rubberneck Posted January 1, 2010 Report Share Posted January 1, 2010 Bansheestang is on the money. And as far as him making you guys look stupid, i am pretty confident he has forgotten more about tuning and compression ratios than any of us know. Here is the thing you guys keep making these posts in multiple threads about how it is ok to run these small domes. Do you not realize how quickly detonation will kill a motor? A couple of very good points were made above, pump gas is unreliable. One bad batch and you lose a motor if your compression is on the edge. Not to mention that more is not necessarily better with compression. So you jack the compression right to the edge of what the fuel you are using can handle. Now you have to richen it up to keep it from detonating. Id rather go more conservative and tune the bike properly. And i bet if you were do dyno both ways the properly tuned bike with less compression will show more power. You guys do what you want, but you can not solely rely on what the bike kicks out to determine what fuel to run and recomending too small of domes is irresponsible. Quote Link to comment Share on other sites More sharing options...
AKheathen Posted January 1, 2010 Report Share Posted January 1, 2010 Quote Link to comment Share on other sites More sharing options...
sheerider1026 Posted January 1, 2010 Report Share Posted January 1, 2010 im running 19cc domes, +5.5 timing on 93 pump gas.. around 162 psi.. been that way for years and no problems.. and it runs! Quote Link to comment Share on other sites More sharing options...
No Limit Powersports Posted January 1, 2010 Report Share Posted January 1, 2010 Its not a stock bike though. The only diff. in that and mine where I had t5s, vf-3 and a dune port and rode with 20cc domes for 2 years with no problems. Hes on stock jugs NOT 78mm. If anything wouldnt you recommend he uses a 21cc too be safe instead of scarying him into thinking were all stupid and dont know what were talking bout and hes going too blow up his bike? Just my opinion. No where did i try and scare him into thinking your stupid. But for anybody to come on here and say that you can run 20cc domes on pumpgas without asking for more information is incorrect. I seen nowhere where you asked about bore size, squish, exhaust height, or most importanly what octane fuel his pump gas was. How can you sell a guy a set of domes without the rest of the information and feel good about him not blowing up his motor. Not saying that a 20cc dome will not be perfectly fine, but from the vague information that was given about the motor its at least on the border of the pump gas compression ratio, at least for the shitty pump gas we have around here. I never said it was a 78 bore but you didnt ask what bore it was on either so that was just a exaggeration to prove a point. There are a million varibles that could make or break the motor, hell it could be worn and run with 18cc domes but that does not mean that would be the correct way of setting it up. im running 19cc domes, +5.5 timing on 93 pump gas.. around 162 psi.. been that way for years and no problems.. and it runs! Again every setup is totally different you said nothing about elevation, squish, jetting... There are def ways to set a motor up with higher compression and make it live on pump gas, and everybody has there own ideas in this area. IMO I feel that the tune is far more important than compression and the bikes will make better power tuned properly at a safe compression level than fat at a higher compression level to prevent deto (or retarded timing). Again a 20cc dome may work perfectly for you. I would typically ask for more information before throwing a number out at you because ive seen it done once or twice or read it on here a dozen times. No offense to anyone sorry if it was taken that way. Quote Link to comment Share on other sites More sharing options...
FASTOYS Posted January 1, 2010 Report Share Posted January 1, 2010 My mods are as follows -Aggressive trail port -ptr mids -boyesen low-mid reeds - +4 timing -billet impellar -pro design cool head (currently running 22's) -single 35mm (if I remember correctly 190 or 195 main 45 pilot and cel middle clip) May have forgotten something but I think thats it for the engine. I'm 200-400 feet above sea level and was wondering if it was safe for me to run pump gas with some new 20cc domes I bought. And If it is what octane I need to run. I also needed to know if I need to change my jetting at all to compensate for the different compression. I'm assuming no but I wanted to be sure before I put them on. Yesterday I accidentally stripped my drain plug threads out pretty bad, and need a quick fix to get my bike up and running again. I heard I can just get a bigger plug and if its only a tad bigger just thread it right in, what do you guys think works best for fixing this problem? Thanks The person who could or should be able to answer your question corectly is the one whom did the "aggressive trail port". Bansheestang is correct that there are many variables in this equation that need to be accounted to get to the correct answer. But by now it sounds like it is a done deal.. Quote Link to comment Share on other sites More sharing options...
alf44 Posted January 1, 2010 Report Share Posted January 1, 2010 Right on man. U have more extensive knowledge about the motors than me. I was giving the simple answer based on my experiance and what i read from all the posts on this thread. Sometimes the simple answer isnt good enough. Understood. No harm no foul. Im just one who goes wth experience, trial and error and just common Knowledge. U no your specs and the internals alot better than me. Knowledge is power! Peace out Quote Link to comment Share on other sites More sharing options...
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