Rebuild time?

[Nubian]

Here are the results of a cold compression test on my XS1100H are they too low?
D / W
1) 110/125
2) 90/110
3) 110/115
4) 90/95

[bikerphil]

Is this test with wide open throttle? Has the bike been sitting for a long period of time? How many miles on the engine?

[Nubian]

Is this test with wide open throttle? Has the bike been sitting for a long period of time? How many miles on the engine?

WOT? held start button for 4-5 kicks, about 1 year, 51K

[bikerphil]

Yes, you want to hold the throttle wide open so the engine can breathe, otherwise the carb throttle plates will be closed and you will get a low reading.

[Nubian]

Here are the results of a cold compression test on my XS1100H are they too low?
D / W
1) 110/125
2) 90/110
3) 110/115
4) 90/95

WOT results (will oil left over from last night's wet test affect results?)
Dry
1) 130
2) 105
3) 120
4) 100

[bikerphil]

I bet if you run the bike some, the numbers will come up. Poor valve adjustment will give low readings too. Those readings aren't all that bad. 51K is nothing for these motors. Yes, if you added oil to the cylinders it may bring the numbers higher.

[Nubian]

I bet if you run the bike some, the numbers will come up. Poor valve adjustment will give low readings too. Those readings aren't all that bad. 51K is nothing for these motors. Yes, if you added oil to the cylinders it may bring the numbers higher.

Well it was running poorly last year and thought I had to do the carbs over, which I just did. having a hard time getting it running right. #1 as hot as others maybe a stuck float, will investigate and report back
thank you

[Nubian]

1 cylinder not firing righting is warm to touch not hot like the others. swapped writes with #4 same result. stuck float? 3 cylinder is suspect from looks of plug. Can't post pix
compression test WOT engine hot
1) 145
2) 125
3) 135
4) 120

[bikerphil]

If the bike sat for 1 year with ethanol type fuel, the carbs are most likely gummed up. Compression numbers look fine.

[Nubian]

If the bike sat for 1 year with ethanol type fuel, the carbs are most likely gummed up. Compression numbers look fine.

The first thing i did was clean the carbs. Could #1 carb be running to rich is that why it's not as hot

[HalfCentury]

Float heights. Check with clear tubing attached to drain holes.

Bowl enrichment circuit possibly clogged

[bikerphil]

Probably gonna have to go back in there and find out what's going on. Does the header heat up at higher RPM's? What does the #1 plug look like?

[Nubian]

floats were set @ 21mm
is that enough (2mm) to cause my problems?
will set to 23 and report back

[motoman]

floats were set @ 21mm
is that enough (2mm) to cause my problems?
will set to 23 and report back

Yup.....21mm is to high a float setting. Actual reality is 1mm of float change equals 3mm of actual fuel level change. So, again, float setting your using allows for WAY to much fuel.....as is WAY rich. Fuel and fuel float level settings are actually done measuring float settings. Then, for 81 and XJ's, as per Yammy manual, actual fuel bowl levels are checked with bike idling, with a clear fuel hose slipped on bowl drain nipples and held up beside carb to see actual fuel level, which should be 3mm down from carb body casting.
Most importantly, running fuel levels in all four carbs need to be EXACTLY the same. Unfortunately, a static float level setting of 23mm is NOT going to leave all four fuel bowls the same fuel level.........so yep, you guessed it.....note fuel levels in all four and remove carb assembly and float bowls and make necessary float adjustments.
FWIW, running fuel levels of 3mm are approx. center of float bowl lock washers.

[Nubian]

Yup.....21mm is to high a float setting. Actual reality is 1mm of float change equals 3mm of actual fuel level change. So, again, float setting your using allows for WAY to much fuel.....as is WAY rich. Fuel and fuel float level settings are actually done measuring float settings. Then, for 81 and XJ's, as per Yammy manual, actual fuel bowl levels are checked with bike idling, with a clear fuel hose slipped on bowl drain nipples and held up beside carb to see actual fuel level, which should be 3mm down from carb body casting.
Most importantly, running fuel levels in all four carbs need to be EXACTLY the same. Unfortunately, a static float level setting of 23mm is NOT going to leave all four fuel bowls the same fuel level.........so yep, you guessed it.....note fuel levels in all four and remove carb assembly and float bowls and make necessary float adjustments.
FWIW, running fuel levels of 3mm are approx. center of float bowl lock washers.

FSM-says 23mm is the height for floats