Air Shock Conditions

On the few rides I've been able to take so far on this trike, the air shocks don't seem to be providing much to the ride, especially when I hit a pot hole or bump in the road. I already new the control panel didn't seem to pump the shocks, it reads 0, but I kind of assumed there was some residual air or spring function still in the shock. I really bottomed out yesterday on a back road I was on.

The picture below is of one of the shocks when I had the wheels off that didn't look right where the two halves of the shock meet. Is the rubber that is on the top half of the shock supposed overlap and attach to the bottom of the shock? (I'm assuming most air shocks regardless of the conversion must use similar shocks?) I'm finding more and more things that I think have been neglected on this trike. How do I test the compressor to see if it is pumping? Jack it up so the wheels are hanging and pull both wheels off? How do I test the shocks? How do I even get to the pump?

When I push the button to pump the shocks I get a clicking but no compressor sound. If these shocks need to be replaced are there common automotive brands that I can get or do I have to go to Motor Trike? When I Google up air shocks I see a wide range of prices if I have to replace them or the pump.
Any comments you folks have are appreciated.

That bag is totally finished

Thanks Panel Man for your answer, I better start calling the air shocks “bags” so I don’t confuse anyone.

I just got done reading several posts about bags , all of which were very informative but realize I’m not even sure where the compressor (that only clicks right now), is on my trike???

I have a 2008 Honda Goldwing with the Motor Trike “Spider” Kit on it. When I removed the seat to put a new air filter in the GWing I saw something under the rear seat that looked like a small compressor but I didn’t have air shocks on my mind at the time.

Should be just visible on left side as you say, can be seen better after removing wheel

Thanks Panel Man, I plan to probably pull the seat in a week or so to dig into my problem. I called my closest Motor Trike dealer to get a price on shocks, oops bags yesterday.

I’m always amazed when I see some of the pictures of the trikes in the UK or Europe. Many have such a more robust set of front shocks and what looks like a “Darksider”/car tire that we put on the rear of two wheelers. I don’t understand why US trikes don’t have that as an option.

Nice looking GL1500 conversion. I had a 1500 a couple of bikes ago and they are an excellent machine.

Had this since October and done a total strip of brakes, exhaust and fairing
Also lifted top box and tidied wiring

I received new air shocks from Motor Trike yesterday and started removing the old ones. I was amazed how tight the steel fitting holding the air line was screwed into the top of the shock. There was a white, kind of crusty residue, that was around the threads of the fitting. It looked like plumbers dope, white, almost toothpaste consistency for sealing threads. When you replace the fittings are you supposed to use something to seal the threads? The 90 degree fitting in the top is free to move back and forth, not as tight as I would think it would be but probably necessary for movement of the suspension. This is a first for me dealing with air shocks so I’m trying to be logical in my work.

One thing that seemed odd to me was the large top nut, (you can see in the picture), on the top of the shock was a plastic nut! Obviously no strength but I guess it just stabilizes the top of the shock.

The shocks are the second thing I’ve bought from Motor Trike, through their a MT dealer, and they ship fast and their prices so far have been very fair. Both items were shipped UPS and received in 4-5 days.

That’s a DOT rated air line push lock fitting. The top is designed to swivel 360 degrees.

The bottom half with the hex and threads will need to be sealed and tightened. If the fitting is new, look and see if it has reddish colored thread sealant already applied to it. If it does, then screw it in and tighten it down.

If it doesn’t or you are reusing the old one, put some quality teflon pipe dope (paste) on it. I personally don’t like teflon tape on air line threads as it shreds when you take it apart. You can potentially get pieces of it in your air system when you thread the fitting back in and it will end up down stream blocking orifices and you’ll pull your hair out trying to figure out what’s wrong.

The plastic nuts only function is to keep the air spring from dropping out of the bracket.

When you push the air line in to the fitting, it feels like it bottoms out. Give it an extra hard push and it will go in another 1/8 - 3/16” and it will lock in. An easy way to remove the air line is to take an open end wrench that just fits over the airline and use it to push in on the collar while simultaneously pulling the air line out.

Have you figured out the compressor yet?

Thanks HDUSA1 for the info. I got both shocks installed this afternoon......and the onboard compressor actually pumped them up but they lost the air in maybe 30 minutes. Then I remembered reading here that you should pump them up high to seat something. So I pumped them up again and then got some soapy water but nothing showed and they went down again. I was puttering around wondering and I found one of the shocks with a little bit of water still on the fitting, burping some tiny bubbles. I tighten it up some more and it held air for about an 1 1/2 hours but by 2 hours they were down again.

The control panel below the left pouch has been intermittent and only shows the voltage now and then. I can't remember though if the voltage lights up with just battery power or the engine has to be running. The trike is completely jacked up with the wheels off so I should be able to start it and see if the windows light up with the voltage and air reading.

Behind the control panel there are a bunch of wires and the two objects below. They are connected into the system but I don't have a clue what they do. The compressor is buried in the back of the trike, under the seat and a bunch of other stuff. What is the next thing I should do to troubleshoot this? I'm assuming the shocks are supposed hold the air for an extended period? Should I try to replace every air line?

I’m sorry, I don’t know how the Mototrikes are set up. I can give you a few general tips though.

I had an old ‘67 Impala back in high school that I put air shocks on to jack the rear end up. With the car on a lift and the shocks extended, they quickly leaked air out. Once I put the car on the ground, they never leaked. Never could figure that out. So you might try putting the wheels back on and setting it on the ground.

