So ive advanced my timing and from my high school years in trade school.I'm pretty sure it raises combustion chamber temperature.so my question is going richer is the best way to combat pinging.I dont have any pinging but Is my thinking correct?
2 options:
1) increase the octane in your fuel. If you are already at the highest octane you can buy from readily available pump gas, then..
2) Richen up the fuel/air mixture in your carbs. (jetting)
Understand that the USA FJ's were set lean at the factory to comply with the EPA regs.
If you increase the timing, you may think you're ok with no knock with a casual ride around town, but with a fully loaded bike, riding up hill on a hot day with a heat soaked engine is when you will hear the marbles.
Therefore, on a stock engine go ahead and change your 1986 FJ's Pilot jets (from 37.5 to 40.0)
Change your mains (from 112.5 to 117.5) and shim your needle 1/2 step via a correct thickness shim washer.
(All available from RPM)
The richer mixture will keep the marbles away and your engine will run cooler. Win-Win
Mike, help me out...go to your Profile and add in your signature line that you have a 1986 FJ1200. Saves me time in looking up your previous posts to see what critter you have... Thanks amigo... Pat
Mike, wait a minute, hold the press....
Didn't you just have your engine rebuilt and carbs rebuilt?
Didn't you ask the guy who did the work, to give you direction on the carbs?
We've agreed to tweek the carbs some.it'll be fine relax
I run only high octane and yes advancining timing will cause a lean condition so it does require either more fuel or higher octane.
Quote from: Pat Conlon on April 30, 2018, 04:01:31 PM
Mike, help me out...go to your Profile and add in your signature line that you have a 1986 FJ1200. Saves me time in looking up your previous posts to see what critter you have... Thanks amigo... Pat
Why haven't you done this yet, Mike?
Mike,
Please do not adjust on your carbs until you have completed the break in & valve adjustment. I am glad to hear the throttle cables have fixed the hanging idle issue and it was not the carbs.
At this point, I would say your combustion temps are probably cooler than they were at the stock timing or retarded position you started at.
When the spark ignites sooner, the flame front burns out sooner and exposes less cylinder wall to the heat source. This actually lowers the temps of an air cooled engine as the flame front is not exposed so long to the cylinders. The cooling fins then draw that heat away better from the cylinders.
unless you experience any pinging, which I highly doubt you will, adjusting or changing the jetting on your carbs is a mistake.
Your carbs are a long way from stock and getting information from people on the forum is information you cannot use for your carb set-up.
Ride that FJ and enjoy it...once it is broken in we will "tweek" the carb settings.
Randy - RPM
Quote from: Mike m on April 30, 2018, 09:03:24 PM
.... and yes advancining timing will cause a lean condition...
No it won't
Quote from: Mike m on April 30, 2018, 01:37:46 PM
So ive advanced my timing and from my high school years in trade school.I'm pretty sure it raises combustion chamber temperature.so my question is going richer is the best way to combat pinging.I dont have any pinging but Is my thinking correct?
Yes... more fuel will decrease combustion temps immediately. That will fix pre-ignition (pinging) immediately.
Sorry for late reply...
Frank