Author Topic: compression test  (Read 701 times)

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Offline waltcentral

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compression test
« on: February 04, 2019, 03:35:47 PM »
well we got a little over 50 today and got to run down the road with my new shovel.    First off when I got home I did a compression test and I got 146 front and 148 rear, I was surprised!  I put a proper set of extended reach plugs in and after a 15 mile ride they were clean.  The plugs that came out were not the extended reach and they were pretty black. Make that very black.

Is 145 high for a stock 7.5 to 1 bike?

I did find that the bike was pig slow and seemed to bog when opening the throttle so most of my riding was 40-45 mph with the throttle barely open, when throttle is cracked open it just sits there and barley acceleratesjust vibrates more.  I am thinking rich.

Online BKACHE

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Re: compression test
« Reply #1 on: February 05, 2019, 12:44:06 PM »
I am not sure of the comp #. I am sure one of the tech guys will fill in the numbers.
As far as the new plugs being clear, and the old black - maybe a intake manifold leak? Is it a o-ring (earlier) or rubber band (later) seal system?  Using 2 wraps of electrical tape around the o-rings is a common practice.
Spray wd-40 around the intake seal area to see if idle changes to determine. 
Next would be if the timing advance is working properly.
Congrats on the shovel!
Now the fun starts.

Online Hossamania

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Re: compression test
« Reply #2 on: February 05, 2019, 02:47:26 PM »
Check your ignition, make sure the weights and springs are moving freely.
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Offline Ohio HD

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Re: compression test
« Reply #3 on: February 05, 2019, 03:50:26 PM »
Pretty sure he has electronic ignition.

Compression sounds reasonable to me. Check out the jetting, make sure the motor is timed correctly, etc. Do the basics first.
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Offline waltcentral

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Re: compression test
« Reply #4 on: February 05, 2019, 03:54:37 PM »
BKACHE - yes the fun starts
Hossamania - I was thinking that it is acting like no ign advance,  I still need/want to check jets especially intermediate jet because the bike seems to be way too sensitive to idle mixture screw adjustment. Not sure where advance is at a fast idle.  I have four days of work ahead of me the the wife and I are going to South Padre island to visit friends who RV there over winter.

Can anyone tell me how many screws hold on the float bowl of an early Super E. I can see two after removing the  backing plate and can feel and almost see one at the rear back. I can feel no other screws and it seems odd only three.

Offline waltcentral

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Re: compression test
« Reply #5 on: February 05, 2019, 04:03:31 PM »
Ohio HD - I just checked my parts book and it looks like 1980 and on no advance weights.  I need to buy a timing light.

Offline Ohio HD

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Re: compression test
« Reply #6 on: February 05, 2019, 04:23:11 PM »
If the ignition cover (used to be points cover) is still riveted on, chances are the timing is fine. It's always possible the ignition plate could have loosened and moved, but not very likely.
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Offline guppymech

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Re: compression test
« Reply #7 on: February 05, 2019, 04:43:15 PM »
Can anyone tell me how many screws hold on the float bowl of an early Super E. I can see two after removing the  backing plate and can feel and almost see one at the rear back. I can feel no other screws and it seems odd only three.

The Super E bowl has 4 screws, the fourth is on the forward side, most inboard of the accelerator pump cover screws, it's probably 2 inches long.
'84 FXE, '02 883R

Offline waltcentral

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Re: compression test
« Reply #8 on: February 05, 2019, 05:08:12 PM »
grumpymech - thanks, that simple fact is invaluable!

Ohio HD - the plate is aftermarket and no rivets , instead it has a series of small allen all around the outside, not sure how this comes off.   The cam cover looks to be aftermarket also - cheep chrome

Offline dusty1

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Re: compression test
« Reply #9 on: February 05, 2019, 06:07:47 PM »
As mentioned,checkout the mechanical advance which it probably has since cam cover is aftermarket

Offline waltcentral

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Re: compression test
« Reply #10 on: February 05, 2019, 06:51:43 PM »
Te 1983 ign unit has no mechanical advance weights. Hence the need to buy another timing light , at least I can check the advance.

Online BKACHE

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Re: compression test
« Reply #11 on: February 06, 2019, 06:52:49 AM »
I had a stumble on my shovel with a 'E' too. One thing that really helped was after taking the bowl of the carb off take the intermediate jet out. I soaked it for a while, but the aerating holes in the top of the jet were a bit clogged even after carb cleaning. I used a very small needle from the wife's sewing kit (don't tell her) to push thru and spin to clean. That was night and day for idling - at least for me. Make sure the small o-ring is on the top of the standoff from the bowl to the bottom of carb body. Look at the exploded view on J&P cycles of the 'E' carb rebuild for a pic.
Good Luck!   

