heater Posted April 23, 2009 Report Share Posted April 23, 2009 ok so i just looked at the timing plate to see where it was set because the guy i had working on my bike is a dumbass. he set the timing at -4 but it seems to be running ok how it is ive had some overheating problems but i think that is all from the fiberglass impeller he put in it that is melted and half there now. by me moving it to +4 timing what issues will i have. im new to this and i just would like to know a heads up before going and doing everything. are my carbs going to be ok how they are or will i need to adjust them? i have 300 main 27.5 pilot, k&n pods, cool head, 19cc domes, i have bored it twice and i dont know really how much he bored it. it is ported, fmf fattys . any and all help is needed to make this thing faster im savin for a few more things, hell what i am sayin im always savin for something else for it or fixin it lol....but i just want to get everything out of what i already have on it. Quote Link to comment Share on other sites More sharing options...
2001Stroker Posted April 23, 2009 Report Share Posted April 23, 2009 It may be set at -4, because you have 19cc domes, and the last guy wanted to run pump gas. If you bump it up to +4, you may need somewhere around 98-100 octane, to prevent detonating. You could set it at +4, but I would say mix 50/50 with 110 octane and premium pump gas. Or, you could set it at +4, and change the domes to like a 21cc. Just my opinion. Quote Link to comment Share on other sites More sharing options...
heater Posted April 23, 2009 Author Report Share Posted April 23, 2009 It may be set at -4, because you have 19cc domes, and the last guy wanted to run pump gas. If you bump it up to +4, you may need somewhere around 98-100 octane, to prevent detonating. You could set it at +4, but I would say mix 50/50 with 110 octane and premium pump gas. Or, you could set it at +4, and change the domes to like a 21cc. Just my opinion. i bought the bike new and i just put in the 19cc domes a couple weeks ago with the cool head i put on it. running the higher octane fuel is fine with me if its going to go faster. so by changing the timing its going to give me more compression is what your saying? so really i need the 110 octane fuel if im going to put it at +4 and then im back ridin? Quote Link to comment Share on other sites More sharing options...
2001Stroker Posted April 23, 2009 Report Share Posted April 23, 2009 No, no, no. Timing doesn't change your compression. Advancing your timing requires more octane. Retarding you timing requires less octane. Smaller domes makes more compression, which also calls for more octane. Less compression calls for less octane. Different octane ratings alone, will not give you more or less power. I'm sure one of the engineers on here will jump in, and fill you in on all of the technical stuff about fuel -vs- octane -vs- timing, and the flash points of different gasoline octanes. Quote Link to comment Share on other sites More sharing options...
heater Posted April 23, 2009 Author Report Share Posted April 23, 2009 No, no, no. Timing doesn't change your compression. Advancing your timing requires more octane. Retarding you timing requires less octane. Smaller domes makes more compression, which also calls for more octane. Less compression calls for less octane. Different octane ratings alone, will not give you more or less power. I'm sure one of the engineers on here will jump in, and fill you in on all of the technical stuff about fuel -vs- octane -vs- timing, and the flash points of different gasoline octanes. i would like that i need all the information i can get because im tired of payin some guy to do something i can learn about and do myself Quote Link to comment Share on other sites More sharing options...
2001Stroker Posted April 23, 2009 Report Share Posted April 23, 2009 Firehead and a few others know their shit about all the flashpoints and stuff. Maybe you can PM him, and paste the link to this thread in it. Quote Link to comment Share on other sites More sharing options...
mopar1rules Posted April 23, 2009 Report Share Posted April 23, 2009 i would suggest running straight 110 as my buddy w/his 19cc domes and 50/50 mix of 93 & 110, couldn't stop the deto, even w/stock timing. Quote Link to comment Share on other sites More sharing options...
KlotzBanshee Posted April 23, 2009 Report Share Posted April 23, 2009 Not trying to hijack your thread or anything, but it brings up a point I Quote Link to comment Share on other sites More sharing options...
oh6banshee Posted April 23, 2009 Report Share Posted April 23, 2009 Ok now Im interested, I have 21 cc domes in my coolhead and stock timing and run straight 91. I have a timing plate that I have yet to install. Reading this thread makes me think that I would need to run a higher octain when i did put the plate on ( at + 4) and it also makes me think that if I got smaller domes, like 19cc ( provided I ran straight 110 octain also) it would have more power. Please give me some insight. Quote Link to comment Share on other sites More sharing options...
2001Stroker Posted April 24, 2009 Report Share Posted April 24, 2009 Detonation is real hard to hear in our loud ass 2-Stroke motors. One sign is spark plugs backing out. Another is pitted pistons or domes. Quote Link to comment Share on other sites More sharing options...
heater Posted April 24, 2009 Author Report Share Posted April 24, 2009 alright so if my left side is backing off and the right side is not....does that mean i am having Detonation? also i dont want to put to high of octane in it if i dont need it because wont that blow a hole in a piston? and since it is at -4 right now do i still need to pull everything apart to adjust it to +4 or can i just loosen it and move it? plus is the oil mix the same when i do the 50/50 or staight 110? lots of questions now i feel like im blind and in the dark with no hands with this bike sometimes Quote Link to comment Share on other sites More sharing options...
2001Stroker Posted April 24, 2009 Report Share Posted April 24, 2009 I'll try to answer those question, short and sweet. Oil mix stays the same. Higher octane will not hurt your pistons. If anything, it's leaded, and will help a little. Adjusting the plate, a 10mm wrench, loosen the plate bolts, and turn it. And, one or both of the spark plugs backing out can be a couple different things. Detonation is one of them. Quote Link to comment Share on other sites More sharing options...
heater Posted April 24, 2009 Author Report Share Posted April 24, 2009 I'll try to answer those question, short and sweet. Oil mix stays the same. Higher octane will not hurt your pistons. If anything, it's leaded, and will help a little. Adjusting the plate, a 10mm wrench, loosen the plate bolts, and turn it. And, one or both of the spark plugs backing out can be a couple different things. Detonation is one of them. sweet that works whats the other thing that will make them backout. Quote Link to comment Share on other sites More sharing options...
FireHead Posted April 24, 2009 Report Share Posted April 24, 2009 It may be set at -4, because you have 19cc domes, and the last guy wanted to run pump gas. If you bump it up to +4, you may need somewhere around 98-100 octane, to prevent detonating. You could set it at +4, but I would say mix 50/50 with 110 octane and premium pump gas. Or, you could set it at +4, and change the domes to like a 21cc. Just my opinion. Ignition timing that is too far retarded can cause detonation and overheating, just the same as if your ignition timing was too far advanced. Do you know what elevation you are running at in MO? I am actually a bit concerned that you might have an air leak somwehre that is causing a lean condition and the detonation you are experiencing. In a good condition, OEM engine, you should be ble to run non-oxygenated fuel premium 92-93 octane pump gas with 19cc domes 1000 feet above sea level with out an problems. :geek: Quote Link to comment Share on other sites More sharing options...
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