preignition

[mason79]

okay i need help, thanks in advance,

i have this nagging preignition, or pinging that i can't get rid of.

engine is tune very well, sync'ed, valves checked, in spec, timing i retared a few degrees to address this issue with nominal affect.

i experimented with grades of gas and have been on high test indefinately.

only on loads like gunning it from 80 to 100 mph i can hear it ping , i have had this since day one, since i got the bike, the compression is 175 across the board,

is it carbon buildup? i see the base metal on the piston tops.

what is the remedy? retarded it till it stops, it wouldn't bother me.

thanks

[randy]

Mason,

May be running a little lean? I had that problem with my '81SH, move the needles up with washers and pinging went away.

Your 79 has three notches on the main jet needles, try moving the clips down one notch.

[mason79]

thanks randy, they are in the middle position, and everything is stock exhaust, air box with foam uni filter,

plz no, don't make me go into the carbs, i have never even tried to change needles postions just looked at it.

i will take this into serious consideration and thank you randy...

[randy]

Well, there you go, the UNI filter will lean it out a bit. Have you tried a stock air filter?

[mason79]

would colder plugs make up the diff?

never ran with the k and n

k and n shrunk after washing so i went to uni,

no experience with stock.

[mro]

ping/knock

I've been experimenting with my 80G as it is rather noisy when accelerating. First have tried raising fuel level in float bowl. This has cut down the noise by about half, but bike does not have the power it should. Next plan to change main jets up one size to see if that will do it and still have all the power it should. If that helps may try changing 2 & 3 another size up.

Possible that CA CA land bikes run a little leaner. Our politicians have a history of fixing things until they are truly broke.


mro

[mason79]

i thought e and f model did not have california specific models and the jetting are the same 50 states.

[planedick]

Answers...

Your high compression is because of carbon deposits. What you see when looking in the spark plug hole isn't representative of what's in the cylinder. That area is always cleaner because it's right where the ignition starts and is hottest and burns best. I think you should run some seafoam through it to get rid of some of the carbon build up. BTW, needles can be adjusted without removing the carbs.

[Incubus]

Don't be afraid of disassembling the carbs, Mason. I've had mine apart about 50 times in the last few months. After the first 25 or 30 times you can do it in a foxhole under fire at night. It's not that hard. You just have to pull the top covers to get to the needles. You don't even have to take them off the rack.

Patrick

[mason79]

believe me my first experience was gas comeing out of the airbox and i had to triple clean them a thousand times, not to mention trying to rejet for some intake and exhaust changes, and back again...
you make it sound like you like to take them apart, well i wouldn't mind if there wasn't gasoline involved i just hate that smell and stinging and getting all over the place, mostly.
okay i'll get to the needles...

[mason79]

thanks randy,


that was it, you gave me a new bottom, mid and top end, esentially a new bike, who knows which xsive was not realizing the bike's true performance potential by shoddy tuning or neglect again a millions thanks,


power plays such a large role in the handling of the bike as well.
now i really need a new clutch

[skids]

What was "it?" Raising the fuel in the bowls or raising the main needle or stock filter?

Originally posted by mason79
thanks randy,
that was it, you gave me a new bottom, mid and top end, esentially a new bike, who knows which xsive was not realizing the bike's true performance potential by shoddy tuning or neglect again a millions thanks,

[mason79]

raised the needle one notch