Compression after port, and noss head with 19 cc domes

[blowit]

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.

 

 

I am still thinking the testing is off. That tester and or lead are giving a false reading. Very possible to have excessive squish but I still think another test with a real tester would help a bunch.

 

 

Brandon

[jbooker82]

If your gauge looks like the one that you posted that would severly cause the compression to be low.

#1 It doent have long threads like the spark plug has. Just has the short ones.

#2 If it doenst have the shrader valve's in the very end and has a long threaded adaptor it will add at least 3cc to the cylinder head.

 

I explained it all in this post. With pic's

Cheap vs Snap On Compression Tester LINK

 

I bought a good used Snap on gauge over a new craftsman.

 

josh

[jayzx10r]

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?

Hey man, you can bring your 'shee over to my house and I'll check your compression for you!! I have an old gauge that reads exactly the same as my buddies expensive SnapOn does.

 

As far as how to check:

Warm it up, pull your plugs, attach your gauge, open the throttle, give it kicks until the reading stops going up, DONE. It should only take less than 10 kicks to max your reading.

Remember that you will have better compression after the rings seat. 100 lbs is not OK nor do you need to run race gas at that low compression level.

Call me if you'd like, Jay.

[Dgrey]

Hey man, you can bring your 'shee over to my house and I'll check your compression for you!! I have an old gauge that reads exactly the same as my buddies expensive SnapOn does.

 

As far as how to check:

Warm it up, pull your plugs, attach your gauge, open the throttle, give it kicks until the reading stops going up, DONE. It should only take less than 10 kicks to max your reading.

Remember that you will have better compression after the rings seat. 100 lbs is not OK nor do you need to run race gas at that low compression level.

Call me if you'd like, Jay.

 

Alright well I really think the tester is a POS that I have because the threads are not long enough.

 

Can I hit up up after I come back from vacation? Im leaving Wednesday for Laughlin for a week. I may be able to make it up there on September 8th unless I can convince my brother to go in on a good gauge with me I dont want to spend $200.

[RagunCajun]

Mine is a cheap one from auto zone. Looks like the one posted. It came with two attatchments, one for normal plugs and one for weedeaters i believe.

 

Mine does 130-135psi on both. I have 20cc domes and im ported. I've always read you take a benchmark setting when you redo a top end and you use that number as a benchmark test number.

[Coupelx]

i have that same cheapy tester. it showed 145-150 on both cylinders on mine. no porting. trinity head and 20cc domes. 1500 feet above sea level. I use it on my cars and its always shows where they need to be .