sounds like marbles in my top end

[blaster240R]

heres an update guys, after putting my new piston in i tested for air leaks and didnt find any. put it all back together and went throug my break in cycle . i still found it to be pinging in the high end of the rpm. so i decided to put my timing back to stock instead of +4 and the pinging is gone. dont quite understand it but i guess my blasty doesnt like the +4.... seems to be running pretty good now.

 

[phragle]

you PROBABLY have too much compression with the advanced timing. try running a tank of race gas with the timing advanced. Race gas not superhorsepower thermonuclear megaturbo $2.99 autoparts store bargin bin octane booster.

 

[4cfed]

you PROBABLY have too much compression with the advanced timing. try running a tank of race gas with the timing advanced. Race gas not superhorsepower thermonuclear megaturbo $2.99 autoparts store bargin bin octane booster.

lmfao!! cmon now!! every kid with a civic with a far can and a 3 foot wing adds 5 bottles of nawz booster to every tank

 

[blaster240R]

my compression is at 130. i wouldnt think that would warrent the need for race gas...

 

[phragle]

Static compression can be very different than th compression ration when it is running because of the effect of porting and the pipe.

 

[blaster240R]

Static compression can be very different than th compression ration when it is running because of the effect of porting and the pipe.

whats the difference.. just asking because i dont know..

 

[phragle]

When you just kick the bike over, part of the charge is lost out of the exhaust port. The pipe is built so that the exhaust wave , for lack of a better term, bounces back towards the cylinder. that returning pressure wave helps keep the charge in the cyl;inder instead of letting it escape. This is where the motor comes 'on the pipe' the design of the pipe effects the RPM range that this happens

 

[blaster240R]

When you just kick the bike over, part of the charge is lost out of the exhaust port. The pipe is built so that the exhaust wave , for lack of a better term, bounces back towards the cylinder. that returning pressure wave helps keep the charge in the cyl;inder instead of letting it escape. This is where the motor comes 'on the pipe' the design of the pipe effects the RPM range that this happens

sorry just tryin to understand this. so how would advancing the timing effect that and make it ping..

 

[OConnor Racing]

Think of your engine as a clock with top dead center of the piston being @ 12 O-clock. Engine timing ( when the spark fires ) is always advanced a certain amount of degrees. When you go to a +4 over stock, you advance the timing way before the piston is at top dead center. This will benefit in the high RPM's but will increase your cylinder pressure because the piston has to overcome the spark. Very dangerous way to get HP. Everything takes time to move...........even the spark in your engine. Octane is a fuels ability to resist preignition. Preignition is when the fuel ignites before the plug fires. Pressure alone will make gas ignite. Kind of like the way a diesel runs. The noise you're hearing is preignition and in turn .......detonation. Your jetting sounds like it's too lean. I run 180 # compression with a +4 timing advance and have no problems on Sunoco 93.............but the NOS works really well.

 

[brandoz28]

great explanation OConnor^^^^

 

[The Ox]

Think of your engine as a clock with top dead center of the piston being @ 12 O-clock. Engine timing ( when the spark fires ) is always advanced a certain amount of degrees. When you go to a +4 over stock, you advance the timing way before the piston is at top dead center. This will benefit in the high RPM's but will increase your cylinder pressure because the piston has to overcome the spark. Very dangerous way to get HP. Everything takes time to move...........even the spark in your engine. Octane is a fuels ability to resist preignition. Preignition is when the fuel ignites before the plug fires. Pressure alone will make gas ignite. Kind of like the way a diesel runs. The noise you're hearing is preignition and in turn .......detonation. Your jetting sounds like it's too lean. I run 180 # compression with a +4 timing advance and have no problems on Sunoco 93.............but the NOS works really well.

You rock man,,,,thats good stuff here.

 

[phragle]

sorry just tryin to understand this. so how would advancing the timing effect that and make it ping..

Simple... if you loose charge thru the exh.port when its not on the pipe, your only compressing so much. if the return pulse from the exhaust keeps the charge from escaping, you now have a bigger charge to squeeze into the same size space.

 

[blaster240R]

Think of your engine as a clock with top dead center of the piston being @ 12 O-clock. Engine timing ( when the spark fires ) is always advanced a certain amount of degrees. When you go to a +4 over stock, you advance the timing way before the piston is at top dead center. This will benefit in the high RPM's but will increase your cylinder pressure because the piston has to overcome the spark. Very dangerous way to get HP. Everything takes time to move...........even the spark in your engine. Octane is a fuels ability to resist preignition. Preignition is when the fuel ignites before the plug fires. Pressure alone will make gas ignite. Kind of like the way a diesel runs. The noise you're hearing is preignition and in turn .......detonation. Your jetting sounds like it's too lean. I run 180 # compression with a +4 timing advance and have no problems on Sunoco 93.............but the NOS works really well.

thanks man for the help. when i first took it apart i could see that it was lean because it was trying to burn a hole it the top of the piston on the exhaust side.. when i put my new piston in and broke it in i still noticed that i was having pinging when i got to the high end of the rev, no matter how fat i went with the jetting i put a 170 main in it and it still did it. so i thought the only thing left to try is putting the timing back to stock. and that did it the pinging went away. now i'm just trying to figure out what size main to use.

 

[Outlawed Genetics]

i had the same problem with the +4 deg and pinging and took it out like i was told to in another thread and the pinging stopped but the motor pretty much did too. once i went back to the stock degree key it ran like crap like the jetting was off but i tried every main jet between 250 and 310. i was at 310 with the timing advanced and it ran good but the pinging bothered me and i thought it may be harming the engine. now without it i cant get it to run worth crap nomatter what jet or needle setting i use. it acts rich one minute and lean the next and has no power.

now the question.... should going from 4 degree advanced timing back to stock timing change the jetting much? if so should i need a smaller jet with stock timing or a larger one?