MotorTrike air ride suspension

[Mr.Wizard]

For those of us that have a MT conversion and suffer the air loss of the air ride suspension and have the on board air compressor with safety switch, this topic is for you. MT says the air suspension system will NOT loose air unless there is a leak. That's in their manual.

How often do you need to hit the button to refill or pressurize your air shocks? Do you lose pressure every few days, once a month, every day? I do. From the first day I seem to lose pressure. At first only a few pounds a week. I keep it set at 40 psi which is the recommended setting for a MT Harley.
With time this has gotten worse. It now loses a few pounds an hour. Last week it lost all 40 psi in one hour.


I've pulled everything apart trying to find this leak. I've used 50/50 soap and water to florescent leak detector on every joint and device from the trunk to the inner fairing but no joy. I had thought it was a bad check valve but after removing it while pressure was in the line it doesn't leak back. I had considered putting Freon in it and using an electronic sniffer but do you guys know how hard that would be? Trust me... not an easy task but I may at a later date.

What I did was to run up the pressure to 50 and test again, no joy, then to 70 and the leak seemed to be smaller but still no joy so I ran it up to 90 lbs and it didn't leak down. It has been two days now an the needle is still sitting on 90 lbs. I lowered to 40 last night and just looked at it this morning. The pressure is still holding at 38 lbs 14 hours later.Here's my thinking.

Additional pressure has caused the leak to get smaller but how? My theory is the leak is in a slip joint connection somewhere in a device. Either the gauge, air reduction tip, safety switch, shock or Tee body. This leak gets worse over time and the extra pressure applies force to the slip joint and tightens up the connection.

Anyone else have/had this problem?
-wiz

[CandyO]

Mr. Wizard, I have the MT IRS Adventure setup. It is not all that old, just a few months. To date, all I have noticed is that the pressure will fluctuate a little, (couple of pounds), from cold to hot running. As for any long-term leaking, I haven't had the problem you describe:no:. I usually run from 25 on straight smooth highways, to 35-40 on the more curvy or windy days. That is a one-up rider status.

[Gorilla]

Wizard that is what we do to solve the same problem on the Stallion. This is straight from the factory as a possible solution to leak down. It worked on our Stallion. I believe the systems are basicly the same

[Big Dog62]

G'day Wizard

I have a GL1500 MT conversion here in Aussie. On the way back from our big trip west, one of the air shocks became a 2 piece instead of a one piece when the clamp ring let go around the the top mount. Before that I was having issues with loss of air pressure myself. There was a very fine air leak on the top mount plate of the shock, it even looked like the air bag rubber itself was possibly porous. The previous owner of the trike replaced the air bags before selling the trike because of porous rubbers.

I was able to repair the shock (Black Mastic sealer and a heavy duty T bar hose clamp) to limp back to one of our stopover places a couple of days later where I was able to get replacement shocks posted to the local post office for pick up. 45 minutes later I had them swapped out and leak free. Since then I've had no air leakage whatsoever!


This shows the repair job I had to do to limp back.


This shows the (now) spare shocks for emergency use only. The liquid on the right hand side shock is a leak sealant call Tru Blu Goo we have here in Aussie.

Hope this helps mate.

[Mr.Wizard]

Thanks guys... I have looked at the shocks, sprayed the entire shock with soap and water and there is no sign of an air leak on the bags. Except for a little dirt my shocks look new.
Since my first post I've been busy at work among other things. Hopefully in the next few weeks I can give it a go again. I may just replace all of my hose end crimps and see if I can kill a fly with a shotgun.

[1550vt]

Hey....I liked the dog better Wizard.

I've had similar issues with tires, especially on trikes where the recommended rear air pressures are lower than normally specified for passenger car service. I had one that would leak down a few pounds a week if it was aired to 25-psi, but would never leak if it was pressurized to 30-psi. I aired it up to 45-psi for a day or two and then dropped it back to around 27, where I ride most of the time. This "set the bead" and stopped the leak. I know you are talking about components other that tires, but the same principle applies....I think you just set-the-bead in whatever is leaking with the higher pressure in the system.

