Where can I get a compression tester adapter to fit my 84?

[Rik'da'rider]

Well, after 9 months/12,000 miles of riding since the last time I had to do any serious wrenching I am now faced with the dreaded alternator replacement, and after much consideration I have decided to go with an OEM replacement. Which of course means I have to remove the engine from the frame. Which of course means that it would be smart for me to ensure that any other work that might need to be done gets done while the engine is out. My first desire is to get a good compression test, but the cheap tester I have does not have the proper adapter to fit into the sparkplug hole on my Wing. Aside from buying a complete set does anyone know where I can find the proper adapter? I really want to do the compression test before I take the engine out of the frame.
And yes the three wire connector was fried and took a goodly section of the wiring with it.

[WingAdmin]

I got mine cheap at Harbor Freight. Might want to have a look there.

[Rik'da'rider]

Thank You. That is where I got the set I have, maybe they will have the single adapter I need.

[TheArtist]

Took my plug with me to Auto Zone and got a large kit for $45.

[WingAdmin]

Many years ago I had a compression tester that had a rubber end to it, you just pressed it into the spark plug hole, held it there and cranked the engine, no threading required. Don't know if they're still around, but it worked great for me at the time.

[RBGERSON]

tAKE AN OLD SPARK PLUG REAM IT OUT(break top off drill out the rest) AND tap it to fit an adapter you have now you have an adapter that fits your GL for free..

[Rik'da'rider]

Thanks for the good ideas. I'll keep you updated.............

[dwight007fchr]

OK......I just used a micrometer to measure the spark plug threads that I just took from my 83 1100. The OD of the plug thread is 11.82.

Now I just measured the brass fitting from my compression tester, and it is coming in at 11.94.

When I first tried screwing it into the spark plug hole, it did not want to go, so I did not force it since I did not want to strip the aluminum threads of the engine. Is 11.94 too tight, or should I just go ahead and apply a bit of pressure and persuade it to go into the plug hole?

I tried the rubber cone adapter on the compression tester, but got poor results.....which leads to my second question. I had the throttle set wide open, the kill switch set to "off", and I was pushing pretty darn hard on the compression tester which had the rubber cone on one end. When cranking the engine about 4 seconds, I was only getting about 75 psi in each cylinder. This is WAY LOW, so I am guessing that the rubber cone just was not making a tight seal during the test. My question is: If my Wing only had 75 psi in each cylinder, would it run with any enthusiasm at all? Before this "miss" that developed while driving, she seemed to have plenty of power. Ok experts.....how would a wing run with only 75 psi in each cylinder?

And the other question.....should I force the 11.94 compression adapter into the Wing's plug threads so I can do a real compression test?

Many thanks.
dwight.

[WingAdmin]

I have a screw-in adapter that I got from Harbor Freight that fit my 1100 (and my 1500) perfectly.

That said, you can get a better seal with the rubber cone type by putting a thin coat of engine oil on the rubber before pushing it against the plug hole (and push hard!).

[dwight007fchr]

Compression Test technical questions:

1. The NGK plug measures 11.82 OD. The brass compression fitting I have measures 11.94 OD. I assume the Wing's threads are exactly 12.0. So, am I risking cross-threading or damaging the threads if I try to force this 11.94 brass fitting into it?

2. Assuming the first test with the rubber boot fitting on the compression tester is accurate.....about 75 psi in all 4 cylinders. Would the bike run even half-decent at this low pressure?

Wingadmin......My compression kit also came from Harbor Freight. Out of curiosity, if you happen to be in your garage, could you measure the OD of this screw-in adapter that you have. If yours is also around 11.94, then I am gonna try again to thread it into the engine.

dwight

[dwight007fchr]

Wingadmin.....I just went to the harborfreight site to check the specs on the kit I have. It states that one of the adapters is a M12. So the one I have is apparently an M12.......but do you think I should risk using it being that it is so tight? (I just would hate to damage the plug threads).

harborfreight compression tester description:
8 Piece Automotive Compression Test Kit:
3" gauge with rubberized portector, 14" extension hose, 6 adapters: straight, angled, M10, M12, M14, M18, carrying case.