Offline waltcentral

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Re: compression test
« Reply #12 on: February 06, 2019, 06:10:58 PM »
My service manager and I agreed on second thought the total electronic ignition has a very small possibility of not working on advance and work ok at idle so I am left with the carb as the most likely offender.  I fully intend to do a full carb rebuild but would like to get the bike to at least accept throttle before a teardown. I am ordering a jet kit and some trick float bowl screws that extend down to protrude slightly below the bottom of the bowl to aid in tuning.
I will have to tackle that after I get back on the 16'th.
BKACHE thanks for the tip on the intermediate jet.

Online BKACHE

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Re: compression test
« Reply #13 on: February 07, 2019, 07:50:55 AM »
The 2 inside screws (one long and one short) do help for turning. The 2 front screws on a 'E' are too tight to get inside the backing filter plate. Of course my 'B' carb on my '83 FXRS 93" has access to all 4 of the standoff screws. 

Offline 72fl

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Re: compression test
« Reply #14 on: February 08, 2019, 05:52:48 AM »
Walt the Super E is pretty simple to remove from the bike, 2 bolts hold it to the manifold, and possibly 1 to hold a bracket onto the engine so you don't have unsupported weight hanging off of the carb.and usually 1 throttle cable sometimes people use 2, if you decide to remove the carb and do a thorough cleaning make sure if you have a spacer block between the carb and the manifold that it is put back and make absolute sure of what bolt comes from where, I tell you that because many a folks have taken their carbs off and didn't install the bolts and spaces where they were and actually run a bolt right into the bowl and thats an expensive mistake.

Another handy tool for cleaning jets is a Torch Tip Cleaner, and 1 day I will invest in or build an Ultrasonic cleaner. I have a ton of jets for Super Carbs that I have purchased and collected over the years, and I actually have 1 New Style E and 1 new style G in my parts inventory  :wink: Super E and G are my go to carbs. E's can be finicky to get set up and I actually would rather have the plugs a little to the dark side (Rich) rather than white (Lean) just remember always better to run a little bit rich than to lean. Do you have the exhaust and air cleaner that you are going to be using on the bike currently ?

Offline waltcentral

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Re: compression test
« Reply #15 on: February 08, 2019, 08:13:41 PM »
I plan on keeping the E but the I want to change the exhaust. Just let me be clear, I am not chasing a poor running condition. I am finding out why the falls on its face above 45 MPH. Since its runs as if the timing does not advance I also need to check the ignition advance setting.
Thanks everyone for there input.

Online Hossamania

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Re: compression test
« Reply #16 on: February 09, 2019, 05:51:57 AM »
The air cleaner is clean, and not deforming or something? Maybe try running around though it for a short time time test.
The choke isn't pulling shut at speed?
Just trying to think of reasons why it's choking at rpms.
I think changing exhaust is not a bad idea either, depending on what you have. Which exhaust is on it now?
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Online Hossamania

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Re: compression test
« Reply #17 on: February 09, 2019, 05:58:03 AM »
You say 40-45 mph, no acceleration. Which gear are you in, does third gear pick up? Does it run through the rpms in first and second, or does it fall flat there too?
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Offline dsvracer

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Re: compression test
« Reply #18 on: February 09, 2019, 06:01:07 AM »
what are the jet sizes since you think they are off ??  i have found with the sns e carbs that jetting is critical.   to much jet and it will not accelerate.  plugs are white you say ? maybe so fat it can not handle all the fuel.  i agree with the above comment that you should start off from the beginning. set your ignition timing and make sure it is correct, then move to the carb and check your jets and post the numbers here.  dsv
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Offline waltcentral

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Re: compression test
« Reply #19 on: February 09, 2019, 02:44:07 PM »
Hoss-it appears stock exhaust with fishtails
Dsvracer - unsure of jets yet, it will be a 9 days before I can get into everything, I think spark plugs were clean because It would only run at very low throttle openings. I will get home next Saturday and have everything I need except a timing light I will buy on Sunday.  I was looking at the timing plate and it is set dead center in its adjustment range, the manual call for setting it there and setting your advance from there.

Offline Wicked

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Re: compression test
« Reply #20 on: February 10, 2019, 08:05:18 AM »
  I was looking at the timing plate and it is set dead center in its adjustment range, the manual call for setting it there and setting your advance from there.
You sure?  The advance weight assy is not adjustable, so that plate needs to be advanced/retarded to get proper timing.....

Offline Ohio HD

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Re: compression test
« Reply #21 on: February 10, 2019, 08:25:54 AM »
Yes the manual states this, but only "IF" the plate is removed from the motor and reinstalled. Just to use as a starting point. With it installed simply just check the timing with a light. Run the motor at 2,000 RPM or a little above when checking timing. It also helps to clean the timing mark on the flywheel with some brake clean, and paint it white. After it dries it's a lot easier to see it in the oil mist while the motor is running.


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Offline waltcentral

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Re: compression test
« Reply #22 on: February 11, 2019, 08:05:44 AM »
No advance weights - 1983
Ohio, thanks for the tip on timing mark,