Compression after port, and noss head with 19 cc domes

[Dgrey]

I just installed ported jugs and a noss head with 19 cc domes. I never checked the compression before the install but I just did today and its at 100 psi. The compression check tool was a $20 one from harbor freight, but isin't my compression supposed to be higher with those domes?

 

Do you think that the rings need to re-seat before the compression will go up?

 

Do you think that the tool is a cheapie and is really readding wrong numbers?

 

Thanks.

 

What are the instructions for checking the compression. I did it in the morning is the bike supposed to be warm?

Edited August 26, 2007 by Dgrey

[blowit]

I just installed ported jugs and a noss head with 19 cc domes. I never checked the compression before the install but I just did today and its at 100 psi. The compression check tool was a $20 one from harbor freight, but isin't my compression supposed to be higher with those domes?

 

Do you think that the rings need to re-seat before the compression will go up?

 

Do you think that the tool is a cheapie and is really readding wrong numbers?

 

Thanks.

 

 

I would want to know your exhaust port duration and your method of checking the comp. I am thinking your tester is lying to you. some testers can be off by over 3ccs by not having a schrader valve in the end of the tester and not threading in all the way.

 

 

Brandon

[Dgrey]

I would want to know your exhaust port duration and your method of checking the comp. I am thinking your tester is lying to you. some testers can be off by over 3ccs by not having a schrader valve in the end of the tester and not threading in all the way.

Brandon

 

 

I was screwed in all the way. I dont know the exhaust port duration.

 

[shee4speed]

How many times did you kick her over at WOT?

[Dgrey]

How many times did you kick her over at WOT?

 

 

lol.. oops I gave it no throttle and I kicked it about 20 times.

[shee4speed]

Keep us updated!

[Dgrey]

OK so the bike needs to be warmed up and I need to hold it wide open while checking the compression yeah?

[shee4speed]

See what it reads cold.

[Dgrey]

See what it reads cold.

 

 

WOT and kicked it more than 20 times. Compression = 110 cold.

Now what? That is to low right? tHE Bike is an 05 w/ low hours but I did just put the jogs on so maybe the rings are not fully seated agaiN?

[XxMeltIcexX]

Theres no way you got a 10 psi difference from being closed to WOT, it should be a dramatic difference... You should have checked the port duration while it was apart, Its not all top end porting is it?? If not then thats way too low... Is it running good? Only way to test that tester is to screw it in to the dome first and use vegetable oil and fill up the dome with it, if it holds more than your dome size(19 ccs), then the tester you have is a cheapy... (add the 1-3 ccs the tester added and calculate)... I have 18 cc domes and all top end porting (forgot the duration off the top of my head, but its very small) and im getting 185 psi in both cylinders... Somethings not right, but we'll figure it out, i dont think you kicked it hard enough... Get your ass out there and get a workout...

 

Eric

[Dgrey]

Theres no way you got a 10 psi difference from being closed to WOT, it should be a dramatic difference... You should have checked the port duration while it was apart, Its not all top end porting is it?? If not then thats way too low... Is it running good? Only way to test that tester is to screw it in to the dome first and use vegetable oil and fill up the dome with it, if it holds more than your dome size(19 ccs), then the tester you have is a cheapy... (add the 1-3 ccs the tester added and calculate)... I have 18 cc domes and all top end porting (forgot the duration off the top of my head, but its very small) and im getting 185 psi in both cylinders... Somethings not right, but we'll figure it out, i dont think you kicked it hard enough... Get your ass out there and get a workout...

 

Eric

 

 

Kevin Herr did a dune port for t-5's.

 

Whatever it runs perfect and its on 100 octane gas so fuck I dont even care about the compression then because that is what he recommended I run as far as gas. The tool does not screw in as far as the spark plug does so maybe that is the problem.

[shee4speed]

Dude kick that thing 50-100 times.See what happens! I'll be drinking my beer while you kick.LOL

[XxMeltIcexX]

Kevin Herr did a dune port for t-5's.

 

Whatever it runs perfect and its on 100 octane gas so fuck I dont even care about the compression then because that is what he recommended I run as far as gas. The tool does not screw in as far as the spark plug does so maybe that is the problem.

 

that would definately change your reading, but like i said i would really invest in another tester or find out the difference between that tester and the plug, compression is a good starting point to work off of, then you know when its time to do some maintenance work.. IMO

 

Eric

[Dgrey]

Dude kick that thing 50-100 times.See what happens! I'll be drinking my beer while you kick.LOL

 

Mmm beer... Check... I have a cold one right here... Samual Adams

 

 

that would definately change your reading, but like i said i would really invest in another tester or find out the difference between that tester and the plug, compression is a good starting point to work off of, then you know when its time to do some maintenance work.. IMO

 

Eric

 

I'll invest in a better one. Do any banshee web sites sell one that you would recommend?

[okbeast]

I think it's something to do with Kevin's porting (not a bad thing at all). I had a port done by him for T-5's as well and with a stock head milled .020 I was reading somewhere around 130, thinking it should be higher.

 

I am right with you that it runs like a raped ape even for low compression so I didn't really care.

 

Try checking your squish clearance, mine was a little high (.053 i believe) so that explains why my compression is a bit low.