I just went to "MARYLAND METRICS THREAD DATA CHARTS", and got this:

Size mm Thread Designation Simple Thread Designation Pitch mm Class Major Dia

Max Min
12 M12x1.75 M12 1.75 6g 11.97 11.7 10.83 10.68 10.072 9.601

So, based on this, my brass compression adapter (11.92) is just barely within the acceptable range(11.97 to 11.7). The NGK plug (11.82) falls almost exactly at the mid range of this tolerance. I could not figure out how to find the technical specs for the internal threads, but I would assume that the Wing's internal threads for the plugs must be slightly above 12.0 on the min side.

So, do I risk using the tight adapter? Maybe use alot of Slick50 or something???? Maybe put the brass adapter in the freezer for a couple hours and heat up the Wing head first? Half-way joking here.

dwight

[dwight007fchr]

Ok.....everyone enjoys pictures, so here are some pics, and maybe everyone can give me their suggestion.

Here is a pic of the micrometer on the NGK plug which reads 11.80:

Here is a pic of micrometer on the Compression Tester No. 12 adapter that reads 11.94:

Here is a pic of the Harbor Freeght test kit and other odds n ends: (I already used-up one of the test kit adapters in making a compression test plug for my 1927 Nash).

I had tried threading the compression hose with the No. 12 brass fitting into the Wing's plug hole, and it seemed too large. You will notice the stiff bend in the hose, so now I have placed the hose into a 1/2" water pipe and plan to try threading it using this "straight-edge".

Here is what the compression tester will look like as it is coaxed into the tight threads.....that is unless I get a VETO from the experts here.

So, should I try to force these tighter threads into the Wings plug hole?

Thanks to all who give advice.
dwight.

[WingAdmin]

When I screwed mine in, it fit with no problem at all, it was not too tight/large. There were quite a few different thread adapters in the kit, I just kept trying them until I found the one that screwed in perfectly.

[dwight007fchr]

Wingadmin.....Looks like most of the guys in here have a "hands off" attitude toward compression testing questions. I was hoping to have these questions answered as to the thread sizes of the Wing's plug vs. the compression tester. I still dont know if the compression fitting size of 11.94 is too big for the Wing's plug hole. I found a website that said the acceptable size is up to 11.97 for a 12mm thread.....and this is very close to the upper limit. So, if she fits real tight when I start threading, do I risk doing damage by continuing to thread it all the way in?

If I do, will the plugs (11.80) then fit a bit "sloppy" after forcing the compression tester in?

Im gonna give her a try today, but was hoping to get some coaxing before trying.....or some "Warning....Stop!....Do Not Go Past Go, Do Not Collect $200....No Get Out of Jail Free cards".

Also:

My first compression test using the rubber boot got only about 75psi from each cylinder. Would a Goldwing run half-right with only 75psi?????? I was pushing with a ton of force on the compression tester, and thats all I could get out of her. I am seriously hoping that when threading in the compression tester, I will get a much higher reading. (I did have the throttle set "wide open" when cranking).

Thanks to all replies.
dwight

[Fatwing Chris]

I personally would never force anything into an alumn head.You should be able to run it right in with your fingers and to answer your other question it's doubtful it would start at all with 75 lbs. comp on all 4.
I did like someone else suggested in an earlier post.I cleaned out an old plug and then welded a barbed airline fitting to it.Fit a tight rubber hose to the barbed section and adapt it to your guage.Works perfect.Haven't used it for years,but it's still sitting in the top of my toolbox.

P.S. In most cases if you get a low/even reading on all cylinders it's time to start looking for a different/better guage.

[eklimek]

Run a 12 mm thread chaser (die) to reassure yourself the adapter meets specifications.

http://oldmanhonda.com/MC/Rplugs.html

[WingAdmin]

Agreed - you should NEVER force thread anything into an aluminum head, you will be asking for trouble with sloppy, loose plugs from then on. You should definitely be able to thread it in all the way by HAND, and then not even use tools to tighten it (mine has a rubber O-ring that seals once it is threaded in).

