pod filters and carb jetting

[andyb]

I've noticed the opposite effect.  Advanced static timing gives easier starting and a pinch more low  rpm power, retarded timing gives a power cut at the bottom (making a more noticable kick up high, sometimes past redline so you'll just lose overall), and the lack of immediate torque makes it harder to start.

YMMV, I suspect!  If you just grind the stock plate a pinch, you'll have the option to return it back to stock as desired, with only time being your loss.

[Flying Scotsman]

I plan on adding a few deg timing what way do you shift the plate cw or ccw.I plan on checking the valves too and adding slotted cam gears.

[Flynt]

I plan on adding a few deg timing what way do you shift the plate cw or ccw.I plan on checking the valves too and adding slotted cam gears.

I did this per RPM Randy's suggestion.  CW and grind the holes out to the edge of the mark left by the screw head...  i.e. grind the holes on the left side as you're looking at the timing plate installed.

Frank

[Flying Scotsman]

Thank you saved me the trouble of figuring it out.Its on the list of things to do.

[Alf]

I've noticed the opposite effect.  Advanced static timing gives easier starting and a pinch more low  rpm power, retarded timing gives a power cut at the bottom (making a more noticable kick up high, sometimes past redline so you'll just lose overall), and the lack of immediate torque makes it harder to start.

YMMV, I suspect!  If you just grind the stock plate a pinch, you'll have the option to return it back to stock as desired, with only time being your loss.

The effect of having an ignition advancer fitted is similar to high compression pistons: with the advancer the spark ignites the combustion chamber a fraction of time before the piston is at TLC, so with the extra gases of the combustion there is more pressure at the chamber = more compression is obtained at this moment

[ribbert]

I've noticed the opposite effect.  Advanced static timing gives easier starting and a pinch more low  rpm power, retarded timing gives a power cut at the bottom (making a more noticeable kick up high, sometimes past redline so you'll just lose overall), and the lack of immediate torque makes it harder to start.

YMMV, I suspect!  If you just grind the stock plate a pinch, you'll have the option to return it back to stock as desired, with only time being your loss.

The effect of having an ignition advance fitted is similar to high compression pistons: with the advancer the spark ignites the combustion chamber a fraction of time before the piston is at TLC, so with the extra gases of the combustion there is more pressure at the chamber = more compression is obtained at this moment

I've noticed the opposite effect.  Advanced static timing gives easier starting and a pinch more low  rpm power, retarded timing gives a power cut at the bottom (making a more noticable kick up high, sometimes past redline so you'll just lose overall), and the lack of immediate torque makes it harder to start.

YMMV, I suspect!  If you just grind the stock plate a pinch, you'll have the option to return it back to stock as desired, with only time being your loss.

The effect of having an ignition advancer fitted is similar to high compression pistons: with the advancer the spark ignites the combustion chamber a fraction of time before the piston is at TLC, so with the extra gases of the combustion there is more pressure at the chamber = more compression is obtained at this moment

[ribbert]

I've noticed the opposite effect.  Advanced static timing gives easier starting and a pinch more low  rpm power, retarded timing gives a power cut at the bottom (making a more noticable kick up high, sometimes past redline so you'll just lose overall), and the lack of immediate torque makes it harder to start.

YMMV, I suspect!  If you just grind the stock plate a pinch, you'll have the option to return it back to stock as desired, with only time being your loss.

The effect of having an ignition advancer fitted is similar to high compression pistons: with the advancer the spark ignites the combustion chamber a fraction of time before the piston is at TLC, so with the extra gases of the combustion there is more pressure at the chamber = more compression is obtained at this moment

Anyone familiar with old cars and bikes fitted with manual advance/retard levers will recall the standard starting procedure is full retard until it fires then advance a little then advance more once under way or under load (pre mechanical/ vacuum advance).  This is now taken care of automatically on modern engines, the "mechanical" advances with revs, the "vacuum" with load. This curve is predetermined by the manufacturer but in most cases the starting point is adjustable. This, and the curve, were often compromised (particularly in the 70's & 80's) to achieve emissions results. While trial and error(advance) may show some improvement over standard, results can be deceptive.  The perceived increase in power or torque may only be relative to a loss of it somewhere else. Retarded engines (within reason) start easily, definitely run hotter and offer no real performance improvement anywhere above idle. These are general observations not specifically Fj.

[ribbert]

Aaaaargh, the first line and a half of the previous post are not mine but part of what I was responding to.  Mine starts with "Anyone familiar with old cars........................"

Noel

[Marsh White]

Aaaaargh, the first line and a half of the previous post are not mine but part of what I was responding to.  Mine starts with "Anyone familiar with old cars........................"

Noel

FYI: you could have just gone back and edited your original post.  You have 30 minutes to make edits.

[andyb]

The effect of having an ignition advancer fitted is similar to high compression pistons: with the advancer the spark ignites the combustion chamber a fraction of time before the piston is at TLC, so with the extra gases of the combustion there is more pressure at the chamber = more compression is obtained at this moment

I agree, but remember to compare fairly modern and relatively efficent, high rpm engines, rather than old technology, low reving engines with less efficent combustion chambers, as well as considering piston area and how that relates to burn time.  The overall goal is to put the peak combustion pressure right where the engine has the best leverage on the rod.  You can read about some of Larry Widmer's (sp?) work, he did a bunch with altering swirl to change how the burn rates changed. 

[Lotsokids]

O.K. - One last shot here. How does 125 Main jets and 42.5 Pilot jets sound?  

Once again, I'm running Vance & Hines SS2R exhaust with pod air filters and no timing advance. I'll be ordering soon.

[Pat Conlon]

O.K. - One last shot here. How does 125 Main jets and 42.5 Pilot jets sound?
Once again, I'm running Vance & Hines SS2R exhaust with pod air filters and no timing advance. I'll be ordering soon.

Sure, Go for it.
I've got 42.5 pilots on my '84, screws @ 2.5 turns.....In the mountains at 6k msl slow speed putting around town, I'm rich, 40.0's would be better, however at sea level in Palm Desert, on a hot summer day my bike is happy happy happy.....

[andyb]

Sounds close.  I'd consider 122's if you tend to ride more in the heat and/or if you are at >1000' altitude, otherwise the 125's will be a pinch fat on hot days.  They'll work fine though, especially when it gets cold.

[Lotsokids]

Sure, Go for it.
I've got 42.5 pilots on my '84, screws @ 2.5 turns.....In the mountains at 6k msl slow speed putting around town, I'm rich, 40.0's would be better, however at sea level in Palm Desert, on a hot summer day my bike is happy happy happy.....

Since I have the illusive '88 / European model, aren't my stock pilot jets 40's? If so, I don't mind leaving them alone. I might also run 122's on the mains.

Sorry if I seem to be beating this to death. It's very difficult for me to get aftermarket parts. I have to order them and send them to the U.S., then get them when I take a trip back to the U.S. - the Hungarian mail system is broken. It's not like I can just go down to the motorcycle shop and get a different size jet. I need to get this right the first time.

Thanks for the input!

[andyb]

In that case, get a couple sets   They're not terribly pricy.  A set of 125's and 120's, some shim washers for the needles, and a set of 42 pilots should cover a pretty wide variety of bases.