P-man Posted April 13, 2008 Report Posted April 13, 2008 Hey i took a compression gauge to my banshee and it came out at 105 on each cylinder, I understand this to be really low. It has been ported but i am not sure what kind of port job, the bike has a lot of pep to it and the guy i bought it from said to run race gas. It has a bit of after market stuff like carbs reeds spacers... Is it possible that the port job made the compression this way? It was ported before i got it so i am not sure where they exactly "machined it". Thanks guys Parker Quote
huskyohilux Posted April 13, 2008 Report Posted April 13, 2008 (edited) Hey i took a compression gauge to my banshee and it came out at 105 on each cylinder, I understand this to be really low. It has been ported but i am not sure what kind of port job, the bike has a lot of pep to it and the guy i bought it from said to run race gas. It has a bit of after market stuff like carbs reeds spacers... Is it possible that the port job made the compression this way? It was ported before i got it so i am not sure where they exactly "machined it". Thanks guysParker Sounds a bit low...are you using a quality compression gauge? It should be screwed down the spark plug hole and engine kicked quite a few times with wide open throttle. Depending of quality on gauge the readings come out a bit different, often on the low side. I think race gas are usually used with compressions over 160 psi or something. Do you still have the stock cylinder head? Edit Remove the carbs and reed cages or the exhaust pipes to confirm if the cylinders really are ported. I got b.s:ed when I baught mine. The guy said it was duncan 403 and I didn Edited April 13, 2008 by huskyohilux Quote
badassbanshee479 Posted April 13, 2008 Report Posted April 13, 2008 155-160 is the point where you need to start running race gas! Quote
dajogejr Posted April 13, 2008 Report Posted April 13, 2008 Hey i took a compression gauge to my banshee and it came out at 105 on each cylinder, I understand this to be really low. It has been ported but i am not sure what kind of port job, the bike has a lot of pep to it and the guy i bought it from said to run race gas. It has a bit of after market stuff like carbs reeds spacers... Is it possible that the port job made the compression this way? It was ported before i got it so i am not sure where they exactly "machined it". Thanks guysParker Two things. A. Is it a name band comp tester? I've seen the cheapy's be off BIG Time, I'm talking 30PSI or more... B. Did you test it hot or cold, throttle held wide open...and did you keep kicking until it no longer went up? Often it can take 20 to 30 kicks...not just 5 or 10. Oh, and what is your elevation...at or near sea level, that's rebuild time...if that compression is accurate. Quote
2strokespirit Posted April 13, 2008 Report Posted April 13, 2008 Do not trust a cheap comp tester, been there done that... Get a good one.. Quote
Animalman294 Posted April 13, 2008 Report Posted April 13, 2008 Ya, 160 is the starting point for the race fuel, but with compresion like that you are no where near race fuel time. You need to get a good tester and ya never know the guy may have had a buddy do it that said, "hey man, I can port it for ya." And just totally screwed up the inside of the cylender's and you are now getting crappy compression............ Quote
fox_forma Posted April 14, 2008 Report Posted April 14, 2008 Is the comp tester your using have an adapter on it which connects to another piece? I had an issue before when I had one of those and I was reading somewhere like 100psi. Once I got the right comp tester I was up at 168psi where I should of been. Quote
P-man Posted April 15, 2008 Author Report Posted April 15, 2008 Is the comp tester your using have an adapter on it which connects to another piece? I had an issue before when I had one of those and I was reading somewhere like 100psi. Once I got the right comp tester I was up at 168psi where I should of been. my compression tester is from pepboys ill get the name tomorrow. i did kick it until the needle stopped moving and i did it warm. i dont remember if i did it open throttle though. ill try what yall said and get back to you guys. Quote
P-man Posted April 15, 2008 Author Report Posted April 15, 2008 ok my compression tester is an "Actron". is that any good? i pulled off one pipe to look at the exhaust to see if it is ported. it is kinda hard to see, how do i tell? Quote
P-man Posted April 15, 2008 Author Report Posted April 15, 2008 ok my compression tester is an "Actron". is that any good? i pulled off one pipe to look at the exhaust to see if it is ported. it is kinda hard to see, how do i tell? I retested my compression and it came out to be 120 on each side, that is still pretty low right? and yea my compression tester does hav 2 fittings, one that screws on the other Quote
huskyohilux Posted April 15, 2008 Report Posted April 15, 2008 ok my compression tester is an "Actron". is that any good? i pulled off one pipe to look at the exhaust to see if it is ported. it is kinda hard to see, how do i tell? If the black paint is still there, then has probably no port work been done...the same way goes for the intakes. Quote
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