You could take a plug to a local hardware shop, or even NAPA - they have a tool there with every thread size and pitch, you can thread the plug into each until you find the right one, then you'll know for sure what it is. The plugs are 12mm, I would guess a 1.25 thread?

Like eklimek said - take a 12mm die (with correct thread pitch) that fits the plugs correctly, and run the adapter through that, to take any excess off. You can then be sure that it will fit the head correctly, and you won't risk damaging the heads.

[seabee_]

I have to agree with the others, DON'T force it into the plug hole. ALL PROPER SIZED PLUGS will screw into the hole easily with your fingers. If it doesn't you have one or more problems, plug and/or hole threads are damaged, threads could be dirty, or wrong thread pitch. Metric threads can be very similar looking at them, but are different enough to do damage. As said before, find a thread pitch gauge and see if they are 1.25, 1.50 or even 1.75. Brass is a softer material, but, aluminum is softer than brass and the aluminum will be damaged before the brass.

[dwight007fchr]

Great....Got some good feedback from the Wingers. Will reply to all:

Wingadmin.....I have the right compression adapter from the kit....the 12mm, but as indicated above, its OD of 11.94 is larger than the plugs OD of 11.80. Too tight to use is the question?

FatwingChris......75 psi in all 4.....well, I surely hope I have twice that amount when I manage to do the real test. I may have to break open a plug and use JB Weld to make a compression fitting.

Eklimek.....Yep, wish I had a 12mm thread chaser to take down that brass fitting some. I wish that link showed the acceptable tolerance for the 12 mm......is 11.94 too tight?

Wingadmin.....Time for me to get a good die set.

Navy Seabee....(My dad was a Seabee in WWII...Okanawia/s. pacific)......The Wing's hole threads are not damaged, as all the plugs thread in just fine. The NGK plugs hand-thread in just fine, but that brass compression adapter with 11.94 OD does not want to go in. So I am thinking that I just happened to get a compression adapter in my set that was at the uppper limits of the acceptable OD range.

Thanks to all...
dwight

[dwight007fchr]

I am reposting this since the discussion was under two seperate threads:


**********HUGE RELIEF!!!********I got the 12 mm compression tester adapter to thread into my 83 1100 Wing without any issues. My concern that the threads of 11.94 were too large was not an issue.....she threaded in by hand without any worries.

I got great compression....two cylinders at 170, and two at 165. The one cylinder that is burning a bit of oil upon start-up was fine at 165.

The engine was cold and had not been run in a week before I did this test. Would a warm engine result in lower or higher compression? (Just curious) Should I take the time to run the engine and redo this compression test, or should I just rest assured that I have decent compression?

My other question is the "leak down" time. The needle would stop on say 170, and then would move very slowly downwards after I stopped cranking. When getting to around 155, the needle would almost stop moving, but still was losing compression at an extremely slow rate. I assume this is good and means the valves are seating great.

Any other comments/info./reccomendations on this test?
Many thanks to all.
dwight

[bustedwing]

The compression tester has a valve in the end of it so air is not supposed to leak back out. That valve gets dirty and you have to clean it out at times. Use a tire core removal tool, take it out spray it off with carburetor cleaner, reinstall. I assume you only did a dry test, and the only information you can gain is by doing a wet test. The test you did was fine but take it one step further by squirting a few ounces of engine oil into the cylinder you just dry tested then re test. That will seal up the rings if they are worn so if you have a jump of more then 10 lbs per cylinder it will tell you how much wear is on the internal parts of the engine.

[dwight007fchr]

BustedWing......I am reposting what RbGerson said on a different thread. In his post he says that 160 to 170 is great compression. Since I did a "cold/dry" test, I imagine squirting some oil in each cylinder would naturally raise the compression a bit higher, and according to him anything over 170 is too high. So if I do the oil-down test, I could get some readings that will freak me out and keep me from sleeping at night. Not sure if I want to get freaked out at this point. Still, I may go ahead and do it or I wont sleep at night wondering what the reading would be with erl in the cylinders. Life is so freakin difficult.

