especially when I mention that basically everything I have is from ESR. Can't blame him there.
 

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Discussion Starter #9
Yeah, Allen has really good information and is very helpful, but its his way or no way. He is very short and abrupt, especially when I mention that basically everything I have is from ESR. Can't blame him there.
this is true, he is not good enough to spend $1000 with, but you want to ask a bunch of questions. Hell I would be pissed also. My whole issue with what was going on was I told them straight out I am not an engine guy but I wanted 16-18cc dome and then all hell broke loose! " you cant do that, that is a banshee size dome , who told you this wrong information"
 

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you really need to check the squish clearence as well............
 

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Discussion Starter #11
you really need to check the squish clearence as well............
neil and I are talking about these things.
 
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