If that don’t work, time to break out the squirt bottle filled with soapy water. I’d start where you were working on the shocks and generously start squirting the shocks first to see if the bags are leaking, then the fittings on the top. Push lock fittings are great, but they are notorious for leaking, especially the swivel ones. There is an O ring down inside that goes bad and the only thing to do is buy a new fitting.

If no luck, keep squirting the airlines generously back towards the pump. Pay close attention to the air lines where it touches ANYTHING. On my semi trucks, the line will look fine, but where it’s touching a clamp, frame, body, or other wiring & hoses, it will rub a hole in it from the vibration.

If still no luck, in your last pic, it looks like an air solenoid valve. I’m guessing when you press the switch to lower the pressure in the system, it energizes the solenoid and it acts as a dump valve. It looks like the exhaust port on it is threaded. You might try temporarily screwing a plug in to it and see if the leak stops. If it does, either the seat in the valve is leaking or has some debris in it. It looks like the kind of valve you can take apart and see. Guessing there is a metal nut on top of the coil. Take it off, pull the solenoid off the stem, then unscrew the stem from the main body. Will probably be a diaphragm and spring inside. The diaphragm may be dirty or just old and cracked. If you can’t fix it, will probably have to buy a new solenoid valve.

There may also be an inline check valve between the pump and solenoid valve to maintain pressure in the system. It could be dirty or bad as well. I’ve seen some pumps where the check valve is built inside the pump and you can’t fix it without replacing it.

Did you happen to shorten or cut any of the air lines? I know it's real important to make sure that the end that gets pushed into the fitting has to be a clean 90⁰ cut or there is a chance of leaking. I have the same setup on my truck but it's an Airlift kit.

No I haven’t cut any lines or taken any of them apart.

It’ll be a couple of days before I can check the system more. If I need new air lines and fittings where do I buy it? NAPA? Is there a common size it comes in? Thanks for all the info!

It is most likely 1/4" air line tubing. You can actually buy full replacement kits on Amazon that includes a variety of fittings as well as the tubing. There are quite a few choices there so you have to spend some time looking at all the options.

OldRider2 said:

No I haven’t cut any lines or taken any of them apart.

It’ll be a couple of days before I can check the system more. If I need new air lines and fittings where do I buy it? NAPA? Is there a common size it comes in? Thanks for all the info!

Click to expand...

Yes, Napa carries some. Or Fleet Pride if you have one. Almost any semi truck repair center will have a big assortment of them. The better quality ones will be DOT rated for air brake use. Online I would go with Grainger or McMaster Carr. They are better quality than Amazon and they ship fast!

Well I’ve found just one leak so far and the shocks stay up for 4-5 hours. I’ll keep checking tomorrow. Of the two pictures in the above thread the first one has mostly oriental characters on it so I’m not sure what it does but the second one is some sort of solenoid, made by Solenoid Solutions.

Good job on fixing your leaks David...

FWIW, my 2008 VTX motortrike used 1/8 air lines. Available at me local NAPA and many other places.
1/8" measured OD, not ID. Hard, nylon or poly. NOT flexible 1/8" ID vacuum line.

EASY peasey to work with. Your image below.


On mine, this device ensures that I have 20# of pressure at all times. You will hear the compressor turn on when first turning on the ignition when the bike has been parked. (There is a possibility that the air line going in the top is pinched, looking at that pic. Has definitely been kinked!! )

The line is connected via a push to connect air line fitting. Of course, there is a tool for them, but other tools work.
With a small open end wrench, like 1/4", press the top of the orange fitting down. With the other hand, pull the line out.

Depending on how long the o ring inside and the line have been together, might need a firm tug. Usually not a bunch of force needed.

Can we link videos?
View: https://www.youtube.com/watch?v=b8RFjh6Y-fM


The end of the airline does not need to be cut perfectly square, but does need to be cut smoothly, and close to square. Use a razor blade on wood, or a shear/blade type cutter.
NOT a pinch type cutter like pliers. This will leave a sloppy, distorted edge that will leak at BEST, destroy the O-ring at worst.

Hope this helps!

I will need new bags soon, how much did the bags cost from MT?

Good info @Volkemon

Thanks for the tips Volkemon. So are the o rings good for more than one use or after you pull out the line does it have to be replaced?

A quick update to my shocks and trouble shooting the leak(s). The only leak appeared to be just the tightness of the fitting on the left shock. After I took it back out, used the plumbers paste, and tightened it, I had no more problem with leaks, however my control panel would pump the shocks up but the digital readout only randomly worked so I didn't know what the PSI was at. I knew nothing about the air bags before buying the trike because they haven't worked in awhile but dumb me didn't know the difference. A cousin who is a former USN ET (Electronics Technician) completely pulled the control panel apart but after puttzing with it for quite awhile I just ordered another one from MT this AM. The small circuit board the two digital readouts are mounted to would do some strange things, touching and prodding it. Sometimes on, sometimes off. Hopefully the new panel will go in fairly easy because there are a mess of wires jammed into the old control panel. Many wires appear to be soldered, taped over, etc., so it won't be a plug and play model.

The air bags are $80 a piece from MT plus $20 shipping. I looked up the bag info (a picture of the bag top is in the thread above), and I found prices listed from $75-$130 or so. I don't like spending money but they seemed fair compared to the other online prices and their shipping is fast, Texas to Maine in 4-5 days.

That is a very fair price on the bags! Will have to make sure they fit mine.

The O rings are generally good for many uses. Generally a poorly cut end and dirt seem to 'kill' most I have seen.

My airbag system has no control board, best of luck on yours!