Lets not be spraying that refrigerant around in the atmosphere polluting stuff all over. We got enough pollution down here already with that well just off the coast spewing between 5,000 and 100,000 barrels of oil a day. It's anybody's guess as to how much is really coming out of there, but some of us down here are contemplating taking our buckets and scoops down there and seeing what we can mine-up off the water...and the birds....and the fish....and the beach.

[Mr.Wizard]

You don't like Mickey Mouse VT?
BP is in a heap of trouble and I feel for you guys but this will effect the entire country and more yet to be seen. From what I hear they haven't been able to clean up Exxon's mess some 25 years later.

[1550vt]

I am around 100-miles north of the coast (as the crow flies) and we have been able to actually smell the odor of the output. It smells something like what comes out of a diesel engine tail-pipe...sort of sweet. They are trying to burn-off what they can and there is a certain amount of gas in any oil well, so some of it will burn.

Those offshore wells are almost unlimited in flow-rate. They just pull tankers up to the spigot of a production platform and open the tap. Those things flow at thousands of barrels a day and I think they have three separate wells free-flowing from this particular platform 5,000 feet down to the sea floor. There is more oil out there along our continental shelf than there is in the Arabian deserts, but this will be another good reason to keep the stuff out of our reach for years to come.

[ultraboy]

Wiz, I think you're on the right track, as well as 1550Vt. Higher pressure tends to stretch or seat the components (if possible) and the leaks appear to stop, or leak down to their own level of sealing capabilities. Kinda Peter principle like. When I built my M/T, I did not care for the low quality air fittings, so I replaced them with a higher grade from Pisco. The Pisco brand uses stainless steel lock sleeves and a heavy duty nitrile elastic sealing sleeve, rather than an o-ring. I have put air in the bags once, and that was 10K miles ago. Check out Pisco:
http://www.pisco.com/index.htm

UB

[Mr.Wizard]

Thanks all

I'll have time this weekend to look more into this... it's not a big problem but if it's not working right I'll break it until it is...

I'm as picky as an old wool sweater.

[Big Dog62]

One other thing I'll be doing to the air bag set up is replacing the plastic hose and fittings with some copper tube and stainless steel high pressure Swagelok fittings. This should also reduce any leakage to either nadda or a smidge not worth worrying about. I just need to find out what size the fitting is that goes into the outlet of the air filter body so I can locate one to "modify" for the Swagelok fitting cap and ferrule without butchering the otignal piece and limit my riding time if I stuff up. Anyone have any idea what size this is please? It's smaller than 1/8th BSP I know that for sure.

[tmaxey]

Wizard,

Just an fyi. I have seen several of the Harley conversions leak inside of the air gauge itself.

[Mr.Wizard]

Wizard,

Just an fyi. I have seen several of the Harley conversions leak inside of the air gauge itself.

Thanks.. I thought of that so I blocked off that line to the gauge. No joy

I think it is simply the hose connection type, cheaply made. About every few months I run it up to 90 lbs and it stops leaking for a while. It's not bad, just a few pounds a week. This seems to coincide with everyone else I speak with.

[tmaxey]

Regardless of what the manual says, losing a few pounds (very few) a week is normal.

[Mr.Wizard]

I agree... at least with the stock tube retainers.

[saab9k]

So when buying a trike kit, go with as few as possible things there can go wrong.

[skuuter]

I finally started airing mine up to 90 lbs+ once a month.....for whatever reason, this would stop the leakage for that month. I could take weekend/Week Long Trips (...such as the TRIKE TALK RALLY), without losing pressure. All I could ever figure was just a "loose/semi-floating" fit on the System's O-rings, etc. at all the connectors, and "maybe" they shrank worse over time, and the tight pressure stretched and re-seated them........I know, grabbing at straws here, but all I could ever assume........my "Every 30 Day High Pressure Air Up" at least fixed the "unknown to me for sure" problem, and made it User Friendly one month at a time.....

...and, "YES", I looked at ALL of the above stated possibilities also....!!!!!

[mcdonaldroadcapt]

Anyone know how much trouble it is to swap out the bags? Cost? Mine have cracks showing thread on the bottoms. Leaks 10 lbs an hour.

[mcdonaldroadcapt]

I agree... at least with the stock tube retainers.

What happens if you run with no air? Are shock springs the only suspension left if air bags are not used?

[Krautster]

HOWDY.. im in Holly Springs..