Power loss

[BA80]

According to the jetting recommendations here I should be right where I was at. Actually I should have been at 145 mains instead of 142.5.

Here is a simple set of jetting guidelines that have worked for me. For those considering jet changes, this might help select a starting point.

1 jet size for custom 4 into 2 exhaust

2 jet sizes for 4 into 1 exhaust

1 jet size for K&N filter (single inside airbox)

1 jet size for drilling out the bottom of the airbox

3 jet sizes for individual filters

2 jet sizes for no muffler (open header)

1 pilot jet size for every 3 main jet size increase

Add up all the jet size increases and subtract one. (Remember they go in steps of 2.5 for each jet size)

Under a mismatch condition, like individual filters and stock exhaust or 4 into 1 header with stock filter and air box, subtract an additional 1 jet size.

Check plug color often, sync carbs after each jet change, make sure the floats are set correctly, and seriously consider purchasing a Colour Tune. (See "Colortuning Carburetors" in the Maintenance Section).

Make sure your carbs are in perfect working order before making jet changes.

Example from my '79 XS1100 F:

Stock main jets: 137.5

Stock pilot jets: 42.5 2 sizes for 4:1 exhaust (Jardine)

1 size for single K&N

1 size for drilled air box

4 (main sizes) - 1 = 3 or 137.5 + (2.5 * 3) = 145.0
1 (pilot jet size) or 42.5 + (2.5 * 1) = 45.0
With this jet configuration I get 32-38 mpg on the open road, Smooth idle, very strong exceleration from off idle to 80+ mph, and steady pull past 120 mph. My "F" has 76K mile on it, of which I have put 44K with this jet configuration.

I have applied this to the '78-'79 carb set with great success. These guidelines should work for the '80-'81 carbs also. The only part I have not tested is pilot jet changing on the second generation carbs.

[BA80]

Looking at that again, XS11's addition is wrong. 137.5 +2.5 = 140, not 145.

If you look at my signature, that's exactly where I've been for YEARS.

[dbeardslee]

Looking at that again, XS11's addition is wrong. 137.5 +2.5 = 140, not 145.

If you look at my signature, that's exactly where I've been for YEARS.

If you're going up 3 jet sizes, it's 2.5 X 3, or 7.5, which would be 145's. But I've noticed on mine that the jetting recommendations tend to overstate by about 1 jet size. According to the recommendations I should have 147.5's in mine, but it runs better with 145's. And on the later model carbs it can really be a crap shoot, depending on your carbs. But they're just recommendations meant to get you close - individual bikes might like things a bit different. I say do it how your motor likes it.

[BA80]

If you're going up 3 jet sizes, it's 2.5 X 3, or 7.5, which would be 145's. But I've noticed on mine that the jetting recommendations tend to overstate by about 1 jet size. According to the recommendations I should have 147.5's in mine, but it runs better with 145's. And on the later model carbs it can really be a crap shoot, depending on your carbs. But they're just recommendations meant to get you close - individual bikes might like things a bit different. I say do it how your motor likes it.

OK, I see. He couldn't find the x so he put a * in there.

I don't have a motor, I have an engine. The starter has a motor.

I don't see anywhere in the recommendations to go DOWN in size.

[dbeardslee]

I don't have a motor, I have an engine.

Sure you do - that's why they call them motor vehicles, not engine vehicles.

Here's the definition of motor, right out of Merriam Webster:

2: any of various power units that develop energy or impart motion: as
a : a small compact engine
b : internal combustion engine; especially : a gasoline engine
c : a rotating machine that transforms electrical energy into mechanical energy

Engines run on tracks.

We could probably get a thread going on this topic to rival some of the oil threads.

[BA80]

Sure you do - that's why they call them motor vehicles, not engine vehicles.

Here's the definition of motor, right out of Merriam Webster:

2: any of various power units that develop energy or impart motion: as
a : a small compact engine
b : internal combustion engine; especially : a gasoline engine
c : a rotating machine that transforms electrical energy into mechanical energy

Engines run on tracks.

We could probably get a thread going on this topic to rival some of the oil threads.

C is the only CORRECT definition. The word has been perverted in modern language.

Look up engine and see if it says ANYTHING about being electrically powered.

[dbeardslee]

C is the only CORRECT definition. The word has been perverted in modern language.

Look up engine and see if it says ANYTHING about being electrically powered.

The etymology of the word motor derives from the Latin word movere, which means to move, and motor in Latin means mover. In late Middle English it denoted a person who imparts motion. The current sense of the noun dates from the mid 19th century.

Looking at the definition I think you'd have to conclude that an internal combustion engine is always a motor, but a motor is not always an internal combustion engine.

[BA80]

Ha ha ha........Take a locomotive for instance, it is considered an ENGINE. Simply because........it is. Started as a steam ENGINE and has evolved into a diesel ENGINE that drives a generator that powers an electric friction MOTOR at each wheel.

[dbeardslee]

Are you saying you ride one of these? I think we found your problem. Stop putting gasoline in it and add more coal.

[BA80]

A motorcycle, a motor vehicle, or a motor car are perfect examples of the perversion of the word. It's imply easier to say motorcycle rather than enginecycle, engine car, or engine vehicle.

The meaning of the word "motor" has simply been perverted into meaning pretty much ANYTHING with an engine.

My motorcycle is powered by an engine and has electric starter motor.

[dbeardslee]

According to Princeton University's Wordnet...

A motor is a machine that converts other forms of energy into mechanical energy and so imparts motion.

An engine is a motor that converts thermal energy to mechanical work.

I told you we could rival those oil threads.

[BA80]

I think I've hijacked my OWN thread.

[motoman]

OK, I see. He couldn't find the x so he put a * in there.

I don't have a motor, I have an engine. The starter has a motor.

I don't see anywhere in the recommendations to go DOWN in size.

Okay......here ya go,,,go down in mains AND pilots to stock now that you've got the metering rods sorted out. Also set the clippy to stock position.

[BA80]

Okay......here ya go,,,go down in mains AND pilots to stock now that you've got the metering rods sorted out. Also set the clippy to stock position.

I've got the clip 1 notch lean Brant and it's STILL too rich for the engine.

Read post #162.

[BA80]

The bike was hard starting this morning leaving for work but ran fair.

Got to work (ha ha...nothing to do) and pulled the carbs and moved the needle down to it's most lean position. Engine very hard starting and misfired when first started. Had a bad hesitation and died several times on take off.

It ran OK when moving, stumble completely gone in high gear and almost gone in lower gear. But, still REALLY hard starting.

Moved the clips to the center (stock) position and it starts right up. High gear is good but you can still tell it's getting too much fuel. Low gear has the same stumble that I've always had but goes like crazy before and after.

Everything back to stock jets and settings. It's staying there because it runs as good as it ever has. I'll see what happens.

I suspect the after market exhaust has a lot to do with the symptoms.