205 lbs. compression?

[MSGT-R]

Shouldn't be too much of a stretch to cut out a plate from some aluminum stock..

 

[joedrum]

shes right dan ....i think thats what id do ...the adapter plates im making for the 1200 project is pretty much the samr thing only harder for the doulble mounting thats involved in what im doing ....simple cover plate sould be easy to fab and i would think look better too :mrgreen:

 

[dan filipi]

Now that the brakes are out of the way it's time to get this beast on the road.

I'm making a fuel pump blank off plate.

A pic is on it's way.

 

[dan filipi]

Old scrap aluminum electrical buss bar comes in handy.
Too bad the tach cable is just plugging the hole.

 

[joedrum]

cant wait for you to get a good ride in on your bike .......im hoping this mod come out good as my 83 with 79 cams or even better ....this has to be a rare or even the first mod of this kind ....this shows that this forum has huge flexability in things we try and support .... k: :mrgreen:

 

[dan filipi]

....this has to be a rare or even the first mod of this kind ....this shows that this forum has huge flexability in things we try and support .... k: :mrgreen:

Doing off the wall mods is what I like. Think outside the box so to speak.

 

[slabghost]

Box? What box? :shock:
:help: Could someone please help me find this box they speak of? :smilie_happy: :smilie_happy:

 

[ekvh]

....the spead of fuctulation is no ]
I love typos.

 

[slabghost]

Joe is our resident professor Spooner. :smilie_happy: :smilie_happy:

 

[dan filipi]

I'd like to go back over theories why I'm getting 200+ compression on the right side but only 160 on the left.

Leaking valves on the left should not be causing it because I've decarboned and lapped all valves on both sides and with 1000 and 1100 cams I get 160 lbs compression on both sides.

Give me your ideas. I want to see 200+ compression on the left side also.

 

[MSGT-R]

The list of things I can possibly think of that would change that much compression:

Carbon build-up (I know, there's none).
Bad valve sealing (but you said you had resurfaced them).
Different combustion chamber size on the two heads.
Difference in the port size left-to-right.
Different piston compression height, either by piston head shape or the surfacing of one side of the block.
Different rocker arm ratios left-to-right, allowing better cylinder filling because valve is open more on that side.. (too weird).
Restriction in the exhaust on one side, but that wouldn't show up in a compression test, only when running (and you had said it runs evenly).
If the test was repeatable, it's not your compression gauge. :ahem:
Have you done a leak-down test on the low-side to see if the rings are getting slightly weak?

I can't think of anything else other than to go back to the old cams and run the test again. Maybe the cam lobes are slightly different in height/duration (?)

 

[dan filipi]

My first thought was maybe the left 2 cylinders are worn to the point they can't do 200 lbs compression so I did a cold wet compression test with atf on cylinder 4.

First reading was 270 pounds with throttle closed.
Next test was 240 throttle wide open.
5 more times throttle wide open, 210
6th time 180.

So it's dropping and I bet after running it will drop back down to 160.

I think my suspicion was correct, left cylinders not able to produce 200 but the right side is but still I'm not convinced because why would both left cylinders read low and both right cylinders read 40 pounds higher.
Just seems odd that they would wear this way.

 

[joedrum]

do the other side too dan you have to get a comparision with the oil test .....that surprises me some it went so high ...looks like your getting closer.... :mrgreen:

 

[dan filipi]

I already warmed it up so to be accurate I'll do the right side in the morning with engine cold.

 

[ekvh]

It must be time for someone else with 1200 cams and an 1100 to try this, right Joe? Ha.

 

[dan filipi]

Right side compression test almost identical to left test:

This is left side:
First reading was 270 pounds .
Next test was 240 .
5 more times , 210
6th time 180.

This is right:
First reading was 270 pounds .
Next test was 240 .
5 more times 210
6th time 210 (the only difference)

 

[user 92]

Right side compression test almost identical to left test:

This is left side:
First reading was 270 pounds .
Next test was 240 .
5 more times , 210
6th time 180.

This is right:
First reading was 270 pounds .
Next test was 240 .
5 more times 210
6th time 210 (the only difference)

If you oil the left side on the 7th time, what happens?
I'm thinking there may be a ring sealing problem. And also, could this problem only show up during extended cranking? Possibly sealing just fine while the engine is running?
Is it only one cylinder, or both cyliners on one side?
Have you tried a running compression test? Cranking compression is a measure of cylinder seal while running compression is a measure of volumetric efficiency
or the cylinders ability to draw the air/fuel mixture into the combustion chamber.

 

[dan filipi]

On the left side I tested both cylinders, they were almost identical.
The right side I tested only #3.

Good idea, I'll try a running compression test.

 

[joedrum]

mistory sovle in my book ....what ever going on is in the bottom not the heads ....iwas looking at the weather today looks like you guys have winters second coming going on... :hihihi: :hihihi: :hihihi: :hihihi: suppose to be mid seventys today im going riding :cheeky: :mrgreen:

 

[dan filipi]

Running test at idle about 800 rpm:

Left #4= 80 lbs.
Right #3= 90 lbs.

So, what does this mean?