nicktoney Posted September 26, 2006 Report Share Posted September 26, 2006 alright, im doing my compression test tonight. quick question, will i get accurate readings if my bike is cold, as opposed to hot? im only asking because id hate to blow it up if i start it and let it warm up? noss head, 20cc domes, +4timing, trinity iv pipes, boyesen superstock reeds, k&n in box, snorkel gone, 290mains, 12-1400ft, 50-60*..... this be safe to let warm up? can i just kick it, and rev it lightly to get it warmed up? Quote Link to comment Share on other sites More sharing options...
dajogejr Posted September 26, 2006 Report Share Posted September 26, 2006 I would say your jetting is safe... As long as you didn't leave a circlip out of the piston, piston to cylinder clearances are ok, rings installed ok and the cylinders and head is tourqued down properly...you SHOULD be ok to start it and warm it. However, you should be ok to test it cold, too. It won't be a 100% accurate reading...normally your compression goes up a bit when warmed, as parts heat up and expand. Not to mention it'll probably go up a bit when the rings seat and break in. However...all that usually adds to 5 to 10 PSI, if even that much. It would be a very good idea to check it cold, just to be sure one isn't WAY OFF from the other! Quote Link to comment Share on other sites More sharing options...
Sprntr81 Posted September 26, 2006 Report Share Posted September 26, 2006 yea,its best to warm the engine to operating temps so you get an accurate reading....just putt around on it a few minutes and then check. Quote Link to comment Share on other sites More sharing options...
BANSHEEMANIAC Posted September 26, 2006 Report Share Posted September 26, 2006 yea,its best to warm the engine to operating temps so you get an accurate reading....just putt around on it a few minutes and then check. WHAT IS GOOD COMPRESSION(PSI) ON A STOCK BANSHEE? AND WHAT PSI WOULD NEED RACE GAS? Quote Link to comment Share on other sites More sharing options...
dajogejr Posted September 26, 2006 Report Share Posted September 26, 2006 WHAT IS GOOD COMPRESSION(PSI) ON A STOCK BANSHEE? AND WHAT PSI WOULD NEED RACE GAS? Without knowing your elevation...I'll take a stab at this taking into consideration I ride at 1000ft or less.... 125 PSI is stock, give or take. Each motor is different. IF your jetting is spot on...145ish to 160ish can need 50/50 race gas. 160ish and above usually needs race fuel. Now...of course, there's timing. Add some timing to that...and it can change. No one can give you a 100% certain answer, these are merely guidelines, and I think pretty safe ones at that. I've read people running 160PSI and pump gas, for years, no problems. Compression has more to do with the need to run race fuel than timing does. But, they both contribute in the overall need. Hope that makes sense.... :beer: Quote Link to comment Share on other sites More sharing options...
nicktoney Posted September 26, 2006 Author Report Share Posted September 26, 2006 everything is stock, i didnt mess with anything but the head/domes/timing... thats why i wonder about testing it cold to be sure? everything piston/cyl./rods are all stock and have not been touched in anyway... I would say your jetting is safe... As long as you didn't leave a circlip out of the piston, piston to cylinder clearances are ok, rings installed ok and the cylinders and head is tourqued down properly...you SHOULD be ok to start it and warm it. However, you should be ok to test it cold, too. It won't be a 100% accurate reading...normally your compression goes up a bit when warmed, as parts heat up and expand. Not to mention it'll probably go up a bit when the rings seat and break in. However...all that usually adds to 5 to 10 PSI, if even that much. It would be a very good idea to check it cold, just to be sure one isn't WAY OFF from the other! Quote Link to comment Share on other sites More sharing options...
dajogejr Posted September 26, 2006 Report Share Posted September 26, 2006 Ride it...you'll be fine. Quote Link to comment Share on other sites More sharing options...
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