You are right about the "leak down" issue. In my brain I was thinking that the compression gauge had a direct link to the cylinder chamber, and the reading was showing how fast air was escaping around the rings or valves. This is a brand spankin new compression tester, so one would think there would be no leak-down going on. This one does have the quick-release on it to remove the hose, but the compression air relief valve is up higher, so some air must be leaking around it. I will take it out and maybe add a drop of oil on it and put her back....maybe the sucker is just not in tight.

Postby RBGERSON » Tue Jan 24, 2012 7:52 am
Ok a complete list:

hot engine
kill switch off
throttle held wide open
all plugs out..well all lose..so gas isn't sprayed out..see tip 6
charger on battery if you like
gas petcock off..I like to run carbs bowls dry too so no gas is being pumped into cylinders

cranks until needle stops moving up may take a few seconds no more than 5

you can make a connector for the Gl's by coring out an old spark plug and tapping out the top end to match a connector you have..use an o ring on the spark plug threads and the connector side. Gls' are 12mm and most kits don't have a 12mm connector.

140 to 150 is OK
150 to 160 is good
160 to 170 is great
over 170 = carbon issues on the pistons
under 140 time for rebuild..new rings or new valves/or lapping valves or both

The spread between cylinders should not be more than 5 lbs.

Note the bike will run nicely even at 130's all around but poor gas mileage.

Read more: viewtopic.php?f=4&t=9810#ixzz2UcqCExSs

[bustedwing]

I believe you have a good engine as it sits and the wet test will not raise your compression by that much. Even if all of them came up 20 lbs, which I doubt, as long as they are within 10 percent of each other it is nothing to worry about. Definitely nothing to loose sleep over. Instead of cranking until the needle stops, keep your eye on the needle and when it pumps 5 times stop. I have used this system for 40 years as a mechanic a as long as you keep them the same it is accurate. Maybe that is why your readings are so hi . I have seen older V8 engines with 90 lbs compression and that engine runs great. The reason we were taught that way was because it's easier on the starter. Let me know what readings you get if you try it this way.

[dwight007fchr]

BustedWing......Good tips you are giving. When I did the first test, I was trying to count " 1-2-3-4-5" pretty slow so as to get about 5 seconds of crank time. Your idea is much better.....just watch the needle pump 5 times and stop. That way you are getting the same number of compression pumps on each cylinder....no cheating. I will give this a try and let you know how it compares with the first test.

Speak of low compression, I rebuilt my 27 Nash Special Six (what a learning experience.....pistons come out from the bottom only), and only got about 85lbs, but she runs pretty strong. If she had 150lbs, Im sure the cloth differentials would be ripped right off the axle.

dwight

[dwight007fchr]

OK, I redid the compression test and this time I squirted 2 pumps of a very light oil into each cylinder. I used a straw on the end of the oil pumper to get the oil into the cylinder and not make a mess of it.

I was really stumped on my first 3 cylinders, getting only 90 lbs of compression with the oil in the cylinders. I got to the fourth cylinder and then it hit me........I did not have the throttle locked "wide-open", and thus was getting the low compression readings....daaaaaaaaaa! So I locked the throttle wide-open and retested:

Note the Kill Switch is "Off" to keep the Tesla electrons away during the testing.

I screwed in the compression tester into each cylinder and allowed the starter to cycle or "pump" the compression needle 5 times. I got really excellent and even results of right around 170 +/- on each cylinder.

So, using the light oil in each cylinder gave a very slight higher reading, and I did not have to crank as long (just 5 pumps) to get the good reading. I did experiment, and if I pumped a few seconds longer, I did manage to get a higher reading....one going to about 180.

Used the battery tender during and after the compression testing:

So, all seems good. Now I can move forward and try to figure out what is causing the "miss" when cruising around.

Thanks to all the tips.
dwight